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MODULE-1: INTRODUCTION TO ANIMAL BREEDING AND DOMESTICATION OF LIVESTOCK SPECIES

INTRODUCTION TO ANIMAL BREEDING

IMPORTANCE OF ANIMAL PRODUCTION IN AGRICULTURAL ECONOMY OF INDIA

Learning objectives

This module deals with,

introduction to animal breeding, importance of animal production in agricultural economy of India, domestication of livestock.

The population explosion and a poor distribution of food are among the world’s greatest problems today. Animals throughout the world supply human beings with milk, meat, egg, draft power, transportation, hides, fertiliser and many other useful products. Therefore, animal breeding is the beginning or the foundation to meet out the requirement. Hence, it behoves agriculturists and livestock breeders especially to give special attention to their programme of animal breeding.

Animal breeding is a fascinating discipline. It has long been recognised as one branch of arts and only recently it started to be recognised as a special branch of science. It is also one of the steps in the process of animal production, but it is the first step and fundamental to a sound animal husbandry. Application of improved methods of breeding, feeding, management and disease control during the last few decades has greatly increased the efficiency of production.

Animal breeding is the application of genetics and physiology of reproduction to animal improvement. The purpose of animal breeding is not only to genetically improve individual animals but to improve whole animal population i.e. to improve future generations of animals. To achieve this, the breeder is provided with two important tools:Selection and Breeding. These two tools are the decision making in livestock improvement.

Selection decides which animals are going to become parents to produce offspring for the future generation and breeding decides which males should be mated with whichfemales. Therefore improvement in type, production, longevity, regularity of breeding etc. as well as the ability to transmit these desirable qualities to many progenies can be expected through application of proper selection and systems of breeding.

Livestock contributes to agriculture economy of India by way of milk, meat, drought power, wool, skin, manure and by-products and serve as the important source of income to about 300 million rural people. India’s economic progress significantly depends on agriculture and livestock and it will remain so, for many decades. The census figures, on livestock and its production status of India are given in the Table 1 & 2.

Realizing the importance of the livestock, the Govt. of India under the Ministry of Agriculture has created an autonomous body namely ICAR

(Indian Council of Agricultural Research) to conduct research on various aspects of livestock production

and health. There are 10 research institutes directly under the control of ICAR, which undertake research on various species of livestock. The institutes are:

1. National Bureau of Animal Genetic Resources (NBAGR), Karnal, Haryana.2. Central Sheep and Wool Research Institute (CSWRI), Avikanagar, Rajasthan.3. Central Institute for Research on Buffaloes, Hissar, Haryana.4. Central Institute for Research on Goats, Mukdoom, UP5. Central Avian Research Institute (CARI), Izatnagar, Uttranchel.6. National Equine Research Centre, Hissar, Haryana.7. National Camel Research Centre, Bikaner, Rajasthan.8. Indian Grass land and Forage Research Institute, Jansi, UP9. ICAR North Eastern Hill Complex, Shillong, Megalaya.10. National Research Centre on Yak, Dirang, Arunachal Pradesh

In addition, there are about 46 State Agricultural Universities, 5 Deemed to be Universities 11 Veterinary and Animal Sciences Universities, Indian Veterinary Research Institute, Izatnagar and National Dairy Research Institute, Karnal conducting research in animal production and health with the help of ICAR.

LIVESTOCK POPULATION TREND IN INDIA (in millions)

Speci es

1951 1956 1961

1966

1972

1977 1982

1987

1992

1997

2003

2007

Cattl e

155.30

158.70

175.60

176.20

178.30

180.00

192.45

199.69

204.53

198.8

185.2

191.2

Buff alo

43.40

44.90

51.20

53.00

57.40

62.00

69.78

75.97

83.50

89.9 97.9 102.4

Shee p

39.10

39.30

40.20

42.00

40.00

41.00

48.76

45.70

50.80

57.5 61.5 68.6

Goat 47.20

55.40

60.90

64.60

67.50

75.60

95.25

110.21

115.28

122.7

124.4

134.7

Hors e & Pony

1.50 1.50 1.30 1.10 0.90 0.90 0.90 0.80 0.82 0.8 0.8 0.7

Cam el

0.60 0.80 0.90 1.00

1.10 1.10 1.08 1.00 1.03 0.9 0.6 0.5

Pig 4.40 4.90 5.20 5.00 6.90 7.60 10.07

10.62

12.79

13.3 13.5 11.6

Mule 0.06 0.04 0.05 0.08 0.08 0.09 0.13 0.17 0.20 0.2 0.2 0.1

Donk ey

1.30 1.10 1.10 1.10 1.00 1.00 1.02 0.96 0.97 0.9 0.6 0.4

Yak NC NC 0.02 0.03 0.04 0.13 0.13

0.04 0.06 -- -- --

Total

292.80

306.60

335.40

344.10

353.40

369.00

419.59

445.28

470.14

485.4

485.0

510.6

Poult ry

73.50

94.80

114.20

115.40

138.50

159.20

207.74

275.32

307.07

347.6

489.0

571.1

Dog

NC NC NC NC NC NC 18.54

17.95

21.77

25.5 29.0 38.8

Source : Department of Animal Husbandry, Dairying & Fisheries, Govt. of India

PRODUCTION TREND OF MILK, EGG AND MEAT IN INDIA

States/UT s

Milk (000 Tonnes) Eggs( Lakhs Nos,) Meat @ (000 Tonnes)

Year 2006-07

2007-08

2008-09

2006-07

2007-08

2008-09

2006-07

2007-08

2008-09

Andhra Pradesh

7939 8925 9570 159411

175884

183446

484 556 604

Bihar 5450 5783 5934.0 9454 10707 10740 21 181 188Chhattisgar h

849 866 908 9216 9184 9738 29 13 20

Goa 57 58 59 135 152 149 178 0.3 0#Gujarat 7533 7911 8386 7757 8256 12675 4 17 19Haryana 5367 5442 5745 39596 40727 38150 2 9 230Himachal Pradesh

872 874 884 772 843 977 18 3 4

Jammu & Kashmir #

1400 1498 1499 6320 6500 6500# 8 28 28#

Jharkhand 1401 1442 1466 7110 7130 7154 3 44 44Karnataka 4124 4244 4538 19498 20181 23688 27 110 115Kerala 2119 2253 2441 11987 13831 15095 44 60 124Madhya Pradesh**

6375 6572 6855 9518 9747 6713 107 21 34

Maharashtr a **

6978 7210 7455 33950 34640 35502 76 250 536

Orissa 1431 1625 1672 14246 15479 19948 20 59 118Punjab 9168 9282 9387 37740 37914 36790 243 109 108Rajasthan 9375 9536 9491 6631 6730 6449 23 71 84

Tamil Nadu**

5560 5586 5673 80435 83937 88098 36 398 419

Uttar Pradesh

18095 18861 19537 9483 9814 10140 10 203 517

Uttarakhan d

1213 1221 1230 1889 1911 1962 63 8 10

West Bengal

3982 4087 4176 30386 30542 31372 55 231 375

Arunachal Pradesh

49 50 24 73 394 361 70 21 21

Assam 751 752 753 5350 4910 4659 69 30 31Manipur 77 78 78 836 845 1105 0 24 22Meghalaya 75 77 77 978 990 995 220 37 37Mizoram 16 17 17 348 403 411 13 11 13Nagaland **

67 45 53 868 802 832 200 22 63

Sikkim 49 49 49# 144 143 143# 7 0 0#Tripura 89 91 96 1193 1320 1388 229 14 19A & N Islands

23 24 26 535 622 618 0.29 0 0

Chandigarh

46 47 47 291 282 273 22 1 1

D & N Haveli

0 0 4 0 0 5 0 0 0

Daman & Diu

1 1 1 11 13 13 0 0 0

Delhi 289 282 285 186 182 41 33 32 26Lakshadwee p

2 2 2 127 128 135 0.29 0 0

Pondicherry

45 46 46 107 137 112 9 8 9

All India 100869

104837

108465

506630

53528

0

556378

2302 2572 3822

# Provisional / Data not received from the state. The figures of 2007-08 have been used for 2008-09

** Unregistered sector also included.@Meat production from recognized sector unless specified otherwise.

Source : Department of Animal Husbandry, Dairying & Fisheries, Govt. of India.

DOMESTICATION OF LIVESTOCK

Man domesticated animals since they have provided him with meat and milk for table, skin for clothing and power for tillage and transport. As civilisation developed, food became more abundant and methods of livestock rearing improved the latent possibilities for rapid growth in body size and milk production began to be realised under man’s selection.

Without agriculture and animal husbandry, there could have been no civilisation. The domestication of animals provided the foundation on which civilisation could be built. Most of the animals currently husbanded by man were domesticated in Neolithic times with the exception of dog that was used in the earlier Palaeolithic era.

Domestication began at the end of Old Stone Age and received decided impetus during the New Stone Age. During New Stone Age, man conceived the idea of domesticating plants and animals to increase and ensure his food supply and this was the greatest turning point in man’s long history. The exact time and places of domestication are not known. It might have taken place simultaneously and independently in several regions. It probably occurred 8,000 to 10,000 years ago in Asia possibly around Mediterranean sea (Egypt) or even in Europe.

Domestication of animals carried out foro Religious rites (as sacrifice to the God)o Gratifying his economic needs ( meat & milk for table and wool

& skin for clothing)o Companionship

Stages of domestication

Free range Confined with human environment but at random Specific breeding pattern to produce progeny Planned development of breeds with traits he desired in them

Effects and consequences of domestication

Domestication led to changes in characteristics of animals domesticated, conditioned by functions for which man domesticated them, i.e., in terms of size, colour, hair, body structure etc. It led to better feeding and caring of animals, selection and rearing of more profitable animals and better breeding.

Order of domestication

1 Pre-agricultural period

Dog, Goat and Sheep

2 Early agricultural period

Cattle, Buffalo, Yak and Pig

3 Transport and labour Elephant, Horse, Camel and Ass

4 Pest destroyers Mongoose, Ferret and Cat

Other animals

Dog was the first animal tamed by man for the sake of companionship and followed by cattle, sheep and goats. Horse was probably the last to be domesticated.

1 Chicken and Elephants

First domesticated in India

2 Swine China3 Horses Eastern Europe and West

Asia4 Guinea pigs and

TurkeyAmerica

Dogo They are represented in Egyptian monuments as early as 3400 B.C.

Cattleo Domesticated as early as early as 2100 B.C. Evidences from tombs

and caves of Egypt also confirmed that cattle were slaughtered for meat. The Mohenjo-Daro seal with a bull known around 2500 B.C makes it almost certain that Indian Cattle (Zebu) originated in India.

o Cow was a very important animal in Greek mythology and was a sacred animal in many older civilisations. They were mainly used for food, draft and tillage. All the present day breeds of cattle derived from Bos taurus (European Cattle), Bos indicus (Indian Cattle) and Bos longifrons (African Cattle).

Buffalo (Bubalus bubalis)o Buffalo was originally confined to India and Sri Lanka; reared for food and skin.

Sheep (Ovis aries)o Domestic sheep was originated in Europe and cooler regions of

Asia. Sheep was originally a hairy animal with an under fur of wool.o People living in cooler places made selection on them which

resulted in the development of the present day woolly breeds.

Goat (Capra hircus and Capra ibex)o Goat was the earliest animal domesticated and the origin of

domestication is doubtful because goat and sheep are similar in bone structure. From the available paintings and sculptures of that area, it is confirmed that goats were reared around 7000 – 6000 B.C in Jordan and between 4000 – 3000 B.C in West Asia.

Swine (Sus domesticus)

MODULE-2: HISTORY OF ANIMAL BREEDING

HISTORY OF ANIMAL BREEDING

LANDMARKS IN ANIMAL BREEDING

o Sus scrofa (European), Sus vittatus (wild boar) and Malayan pig were domesticated around 2500 – 2400 B.C. They were domesticated latter than cattle and sheep but earlier than horse.

Horses The present day horses are all traced to one of the three types of horses viz.,o Przhevalski’s Horse (Steppe Horse) (Central Asia)o Desert Horse (Mangolian Horse)o Forest Horseo According to Ridgeway (1905), the origin of horses were from

Przhevalski’s Horse (Steppe Horse) (Central Asia), Celtic Pony (Northern Europe) and Libyan Horse (North Africa). Gay (1913) and Matthew (1926) also endorsed Ridgeway’s statement.

Fowlo Red Jungle fowl (Gallus gallus) was the chief ancestor of the

domestic fowl. Evidences from Mohenjo-Daro seals and Egyptian era from 1500 – 1400 B.C confirmed the domestication of poultry.

Learning objectives


history of animal breeding, landmark of animal breeding.

Till 500 A.D. when the fall of Roman Empire began animal breeding was at its esteem. With the fall of Roman Empire for about 1000 years called Dark and Middle Ages, animal husbandry was at a still.

From 1700 A.D., again there was an improvement. The beginning of modern animal breeding is to be found mainly in England and Europe.

The British Royalty encouraged horse breeding especially for race horses. The Earls and Dukes imported bulls from Holland and bred their native stocks. Dutch cattle were introduced into Herefordshire that laid the foundation of the present Hereford cattle. By crossing the native and Dutch cattle and subsequent inbreeding, the British cattle were improved far beyond the best.

1677 Anton Van Leeuwenhock & his student Jonn Hamm; Observed sperms through a magnifying lens

1725 – 1795 Robert Bakewell, an English man began his animal breeding work at Dishley, Leicestershire, England with horses, sheep and cattle. He is called Father of Animal Breeding. He travelled extensively for his time both in England and on the continent in quest of superior breeding stock. He developed theories and tested them with experiments. He concentrated on producing farm animals with increased efficiency. Bakewell’s two remarks were “Like begets like” and “Breed the best to the best”.

The reason for Bakewell's success in animal breeding experiments was due to the fact that he followed certain strong principles. They were as follows:

o Has got definite ideals/objectives/goals. For example, beef cattle – a low set blocky and quick maturity.

o Practised sire testing by leasing the sires to other breeders and those that proved most satisfactory was brought back for use on his own females.

o “Breed the best to the best” regardless of relation ship and this led to extremely close breeding.

o Performed progeny testing of bulls and rams.o Introduced inbreeding as tool in livestock improvement.o “Like begets like”

Superior animals are more likely to produce superior offsprings than inferior individuals. He is very critical in his selection of breeding stock not only as to appearance but also as to performance.

Bakewell’s methods were widely copied and thus the foundation of purebred was laid. He laid the foundation for the Shire horses, Leghorn cattle and Leicester sheep.

1775 Collings brothers copied the Robert Bakewell’s method and laid foundation for the Shorthorn cattle.

1780 L. Spallanzani of Italy: First scientific work on A.I. Successfully obtained three pups by A.I. in dogs.

1791 British Royalty encouraged horse breeding for races, which results in English thoroughbred and general studbook.

Tompkins and Galliers laid the foundation for Hereford breed of cattle in England. 1775 – 1849 Thomas Bates developed highly inbred herd of cattle. 1822 Coats first published a herd book for Shorthorn breed of cattle.

Settlers in America developed American saddle horse. 1846 English herd book for Cattle 1862 Herd book for Aberdeen Angus Cattle 1866 Mendel published the law of heredity in Journal of Zoological Society of Austria 1875 Herd book for Dutch Friesian Cattle 1879 First work of trap nesting of birds in Austria 1890 Babcock's method of fat % estimation (USA) 1893 Gerber’s method of fat % estimation (Germany) 1895 Milk recording Association in Denmark 1899 E.I. Ivonoff; Practised A.I. in many stud farms (horses). First to

undertake A.I. successfully in Cattle and Sheep 1903 Mendel’s principles were rediscovered by DeVeris of Holland, Von

Tschermark of Austria and Correns of Germany 1907 Growth rate, Feed consumption and Carcass quality for meat

production in swine in Denmark 1908 G. H. Hardy and Weinberg Independently formulate the Hardy-

Weinberg law of population genetics 1923 Pig testing station in Sweden 1939: Sampath Kumaran of Palace Dairy Farm, Mysore used A.I. for the

first time in India. 1942 P.Bhattacharya of Indian Veterinary Research Institute, Izatnagar,

first scientific work on A.I. in India. 1953 J. D. Watson and F. H. C. Crick Propose the double-helix model for

DNA; Discovery of DNA as the genetic material 1980 Martin Cline and co-workers created a transgenic mouse

MODULE-3: CLASSIFICATION OF BREEDS - CATTLE, BUFFALO, SHEEP AND GOAT

TAXONOMIC CLASSIFICATION OF CATTLE AND BUFFALO

1990 The first genetic engineering company “Genetech” founded in San Francisco in USA.

1990 Formal launch of the international Human Genome Project 1990 Publication of Michel Crichton’s novel “Jurassic Park” in which bio-

engineered dinosaurs roam in a palentological theme park 1997 Researchers at Scotland’s Roslin Institute lead by Ian Wilmut have

cloned a sheep called “Dolly” from somatic cell of an adult ewe. 1998 Scientists from University of Hawai cloned a mouse using

Wilmut’s technique creating not only dozens of copies but three generations of clones.

1998 Scientists at Japan’s Kinki University cloned eight identical calves using cells from a single adult cow.

1998 Scientists at USA created a cloned calf from a Friesian cow and named as “Jafferson”.

2000 Cloned dairy calf at University of California at Vermont. 2010 Cloned a buffalo calf named ‘Shresth’ at National Dairy Research

Institute, Karnal, India. Registry books were set up to safeguard the purity of the breed and to

supply authentic record of performance. Livestock shows were also made. From 1880 to 1950, the livestock population has risen in numbers but the number per head compared to human population has declined. But the increase in productivity of dairy cattle, faster maturity and meatier carcasses in meat animals have tended to offset the decrease in number.

In India, though developments have taken place and many breeds evolved still there is no definite record. Livestock census for the whole India was not available till 1920. The presence of princely states and the absence of uniform policy in taking census and maintaining records, partition of India in 1947 have made these figures only partly reliable. ICAR has started herd books for the first time India for Red Sindhi and Sahiwal breeds of cattle in 1941. Subsequently herd books were also established for Hariana, Murrah, Gir, Kankrej, Tharparkar, Kangayam and Ongole breeds.

Superior animals more likely produce superior offspring than inferior individuals. He is very critical in his selection of breeding stock not only as to appearance but also as to performance.

In spite of the large animal population, India is deficit in all livestock production. This is due to poor genetic worth of our livestock, shortage of fodder, poor economic condition of our farmers and adverse climatic conditions. With determined effort and scientific animal husbandry practices, it should be possible to make the country self sufficient in all livestock products in the not distant future.

Learning objectives

This module deals with the classification of breeds like,

cattle, buffalo, sheep and goat.

Phylum CordataSub- phylum

Craniata (Vertebrata)

Class MammaliaSub-class Theria (Viviparous)Infra- class

Eutheria (Placenta)

Order Ungulata (hoofed mammals)Sub-order Artiodactyles (even-toed)Sub- division

Pecora (true ruminants)

Family Bovidae (hollow -horned)Genus BosSpecies taurine group

taurus (European cattle – without hump)

indicus (Indian cattle- humped)

bibovine group

gaurns (gaur), frontalis (gayal), sondaians (banteng)

bisotine group

grunniens (yak), bonasians (European bison),

bison (American bison)

bubaline group

caffer (African buffalo), bubalis (Indian reverine buffalo), mindorensis (Mindora buffalo),

depressicornis (Celebes buffalo)

The Bos taurus is again divided into three subgroups:

CATTLE BREEDS

Bos primigenins – Strong horns, narrow fore head. Example-Angus, Ayrshire, Short- horn, Holstein Friesian, Red Poll.

Bos longifrons – Broad and dished fore head. Example - Jersey, Guernsey, Brown Swiss. Bos brachycephalus – Short and broad head. Example - Canadian, Hereford, Kerry.

The genus Bos, is classified into Bos indicus (Tropical, humped cattle) and Bos taurus (temperate, hump-less cattle)

Exotic cattle breeds

Milch breeds Beef breeds Dual purpose breeds

Ayrshire Hereford Red Polled

Holstein Friesian

Short horn Devon

Jersey Polled Milking short horn

Guernsey short horn

Red Dane Galloway

Brown Swiss Aberdeen Angus

Dexter Brahman

Dutch Belted Beef master

Indian cattle breeds

Milch breeds Dual purpose (or) General utility breeds

Red Sindhi

Nimari

Sahiwal Tharparkar Kankrej Nellore Gir Dangi

Rath Deoni Hariana Krishna Valley Ongole

BUFFALO BREEDS

TAXONOMIC CLASSIFICATION OF SHEEP AND GOAT

Draught Breeds – Four Types

Short horned : White (or) Grey with long coffin shaped skull - Nagori, Bachur Lyre horned : Grey with wide fore Head - Malvi, Kherigarh Small black, red or dum cattle with large patches of white marking found

in Himalayan Region - Ponwar, Siri Mysore type : Prominent fore head with long and pointed horns which rise close together

- Hallikar, Umbalachery, Alambadi, Pulikulam, Amritmahal, Burgur, Khillari, Kangayam

Buffalo breeds are classified as Riverine type (or) Water buffaloes and Swamp type

Murrah Group - Murrah, Nili-Ravi and Kundi Gujarat Breeds - Surti, Mehsana and Jafarabadi U.P. breeds - Bhadawari and Tarai Central Indian varieties - Nagpuri, Pandharpuri, Manda, Jerangi,

Kalahandi and Sambalpur South Indian breeds - Toda and South Kanara

Swamp

The swamp buffaloes are also found in India, mostly in the Brahmaputra area that is Assam and West Bengal with average mature live weight of 340 kg. There are 18 known Swamp buffaloe breeds/strains in China (Yang & Zhang, 2006) while Indonesia has identified seven breeds/strains (Triwulanninghsi el al., 2006). Among the breeds of Indonesia, the spotted swamp buffalo is more unique and is largely raised for socio- religious purposes. Animals used for special rites command very high prices. The swamp buffalo found in the Philippines are believed to have originated from China, although some deliberate efforts were made to import Chinese Shanghai buffaloes in the early part of the century (del Barrio, 2009). Thai swamp buffalo are found mostly in the Northeast of Thailand and have received special program of selection and improvement for growth and size. Selected breeders have 900 to 1000 kg live weight (Pak- Uthai, 2009).

Taxonomic classification of Sheep (domestic group)

Taxonomic classification of Goat (domestic group)

Phylum Cordata CordataSub- phylum

Craniata (Vertebrata) Craniata (Vertebrata)

Class Mammalia MammaliaSub-class Theria (Viviparous) Theria (Viviparous)Infra- class

Eutheria (Placenta) Eutheria (Placenta)

Order Ungulata (hoofed mammals) Ungulata (hoofed mammals)Sub-order

Artiodactyles (even-toed) Artiodactyles (even-toed)

Sub- division

Pecora (true ruminants) Pecora (true ruminants)

Family Bovidae (hollow -horned) Bovidae (hollow -horned)Genus Ovis CapraSpecies Aries hircus

Other groups of sheep: Bighorn group, Aragalis group, Urial group and Bharal group Other groups of goats: True group, Pasang group, Ibex group and Markhor group

SHEEP BREEDS - INDIAN BREEDS OF SHEEPNorthwestern arid and semi-arid region

Northern temperate region

Sourthern peninsular region

Eastern region

Chokla Gaddi Deccani Chottanagpuri

Nali Rampur Bushair Bellary Balangir

Marwari Bhakarwal Nellore Ganjam

Jaisalmeri Poonchi Mandya Tibetan

Pugal Karnah Hassan

Malpura Gurez Mecheri

Sonadi Kashmir Kilakarsal

Patanwadi Merino Vembur

Muzzafarnagri Changthangi Coimbatore

Hissardale Nilgiri

Ramnad White

Madras Red

Trichy black

Ganjam BengalSangamneri Malabari Osmanabadi Kanni aduGaddi Changthangi ChiguSirohi Marwari Beetal Jhakarna Barbari Jamnapari Mehsana Gohilwadi KutchiSurti

Eastern regionSouthern peninsular regionNorthern temperate regionNorthwestern arid andsemi arid region

GOAT BREEDS - INDIAN BREEDS OF GOAT

Learning objectives


MODULE-4: CLASSIFICATION OF BREEDS - PIG AND POULTRY

Breeds in Tamil Nadu: Mecheri, Kilakarsal, Vembur, Coimbatore, Nilgiri, Ramnad White, Madras Red, Trichy black

Exotic breeds of sheep

Mutton type - Dorset Horn, Suffolk, Cheviot, Southdown Wool type - Merino, Rambouillet Fur type - Karakul

Exotic breeds of goats

Milch breed : Saanen, Alpine Mohair breed : Angora Dual purpose : Anglo-nubian.

Taxonomic classification of Pig

Taxonomic classification of Horse



Class Mammalia MammaliaSub-class Theria (Viviparous) Theria (Viviparous)Infra-class Eutheria (Placenta) Eutheria (Placenta)Order Ungulata (hoofed mammals) Ungulata (hoofed mammals)Sub-order Artiodactyles (even-toed) Perissodactyles (uneven- toed)Sub- division

Sunia

Family Suidae (True pigs) Equidae (hollow-horned)Genus Sus EquusSpecies scrofa (European wild

pigs) domesticus

(domestic pigs)

cristatus (Indian wild

pigs)

andamanensis (Andaman Islands)

verrucosus (Malayan pigs)

vittatus (Malayan pigs)

barbatus (Malayan pigs)

salvanius (Himalayan pigs)

africanus, procus (African pigs)

E.caballus (the

horse)

E.asinus(the ass)

E.zebra (the zebra)

CLASSIFICATION OF BREEDS -

pig and poultry.

Pigs breeds

CLASSIFICATION OF BREEDS - POULTRY

Indigenous pigs are known as Desi pigs, mostly black in colour and smaller in size when compared to western breeds.

Exotic breeds of pigs - Large white Yorkshire, Middle White Yorkshire, Landrace, Duroc, Berkshire, Hampshire, Tamworth

Taxonomic classification of Fowl Taxonomic classification of Duck

Phylum Chordata ChordataClass Aves AvesOrder Galliformes AnseriformesSub-order

Galli

Family Phasianidae AnatidaeSub- family

Phasianinae Anatinae

Genus Gallus AnasSpecies gallus (Jungle fowl),

domesticus (domestiated)plathyrhynchos

Breeds of fowls

Fowls are often classified based on the purpose for which they are developed such as egg type, meat type and dual purpose (for both egg and meat), but it is mostly on the basis of their origin. According to the latter, the birds are classified into the following major classes: American, Asiatic, English and Mediterranean. A breed refers to a group of domestic fowls with a common ancestry, and having similarity in shape, conformation, growth, temperament, shell colour of egg and breeds true to type. Variety is a subdivision of breed and within a breed there may be several varieties. The term variety is used to distinguish fowls having the characteristics of the breed to which they belong but differing in plumage colour, comb type, etc., from other groups of the same breed. A breed or a variety may have several strains or lines identified by a given name and produced by a breeder through at least 5 generations of closed flock breeding. Several strains within a breed or variety phenotypically may look alike but often differ in their production performance depending upon their breeding history.

Class Breed VarietiesAmerica

nPlymouth Rock Barred, Whites, Buff,

Patridge,

Silver pencilledWayandotte Whites, Silver laced,

Patridge

Rhode Island Red

Rose comb, Single comb

Rhode Island White

Rose comb

New Hampshire Single combJersey Black Giant

Only single comb

English Orphington Buff, Whites, BlackSussex Light, SpeckledAustralop BlackDorking BlackCornish Whites, Rock

Asiatic Brahama Light, DarkLong Shan Black, WhitesCochin Buff, Whites, Black,

PatridgeMedetaranian

Leghorn White, Dark, Light, Buff

Minorca White, Black, BuffAncona Single comb, Rose combBlue Andulusian Single comb

Spain Spanish

Butter cupPolish PolishHamburg HamburgFrench Hounder

Crevecoc

us

LaflecheGame GameOriendae Sumatr

a

Malaya

CubalayaMiscellaneous

Sultan

Frizzle

Classification based on utility

Game: Aseel

MODULE-5: CLASSIFICATION OF BREEDS - HORSE, DONKEY, CAMEL, YAK AND MITHUN

CLASSIFICATION OF BREEDS - HORSE AND DONKEY

Meat type : Cornish Egg type : Leghorn Dual type : Rhode Island Red Fancy / Exhibition type : Silky, Frizzled, Bantams, Nacked neck etc.,

Learning objectives


horse, donkey, camel, yak and mithun.

Taxonomic classification of Horse

Taxonomic classification of Donkey



Class Mammalia MammaliaSub-class Theria (Viviparous) Theria (Viviparous)Infra-class


Order Ungulata (hoofed mammals) Ungulata (hoofed mammals)Sub-order Perissodactyles (uneven- toed) Perissodactyles (uneven- toed)Family Equidae EquidaeGenus Equus EquusSpecies E.caballus (the

horse)

E.asinus(the ass)

E.zebra (the zebra)

E. africanus

E. africanus asinus

Horse

CLASSIFICATION OF BREEDS - RABBIT, CAMEL, YAK AND MITHUN

Arabian Australian Stock Horse Australian Stock Horse French Saddlebred Mongolian Palomino Prezwalski (sha-val-ski) Quarter Horse Marwari Manipuri Horses Spiti Horses Kathiawari Horses Bhutia Horses Zanskari Horses

Donkey

It is considered that asses are of purely African origin. The ass was first domesticated in the valley of the Nile. Three wild races of asses were observed:

North-East African race (Nubia). North-East African race (Sudan) and Somalian race (Somali-land).

Taxonoic classification of rabbit and camel

Taxonomic classification of Rabbit and Hare

Taxonomic classification of Camel



Class Mammalia MammaliaSub-class Theria (Viviparous) Theria (Viviparous)Infra- class


Order Lagomorpha ArtiodactylaSub-order Leporidae (rabbits and hares) --Family Leporinae Bovidae

Genus Oryctolagus (rabbits),

lepus (hares)

Camelus

Species cuniculus (rabbits),

negricolli (hare)

Dromedaries

bactrianus

Taxonoic classification of yak and mithun

Taxonomic classification of Yak

Taxonomic classification of Mithun



Class Mammalia MammaliaSub-class Theria (Viviparous) Theria (Viviparous)Infra-class Eutheria (Placenta) Eutheria (Placenta)Order Ungulata (hoofed mammals) Ungulata (hoofed mammals)Sub-order Artiodactyles (even-toed) Artiodactyles (even-toed)Family Pecora (true ruminants) Pecora (true ruminants)Genus Bovidae (hollow -horned) Bovidae (hollow -horned)Species bisotine group

grunniens (yak),

bonasians (European bison),

bison (American bison)

bibovine group

gaurns (gaur),

frontalis (Mithun,

Dulong, Gayal),

sondaians (banteng)Yak (Bos grunniens)

Yak is being reared in different pockets like Lubrang, Chhander, Madla, Phudung, Jang, Thembu, Broxer, Mago, Lunger, Chunna, Sella pass and Tawang of West Kameng and Tawang districts.

Mithun (Bos frontalis)

Mithun (Bos frontalis), the domesticated free-range bovine species, is an important component of the livestock production system of North-Eastern hilly region of India.

ECONOMIC TRAITS TO BE FOLLOWED IN CATTLE

MODULE-6: ECONOMIC TRAITS OF CATTLE AND BUFFALO AND THEIR IMPORTANCE

INTRODUCTION

INTRODUCTION

This unique bovine species is believed to be domesticted more than 8000 years ago. Mithun is primarily reared as meat animal and highly preferred among the tribal people of North-Eastern region of India. Mithun is also used as a ceremonial animal and plays important role in economical, social and cultural life of the tribal people of North-East. Besides, it is now established that superior quality milk and hide can be obtained from mithun. National Research Centre on Mithun was established by ICAR in the year 1988 in the state of Nagaland to conserve, propagate and improve this species for future use.

Learning objectives


economic traits to be followed in cattle and buffalo, economic traits of livestock for milk and economic traits of buffalo for meat.

The genetic improvement of dairy animals depends on animal breeding technologies. In most of the developing countries including India the animal breeding technologies are neither advanced nor widely adopted because of considerable geographical variation in environment, fragmented farming mostly at a subsistence level, poor maintenance of records, substantial livestock genetic diversity, lack of awareness of rural households and many other problems directly and indirectly associated with the genetic improvement of animals. As a result, in spite of some important genetic resources available in the country, the productivity of dairy animal in general is very low in India in comparison to the dairy animals of developed countries. Thus, the reasoning for genetic improvement of dairy cattle and buffaloes would be critically differentiated in institutional / organised herds and field condition in our situation.

The genetic improvement of dairy animals depends on animal breeding technologies. In most of the developing countries including India the animal breeding technologies are neither advanced nor widely adopted because of considerable geographical variation in environment, fragmented farming mostly at a subsistence level, poor maintenance of records, substantial livestock genetic diversity, lack of awareness of rural households and many other problems directly and indirectly associated with the genetic improvement of animals. As a result, in spite of some important genetic resources available in the country, the productivity of dairy animal in general is very low in India in comparison to the dairy animals of developed countries. Thus, the reasoning for genetic improvement of dairy cattle and buffaloes would be critically differentiated in institutional / organised herds and field condition in our situation.

BUFFALO

Growth rate

The delayed maturity affects the age at first calving and ultimately the total productive life of the animal. The growth rate of the domestic water buffalo is lower than that of cattle. It is a slow maturing animal and its growth continues till 10th year, although rate of growth is slower after the fifth year.

Age at first calving

The economics of a dairy animal is directly depend on age at first calving. A reduction in the age at first calving has following advantages.

productive period during the life time of an animal is increased. act as guideline for easier culling.

Species

Age at first calving (Days)

CattleBuffalo

Peak yield

Peak yield in lactating animal is the initial maximum production of milk in a day. Peak yield generally taken to be criterion for evaluating dairy animals because of absence of pedigree and performance records and market prices are fixed on the quantity milk given by buffalo as peak yield.

Species

Average Peak yield (kg)

CattleBuffalo

Lactation yield

It is the total milk production in complete lactation. For any breeding or genetic improvement program whether it is through selective breeding or through cross breeding the performance of dairy buffalo in terms of production of milk has to be of top consideration.

Species

Lactaion yield (kg)

CattleBuffalo

Life time milk yield

The importance of life time milk production has got economic bearing on the up keeping of dairy animals. An animal which produce more milk during its productive life is bound to be the most profitable unit in a dairy enterprises.

Species

Lactaion yield (kg)

CattleBuffalo

Lactation length

It is the no. of days animal gives milk. The amount of milk produce by an animal in a lactation depends on the initial maximum milk secretion, persistency of production and lactation period.

Species

Lactaion length (Days)

CattleBuffalo

Dry period

It is the period during which an animal remain out of production. An optimum dry period or the period of rest is essential to recoup its depleting potentialities owing to production of milk for prolong period.

Species

Dry period (Days)

CattleBuffalo

Service period

The period between date of calving and date of conception. There is positive phenotypic correlation between service and lactation period.

Species

Service period (Days)

CattleBuffalo

Breeding efficiency

Frequency of reproduction or birth of many offspring at one time and / or during the life time reveal the genetic variability in an individual and thus allows more efficient chance for selection.

ECONOMIC TRAIT OF LIVESTOCK FOR MILK (QUALITY)

ECONOMIC TRAITS OF BUFFALO FOR MEAT/ CARCASS TRAITS

Species

Breeding efficiency

CattleBuffalo

Average calving interval

It is the average period in days or months between two successive calvings.

Species

Calving Inteval

CattleBuffalo

Milk from buffalo differs from that of Cattle. The biggest difference is with respect to fat. In Cattle, the milk contains between 3 to 5% fat, depending on feed and breed. In Buffalo milk the average fat content is usually 7 to 8% but may be as high as 13%.

Fat %

It is average % of fat in milk over the month in lactation.

Species

Average milk fat %

CattleBuffalo

Protein %

It is average % of protein in milk over the month in lactation.

Species

Average protein %

CattleBuffalo

Buffalo meat production accounts for about 30% of the total 4.9% million tonnes meat production in country and their contribution is next to milk as major source of live stock economy and come to about 16% of the total

output of livestock sector. During the last 25

MODULE-7: ECONOMIC TRAITS OF SHEEP AND GOAT AND THEIR IMPORTANCE

SHEEP PRODUCTION IN INDIA

years meat production has increased from 764,000 tonnes in 1970-71 to 4.9 millon tonnes indicating average growth rate during the last two decades at 4.6% as against 21% during the last 5 year.

Dressing percentage

Dressing percentage in buffalo is 40% - 45%. This is slightly lower than in cattle. The dressing % is higher in Murrah followed by that in crossbred and Bulgarian Buffalo.

Average daily gain

The average daily gain in buffalo calves is 478 gram. The crossbreds of Murrah with Bulgarian Buffaloes have shown slightly better ADG.

Muscle PH

The PH should be alkaline.

Birth weight

The birth weight of water buffalo is higher than of all domestic breeds of cattle except Friesian cattle. The birth weight of buffalo varies with respect of the sex of calf and the calving sequence. The average birth weight of male buffalo is significantly higher than the female buffaloes. During subsequent calving the birth weight of calves increases up to the fourth calving when the dams attain full maturity weight. The average birth weight is found to be ranging between 27.3 to 33.2 kg.

Learning objectives


sheep and goat production in India.

Sheep is a important livestock species of India. They contribute greatly to the agrarian economy, especially in the arid/semi-arid and mountainous areas where crop and /or dairy farming are not economical. They play an important role in the livelihood of a large percentage of small and marginal farmers and landless labourers engaged in sheep rearing. A number of rural-based industries use wool and sheep skins as raw material. Sheep manure is an important source of soil fertility, especially in southern states.

Sheep in India are mostly maintained on natural vegetation on common grazing lands, wastelands and uncultivated (fallow) lands, stubbles of cultivated crops and top feeds (tree loppings). Rarely are they kept on grain, cultivated fodder or crop residue.

Sheep are mostly reared for wool and meat. Sheep skins and manure constitute important sources of earning, the latter particularly in southern India. Milk from sheep is of limited importance and that too in very limited areas of Jammu and Kashmir, Rajasthan and Gujarat. Indian sheep are not regarded as dairy sheep.

The productivity of Indian sheep is lower than those of agriculturally more advanced countries. Yet considering their nutritional and physical environment, their productivity cannot be considered as inefficient. The major reasons for low productivity are inadequate grazing resources, diseases causing high mortality, morbidity and consequent reduced production, and serious lack of organized effort for bringing genetic improvement.

Productivity

Sheep in the Northern temperate region produce wool of good apparel quality. Similarly, in climatically alike areas of southern hills, the Nilgiri sheep also produce wool of similar quality. This, however, goes down as we move from Northern temperate to North- western region where sheep produce wool of superior to coarse quality. Sheep of Southern peninsular region either produce no wool or very little of 36s quality and are primarily used for meat production. Same is the position in Eastern region as the area is of very high humidity and is not suitable for extensive sheep raising, especially for wool.

Colour of fleece is generally white in the North-western hilly region, though black is not uncommon. Black and brown colour appears in greater proportion as we move towards North-west. In North-western plains containing arid and semi-arid sub-tropical conditions, fleece colour is again predominantly white with black and brown mostly on non-fleece points such as head and neck. In this region, problems of canary colouration of wool (non-scourable golden yellow colour) is usually observed in the autumn season. This results in almost 82% canary staining of the autumn clip which fetches 8-20% lower price resulting into a loss of about 1.5 crores per annum. A biological phenomenon of this colouration is presumed to be a sequel to an adaptive thermo-regulatory mechanism in hot and humid climatic conditions which requires dissipation of body heat through cutaneous evaporative cooling. The alkaline sweat under the conditions of high temperature and humidity reacts with wool fibres and thus causes the yellow colouration.

Grazing management and Migratory patterns

In spite of a number of sheep development activities in operation in different states of the country, sheep rearing still continues to be a nomadic/backward proposition and thus mostly concerned to poor and landless people. For scanty suitable grazing lands in most of the states, the shepherds keep on migrating their flocks over extensive areas within or even in the neighbouring states. Sheep rearing is thus practiced in a diversified form depending upon the region and the location. In Rajasthan, around 5 lakh sheep are in permanent migration where the flocks do not return to their home tract at any time of the year. The shepherds, however, keep on relieving one another and return home in turn. These sheep are mainly grazed in MP, UP and parts of Rajasthan.

Generally there are two types of migratory flocks:

Truly nomadic flocks with no fixed centres but following seasonal migratory routes to grazing areas; they are largely governed by the availability of foraging and drinking water resources.

GOAT PRODUCTION IN INDIA

Flocks on the fallow land, but following definite migratory routes to the season pastures and returning to their permanent abodes during other seasons.

o Sheep are grazed on fallow lands during monsoon and after the Kharif crops are harvested on stubbles in the harvested fields

o During the later part of the year starting from Sep-Oct, they are mostly grazed on uncultivated areas where the flocks are non-migratory

o In the case of migratory flocks, the animals are grazed on the harvested fields and the reserve forests in their migratory tracts on nominal fees from Nov-Feb

o Shepherds also book harvested fields where the cost of grazing on stubbles and gram husk in minimal

o In both the migratory and non-migratory flocks, top feeding by lopping tree branches and shaking of pods is also common

o During extreme summer months of the year, the flocks are grazed in the cooler hours of the day; grazing starts in the late hours of the day and the animals are brought to the water points some time in the noon hours of the following day. Animals are rested during the hotter part of the day between noon to around 4-5 PM.

o About 5 million households in the country are engaged in the rearing of small ruminants (sheep, goats & rabbits) and other allied activities. (2003 census)

o The main reasons for low productivity are poor exploitation of genetic potential of indigenous animals, low absorption of available technology, inadequate resource of feed and fodder, insufficient health cover, inadequate marketing and credit support etc.

India possesses the second-largest goat population in the world. In the prevailing socio-economic conditions in the country where per capita land holding is hardly 0.2 Ha, goat rearing becomes an inseparable component of mixed farming system. Goat farming has been recommended as the best choice for the rural people in developing countries because of the low investment, wide adaptability, high fertility and fecundity, low feed and management needs, high feed conversion efficiency, quick pay-off and low risk involved. Goats play an important role in income generation, capital storage, employment generation and improving household nutrition.

Goat rearing is the backbone of the economy of small and landless farmers in India. It is an insurance against crop failure and provides alternate source of livelihood to the farmers all year round. Goats provide dependable source of income to 40% of the rural population who are below the poverty line.

The controversy over goats is on damage it causes to the environment, predominantly due to its browsing nature. On one hand, the goat is accused as the major cause of deforestation and soil erosion, and on the other hand, it is claimed as a useful animal for poor people and is responsible for clearing the bushes and making the land worthy of cultivation. The goat’s bad reputation arises mainly from its mismanagement by man rather than any inherent fault. Nevertheless, the trend is slowly changing, and several states are now encouraging

goat husbandry.

Production Systems

In our country, goats are reared by men and women with diverse working and professional background. The production systems are as numerous as the socio-economic and varied agricultural situations in the country. However, they can be broadly classified into the following:-

Tethering: This is common in the sub-humid and humid zones, where probably because of intensive cropping, it is a convenient means of rearing goats from the stand point of control, minimum labour input and utilization of feed in situ. It is thus a sedentary system. A variation of this method is combining tethering with grazing up to 5 goats at a time, led by ropes held by women and children.

Extensive production: This involves low carrying capacity in situations where land is marginal and is plentiful. It is characterized by low rainfall and various browse plants. The system is used by nomadic people, usually in very low rainfall areas or during winter months when crop resides are available.

Intensive production: The goats are fed in confinement with limited access to land. It involves high labour and cash inputs. Cultivated grasses and agro-industrial byproducts are fed in situ. This system also has the advantage of allowing control over the animals.

Semi-intensive production: This system is practiced to some degree in most of the situations, but the nature and extent of integration depend on the type of crops grown and their suitability to goats. The advantages of this system are increased fertility of land via the return of dung and urine, control of waste herbage growth, reduced fertilizer usage, easier crop management, increased crop yields, and greater economic returns.

Status of Goat industry

The goat industry in India has yet to be firmly laid down on scientific lines. Goat keepers are maintaining goats in all kinds of situations depending upon the ecology and their circumstances. The minimum goat unit could consist of one goat and the maximum could go to a few hundreds under range management. Goat farming in the country is mainly based on ‘zero input’. The fear of mortality has perhaps been largely responsible for not starting many large-scale goat farms. However, large-scale goat farms have successfully running since over last 30 years at the CSWRI Avikanagar, MPKVV Rahuri, and at Leh.

Constraints of the Goat industry

The following could be considered as the technical constraints for securing a thriving goat industry in the country:-

Non-availability of high-yielding breeding stock. Low level of nutrition and managerial efficiency. Lack of definition of the production objectives. Limited attention to application of the modern techniques for

improving the reproductive efficiency, eg. AI, synchronization of estrous, semen freezing etc.

Limited use of outstanding exotic breeds for improvement.

Inadequate control of diseases and parasites due to non-availability of prophylactic vaccines against important contagious diseases.

MODULE-8: ECONOMIC TRAITS OF SWINE AND POULTRY AND THEIR IMPORTANCE

ECONOMIC TRAITS OF SWINE

Lack of knowledge on successful rearing of kids. Kid mortality is very high when weaning is practiced at a very young age.

Lack of knowledge on silvi-pastoral system. Housing for goats in different eco-zones requires a very elaborate

and systematic study. Organized marketing is very limited. This has resulted in unscrupulous

exploitation by the middle-man who is often seen moving with the goats along the migratory routes.

Learning objectives


economic traits of swine and economic traits of poultry.

Scope of swine production

The challenges faced by our country in securing the food as well as nutritional security to fast growing population need an integrated approach for livestock farming. Among the various livestock species, piggery is most potential source of meat production and more efficient feed converters after the broiler. Apart from providing meat, it is also a source of bristles and manure. Pig farming will provide employment opportunities to seasonally employed rural farmers and supplementary income to improve their living standards. The advantages of the pig farming are:

The pig has got highest feed conversion efficiency i.e. they produce more live weight gain from a given weight of feed than any other class of meat producing animals except broilers.

The pig can utilise wide variety of feed stuffs viz. grains, forages, damaged feeds and garbage and convert them into valuable nutritious meat. However, feeding of damaged grains, garbage and other unbalanced rations may result in lower feed efficiency.

They are prolific with shorter generation interval. A sow can be bred as early as 8-9 months of age and can farrow twice in a year. They produce 6-12 piglets in each farrowing.

Pig farming requires small investment on buildings and equipments Pigs are known for their meat yield, which in terms of dressing percentage

ranges from 65 - 80 in comparison to other livestock species whose dressing yields may not exceed 65%.

Pork is most nutritious with high fat and low water content and has got better energy value than that of other meats. It is rich in vitamins like thiamin, Niacin and riboflavin.

Pigs manure is widely used as fertilizer for agriculture farms and fish ponds. Pigs store fat rapidly for which there is an increasing demand from

poultry feed, soap, paints and other chemical industries.

Pig farming provides quick returns since the marketable weight of fatteners can be achieved with in a period of 6-8 months.

There is good demand from domestic as well as export market for pig products such as pork, bacon, ham, sausages, lard etc.

Contribution of pig farming to national economy

The pig population of the country is 12.79 million as per the 1992 livestock census and13.291 million as per 1997 provisional result of census from states and constitutes around 1.30% of the total world's population. The state wise pig population are given in Annexure I . The pork production stands at 4.20 lakh tonnes (1995). During 2001-02 the production of pork and pork products were estimated to be 612550 mt with 3.03% growth rate in last decade. If comprised over 38% of the total world meat product Indian share in piggary meat production moderately increased from 0.53%in 1981 to 0.63 in 2002. The contribution of pork products in terms of value works out to 0.80% of total livestock products and 4.32% of the meat and meat products. The contribution of pigs to Indian exports is very poor. About 934 tonnes of pork and pork products were exported during 1995-96. The value of pork and pork products exported is Rs. 262 lakhs against the total value of Rs. 61604 lakhs on account of meat and meat products export.

The pig farming constitutes the livelihood of rural poor belonging to the lowest socio- economic strata and they have no means to undertake scientific pig farming with improved foundation stock, proper housing, feeding and management. Therefore, suitable schemes to popularise the scientific pig breeding cum rearing of meat producing animals with adequate financial provisions are necessary to modernise the Indian pig industry and to improve the productivity of small sized rural pig farms.

In view of the importance of pig farming in terms of it's contribution to rural poor and possible potentials for pig rearing in our country, Government of India has initiated measures to promote the pig farming on scientific lines under it's five year plans. The first step towards this direction is establishment of eight bacon factories and organisation of pig production in rural areas attached to bacon factories. In order to make available good foundation stock, regional pig breeding stations were established for each bacon factory.

Economic traits

Many important production traits in animals such as milk yield, body weight, Total fat, carcass weight in animals, fat content of meat are quantitative traits, and much of the pioneering research into the modes of inheritance of these traits was performed by animal geneticists. These traits are controlled by multiple genes, each segregating according to Mendel's laws. These traits can also be affected by the environment to varying degrees .

The following are examples of economic traits or quantitative traits that we are concerned with swine production are.

Litter size at birth Litter size born alive Litter size at weaning Birth weight

Litter weight at birth Weaning weight

ECONOMIC TRAITS OF POULTRY

Litter weight at weaning Weight at market age Growth rate Feed efficiency Mortality percentage

Poultry industry in India

Poultry is one of the fastest growing segments of the agricultural sector in India today. While the production of agricultural crops has been rising at a rate of 1.5 to 2 percent per annum, that of eggs and broilers has been rising at a rate of 8 to 10 percent per annum. As a result, India is now the world's fifth largest egg producer and the eighteenth largest producer of broilers. Driving this expansion are a combination of factors - growth in per capita income, a growing urban population and falling real poultry prices.

In the context of this emerging scenario, questions are being raised about the impact of the scaling up of production-through structural factors, externalities and policies-on small-scale producers. Do the transaction costs, policy distortion and environment externalities place the small-scale producer at a disadvantage? Why do some poultry farms have higher income than others? Do large farms earn more profit per unit of output than small ones? What explains the differentials in profitability?

Transformation from a Backyard Activity to a Major Commercial Activity

The poultry sector in India has undergone a paradigm shift in structure and operation. A significant feature of India's poultry industry has been its transformation from a mere backyard activity into a major commercial activity in just about four decades. This transformation has involved sizeable investments in breeding, hatching, rearing and processing. Farmers in India have moved from rearing non-descript birds to today rearing hybrids such as is Hyaline, It is Shaver, II and in Babcock, It which ensure faster growth, good liveability, excellent feed conversion and high profits to the rearers. The industry has grown largely due to the initiative of private enterprise, minimal government intervention, considerable indigenous poultry genetics capabilities, and considerable support from the complementary veterinary health, poultry feed, poultry equipment, and poultry processing sectors. India is one of the few countries in the world that has put into place a sustained Specific Pathogen Free (SPF) egg production project.

Regional Variation in Poultry Development

Another important aspect of poultry development in India is the significant variation in the industry across regions. Figure 1.1 illustrates egg production in India by state during 1998-99. The four southern states - Andhra Pradesh, Karnataka, Kerala and Tamil Nadu- account for about 45 percent of the country's egg production, with a per capita consumption of 57 eggs and 0.5 kg. of broiler meat. The eastern and central regions of India account for about 20 percent of egg production, with a per capita consumption of 18 eggs and 0.13 kg. of broiler meat. The northern and western regions of the country record much higher figures

than the eastern and central regions with respect to per capita availability of eggs and broiler meat.

Growing Production of Eggs and Broilers

Table eggs and broiler meat are the major end products of the poultry sector in India. Presently production of eggs is estimated to number about 37 billion, that of broilers 895 million, and that of poultry meat 735,000 tonnes. In addition, organized facilities have been set up over the years for the manufacture of egg powder and frozen, processed broiler meat essentially to cater to export markets and markets in the metropolitan areas of India.

Increasing Scale of Operation

The growth of the poultry sector in India is also marked by an increase in the size of the poultry farm. In earlier years broiler farms had produced on average a few hundred birds (200-500 chicks) per cycle. Today units with fewer than 5,000 birds are becoming rare, and units with 5,000 to 50,000 birds per week cycle are common. Similarly, in layer farms, units with a flock size of 10,000 to 50,000 birds have become common. Small units are probably finding themselves at a disadvantage because of high feed and transport costs, expensive vaccines, and veterinary care services and the non-availability of credit. Some small units are reported to be shifting from layer to broiler production because output in broiler units can be realized in six weeks.

Structure of the Poultry Industry

The structure of India's poultry industry varies from region to region. While independent and relatively small-scale producers account for the bulk of production, integrated large- scale producers do account for a growing share of output in some regions. Integrators include large regional firms that incorporate all aspects of production, including the raising of grandparent and parent flocks, rearing DOCs, contracting production, compounding feed, providing veterinary services, and wholesaling.

Concentration of Poultry Units around Cities and Urban Centers

There has also been a growing tendency for poultry units to be concentrated around urban areas because of the existence of ready markets for the end products of poultry production.

Low Per Capita Consumption

Even though India is the world's fifth largest egg producer and the eighteenth largest producer of broilers, its per capita consumption of these products is poor - 37 eggs and 1 kg. of poultry meat per capita per annum. Here, again, there is considerable variation in per capita consumption between rural and urban areas and also across the region. Per capita consumption of eggs is only 7.7 per annum in rural areas compared with 17.8 per annum in urban areas. In seven states, per capita consumption is less than 3.5 per annum. Similarly, per capita consumption of poultry meat is 0.24 kg. in rural areas and1.08 kg. in urban areas.

Slow Changes in Consumption Habits

An analysis of consumption data originating from National Sample Survey (NSS) rounds reveals many interesting facts. First, 42 percent of households are vegetarian in that they do not eat fish, meat or eggs. The remaining 68 percent of households are non- vegetarians. Over time there has been a gradual shift from vegetarianism to non- vegetarianism. The change is more visible in rural areas than in urban areas.

Exports

Exports of poultry products from India comprise table eggs, meat, live birds and value- added products such as egg powder and frozen yolk. The value of aggregated exports was Rs. 1,683 million in 1996-97. Exports were expected to reach the level of Rs. 5 billion by the year 2000.

Employment

Three decades ago, when egg and broiler production was 10 billion and 30 million, respectively, the total employment numbers in the poultry sector were not so encouraging. As income and employment in the crop sector started diminishing, the non-crop sector, which includes dairy and poultry, underwent a significant shift. With the demand for poultry increasing and production reaching 37 billion eggs and 1 billion broilers, this sector now employs around 1.6 million people. At least 80 percent of employment in the poultry sector is generated directly by these farmers, while 20 percent is engaged in feed, pharmaceuticals, equipment and other services required by the poultry sector. Additionally, there may be a similar number of people roughly 1.6 million who are engaged in marketing and other channels servicing the poultry sector.

Issues Relating to Animal Welfare and Environmental Pollution

Issues relating to animal welfare and environmental pollution by poultry units have been of increasing concern in developed countries such as the U.S. and the European Union (E.U.). But in India these issues have not yet emerged as critical although they are discussed at length in various seminars and forums on poultry production. Considering globalization and the international trade in poultry products, however, these issues may assume significance in a few years because of pressures from importing countries such as those in the E.U.

Constraints on the Growth of the Poultry Industry

A major constraint affecting the growth of the poultry industry in India is the lack of basic infrastructure such as storage and transportation, including cold chain. As a result, there are wild price fluctuations in the prices of poultry products, i.e., eggs and broilers. Another constraint to growth is an inefficient marketing system. The presence of so many market intermediaries harms both the producer and the consumer. A third problem relates to the price availability of feed resources. Maize or corn plays a major role in broiler production, as it constitutes 50 to 55 percent of broiler feed. As the broiler industry is growing at the rate of 15 percent per annum, the demand for maize is thus likely to increase. Presently India grows only 11 million tonnes of maize and only 5 million tonnes are available for poultry, which is not sufficient if the current growth rate of the industry is

to be maintained.

MODULE-9: BREEDING/SELECTION TECHNIQUES FOR OPTIMAL PRODUCTION

INTRODUCTION

Some of the economic traits or quantitative traits in poultry are as follows:

Hatch weight Weight at 20 weeks Age at maturity Weight at maturity Age at maturity in flocks without trapnesting Egg production at 40 weeks Egg production at 72 Weeks Hen-day production at 40 weeks of age Hen-housed production at 40 weeks Hen-day production at 72 Weeks Hen-housed production at 72 Weeks Livability (0-20 weeks) Livability (20 to 72 Weeks) Egg weight or egg size Hatchability Hatch weight Fortnightly weights up to 8 weeks Feed efficiency etc.,

The economic traits in each generations are measured, using selection and mating we can aim for improving the traits in different species. Without economical traits measurements it is not possible for having any improvement in animal breeding.

Learning objectives


genetic effects of selection and complications of selection.

The purpose of animal breeding is not to genetically improve individual animals but to improve future generation of the animal population. The method used by the breeder to make long-term change in animals is called selection. Selection is the process in which certain individuals in a population are given an opportunity to produce offspring while others are denied this opportunity. It also decides about how many offspring it should produce and how long they should remain in the breeding population. Selection is an important tool for changing gene frequencies to better-fit individuals for a particular purpose. Selection is not an invention of modern man. It has been going on in nature since life existed in the world. Selection is choosing of individuals that will be parents of next generation.

GENETIC EFFECTS OF SELECTION

COMPLICATIONS OF SELECTION

Effectiveness of selection depends on ability to recognize those animals, which possess superior inheritance. Those superior animals must be mated together for the production of offspring. The aids available to estimate the breeding value of an animal is through the phenotype of an animal or its relatives.

Various aids available for selection are: (a) Individual selection or mass selection, (b) Pedigree selection, (c) Progeny testing and (d) Family selection and sib selection.

Breeders always tend to go for selection of several traits at a particular time. Because, the net value of an animal would depends on several traits that may not be equally economically important. The desirable trait will depend on the economic value but only of real importance may be considered. If too many traits selected for one time there will be less progress in improvement of any particular trait. There are three methods of selection viz., tandem method, simultaneous but independent culling level method and selection index method.

Selection does not create new genes. It is practiced to increase the frequency of desirable genes in a population and decrease the frequency of undesirable genes. Since theselected individuals can transmit only sample halves of genes they have to their offspring, so if animals with better quality genes possessed are selected then the offspring will also posses the same. If the frequency of desirable gene is increased, the proportion of individuals homozygous for that desirable gene is also increased. The changes thus obtained in gene frequency due to selection are permanent even if selection ceases thereafter. The higher frequency obtained by initial selection can be maintained by random mating. Hence, selection has been aptly called the keystone of the arch in animal improvement. Man’s selection even in the absence of genetic knowledge has been highly effective.

Selection is carried out for a variety of traits in different species. For e.g., speed in racehorses, milk yield in dairy cattle, litter size in swine, wool yield in sheep, market weight in goats and egg production in poultry. In farm animals, selection should always be directed to greater utility. However, selection is not so simple a task to produce immediate results. Selection is also not always successful. If selection were always being

effective, the animal breeders’ problems would be largely resolved. But the failures of

GENETIC COMPLICATIONS

selection dampen the enthusiasm of many people engaged in animal breeding. The complications can be classified genetic and operational complications. The genetic complications are: heredity and environment, genotype and phenotype, heritability, regression to the mean, types of gene action, correlation of traits and effects of inbreeding. The operational complications are: objectives in selection, number of traits, foundation stock, level of performance, systems of selection, length of time and number of animals.

Heredity and environment

Most traits of economic importance are controlled by many genes and are greatly influenced by environment also. The environment may alter the traits and mask the real genetic worth of the individuals. For example, an animal with a faster growth rate rose in a faulty environment (deficient diet) and an animal with poor genetic constitution for growth rate but raised in a good environment can be responsible for mistakes in selection. This effect of environment can be responsible for mistakes in selection. However, this effect could be overcome by keeping the stock under selection in a standard and suitable environment wherein the better genotype will be able to express itself fully. Under such conditions, the breeder will have a chance to recognise the differences that are hereditary and thus increase the accuracy of selection.

Genotype and phenotype

Genotype is animal’s genetic constitution. The genotype remains constant for an animal throughout its life. But phenotype is the result of interaction between the genotype and environment in which the animal is developing. The phenotype, unlike the genotype, changes with time. Hence it affects selection. Selection is done for the genotype, but seldom, it could be assessed correctly. So the genotype is assessed based on phenotype of the individual though it is not accurate. So, for selection to be effective, phenotypic selection should be done at the age when the economic traits are expressed, for e.g., meat animals like sheep, swine and poultry, phenotypic selection should be done at market age. Cows should be selected at the end of first lactation.

Heritability

Most selection processes are based on phenotypic differences. Though we are selecting on phenotypic basis, our aim is to effect selection on genotypic basis. If the phenotype accurately reflects the genotype, the selection will be quite accurate. But phenotype is not a true indicator of genotype. Heritability of a trait may be defined as that portion of the phenotypic variation that is due to additive gene action. If most of the phenotypic variation is due to environment, progress from selection will be slow. On the other hand, if the additive genetic variation is larger, then the heritability estimate will more accurately predict the genotype. The heritability values are not constant and vary from herd to herd and in the same herd from time to time. Inbreeding for instance increases homozygosity of genes and reduces the hereditary variation. Therefore, heritability will decrease with

inbreeding and increase without crossing. In other words, phenotype or individual selection will be more effective in herds and for traits where the heritability is

high. Hence, knowledge of heritability of economic traits in livestock is therefore essential for a breeder.

Regression to mean

The offspring of outstanding parents often have a tendency to regress towards the average of the breed from which they were selected. This is referred to as Galton’s law of filial regression. This is because (i) due to combination of genes; when they reproduce due to segregation and independent assortment of genes, the suitable combination is broken up and the average results and (ii) due to environment; the offspring are brought up in an environment which is much different from that of the parent. If the superiority of the parents is due to lucky combination of genes, little could be done to interfere with the laws of segregation and independent assortment. If the superiority of the parents is due to high percentage of homozygosity of favourable genes, by adopting inbreeding the gene pool could be maintained in the offspring. If the superiority of the parents is due to heterosis i.e., Aa (heterozygous) better than AA or aa (homozygous), it is not possible to control the segregation of genes. So, heterozygous individuals that are superior could be used for market but not for breeding. The environmental part of regression can be levelled out a great deal by keeping the same environment as far as possible from year to year. This is another reason why animals should be tested and selection should be made under conditions similar to one in which their offspring are to perform.

Type of gene action

Genes act differently in different combinations. This makes accurate selection more difficult. For instance, when “A” is dominant to “a”, AA and Aa individuals who have the same phenotype will be selected with equal preference. But AA will breed true whereas Aa will segregate. But in case of over dominance, Aa will produce larger effect than AA / aa. So in heterozygous condition, selection will not produce desired results. Only crossing of appropriate inbred lines will produce the desired effect. Hence the job of the breeder is to increase the frequency of favourable alleles and to discard the less favourable ones.

Correlation of traits

Some characteristics are positively correlated, for example, rate of gain in weight and efficiency of gain in swine. Whereas some others are negatively correlated, for example, milk yield and butter fat percentage in dairy cattle. If the desirable traits are positively correlated selection becomes somewhat easier. If you select for one trait it automatically improves the other trait also. When the traits are negatively correlated, selection for one trait will affect the other trait. Hence, knowledge of correlation of different traits will be of great help in avoiding mistakes in selection.

Effect of inbreeding

It is generally known that a decline in all attributes of vigour usually accompanies inbreeding. Breeders therefore hesitate to practice inbreeding. However, it is necessary to practice inbreeding in order to

induce gene segregation and to fix desirable gene combinations. Inbreeding increases prepotency. Regularity of transmission is increased with increased homozygosity, which is obtained only through inbreeding and selection.

OPERATIONAL COMPLICATIONS

To avoid depressing effects of inbreeding: choose foundation stock that is superior in production, rigid selection from beginning to offset the possible bad effects of inbreeding on performance and flexible system of mating that permits besides close breeding, mating of best individuals that is controlled breeding.

Objectives in selection

Many failures in selection of livestock may be attributed to lack of definite objectives as a result of which selection has changed its direction frequently. Selection will be more effective when the breeder has definite objectives for which to strive. The objectives should be defined by measurements. Judgement should be used along with measurements, but should never replace measurements.

Number of traits

When a single trait is subjected to selection, it is very simple to rank the individuals in order of their merit for the trait. This becomes increasingly difficult as the number of traits is increased. An animal may be good in one trait and deficient in another. Only a few individuals will be good in all the characters that are under selection. To simplify this problem, the number of traits must be kept as small as possible and must be those with greatest value from the stand point of utility.

Foundation stock

Selection will be ineffective if the foundation animals are genetically poor and also where there is no genetic variability. Selection merely sorts genes and permits the better ones to be saved and poorer ones to be discarded. Therefore, it is important to start with good foundation stock.

Level of performance

In available stock, selection will be effective for the first few generations and then it becomes ineffective for further progress. When the level of performance rises after a few years, due to increased homozygosity and frequency of desirable genes, further progress is slow, unless it is accompanied by a system of mating that will bring about new gene combinations. For example, by artificial insemination is used as a tool, for increase in milk production. The improvement will be achieved in few generations and afterwards the progress is slow. Then it does not mean that the sire used is inferior, but the level of performance of the herd has become higher.

System of selection

Too much rigidity in the systems of selection may be a handicap to progress in animal breeding programme. For example, a breeder may specify that no cows should be selected with the lactation yield less than 2000 kg. But only few cows will be available and after few years very few animals will reach

the standard. A selection index giving relative importance to each trait is good. But the importance of the trait at that particular time should be taken into consideration for selecting the trait.

MODULE-10: SELECTION - CLASSIFICATION OF SELECTION

SELECTION

NATURAL SELECTION

Number of animals

Where there are few animals in the herd, selection is very much restricted. Selection pressure will be applied effectively since it will cull most of the animals leaving few that will not be able to replace the stock. Also there will be little opportunity for genetic segregation.

Length of time

The turnover in livestock is slow in number of animals and in number of generations because small herds or flocks offer so little opportunity for genetic segregation. So the breeder must be prepared to continue his project for a relatively longer period of time. Progress in a single generation is apt to be masked by environmental effect and it takes many years to turn over several generations in large animals. Although progress per year is small, real improvement can be effected over a long period of time.

Learning objectives


selection and its classification.

Selection is of two kinds namely, natural and artificial selection. Again the artificial selection is divided into different methods, they are Tandem method, independent culling level and selection index or index selections.

The main force of natural selection is the survival of fittest in a particular environment. The survival is for the particular environment in which the population lives e.g., wild animals. In nature, the animals best adapted to their environment survived and

ARTIFICIAL SELECTION

CULLING

Learning objectives


MODULE-11: BASES OF SELECTION - INDIVIDUAL SELECTION

produced the largest number of offspring. This natural selection acts through the variations produced by mutations and recombination of genetic factors and eliminates unsuccessful genetic combination and allows nature’s successful experiments to multiply.

Natural selection is a very complicated process and many factors determine the proportion of individuals that will reproduce. Those factors are:

o differences in mortality in the population especially early in life,o differences in the duration of sexual activity,o degree of sexual activity ando differences in the degree of fertility of individuals in that population.

Natural selection operates through differences of fertility among the parents or of viability among the progeny. Therefore, in natural selection by means of survival of the fittest, there is a tendency towards elimination of the defective or detrimental genes that have arisen through mutation.

It is the selection practised by man. This can also be defined as the efforts of man to increase the frequency of desirable genes or combination of genes in his herd or flock by locating or saving those individuals with superior performance or that have the ability to produce superior performing offspring when mated with individuals from other lines or breeds. This can be classified as:

automatic selection, deliberate selection and replacement selection and culling. Replacement selection decides which

animals will become parents for the first time i.e., new animals to replace parents that have been culled. These new animals are called replacements.

Culling decides which parents will no longer remain parents. It is the removal of inferior animals rather than the more positive selection of good ones. While doing culling, decision should be firm that culling has been made for genetic or environmental reasons. It is easy to cull poor looking stock but genetically this achieves little if they are poor because of environmental reasons. Thus, selection and culling go together. The risks of this type of error are higher when animals examined after a period of high production such as lactation. E.g. In ewes, twin born will be thin and poor looking and barren ewes will be fatty. Similar observations can be seen in sows. Therefore, replacement selection and culling are really just different sides of the same coin. They involve different sets of animals, but their purposes are the same i.e., to determine which animals reproduce. Hence, both are integral parts of selection as a whole.

TYPE

individual selection and probable breeding value.

SELECTION BASED ON INDIVIDUALITY

An animal may be selected for breeding based on the basis of its own performance one or more traits. This selection based on its own performance is called mass selection or individual selection. Here the selection is based on type (appearance) of the animal and its performance (production). This comparison of performance based on its own individual performance is called performance test. Selection based on individuality is strictly phenotypic and phenotype is taken as the sole estimate of the genotype.

Last modified: Friday, 30 March 2012, 04:52 PM

It is the outward confirmation of individuals i.e. the relative proportion, length, breadth and size of different parts of the body that include colour, size and shape of horns, ears etc.

Selection depend on type is inevitable when

Reliable records of production are not available. Selection is to be made early in life before the availability of production

records in order to reduce the cost of culling. When records are available in only one sex as milk yield, males have to be

selected only as type. When production records come after the death of the individual e.g. Meat animals. Where productivity is not easily and completely measured as in works and speed. When market demands a particular type that is more profitable. Where beauty is the main consideration as in pet and fancy stock.

Production

This needs accurate production records for all animals under selection. But the actual records available are varying when comparable with one another. E.g. In dairy cattle milk production in lactation is significantly correlated with lactation period and age of the cow. Dairy cows gradually increase their yield till 6th or 7th lactation and then decline.

Similarly in sows, they produce more piglets than gilts, do owing to an age effect on fertility. Hence, it is necessary to standardize all the records to a uniform comparable basis. E.g. In cows – milk production should be adjusted to 305 days, 6 years and 4% fat.

Similarly in sows all furrowing records should be adjusted to an equal gilt basis by correction factors. Then only the figures will be comparable. Average of many records will reduce the environmental variations in production. While using record all the available record should be used and not the selected ones. No records should be omitted except when circumstances are so definite that no doubt exists e.g. Foot and mouth disease, abortion etc. A poor setback in health should not be omitted as in itself is an indicator of poor genetic constitution and conducive for high

production. Incomplete record should not be considered. Constitution, longevity, disease resistance, adaptation to climate is the other factors that should be considered in production and selection.

PROBABLE BREEDING VALUE (PBV)

Selection for qualitative traits

Here the animals are kept or rejected for breeding purpose on the basis of its own phenotyp0e for that particular trait. The progress made in selection depends on how closely genotype is correlated with phenotype. Phenotype of the individuals is often used to estimate the breeding value for qualitative traits such as colour and horned or polled conditions. Selection for such traits based on mass or phenotype is more effective than others.

For e.g. In Angus cattle the coat colour Red (rr) is recessive to dominant black (BB) colour. But it is practically difficult to distinguish and differentiate the genotype BB and Bb phenotypically. Thus selection on the basis of individuality will be useful but not always completely accurate.

Selection for quantitative traits

Quantitative traits are controlled by many genes and various environmental factors. There is no sharp distinction among the phenotypes and affected by both additive and non-additive gene action. No trait is 100% heritable, because the environment always affects the phenotype to a certain extent. Therefore phenotype of an individual for quantitative traits is not the true indicator of genotype. The phenotypic merit of the individuals for quantitative traits is determined by comparing the individual’s own phenotype with that of the average of all the individuals within a group from which it is selected and is called trait ratio.

Trait ratio = Individual’s record for a trait / group average for the same trait x 100

Accurate records are also required. The individual’s record is of little value unless it shows where the individual ranked relative to others under similar conditions. The environmental part of phenotypic superiority or inferiority will not be transmitted to the offspring. Therefore in general there is tendency for the average phenotype of the offspring of a phenotypically superior individual will tend to regress toward the average of the population, whereas the average phenotype of the offspring of a phenotypically inferior individuals will tend to rise toward the average of the population.

PBV of an individual for a particular trait may be determined by

PBV = P1 + b (Pi – P1)

Where,

P1 – phenotypic average of individual

contemporaries Pi - phenotypic value of

individuals selected

B – regression coefficient

MODULE-12: BASES OF SELECTION - FAMILY SELECTION

The PBV of an individual is the estimated genetic superiority of the individual over the average of the group from which it is selected. PBV is always near the group average than its phenotypic value because environmental effects which are not transmitted to the individual’s offspring.

In individual selection, best animals are selected from within a group of animals of similar age group that have been reared and treated similarly at the same time i.e. contemporaries. In individual selection the breeder will be having a single record of each animal’s performance (performance test) and hence an estimate of breeding value (BV) for a given trait is calculated as:

BV = h2 x (Individual average – Average of contemporaries)

= h2 x Individual deviation

Hence selection based on individual selection is strictly phenotypic and the phenotype is taken as the sole estimate of individual’s genotype and thus the PBV.

Advantages

Used for traits of high heritability. Traits such as body type, growth rate, fleece production, horn pattern,

colour and others of a similar nature can be evaluated if suitable records are available.

Useful for traits expressed in both sexes and performance of the individual is above average for breeding, regardless of the merit of near relatives.

In the absence of pedigree and progeny records, this is the only available guide for selecting the breeding stock.

Demerits

Not useful for sex limited traits such as milk production, egg production, maternal abilities, semen production and litter size etc.

If heritability is low, then individual selection is the poor indicator of breeding value such as reproductive characters.

Not possible for traits expressed only after sexual maturity, because selection has to be delayed till maturity resulting in waste of time and money.

The easy appraisal of appearance often tempts the breeder to overemphasis this evaluation in selection.

It is concluded that the Individual selection on the basis of individual’s phenotype (appearance) and performance. Individuals are selected solely in accordance with their own phenotypic values. This is the simplest and yields more rapid response. It is the most commonly used method for selective improvement of livestock. Undoubtedly, most of the progress in livestock improvement can be credited to individual selection. Traits such as body type, growth rate, fleece production and other of similar nature can be evaluated directly from the performance of the individual animal, if suitable performance records are being kept; such evaluations are usually available by the time initial selection of breeding stock has to be made. In contrast, only a few can be progeny tested.

Learning objectives

FAMILY SELECTION

PROBABLE BREEDING VALUE


family selection and probable breeding value.

Family names are used in at least two senses in animal breeding. The family name has been traced through the dam and sires. Family, in animal breeding, includes full-sib and half-sib families. In a random mating population, half-sibs have a relationship coefficient of 0.25 and full-sibs have a relationship coefficient of 0.5. Such family members are collaterally related not directly related. They are neither ancestors nor descendants. Because of their common ancestry, they would have some genes in common and thereby some performance in common.

If the records of the individual are included in the family average and used as a criterion for selection, it is known as family selection. If the individuals’ records are not included in arriving at the average, then it is known as sib selection. When selection is carried out for market weight in swine, the market weights of all males and females in the family are considered in the calculation of family average (family selection). But when selection is carried out for fertility traits and milk yield, the performance of males cannot be included but they are selected on the basis of sibs’ average (sib selection).

The family selection can be represented as a part of pedigree selection. The families are ranked and based on this, the entire family is selected or rejected. Family/sib selection is used more frequently in swine and poultry where the number of progenies produced by females is high. The family selection does not increase generation interval. The information from family/sib is combined with individual information in the form of index and selection is based on the index.

Collateral relatives are those not directly related to an individual as ancestors or progeny. The relatives are neither direct ancestors nor direct descendants of an individual. They may individual’s brothers, sisters, cousins, uncles, aunts, nieces, nephews, etc. The more closely they are related to the individual in question, the more valuable information they can supply for selection purposes.

If information on collateral relatives is complete, then it will give an idea of the kinds of genes and combination of genes the individual is likely to possess. It will be of much useful in selecting traits that can be measured only after the sacrifice of the individual e.g. carcass traits. Similarly it is also useful in selecting dairy bulls, since milk production can be measured only in cows though bull possesses and transmits genes for milk production to his progeny. It is also used in selection of poultry for egg and meat production andalso for all or none traits such as mortality, disease resistance and fertility. Selection on the basis of sib tests (Half sibs or Full sibs) means that an individual id kept for breeding or is rejected on the basis of the phenotype of its brothers and sisters. They may be maternal half sibs or paternal half sibs or full sibs.

The accuracy of selection on the basis of collateral relatives depends upon

the degree of heritability, closeness of the relationship ® of the sibs and individual being selected, number of sibs used to determine the sib average, degree of correlation (t) between the phenotypes of sibs.

Accuracy of selection = Rh n / 1 + (n-1) t

If environmental correlation among the phenotypes of the sibs are zero, then t = Rh2

The accuracy of selection increases as the records on a large number of half sibs are considered and as the heritability increases. The accuracy of selection never exceeds 0.5, regardless of the number of half-sibs tested and the degree of heritability of that trait.

Nearly 30 half sibs are required to give the same accuracy as information on the individual’s own record when heritability is as low as 0.10 and 100 or more when heritability is higher than 0.10. The addition of the record of another half sib is affected by the law of diminishing returns. However in instances where information cannot be obtained from the individual, such as sex limited traits can be used effectively in selection.

Full sibs may be used in selection, but they have a similar maternal environment from conception to weaning lowers the accuracy of their use for such a trait. The selection on the basis of individuality is relatively more accurate than selection on the basis of full sib records when the trait is highly heritable. However, when heritability is low, and records on six or more full sibs are available then selection on the basis of full sibs is more accurate.

The combination of records on the individual and its sibs for selection is more advantageous than records on the individual’s own performance when R and t are greatly different. It is more useful when difference between families are mainly due to environment possibly because different families have been treated differently.

Families can be broadly classified into three types:

Sire families: These are progeny of one sire.o Out of different dams – born in the same year (contemporaries)o Out of different dams – born over a number of years

Dam familieso By different sire – born in the same year i.e. by super ovulation

before artificial insemination with mixed semen from number of sires and identification of sires by blood typing

o By different sires – born over a number of years Sire and dam families: These are progeny by one sire out of one dam.

o Family selection is more effective when the genetic relationship between members of the same family is large, and the phenotypic relationship between members is small. When heritability is low, the use of family data is most valuable as it reduces the chances of making wring decisions.

Indications

For sex-limited traits, For carcass traits and For traits of low heritability.

Limitations

If selection intensity is more, then there may be an increase in inbreeding and Increase in cost and space in raising larger population.

MODULE-13: BASES OF SELECTION - PEDIGREE SELECTION

SELECTION BASED ON PEDIGREE

Precautions

Number of progeny in each family should be large and There should not be common environment between sibs.

Learning objectives


pedigree selection, advantage and disadvantages of pedigree selection and its limitations.

Pedigree is a record of an individual’s ancestors related to it through its parents or selection based on the information of the ancestors of individuals that are related to it. Performance records from ancestors can provide useful information about the potential genetic worth or the breeding value of the individuals in question. This will give useful information before the animal is old.

An estimate of calf’s potential milk yield could be assessed based on milk yield of its mother until such time as the calf is grown up and can be milked. Much attention is to be paid to pedigree when no adequate information on the merit of the individual is available.

It is usual to expect offspring of outstanding parents to be of higher genetic value than the average of the individuals of the herd. Each parent transmits only sample halves of its genes to each offspring and only one quarter of genes from each grand parent. So parents never provide as much information about the breeding value of an individual than individual’s performance itself would provide. Unless the performance of ancestor is known, selection based on pedigree is meaningless. Even when the performance is known the relationship between the individual and ancestor is very important. Distant ancestors of an individual provide even less genetic information about the individual’s breeding value especially for production traits. This pedigree can be classified into two as direct and collateral. Collateral means those descended from same ancestors.

Selecting a cow based on the performance of its great grand parent is as good as random selection because the relationship is (1/2)3 = 1/8 i.e. only 1/8th of the superiority can be expected in the progenies. It will not do much good to go beyond three generations into pedigree due to halving process of the chromosomes in each generation.

Pedigree selection can be made more useful by giving all information good and bad about ancestors, including the collateral relatives. Pedigree selection is particularly useful for initial selection for traits that are expressed in only one sex. Such selections can be made early and inexpensively. However the accuracy of ancestor’s performance may not be highly reliable because they have been recorded under different environmental conditions. Rarely the pedigree records possess the presence of recessive genes or defective animals. So when the ancestors are relatives for traits that are linked with lethal genes then chances of

getting offspring with such lethal defects is more and use of such animals should be avoided.

For traits of high heritability little is gained from considering ancestors and the most progress could be made by evaluating the individual itself e.g. horned condition. The

ADVANTAGE AND DISADVANTAGES OF PEDIGREE SELECTION

main danger in pedigree selection is that the harm done by lowering the intensity of individual selection is greater than the good made by making the selection more accurate.Hence pedigree should be used only as a minor ancestry to individual selection. It may be used to tip the balance between two individuals who are very close on individual merits.

The selection based on pedigree is only useful than of individual selection only when heritability is moderate or low. The average relationship between one parent and offspring is 0.5. Therefore when pedigree information on both the parents are available, that gives more reliable estimate of the genotype of the offspring. When the pedigree data provides information on the phenotypic and genotypic merit of the ancestors then it is called performance pedigrees. If the selection differential for the ancestor could be presented in the pedigree or if the performance record of ancestor could be expressed as a percentage of the average contemporaries (Trait ratio), the ancestor’s records would be of greater predictive value.

o Degree of relationship If ancestors are more closely related to the individual (Parent –

0.5, grand parent – 0.25 and great grand parent – 0.125) should receive most emphasis in pedigree appraisal.

o Degree of heritability When heritability of the trait is low, the more remote

ancestors should receive relatively more emphasis, but when it is high they provide almost no new information.

o Environment correlation Pedigree selection is accurate when heritability is high. The

correlation between pedigree information and individual’s breeding value approaches the theoretical 0.71 as heritability approaches 1.0.

o How completely the merit of ancestors used in the prediction is known.

Dangers of pedigree selection

Undue emphasis on remote relatives. Unwarranted favouritism toward the progeny of favoured individual.

Advantages

Pedigrees do have the advantage that they are cheap to use. Used to select traits not expressed early in life or still immature and have

not had their production records e.g. cancer, tumour, longevity etc. Used to select traits expressed in only one sex (sex limited) such as milk

production, egg production, semen production, etc., Useful when selection based on individuality is not accurate i.e. to

supplement selection based on individuality. When production performances of the individuals are not available, For making preliminary selection of sires in progeny testing When the characters are expressed late in life For traits with low heritability pedigree information can be combined with

individual’s record.

LIMITATIONS OF PEDIGREE SELECTION

MODULE-14: BASES OF SELECTION - SIB SELECTION AND PROGENY TESTING

Disadvantage

A disadvantage of the use of the pedigree in selection against a recessive gene is that there are often unintentional and unknown mistakes in pedigrees that may result in condemnation of the entire family from breeding even when actually it may be free of such a defect.

Since phenotype is not surely the true indicator of genotype due to complications by dominance, epistasis and environment prediction of genotype is difficult. When the phenotypic value of an individual is known not much is gained by the use of pedigree,

The sampling nature of inheritance, the genetic makeup of the parents cannot be known definitely of genes that are heterozygous makes it impossible what the individual offspring has got from its parents (Better half or poor half).

Usually pedigree contains ancestors that are selected and hence contains only selected information to show them in a favourable light and tells very little about the collateral relatives.

The pedigree records are made in different environment and hence the accuracy of the ancestry may not be reliable and

Unwanted favouritism towards the progeny of the favoured individual.

An unusually good animal in poor parentage always suggest that it is the result of lucky combinations of genes each manifesting the desirable effects. Mostly the animals will be heterozygous for many genes and its regularity of inheritance is questionable due to sampling nature of inheritance. On the other hand a poor animal from good parentage does not have the good stock of genes. The offspring may not able to express itself fully probably due to lack of few genes necessary for a successful combination. Therefore, it will be able to inherit the good genes and most probably its mate will supplement the few genes it lacks. So it may be preferred to a good individual of poor parentage.

In nutshell, pedigree is a record of an individual’s ancestors related to it through its parents. Knowledge of the productivity of the ancestors is necessary if pedigree is said to be useful. Such pedigrees are known as performance pedigrees. Ancestors more closely related to the individual should receive most emphasis in pedigree appraisal. The basis of pedigree selection is the fact that an individual gets half of its inheritance from each of the parents and it is usual to expect offspring of outstanding parents to be of higher genetic value than the average of the individual in the herd. Pedigree should be used only as additional information to individual selection.

Learning objectives


progeny selection, use of progeny selection

SELECTION BASED ON PROGENY TESTING

USE OF PROGENY TESTING

precautions of progeny selection and advantage and limitations of progeny selection.

The idea of progeny testing is not new, having been advocated 2000 years ago by Roman Varro. Robert Bakewell is reported to have used in the eighteenth century by letting out bulls and rams on an annual basis. Then he could later use those which proved to be outstanding transmitters.

o Individuality tells us what an animal seems to be,o his pedigree tells us what he ought to be,o but the performance of his progeny tells us what he is.”

This progeny testing is used to rate a sire or dam’s breeding value. It attempts to evaluate the genotype of an individual on the basis of its progeny’s performance.

It is the best way of determining the genetic make up of an individual. Each parent contributes sample halves of genes to each offspring. Thus an effort to evaluate an individual (usually a male) on the basis of one or a few offspring can be misleading.

Chance at segregation may result in any one or a few offspring receiving a better or poorer than average sample of genes from the parents. Progeny testing is a technique generally used for males because they are responsible for more progenies in their lifetime than any one female.

Use of progeny test is not a very practical preposition to establish the breeding value of females, since the number of offspring per female is small. When the individual produces sufficiently large number of offspring, the individual has already completed its productive life and the need for selection will be already over.

It is very important that all of the progeny and not just a selected sample of the progeny be included in the progeny test appraisal. Omitting the poor progeny is unfair and misleading because, similar poor progenies are just as likely to be produced among the next group of progeny.

Progeny testing may be used in selection of traits expressed in both traits. When heritability is low, fewer progenies are required to make the progeny test.

However the accuracy of progeny test is reduced when there is an environmental correlation among progenies due to non-genetic factors. This situation arises when several progeny tested sires are being compared, but their progeny had been tested at different locations.

Feeding and management also influences the progeny group differences. These will reduce the accuracy of progeny testing. Progeny testing are conducted to compare the performance of progeny of two or more parents.

Usually sires rather than dams are progeny tested because generally sires produce more progeny in a given season or year.

Use of progeny test depends upon

o Accuracy of the test.o The number of sires to be tested during specified period of time.

For greater accuracy greater numbers of offspring are needed. If more number of offspring has to be produced, then large numbers of females

have to be mated, thereby reducing the number of bulls tested.

PRECAUTIONS FOR PROGENY TESTING

Progeny testing is carried out based on the assumption that most of the inheritance in the livestock is due to additive genetic effects. If there are sizeable dominant and epistatic effects, then the following to be accounted i.e. whether the offspring’s performance is due to additive genetic effects alone or is due to dominant and epistatic effects.

If some offspring of a male mated to certain set of females, perform better than offspring of the same male mated to another set of females. Then a male and female that produce better averages in the offspring will be chosen to exploit dominant and epistatic effects over and above additive effects.

In livestock breeding, progeny test based on more than five unselected offspring usually reduces the chances of error considerably. With traits having very low heritability, large number of offspring (10 or more) has to be used to get a reliable progeny test. The rapid acceptance of artificial insemination and the advancement of techniques for the freezing and storage of bovine semen have greatly extended the use of outstanding progeny tested sires.

Points to be considered

Test as many as sires possible (5 to 10 would be minimal) Make sure that dams are mated to sires at random, within age group is possible. Produce as many progeny per sire as possible (10 to 15 progenies of either

sex for growth traits but up to 300 to 400 progeny is required for traits like calving difficulty and fertility).

No progeny should be culled until the end of the test. Offspring that are being tested are not a select group. Performance of an adequate sample of an animal’s progeny under normal

environmental conditions will give a true indication of its genotype than any knowledge of individuality or pedigree.

Precautions to be taken to make progeny tests more accurate

Dams mated to all sires on a given progeny test should be selected randomly. Feed all animals the same ration and in same manner to avoid bias. Compare different parental groups raised in as nearly the same environment as possible. Compare the parent groups born during the same year or same season of

the year when possible. Include all healthy progeny of a particular parent in the test, if possible

whether they are inferior or superior. This tends to average the Mendelian and environmental errors for each sire group.

Pens should be rotated among progeny groups to reduce the pen effects. Larger the number of progeny tested per parent, within limits, the more

accurate the estimate of that parent’s probable breeding value. Errors like effects of year, season and location should be eliminated as far as possible.

The accuracy of selection that is the correlation of the genotype of the parent with the average genotype of its progeny may be calculated as:

PBV = h / 2 n /1 + (n-1) t

ADVANTAGE AND LIMITATIONS OF PROGENY TESTING

MODULE-15: METHODS OF SELECTION

Where,

h – square root of heritability

n – number of progeny per parent used in the average

t – ¼ h2 if progeny group is composed of half sibs and there is no environmental correlations between sibs.

Testing of progeny at several locations using artificial insemination and adoption of comparison of performance with contemporary animals can increase the accuracy.

Advantages

For selecting sex limited traits. For selecting traits require sacrifice of the animal (carcass traits) For selecting traits expressed late in life For traits having low heritability value. For selection of animals that nick or combine well. For testing animals for recessive traits.

Limitations

More number of animals must be progeny tested. It prolongs the generation interval. Hence it is time consuming and expensive Use of superior animals extensively once they have been located and

errors due to environment that are not standard for the progeny are more serious limitations.

Sires can be selected only when the progenies come for production and by the time the sire may become old and useless. Therefore, the annual rate of genetic gain is lowered.

Hence it is time consuming and expensive

In conclusion, Progeny testing is estimating the breeding value of a sire based on the average performance of its offspring. Each offspring receives a sample half of genes from the sire.Therefore, the performance of large number of daughters will indicate the breeding value of sire on progeny testing. Progeny testing is usually conducted for males as more number of progenies can be produced for males and also proven bulls can be extensively used for production of more number of progenies. The primary selection of the bulls is based on the sibs’ average. The bulls with highest averages are selected and included in the progeny testing. Then the bulls are used on many females to produce many progenies. The performances of progenies are then studied to estimate the breeding value of each bull. It is the best way of determining the genetic makeup of an individual. The genetic principle behind progeny testing is that the more the number of progeny are tested the greater the accuracy of assessment of the parents, since the errors in sampling are reduced.

SIMULTANEOUS BUT INDEPENDENT CULLING METHOD

Breeder selects and improves only one trait at a time until it reaches an acceptable level, and then he shift to another and so on for a third. The efficiency of this method is dependent on the genetic relationships among the traits. If the two traits are favourably or positively correlated, selection for the first trait will also automatically improve the other trait and vice versa.

Here, the trait A was improved quickly in one generation, whereas B took more time (two generations) and C took very much longer (few generations). A remains stable when worked on B, and both A and B remained stable when worked on C. Therefore the traits are assumed to be independent. On the other hand if they are not independent, then the situation could be seen by the dotted lines A’ whereas B went up, A came down i.e. See- saw effect caused by a genetic antagonism between them. The efficiency depends on genetic correlation between traits.

It is easy method. This is a highly inefficient method as unless the traits selected are genetically positively related. If they are not genetically related, whatever achievement is made in the first trait is lost when attention is directed to another trait. Therefore, the rate of net improvement becomes very small. Since a very long period is involved in the selection practiced, the breeder might change his goals too often or become discouraged and not practice selection effectively.

In general, the efficiency of this method is very low. If there is a positive correlation, then the results may be desirable in the other trait also. If there is a negative correlation, the efforts will be undesirable. Since very long time would be involved in selection practice, the breeder may change one goal to another and discourage one trait.

TANDEM METHOD

Learning objectives


tandem method, culling method and selection of index.

SELECTION INDEX OR INDEX SELECTION OR TOTAL SCORE METHOD

In this method, selection may be practiced for two or more traits at a time. But for each trait, a minimum standard (culling level) is set, so that every animal must meet the minimum standards to be selected for the breeding purposes. The failure to meet the minimum standard for any one trait makes the animal to be rejected. Therefore, in actual practice, it is possible to cull some genetically very superior animal when this method is used. The properties selected for each trait will depend up on the total number of animals screened for the breeding.

This method reduces selection intensity of the traits to be selected. The negative correlation among the traits will make the further reduction in selection intensity. Selection based on independent culling method is easy to perform but becomes complicated when more traits are considered and if there is negative correlation between traits. Therefore, only few important traits should be considered in this method.

It is the most effective method of selection. Selection index is a single numerical value within the total scores given for each trait considered in the selection. Each trait is weighted, by giving score and an individual trait score is summed up to the total score for the each animal within the selection criteria. The individual specification for a number of traits can vary greatly and is combined into one value for the animal called a Total score or an Index. The high merit in one trait can certainly be used to compensate the deficiencies in other traits. An index is simply a means of putting a whole lot of different information into one value. The information and the score should be fixed based on

o Variation seen in each trait – the phenotypic standard deviationo Heritability of the traitso Phenotypic and genetic relationships (correlation) between the traitso Relative economic value of the traits

The aim in computing an index is to derive an estimate in which the various traits are approximately weighted to give the best prediction of the animal’s breeding value i.e. what it will produce when the animal breeds. An advantage of this index is suppose if one component is missing then benefit can be obtained by predicting the missing one from the others that are present.

Index selection is predicted to be n times as efficient as independent culling levels where n is the number of traits involved. The greater the number of traits involved, the index becomes more reliable than the independent culling method.

In dairy cattle, milk production is the most important economic trait, whereas the reproductive efficiency that is also important may not be as important in magnitude as milk production. Hence, higher economic value should be given to milk production and correspondingly lower economic value to the reproductive efficiency.

I = b1X1 + b2X2 + b3X3 + + bnXn

Where,

I – Index value or genetic prediction

MODULE-16: RESPONSE TO SELECTION AND FACTORS AFFECTING IT

RESPONSE TO SELECTION

n – Number of traits of information

b1 to bn – coefficients obtained based on the relative importance of heritability of each trait and genetic relationships of the traits concerned.

X1 to Xn – Measurement of each of the traits incorporated (phenotypic values)

The animals are arranged based on index values and those with the highest scores are kept for breeding purposes and the animals with lower index values are eliminated from the breeding population. The net value of an animal is dependent upon several traits that may not be of equal economic value or that may be independent of each other. Hence, it is necessary to select more than one trait at a time. The desired traits will depend upon their economic value.

This method of selection leads to most efficient improvement in livestock breeding. Selection indices are constructed with a view to making maximum improvement in the total performance. All the characters selected are combined into one figure.

Index selection has been more widely used with sheep and swine than in beef and dairy cattle. Large volume of accurate data of population is necessary to provide information to compute the selection index. Indices computed from inadequate or erroneous information can be ineffective in selection. A trait that is highly heritable can be given adequate weightage than one with low heritability.

In conclusion, the selection index is a total score that includes all the advantages and disadvantages of an animal for those traits considered for selection. The amount of weightage given to each trait depends on their relative economic value, heritability of the character and genetic correlation between characters. A trait, which is highly heritable, can be given greater score than a trait, which has a low heritability. The selection index method is the most efficient (best method) among the three (Tandem, Independent culling and Selection Index) methods because it results in better genetic improvement. The index is the best estimate of an animal’s breeding value. The only disadvantage is that the traits vary in importance from time to time and the index built at one time will not be applicable for all times. Hence, it has to be constructed and modified from time to time.

Learning objectives


response to selection, factors affecting genetic gain and selection differential.

The change produced by selection is the change of the population mean in

the offspring. This is called as the response to selection, symbolized by “R”. The response to selection is the difference of mean phenotypic value between the offspring of the selected parents

FACTORS AFFECTING GENETIC GAIN

and the whole of the parental generation before selection. The response to selection is also called as the expected genetic gain, symbolized by G.

R or G = h2 S where,

h2 = heritability

R or G/ year = h2 S / GI

S = selection differential where,

h2 = heritability

S = selection differential

GI = generation interval

The factors affecting the response to selection are heritability, selection differential and generation interval. Maximum gain will result when the selection differential (S) and the heritability (h2) are high and the Generation Interval is low.

Heritability: The genetic gain depends on the h2 of the character in the generation from which the parents are selected and if the h2 is high, the genetic gain will also be more, because the environmental variation will be less.

Selection differential: The average superiority of the selected parents is called as selection differential, symbolized by “S”. It is defined as the difference between the mean phenotypic value of the individuals selected as parents and the mean phenotypic value of all the individuals in the parental generation before selection.

S = (Ps - P) where,

Ps = mean of the selected parents

P = mean of the population

The selection differential may also be expressed in terms of phenotypic standard deviation (standard deviation is the measure of variability) as,

FACTORS AFFECTION SELECTION DIFFERENTIAL

S = i p where

i = intensity of the selection

p = phenotypic standard deviation

The intensity of the selection is also called as selection pressure and it is the mean deviation of the selected individuals in units of standard deviation. The intensity of selection is symbolized by “i”. It depends on the proportion of the individuals selected and it can be determined from the tables of properties of normal distribution.

i = Selection differential / Phenotypic standard deviation

proportions of the animal selected for breeding; smaller the number larger the selection differential,

herd size; larger the herd size, smaller the proportions of animals selected, reproductive rate; in cattle selection differential will be less whereas in

pigs, it will be more because of more litter size and use of artificial insemination and frozen semen increases selection

differential or selection intensity in case of males and in females, super ovulation and embryo transfer increases the selection differential or selection intensity.

The following table gives the percentage of males and females to be selected for breeding to maintain a constant herd size for different species:

Species Percentage of animals to be selected

Females

Males

Dairy cattle

4 - 5 50 - 60

Beef cattle

4 - 5 40 - 50

Sheep 2 - 4 45 - 55

Swine 1 - 2 10 - 15

Chicken 1 - 2 10 - 15

Horse 2 - 4 40 - 50

o Generation interval: It is the time interval between generations and is defined as the average age of the parents when the offspring is born. This varies between species and selection procedure. Management practices for early breeding in

MODULE-17: CLASSIFICATION OF MATING SYSTEMS

SYSTEMS OF BREEDING

females reduces GI and breeding practices like progeny testing increases the GI. The average generation intervals for different species are:

Species Generation Interval (in years)Male

sFemale

sAverag

eDairy cattle

3 - 4 4.5 - 6.0 4 - 5

Beef cattle

3 - 4 4.5 - 6.0 4 - 5

Sheep 2 - 3 4.0 - 4.5 3 - 4Swine 1.5 - 2 1.5 - 2.0 1.5 - 2.0Chicken 1 - 1.5 1 - 1.5 1.0 - 1.5Horse 8 - 12 8 - 12 8 - 12

o Accuracy of selection: The accuracy for selection is directly related to the heritability of the trait. The heritability is high, the selection on phenotype will permit an average estimation of breeding value. If heritability is low, many errors will be made. Increased accuracy in selection can be obtained by comparing the animals in controlled environmental conditions. Correlation may be made for the age of the individual, age of the dam and sex to remove non-genetic variations. The techniques may increase the heritability of the trait by reducing the environmental variation. When the accuracy of selection on individual is low, accuracy can be increased by

using additional measurements for the trait from the same individual, using measurements of correlated traits and using measurements of relatives.

o Selection limit: When the selection is carried out continuously, the response to selection will be more for a few generations, and then it slows down and finally stops. When the response to selection has stopped, the population is said to be at “plateau” or “selection limit”. The main cause for this is fixation of favourable genes. This causes reduction or absence of genetic variation. Therefore further improvement depends on introduction of new genetic variation. The new genetic variation can be introduced by cross breeding, mutation and genetic engineering.

Learning objectives


systems of breeding and mating based on genetic relationship.

There are only two ways in which the breeder can change the genetic properties of the population.

By selection: Choice of individuals to be used as parents. By controlled mating: Controlled mating of selected parents.

Although selection is the most important method for increasing the frequency of desired genes, same genetic control over the population is provided by the mating system. Mating animals which are alike in pedigree or visible characters tend to increase the homozygosity. Mating unlike individuals will increase heterozygosity.

Inbreeding is a system of mating where by the mates are more closely related than the average members of the population.

Grading: is the practice of using registered sires of a given breed on scrub or native females generation after generation.

Crossbreeding is the mating of pure bred animals from two different breeds. Out crossing is the mating of animals of the same breed but with

no traceable relationship for several generations back in the pedigree.

Mating system based on phenotypic resemblance or dissimilarity Mating system based on phenotypic resemblance. This is also known as assortative mating. In this system mates are chosen on the basis of external appearance in a particular character.

Assortative mating: Mating based on phenotypic resemblance or dissimilarity. Positive assortative: Mating of phenotypically similar individuals (i.e

like with like mating).o Eg. Mating biggest with biggest ; Mating smallest with smallest.

Negative assortative matingo Mating between dissimilar individuals.o Breeding best to worst.

Positive assortative mating tends to create more genetic, phenotypic variation than would be found in comparable with random mating population,in the population undergoing the assortative mating (Mating high X high, low X low) tends to spread the distribution away from the centre towards the extreme. So, the phenotypic variation caused by the assortative mating normally considered as draw back.

However increase in genetic variation can be beneficial from the selection point of view. Greater the genetic variation faster the genetic change. Eg. To increase dairy milk yield, mating the high producing cows to bulls with highest predicted performance.

Negative assortative mating or disassortative mating is mating like

with unlike. Best X Worst Tall X Dwarf.

Negative assortative mating tends to decrease the variation. That is intermediate types are produced due to mating of such individuals. It is not good strategy if we want to speed up directional genetic change. It reduces genetic variation, decrease response to selection. Eg. In layers Rooster having high breeding value for egg size mated with hen with small size eggs.

Properties of assortative mating

MATING BASED ON GENETIC RELATIONSHIP

Sewall Wright (1921) studied and formulated same properties

With complete + ve assortative mating complete homozygosity of population is obtained but slowly

Assortative mating based on external resemblance may had a population of genetic composition may different from that reached by inbreeding based on genetic relationship.

Eg. Metric character depend on 2 pair of genes with additive and equal effects, assortative mating lead to 2 extreme types AABB, aabb But close inbreeding leads to AABB, aaBB, Aabb, aabb (4) phenotypes.

Mating based on genetic relationship

Eg. Mating

Brother x Sister

Parent x

Offspring

It takes into account of the relationship of mates. This mating exerts its influence on all the characters simultaneously. The coefficient of relationship between parent and offspring is half. So when mated, the relationship exerts its influence on milk production, age at first calving and other characters.

Mating system can be classified into two major groups.

So far, we have studied how the breeder selects the parents for the next generation. The next step is to decide how to breed them. Systems of breeding do not create new genes. They sort out available genes into new patterns. Success in animal breeding depends on the proportion of favourable genes present in the foundation stock. Genes that are not present in the foundation stock can be found in other populations or strains or breeds and can be introduced through crosses.

Systems of breeding are classified as follows.

Mating system based on genetic relationship is divided into

1. Inbreeding2. Out breeding

Inbreeding is defined as mating of animals more closely related to each other than the average relationship with in the population concerned. Inbreeding includes matings like parent – offspring, brother –sister, eg. Brother, half sister and among cousins and other collateral relatives.

Inbreeding

Inbreeding is classified into two types

1. Close inbreeding2. Line breeding

Out breeding

It is a form breeding where the mates are chosen on the basis of not being related.

1. Out crossing2. Top crossing3. Line crossing4. Grading5. Crossbreeding

MODULE-18: INBREEDING, GENETIC AND PHENOTYPIC EFFECTS OF INBREEDING

INBREEDING

6. Species hybridization

Out crossing: It is usually applies only to matings with in a pure breeds. In two herds or flocks within the same breed or separated for 4 or 5 generations and the sire from one herd or flock is used in the another herd their amounts to out crossing.

Top crossing : This is a system of crossing which is normally used with in pure breeds; It refers to the use of highly inbred male with females of base population or non-inbred population. Top cross in dairy cattle usually refers to the last sire in a pedigree. Top crossing also refers to the continued use of sires to different families with in a breed.

Line crossing : It usually refers to crossing of inbred lines within a specific breed. It takes advantage of both increased homozygosity with in a line and difference between lines.

Grading: It is the continuous use of sire of one pure breed starting with foundation of which were of another breed or non descriptive animals.

Cross breeding: It is the mating of two individuals from different breeds. Breeds represent tremendous resources of varying genetic material

Species hybridisation: By crossing of two different species is called species hybridization. The mule is a good example of a commercially important species hybrid. Mare x Jackal ass = Mule.

Learning objectives


inbreeding, genetic and phenotypic effects of inbreeding, prepotency.

Inbreeding is the mating between animals, which are more closely, related each other than the average relationship between all individuals in a population or inbreeding is mating between animals related by ancestors. When the animals are considered as closely related when they have one or more common ancestors in common, in the first 4 to 6 generations of their pedigree. Example: Sire-daughter, Son-daughter or Brother-sister. In general, inbreeding refers to close breeding. Inbreeding is classified into two types

Close Inbreeding: Such as mating between sibs or between parents and progeny in order to achieve inbred lines with relatively high degree of homogenisity. In most of the time we use full sib mating method. The same effect can be achieved by consistently back crossing the progeny to the younger parents. Half sib mating is much slower, rich in homozygosity but it is also less risky.

Line breeding: It is a system of mating in which the relationships of an individual or individuals are kept as close as possible to some ancestor. In general line breeding is a milder form of inbreeding. As a general rule sire is

not mated to its daughters but half sib matings are made among the offspring of the particular sire. Line breeding was used extensively in the past in development of British breeds of cattle such as Angus, Hereford

GENETIC EFFECTS OF INBREEDING

PHENOTYPIC EFFECTS OF INBREEDING

PREPOTENCY

and Shorthorn. The following points should be remembered while practicing line breeding,

o Line breeding should be practiced in purebred population of high degree of excellence, after identifying outstanding individuals.

o Line breeding is probably most useful when an out standing sire is dead or not available for breeding purpose.

o To form new breeds, line breeding can be advocated.

Disadvantage of line breeding

Line breeding tends to make gene good or bad, homozygous rapidly. Hence choosing of a ancestor (sire) to line breed is very important. Those that are definitely superior should alone be selected. Beside rigid selection, culling of undesirable recessive is highly essential. Line breeding should be practised only in herds distinctly superior to the general average of the breed.

Inbreeding makes more pairs of genes in the population homozygous irrespective of the type of gene action involved. The consequences of homozygosity are:

Inbreeding does not increased the number of recessive alleles in a population; but merely brings to light through increased homozygosity.

Inbreeding fixes characters in an inbred population through increased homozygosity whether the effects are favorable or unfavorable.

As a result of homozygosity, the offsprings of inbred parents are more likely to receive the same genes from their parents than of offspring of non-inbred parents. This is another way of saying that inbred parents are more likely to be pre-potent than non- inbred parents.

If overdominance exists (Aa is superior than AA or aa), inbreeding decreases the overdominance by changing the Aa genotype to AA and aa.

When the animals are homozygous for a no. of traits, the regularity of inheritance is assured (i.e it fixes the characteristics). Inbreeding reduces vigour is called inbreeding depression. Increased inbreeding results in

Reduced fertility, Reduced mothering ability, Reduced viability and growth rate Inbreeding if accompanied by selection may increase the phenotypic uniformity.

Prepotency is the ability of the individual to stamp its characteristic on its offspring to such an extent that they resemble their parents more closely than in usual. It is the property of the characteristic and not the individual breed or sex. When two individuals are mated one may have

more influence than the other on offspring.

Similarly some lines and breeds are more pre-potent than others. However prepotency can’t be passed on from one generation to another unless it is possessed by both sires and dams.

A high degree of homozygosity and possession of a high per cent of dominant genes are the inherent qualities that will enable an animal to stamp its own characteristic on majority of its offspring. A perfectly homozygous animals produce only one kind of gametes and all the offspring will receive exactly the same gene from each. Any genetic difference between the offspring would depend entirely on the halving process and on number of different genes received from the other parent. If the parent is homozygous for several dominant gene all the offspring will resemble it irrespective of what they received from other parent. Here prepotency is the maximum.

Measure of prepotency

In breeding and increasing of homozygosity is the only means of mating animals prepotent for characteristics. The more the animals are inbred the more they become homozygous for a number of genes. The inbreeding coefficient then is the best estimation of animal’s prepotency. Prepotency however is not transmissible from parent to offspring.

Development of Strain

A strain could be defined as a group of birds or animals which have been closed for outside breeding and the herd or flock has been randomly mated with intense selection for a particular trait or traits for 5 generations and give a name. The description of the strain should always followed by a economic trait. This is considerably milder form of inbreeding in which strain forms. When the population of animals closed for outside breeding, the population becomes closed flock. Estimate the genetic parameters, once the average performance of the closed flock are known, rigid selection is followed to improve particular trait in subsequent generations. The selected strain should have superior breeding quality. In breeding point of view are more or less isolated from each other. Since the populations are close from the entry of new animals, homozygosity increases as a result of small population size. The superior strain formed within the breed could cross among them for exploiting heterosis or hybrid vigour.

Development of Line

The line can be defined as a collection of animals, as a result of inbreeding or more closely related to each other than the individuals in the strain. The line should be always qualified by inbreeding coefficient. From the strain, the birds are chosen at random. Full sib or half sib matings are taken for successive generations. The progeny has a co-efficient of inbreeding for excess of 50%. Then perform selection among the population and fix a particular trait in that line which is homozygous for a particular trait.

Uses of Inbreeding

In spite of certain obvious disadvantages of inbreeding, there are certain instances where it may be used as advantage of livestock production.

The most practical use of inbreeding is to develop strains and lines that can be used for crossing purposes to exploit heterosis.

Inbreeding may be used to determine the actual genetic worth of an individual, is done by mating to a sire with 25 to 35 daughters before it is used extensively in AI programme.

Inbreeding could be used as a practical way to select against the recessive genes of economic importance. Such inbreeding brings out the hidden recessive genes both recessive homozygous and heterozygous parents can be identified and culled.

Inbreeding may be used to form distinct families with in a breed especially the selection is practiced along with it.

To maintain genetic purity and thereby to increase prepotency To eliminate undesirable recessives. When a sire is mated to 20 of its

daughters and does not produce any recessive characters in the offspring, it may concluded that the sire is not heterozygous for recessive characters.

To develop inbred lines. To regroup the genetic material To produce uniform progeny To determine the type of gene action. If inbreeding effects are large, the

type of gene action is non – additive: if inbreeding effects are small , then the type of action is additive.

Disadvantages of Inbreeding

Undesirable traits appear with increasing frequency as intensity of inbreeding increases (lethal and sub lethal).

Growth rates in farm animals reduced by inbreeding. Inbreeding reduces the reproductive efficiency. Reduced vigour lower vitality due to inbreeding depression

Inbreeding depression

The most striking observed consequence of inbreeding is the inbreeding depression. It is the reduction in the mean phenotypic value shown by characters connected with reproductive capacity or physiological efficiency. In general inbreeding tends to reduce the fitness. Thus, characters that form an important component of fitness, such as litter size show reduction on inbreeding. Whereas characters that are not closely related with fitness show little or no change. Inbreeding depression for a single locus can be expressed as follows.

MF = Mo - 2dpqF and for all loci concerned

it is, MF = Mo - 2 F pqd

Where,

Mo - Mean value of a population for a particular character before inbreeding.

MODULE-19: MEASURES OF INBREEDING

MEASUREMENT OF COEFFICIENT OF RELATIONSHIP

MF - Mean value of the population for a particular character after inbreeding.

F - Inbreeding co.efficient

d - dominance, i.e heterozygote does not have a value average to that of

homozygote p - Frequency of one allele

q - Frequency of other allele

Therefore, inbreeding depression is – 2F pqd which depends on dominance (d), inbreeding coefficient (F) and relative frequencies of alleles (p & q). Genes are at intermediate frequency at the beginning of breeding show highest depression. Economic traits like reproductive viability, milk yield and growth rate show inbreeding depression. Characters like fat % and back fat thickness do not show much inbreeding depression.

Inbreeding is to be practised only when

the herd is better than the average. I.e when the frequency of desirable genes are more

the herd has an outstanding sire the breeder knows the merits and demerits of inbreeding the herd is not maintained for commercial purpose.

Learning objectives


measurement of coefficient of relationship, inbreeding depression and coefficient of inbreeding.

The relationship between two animals is expressed as coefficient of relationship, symbolised by “R “. It measures the probable portion of genes that are the same for two individuals due to their common ancestors, over and above the base population.

Relationship may be two kinds.

1. Direct2. Collateral

Direct relationship: You are directly related to your father or mother. You and your father have 505 common genes and you and your mother have 505 common genes.

EXAMPLES

Collateral relationship: You and your cousin’s are collateral relatives because you both have some common ancestors.

You and your cousin have the same grand parents C and D. The important step in measurement of relationship is the number of generations between the animals studied and that common ancestor.

The formula for relationship between individual X and Y is

Rxy =∑ [(1/2) n+n’ ]

Where

∑ = summation

½ = Halving of inheritance in each generation

n = No. of generations between X and the common ancestor or the no. of times the halving process has undergone between X and common ancestor

n’ = No. of generations between Y and the common ancestor or the no. of times the halving process has undergone between Y and common ancestor.

1.Relationship between son and father

Rxy = [(1/2)n+n’ ]

= [(1/2)1+0 ] = ½ or 50%

There is one generation between son and father and genetic material is halved once. There is no generation beyond father and hence n’ is zero.

2.Relationship between son and grand father

Rxy = [(1/2)2+0 ]

= ½2 =1/4 or 25%

There are two generations between son or (X) and grand father © and n=2. There is no generation beyond C and n’ = 0.

3.Relationship between brother / sister / brother and sister

First find the no. of common ancestors. In this example there are two common ancestors, A and B.

Relationship

through A Rxy =

[(1/2)1+1 ]

= ½2 =1/4 or 25%

Relationship

through B Rxy =

[(1/2)1+1 ]

= ½2 =1/4 or 25%

sum of relationship = ½ or 50%

4. Relationship between first cousin

Relationship

through C Rxy =

[(1/2)2+2 ]=1/16 or 6.25

Relationship

through D Rxy =

[(1/2)2+2 ]=1/16 or 6.25

sum of relationship = 1/8 or 12.50%

5.Relationship between half first cousin

Relationship through C

only Rxy = [(1/2)2+2 ]=1/16

or 6.25

6. Relationship between double first cousins

INBREEDING DEPRESSION

COEFFICIENT OF INBREEDING

Relationship through C = [(1/2)2+2 ]=1/16 = 6.25% Relationship through D = [(1/2)2+2 ]=1/16 = 6.25% Relationship through I = [(1/2)2+2 ]=1/16 = 6.25% Relationship through J = [(1/2)2+2 ]=1/16 =

6.25% Sum of relationship = 25.00%

Direct and collateral relationship simultaneously

A degree in the performance of inbred mostly in traits like fertility, survivability and reduction in overall performance noticed in inbred is called inbreeding depression. It is a manifestation of poor gene combination value, which is direct result of increase homozygosity. Decline in performance of inbred over the mean of their parents is also called inbreeding depression. Decline is more pronounced in traits which are close to reproduction or fitness.

Eg. Reduction in growth rate, reduced No. of ova, increase in early embryonic mortality, increase in mortality.

Inbreeding increases homozygosity and decreases heterozygosity. The average percentage increase in homozygosity or decrease in heterozygosity in an inbred animal in relation to an average animal of the same breed or population is known as coefficient of inbreeding symbolised by ‘F’. It ranges from 0 to 100.

The degree of inbreeding inb any individual may be calculated by using the formula Wright 1921.

Fx = [(1/2)n1+n2+1 (1+FA)]

Where,

Fx = Coefficient of inbreeding of X.

= Summation

n1 = No. of generation from the sire of X back to the same

common ancestor n2 = No. of generation from the dam of X

back to the same common ancestor FA = Coefficient of

inbreeding of the common ancestor

When common ancestor is not inbred then

Fx = [(1/2)n1+n2+1]

To calculate the inbreeding coefficient the pedigree should be known. The pedigree can be represented in two ways.

Bracket form Path diagram (Arrow diagram)

In the arrow style, each common ancestor is included only once, with lines drawn to each of his or her offspring in the pedigree. These lines represent the paths of inheritance by which genes are transmitted.

To calculate the Fx

Convert the bracket form of pedigree to path diagram Draw arrows from parents to offspring Besure that each individual appears only once in the path diagram

Full sib mating (Brother X Sister)

Common ancestor n1 n2 contribution C 1 1 (1/2 )1+1+1 =( ½)3 = 12.5 % D 1 1 (1/2 )1+1+1 =( ½)3 = 12.5 % Sum = 25.0 %

Half – sib mating

1

Common ancestor n1 n2 contribution D 1 1 (1/2 )1+1+1 =( ½)3 = 12.5 % Fx = 12.5 %

Parent offspring mating Father X Daughter, Mother X Son

Common ancestor n1 n2 contribution Common ancestor n1 n2 contribution A 0 1 (1/2 )0+1+1 =( ½)2 = ¼ = 25 %

The coefficient of inbreeding ( Fx = 25 or 12.5 or 25 % in the egs) means that the animal “X” is 25 % or 12.5 % or 25 % less heterozygous than the animals in the herd.

Let us see an example with an inbred common

ancesstor. Common ancestor are

B as sire of X and I B as sire of X and J E as dam of B and J F as dam of D and E

B ais the only common ancestor which is already

inbred. FB = (1/2) 1+1+! = (1/2)3 = 0.125 or

12.5%

By using formula

Fx = [(1/2)n +n +1 (1+FA)]

The coefficient of inbreeding Fx can be calculated as follows

MODULE-20: OUTBREEDING, GENETIC AND PHENOTYPIC EFFECTS OF OUTBREEDING

OUT BREEDING

Out crossing usually applies only to mating within a pure breed. If two lines or flocks within the same breed are separated for four or five generations and the sire from one

OUT CROSSING

Learning objectives


out breeding out crossing top crossing line crossing back crossing grading/gradingup cross breeding and species hybridisation.

Out breeding is the mating of animals which are less closely related to each other than the average of the population. Its general effects are the opposite of those of inbreeding. Out breeding increases the heterozygosity of the individual. The maximum practical usefulness of out breeding systems is the production of animals for market. Out breeding systems are broadly classified as follows:

1. Out crossing2. Top crossing3. Line crossing4. Grading5. Crossbreeding6. Species hybridization

LINE CROSSING

BACK CROSSING

GRADING / GRADINGUP

This is a system of crossing which is normally used within pure breeds. Top crossing refers to the use of highly inbred males to the females of the base population or non- inbred population. Top cross usually refers to the best sire in a pedigree. Top crossing also refers to the continued use of sires to different families within a pure bred, same breed or different breed.

Line crossing usually refers to crossing of inbred lines within a specific breed. Line crossing takes advantage of both increased homozygosity within a line and the difference between lines.

Line crossing is mainly done to exploit heterosis or hybrid vigour.

It is the mating of a cross bred animal back to one of the pure parent races, which were used to produce it. It is commonly used in genetic studies, but not widely used by breeders. When one of the parents possess all or most of the recessive traits, the back cross permits a surer analysis of the genetic situation than the F2 does.

A heterozygous individual of F1 when crossed with a homozygous recessive parent the offspring group themselves into a phenotypic ratio of 1:1. On the other hand if theF1individual is crossed with the homozygous dominant parent then all the offspring will be phenotypically alike.

Grading up is the continual use of sires of one pure breed starting with foundation females which were of another breed or no particular breed at all (Non-descript or Mongrel). Marked improvement in crosses if sires from a particular breed (A) are repeatedly back crossed to another breed / non-descript animals (B). Five generations

TOP CROSSING

herd is used in another herd that amounts to out crossing. The use of out crossing in purebreds are

When there is lack of selection response due to reduced genetic variability.

To reduce inbreeding in a closed population. To introduce new genes with reference - colour, horn type, etc.

are sufficient to raise the level of inheritance of breed A to 96.9% (0.969) in the fifth generation. After five generations of repeated back crossing to a particular breed, the animals after the end of fifth generation become eligible to be registered as purebred.

Generation Level of pure bred blood of sire used %

Foundation stock

0

First generation 50Second generation

75

Third generation 87.5Fourth generation

93.75

Fifh generation 96.875Sixth generation 98.4375Seventh generation

99.23875

CROSS BREEDING

Cross breeding is mating of two individuals from different breeds. Breed represents tremendous resources of varying genetic material. Cross breeding is done. Cross breeding is done to exploit hybrid vigor or heterosis and to sell the crossbred to market. Every time, the parental breeds have to be crossed for producing market animal.

Crossbreeding has been used in recent years to establish a broad genetic base in the development of new breeds or synthetics: one or two crosses between the two or more populations are made in order to produce a single population of animals containing genes from each of the population involved. Once a synthetic has been formed then the main aim is to improve it as rapidly as possible by selection within it. For example: Santa Gertrudis, The Jamaica Hope, the Norwegian Red and White, the Australian Milking Zebu, Hissardale, Karan Swiss, Sunandhini, Taylor breed. The main guidelines to be followed in crossing to produce a synthetic are:

o Ensure that the animals used in the original crossings have been intensely selected in terms of relevant characters; it is of no use starting a synthetic with inferior animals.

o Maximise variance in breeding values amongst the foundation animals in the synthetics using as many unrelated animals as possible from each of the contributing populations.

SPECIES HYBRIDISATION

Hybrids can occur where the species are closely related for the egg and sperm to result in a viable embryo. Where the two species are very closely related, the hybrids may even been partially or fully fertile. Some hybrids are bred for curiosity or public display, others are bred by researchers involved in genetic researcher and a few occur naturally. Chimeras are not the same as hybrids. Hybrids have intermediate features and each cell is a mix of chromosomes from the parental species. Chimeras are a mix of genetically different cells to form a mosaic animal.

Crossing the species boundary

Speciation (one species evolving into two) is usually a slow process. It is generally accepted that different species usually cannot mate and reproduce - this is called "reproductive isolation". The exception was closely related species which can produce hybrids, although those hybrids have reduced fertility.

Sometimes, one species can split into two through behavioural isolation. Some individuals develop behaviour patterns which limit their choice of mates e.g. they might be attracted to certain colours or might be active at different times of day. Though they are fully capable of interbreeding with the other group, their different behaviours keep them apart. If their habitat became permanently overcast, those behaviour barriers would break down and they would interbreed freely; their hybrids might become new species.

Another way reproductive isolation occurs is when fragments of DNA accidentally jump from one chromosome to another in an individual i.e., chromosomal translocation. The mutant individuals cannot reproduce except with other mutant individuals - not much good unless the individual has mutant siblings to mate with! There are also "master genes" which govern general body plan (Hox genes) and those which switch other genes on and off. A small mutation to a master gene can mean a sudden big change to the individuals that inherit that mutation. Sometimes, those radical mutations can "undo" generations of evolution so that two unrelated species can mate with each other and produce fertile young (only seen in micro-organisms).

In mammals, hybrid White-Tail/Mule Deer don't inherit either parent's escape strategy (White Deer dash. Mule Deer bound) and are easier prey than the pure-bred parents. Another example is seen in Galapagos Finches. Healthy Galapagos Finch hybrids are relatively common, but their beaks are intermediate in shape and less efficient feeding tools than the specialised beaks of the parental species so they lose out in the competition for food.

Mechanisms for keeping species separate

Physical separation: the species live in different geographic locations or occupy different ecological niches in the same location and so never have the chance to meet each other.Temporal isolation: the species that mate during different seasons or different time of day and cannot breed together.

Behavioral isolation: members of different species may meet each other, but do not mate because neither performs the correct mating ritual. Imprinting by fostering the young of one species on a female of the other species can overcome this in some cases.

Mechanical isolation: copulation may be impossible because of

incompatible size and shape of the reproductive organs. Morphological isolation: copulation may be impossible because of the

difference in body size or shape.

Gametic isolation: the sperm and egg may not fuse and hence fertilization cannot occur; if it does occur then the embryo fails to get past the first few cell division.

Haldan's rule

Haldane's Rule states that in animal species whose gender is determined by sex chromosomes, when in the first cross offspring of two different animal species, one of the sexes is absent, rare or sterile, that sex is the heterogametic sex. The "heterogametic sex" is the one with two different sex chromosomes (e.g. X and Y); usually the male. The "homogametic sex" has two copies of one type of sex chromosome (e.g. X and X) and is usually the female.

Haldane's Rule for Hybrid Sterility states that a race of animals could diverge enough to be considered separate species, but could still mate to produce healthy hybrid offspring in a normal ratio of males and females. If any of the hybrid offspring were sterile, the sterile offspring would be the heterogametic offspring (males). If the heterogametic offspring was fertile, it produced the normal 50:50 ratio of X and Y sperm.

Haldane's Rule for Hybrid Inviability states that if the divergence between the species became large enough to generate genic differences, but not to prevent mating, then parental gene products may fail to co-operate during development of the embryo, resulting in hybrid inviability (the hybrids are aborted, stillborn or don't survive to maturity). In this case, the male to female ratio of hybrid offspring is skewed with more homogametic offspring while the heterogametic offspring (males) are absent or rare.

By crossing two different species, sometimes we get good individuals. The mule is a good example of a commercially important species hybrid. Mare x Jackal ass = Mule, She ass x stallion – Hinny. Male Mules are always sterile as for as it yet known. A few cases of fertile mare mule have however reported, but they are very rare. Hinny is generally inferior to Mule as a worth animals. Hinny is also sterile. Horse having 32 pairs and Ass 31 pairs. Mules comes to possess 63 chromosomes in all. The mare mules have given birth to mule foal and horse foal when bred to Jack and stallion respectively. The inference is that the mare follicles occassionally produce an egg containing nothing but horse chromosomes, and all of the Ass chromosomes have been extruded in the polar body. The fertile mare mules essentially function as mare as far as the genetics of the egg is concerned. If all the horse chromosome where extruded in the polar body the Mules will function genetically as assess. But no case of this sort has been reported.Pure breeding of Mules as such also theoretically impossible.

European cattle and American Bison when crossed produce sterile Males and Fertile females. By Back crossing the females to Bison and Cattle attempts are being made to form a new breed of cattle called cattallo.

Male Jackals only mate with domestic bitches if the Jackal pups are raised by a domestic bitch (to become imprinted on dogs). There is a psychological barrier, but the offspring are fertile (pre-zygotic barrier, but no post-zygotic barrier).

Lions and Tigers must overcome behavioural (courtship) barriers, but produce fertile female offspring and sterile male offspring (pre-zygotic and post-zygotic barriers). Lions and leopards have some physical barriers

(size), but these are overcome if the lioness lies on her side to let the leopard mount her; the male Leopons are sterile, though female offspring are fertile (pre-zygotic and post-zygotic barriers). In these cases, pre- zygotic barriers are overcome by rearing the two species together (in whales and dolphins this occurs naturally).

Some cases seem to need additional rules! In Beefalo, Domestic cows may have an immune response against Bison/Cow hybrid calves - this is a physiological barrier, but does not prevent conception. Bison cows don't have this immune response against hybrid calves and hybrid Beefalo males can be fertile. In some hybrids of domestic cats with small wildcats, a proportion of hybrid males are claimed to be partially fertile (incomplete post-zygotic barrier?) and though the hybrid females are fertile they may not successfully raise their young - a psychological barrier, but one which does not prevent mating/conception.

By crossing the two different species, sometimes good, visible individuals are produced. The mule is a good example of species hybridisation.

Several other species hybrids have been produced. Some of them are

bridsny

Sire

StallionJennet

Dam

RemarksIt is inferior to mule as a work animal and is

also sterileroid

Zebra

Horse

Popular in tropics – docile – better disease and heat resistance

talo Cattl

eBison

Bison is known as American buffalo. Males are sterile and females are fedomestic bull/Bison cow crossings have a lower infant mortality rate (co systems can reject hybrid calves)

falo America

nDomestic Cattle

Beefalo have been back-crossed to Bison and to domestic cattle; some of

Bison resemble pied Bison with smooth coats and a maned hump. The aim is t

high protein, low fat and low cholesterol beef on animals which have "les and more rump". Although Bison bull/domestic cow crossings are more

n niu

Cattle

Yak

Found in Tibet.

p

GoatSheep

Sheep and goat are not so closely related. When crosses are made betwee

fertilization sometimes takes place. However the embroys die before par and are resorbed or aborted.

ron Domesti

cWisent (European

Zubron was considered as a possible replacement for domestic cattle as t

cattle

Bison, Bison

durable and resistant to many cattle diseases. They also thrived on poor

bonasus). harsh weather and with minimal husbandry. First generation Zubron ma

infertile and cannot be used for breeding, but the females are fertile and bred back (back-crossed) to either Wisent or to domestic bulls. Males fro back-crosses are fertile.

alo Biso

nDomestic Tibetan

In Nepal, Yak/Cow hybrids are bred using Yak bulls on domestic cows or

(American

Yak

often, domestic bulls on Yak cows. The Yak-Cow females are fertile, the

"Buffalo") sterile and the meat is considered superior to beef. In Nepalese, the hybr

a Khainag or Dzo (male)/Dzomo (female). A Dzomo crossed with either bull or yak bull results in an Ortoom (three-quarter-bred) and an Ortoom with a domestic bull or yak bull results in a Usanguzee (one eighth bred)

p Goat embryo

Sheep embryo

Although often cited as a hybrid, the famous "Geep" is not a true goat/shhybrid, but was a laboratory experiment which fused a sheep embryo wit embryo (a type of animal called a chimera). The geep is a mosaic of mism goat and sheep parts; the parts which grew from the sheep embryo are w while those which grew from the goat embryo are hairy. Each set of cells

own species identity instead of being intermediate in type. It could be fer will produce either goats or sheep depending on whether its reproductiv grew from the goat embryo or from the sheep embryo.aLlama is a hybridAgeResemble early domestic pigs

Tamworth pigsAmerican wild hogsLlamaCamel

MODULE-21: CROSS BREEDING - METHODS OF CROSS BREEDING

CROSS BREEDING

METHODS OF CROSS BREEDING

Learning objectives


cross breeding and methods of cross breeding.

Cross breeding is mating of two individuals from different breeds. Various breeds represent tremendous resources of varying genetic material. Cross breeding is done for any one of the following reasons.

o Complimentarity of different breeds.o Cross breeding is done to exploit hybrid vigor or heterosis.o Every time, the parental breeds have to be crossed.

Wide genetic base for producing synthetics.

Single two way cross or Single cross (Click here to view the animation...)

Two different breeds are crossed with each other to produce an F1 which is useful for production purposes and not for breeding.

Breed A and Breed B : Straight

bred F1 progeny AB :

Crossbred

Three way crosses (A,B, C) (Click here to view the animation...)

The first generation crossbred females are crossed with females of the third breed, then using the hybrid vigor of dam.

Double cross or Four way cross (Click here to view the animation...)

There are four breeds are involved in this type of crossbreeding programme. First two breeds are crossed to get F1 and second two breeds are crossed for getting another F1 the both F1s are crossed to produce F2 which having 25% of genes each from four different breeds, so all the different characters are combines well. By inter- se mating the selected characters are fixed in the four way cross

Systematic cross breeding

Back cross (AB)o Usually the F1 females are back crossed to one of the parent

breeds. In this cross, the maternal heterosis is exploited.

Criss crossing (Reciprocal back crossing)o Breeds A and B are crossed to produce F1 generation, then

F1(AB) females are back crossed to B and F1 (AB) males back crossed to breed A and so on.

MODULE-22: HETEROSIS - GENETIC BASIS OF HETEROSIS

HETEROSIS OR HYBRID VIGOUR

Three way rotational cross

Commercially used in pig industry. Breeds A, B, C are crossed in tradition.

Three way rotational crossing maintain a high degree of heterozygosity. For three way rotation, frozen semen/sire can be used without maintaining purebred population.

Learning objectives


heterosis, breeding for heterosis and causes of heterosis.

Crosses of animals from different strains or lines of the same breed, from different breeds or from different species, result in offspring whose level of production is above that of the average of the parents. The increased production may be due to increased fertility, increased pre and post natal viability, faster and more efficient growth, improved mothering ability etc. The increased level of performance as compared to the average of the parents is known as heterosis or hybrid vigour. The heterosis can be either positive or negative. Heterosis is the phenomenon in which progeny of crosses between inbred lines or purebred populations exceed the average of the two parental populations.

It is just the opposite of inbreeding

depression. Heterosis can be measured

by using the formula

Heterosis (H) = [ (Mean of F1 offspring) - (Mean of parents) /Mean of Parents ] x 100

Example: The mean litter size at weaning

in pigs Breed A = 7.0

Breed B = 8.0 Mean of A & B

= 7.5 F1 offspring = 8.5

Heterosis = (8.5 - 7.5) / 7.5 = 1.0/7.5

= 0.13333

= 13.33%

Various types of heterosis are recognised in breeding.

Parental heterosis (maternal and paternal) Individual heterosis referring to the non-parental performance. Heterosis is due to non-additive gene action.

Genetic basis of heterosis

The theories put forward to explain heterosis are

Dominance Theory : It postulates that the parental lines are homozygous dominant for different loci – when crossed produces progeny with dominant gene at all loci.

Overdominance Theory : It postulates that the heterozygote is superior to either homozygotes (parents).

Epistasis Theory : It postulates that gene interactions are responsible.

But in practice the heterosis is due to combination of dominance, overdominance and epistasis in any proportion. However, the contribution of epistasis to heterosis is negligible in crossbred of domestic animals.

Generally all the quantitative characters are governed by many genes and no animal is likely to carry all of them in homozygous dominant state. In living organisms, dominant genes are more often favourable than the recessive genes. Crossing of two different lines or breeds has a greater chance of contributing different dominant genes to the progeny.

Since the offspring carries more dominant genes than the parents, it will be more vigourous or productive. All the recessives (aa bb dd ee) except ‘cc’ are masked by the dominant alleles. The degree of heterosis depends on the no. of dominant genes present in the crossbred individual. Maximum heterosis could be obtained if animals carrying all desirable homozygous dominant genes are used for crossing. It would never be possible to have such animals. Eg. Two animals

BREEDING FOR HETEROSIS

CAUSES OF HETEROSIS

MODULE-23: SYSTEMS OF UTILIZATION OF HETEROSIS

heterozygous for ‘n’ pairs of genes can produce 3ⁿ types of offspring. If only seven pairs of genes are heterozygous, 37 or 2187 types of offspring. If 10 pairs of genes are heterozygous, 310 or 59049 types of offspring are possible.

As the quantitative traits are polygenic in nature and the animals produce only a few offspring, it is not possible to produce animals with perfect combination even after many generations of selection. The chance is further reduced by other genetic factors like undesirable recessives, linkage between desirable and undesirable genes and by non-genetic factors like environment.

Formulae HF1 = dy2 and HF2 = 1/2 dy2

To exploit heterosis, lines or breeds with good nicking ability or combining ability are crossed. The combining ability can be determined only by test crosses. A breeder attempting to produce lines which will combine well with each other has to produce large no. of lines. Then he can test them in crosses and find those which give best results. This idea is expensive, time consuming and uncertain. As a general rule the lines or breeds totally unrelated give better heterosis in crosses.

There are two types of combining ability

General combining ability (GCA) is the mean performance of F1 expressed as a deviation from the mean of all crosses and it is due to additive genetic variance.

Specific combining ability (SCA) is the superiority of a particular cross over the average GCA of the two lines and it is due to non-additive genetic variance.

Difference in gene frequency between two population for several generations. Dominance, overdominance and epistasis.

Complementarity is the second reason for cross breeding. This refers to the additional profitability obtained from crossing two populations resulting not from heterosis but from the manner in which two or more characters complement each other. E.g. Crossing Angus carcass quality with Zebu Brahman (adaptability).

Complementarity is not heterosis. Complementarity is due to additive gene action. If there is complementarity, the crossbred progeny are in midway between these two breeds. Traits which show heterosis would rank above the average of parental breeds in the crossbred progeny and often would be superior to either.

Learning objectives

SYSTEMS OF UTILIZATION OF HETEROSIS

GENETIC BASIS OF HETEROSIS


systems of utilization of heterosis and genetic basis of heterosis.

Heterosis is a phenomenon in which the crosses of unrelated individuals often result in progeny with increased vigour, much above their parents.

The progeny may be from the crossing of strains, varieties or species. Hybrid vigour includes hardiness, greater viability, faster growth rate,

greater milk producing ability, fertility etc. One of the best-known examples for hybrid vigour is MULE, which is

proven for hard work in extreme climatic conditions.

Heterosis is caused by heterozygosity of genes involving non-additive effects, which mainly includes dominanace, over dominance and epistasis.

Dominance

When several pairs of genes control one trait, one breed could be homozygous dominant for several pairs and homozygous recessive for another pair (AA BB CC dd) and another breed could be homozygous recessive for respective several pairs and homozygous dominant for respective another pair(aa BB CC DD). Assume that the recessive genotype contributes 1 unit and dominant genotype contributes 2 units of phenotypic values. If these two breeds are crossed:

This hybrid will be superior to either parent because of presence of at least one dominant gene in all pairs of genes which affect the particular trait.

Over dominance

For some pairs of genes, the heterozygotes may be more vigorous than either of homozygotes. Here heterozygosity produces hybrid vigour. Consider the same illustration given for dominance producing heterosis. Assume that recessive,

heterozygous and homozgous genotypes contribute 1, 2 and 1.5 units of phenotypic values.

The F1 hybrid generation, phenotypic variability is generally much less than that exhibited by the inbred parental lines or strains or breeds. This shows that heterozygotes are less influenced by environmental factors than the homozygotes. This phenomenon is termed as “buffering”, which means that the organisms’ development is highly regulated by genetics. Another term often used in this connection is “homeostasis”, which means the steady stse in the development of the organism within a normal range of environmental fluctuations.

Epistasis

To a lesser degree, interallelic interaction or epistasis can account for heterosis. In dominance and over dominance, the heterosis is due to the interaction of genes that are alleles. In epistasis, the interaction is between pairs of genes that are not alleles.

Contribution of AaBb results in an interaction such that the presence of both A and B gives a phenotype larger or in other words more desirable than would be expected from average phenotypes of AAbb or aaBB.

Application of heterosis in animal breeding

Not all traits in farm animals are affected to the same degree by heterosis. Those traits expressed early in life, such as survival and growth rate to weaning seem to be affected

MODULE-24: SIRE EVALUATION

SIRE EVALUATION

most. Feed-lot performance as measured by rate and efficiency of gain after weaning is moderately affected. Heterosis has very little effect on carcass traits. Traits, which show the greatest degree of heterosis are the same ones which show the greatest adverse effects when inbreeding is practiced. Highly heritable traits seem to be affected very little by heterosis; whereas, those which are lowly heritable are affected to a greater degree.For example, fertility and litter size in swine (heritability is 15 to 17%).

The degree of heterosis depends on degree of genetic diversity of the parents. Therefore, heterosis will be higher when breeds are crossed than lines within the breeds are crossed. Crossing breeds having greater differences in genetic backgrounds should give more heterosis than crossing breeds having similar genetic backgrounds. This is because unrelated parents are less likely than related parents to be homozygous for the same pairs of genes.

o Heterosis is much employed to produce commercial stock where the individual merit is promoted, but the breeding value is lowered.

o The successful exploitation of heterosis depends upon how superior the crosses are over the purebreds and whether it is worth considering the lowering the breeding value of the individual and cost of replacement of purebred stock.

For these reasons, it is commonly practiced in poultry, swine and sheep where the fertility is high and the cost of replacement of purebred stock is necessary

Learning objectives


simple daughter average index, equiparent / Intermediate / Dairy bull index / Yapp’s Index, mount hope index, heizer’s index, gifford’s index, regression index or rice index, tomar index, corrected daughter average index / Krishnan’s index, dairy search index / Sundaresan index, contemporary and herd-mate comparison, best linear unbiased prediction (BLUP).

There is urgent need to increase the production in order to meet the demand for the exploding population. This could be achieved by applying various modern methodologies in selection and breeding of livestock. Increasing the productivity through genetic improvement requires adequate identification and intensive selection of genetically superior sires. About 93 per cent of the total herd improvement comes from breeding of young bulls from tested sires and only six per cent from selection of dams. With the advances in artificial insemination and cryopreservation of semen, a sire has a potential of serving 3/4th million cows and producing 1/4th million progenies. Thus, selection of bulls is of great importance in dairy herd

improvement.

SIMPLE DAUGHTER AVERAGE INDEX

EQUIPARENT / INTERMEDIATE / DAIRY BULL INDEX / YAPP’S INDEX

For maximising the genetic gain by sire selection, it is essential that the method of estimating breeding values of sires should be unbiased and efficient. The breeding value refers to the average genetic effect of the genes passed on by the individual to its offspring and is estimated to know whether the individual is genetically superior to other individuals or not for the trait concerned.

A sire’s production transmitting ability can be estimated by mathematical means and expressed as a single figure known as sire index. In other words, an attempt to express what a sire would have produced, has he been a cow, is the sire index of that bull.

The simplest way to evaluate a bull is by his daughter’s production alone (Edward, 1932). The fault with this method is that it does not consider the probable contributions of the dam. It would be all right if all the bulls were bred to average group of cows.

SI = Di = (1 / mi )Σ Dij

where,

Dij = yield of jth daughter of the

ith sire mi = number of dams

mated to ith sire

This index when used for ranking sires would be subject to bias if the levels of production of dams allotted to different sires were unequal.

This index (Yapp, 1925) is based on the principle that the two parents contribute equally to the genetic make up of the progeny. This index overestimates the breeding value of a sire mated to set of dams inferior on the average and underestimates if dams happen to be superior on the average to the general level of herd.

SI = 2D – M

where,

D = average yield of daughters of the

sire; M = average yield of dams

mated to the sire

In Yapp’s formula, the potential transmitting ability can be expressed in terms of 4% fat corrected milk.

MOUNT HOPE INDEX

HEIZER'S INDEX

GIFFORD'S INDEX

Goodale (1927) proposed the index and he suggested that in matting between animals of unequal levels of milk production is on the average about 7 / 10 of the distance above the level of the lower parent. While butter fat production is about 4 / 10 of the distance above the lower level. To get this index, compute the average mature equivalent of milk production of the dams of these daughters and take the difference between these averages.

If the daughter’s average exceeds the dam’s average, add 3 /7 (0.4286) of the difference to the daughter’s average to get the bull’s milk index figure.

If the daughter’s average is less than the dam’s average, subtract 7 / 3 (2.333) of the difference to the daughter’s average to get the bull’s milk index figure.

If the daughter’s butter fat average exceeds the dam’s average, add three halves or 1.5 of the difference to the daughter’s average to get the bull’s butter fat index figure.

If the daughter’s butter fat average is less than the dam’s average, subtract 2 / 3 or 0.6667 of the difference to the daughter’s average to get the bull’s butter fat index figure.

Formula

For milk yieldo S = D + (D - M) x 3/7 if D>Mo S = D - (M - D) x 7/3 if M>D

For Butter fat %o S = D + (D - M) x 3/2 if D>Mo S = D + (M - D) x 2/3 if M>D

This index is used to determine the transmitting ability of individual bulls with regard to milk production. This method is based on progeny selection.

Y = 3 / 8 X + 3 / 4 I + 1 / 4 B

Where,

Y - daughter’s average

production X - dam’s average

production

I - sire’s index

B - Breed or Herd average

Gifford (1930) suggested that the bull index can be estimated from the daughters’ records ignoring the dams, provided the dams are not a selected group.

SI = 2P - H

where,

REGRESSION INDEX OR RICE INDEX

TOMAR INDEX

DAIRY SEARCH INDEX / SUNDARESAN INDEX

H = herd average;

P = daughters average

Regression in the biological sense means the degree of relationship between parents and offspring when used as a measure of inheritance. The regression could move forward as well as backward or towards breed average. Rice has proposed this index based on the fact that the overall regression of the daughter’s records on those of their dams was approximately 0.5. This index simply regresses the equal parent index half way.

Regression index = 0.5 (Equal Parent index) + 0.5 (Breed Average)

This index depends on dam-daughter comparison and on simultaneous use of the merits of the dams and the daughters over their contemporary herd averages.

I = D + (De – Me)

Where,

De - daughter’s expected average = D x daughter’s contemporary

herd average Me - dam’s expected average = M x dam’s

contemporary herd average

CORRECTED DAUGHTER AVERAGE INDEX / KRISHNA'S INDEX

This index (Krishnan, 1956) corrects the daughters’ average for the influence of different production levels of dams sired by different bulls on the basis of regression of daughters’ records on dams. The term “b(M - A)” appearing in the index is correction for the genetic superiority or inferiority of a set of dams allotted to the sire over the herd average.

SI = D – b (M – A)

where,

D = daughter’s average; M = dam’s average; A =

herd average b = regression coefficient of

daughters’ yield on dam’s yield

CONTEMPORARY COMPARISON

HERD-MATE COMPARISON

Under Indian conditions, evaluation of bulls is made with information from a very few daughters and from records subjected to serious environmental differences. Sundaresan (1965) gave two methods one for sire evaluation at farm level and another for key-village.

The farm method takes dam-daughter records in to consideration.

SI = µ + n / (n + 12) (D – CD) – b (M – CM)

For key-village level the dam’s record is not available so, he modified the formula as

SI = µ + n / (n + 12) (D – CD)

where,

µ = herd average; n = number of daughters per sire;

D = average of daughters; CD = average of contemporaries

of daughters; b = intra-sire regression of daughters on dam;

M = average of dams; CM = average of contemporaries of

dams

If changes in the environment conditions from time to time were of significance, then the relevant records made at different times needed adjustments. The value was based on the comparison of average of the daughters of the bull with average of the contemporary daughters of the same group but sired by different bulls. The difference between the two averages was weighted for the number of heifers in each sire group. The contemporary group will allow effective adjustment of major environment effects.

SI = µ + {n / n + k} (D - C)

where,

n = number of daughters;

C = average of daughters’

contemporaries; k = ratio of error

variance to sire variance

This method (Henderson and Carter, 1957) compares each cow’s record

with the records of other cows milking in the same herd at the same time. The total variation in age- adjusted milk production is due to sire (7%), herd (30%), year/season (4%), sire X herd (2%), herd X year (14%) and residual (43%) effects. The herd, year and season variations

MODIFIED CONTEMPORARY COMPARISON

BEST LINEAR UNBIASED PREDICTION (BLUP)

account for about 50% of the total variation in milk production. This method eliminates the herd-year-season variation from the estimate of the sire index.

PD = [(ni / (ni + 20)] {Di - 0.9 (HMi – A) – A}

where,

PD = predicted difference; ni = number of daughters at the ith

herd-mate level Di = average of the daughters at the ith herd-mate

level

HMi = average of the herd-mates at ith herd-mate level

Since only contemporaries of first calvers are considered, the herds less than 20 to 30 cows might not have any contemporary for comparison. However, the comparison of progeny with contemporaries of all ages might improve the accuracy of sire evaluation. But comparing cows in first lactation with older cows that are survivors of culling for yield could be important sources of biases in dairy sire evaluation.

MCA = [n1 X1 + W (Xi – Bias)] / (n1 + W)

where,

n1 = number of contemporaries of first lactation

X1 = average of the contemporaries of first

lactation Xi = average of the

contemporaries of later lactation W =

weight given to later lactation herd-mates

Bias = adjustment for later lactation cows, being the survivors of culling

The bias is calculated as average within herd-year-season difference between first and later lactation cows, adjusted for genetic trend

SI = A + {n / (n + k)} (D – MCA)

When the performance records are used as clues in selection index, it is automatically assumed that the records have been adjusted previously for all known sources of environmental bias using adjustment factors. This

method (Henderson et al., 1975) is mainly based on least-squares method. The basic steps involved in BLUP estimates are as an expression (model) that describes an individual’s performances in terms of all factors, that need to be taken into account i.e., herd-year-season model will be

MODULE-25: FIELD PROGENY TESTING

INTRODUCTION

Yijk = µ + fi + sj + eijk

where,

Yijk = measurement on the kth progeny of the jth sire born in the ith herd- year- season

µ = over all mean

fi = effect of the ith herd- year-

season sj = effect on the jth sire

born

eijk = residual error

BLUP is the best method for evaluating the breeding value of bulls and rank the sires according to their genetic merit because of the following reasons:

Corrects the data automatically for all known non genetic sources Estimates simultaneously all the factors concerned Uses available a priori information more efficiently and more flexibly Maximizes the correlation between predictor and predict Provides an estimate of response to selection for groups of animals born

in different years Accounts for complications such as non-random mating, genetic and

environmental trends over time, herd differences in the average breeding value of dams and bias due to selection and culling

Estimates also the breeding value of individual having no records.

Learning objectives


field progeny testing programme, strategy for field progeny testing programme and steps to be adopted in the field progeny testing program.

India is traditionally an agricultural country and animal husbandry forms the backbone of the livelihood security for more than 70 per cent of the population. Though the growth of agricultural sector was found a negative 5.2 % in 2002-2003, however, during 2004-09 the agricultural growth in India is increased at about 4.4 % per year. This is mainly because of livestock sector contributing steadily to the annual growth at the rate of 4.0 -6.5 % and about 8-9 % of the total national exports and as a result, the Govt of India has targeted about 4% growth in agriculture sector by 2012.

FIELD PROGENY TESTING PROGRAMME

STRATEGY FOR FIELD PROGENY TESTING PROGRAMME

Genetic improvement of dairy animals involves

Breeding goal of dairy animals Types of genetic resources Dairy animal breeding policy and programme Scientific interventions and human resources Performance recording Progeny Testing - Evaluation of breeding bulls (field and farm based) Use and dissemination of superior germplasm Exploiting the future animal breeding technologies

The current breeding policy recommended by the National Commission on Agriculture (NCA) and adopted by the Central and State Governments was based on the important considerations which were similar to those of the Scientific panel on Animal husbandry.

The Field Progeny Testing Programme of the Project Directorate on Cattle, Meerut, India, has new dairy breed (Frieswal) by crossing 30 progeny tested Holstein × Sahiwal bulls with approximately 24 000 females at 3 locations. The new breed is expected to have62% Holstein inheritance, and cows of the breed should be able to yield 4000 kg milk in a mature lactation of 300 days.

Bulls are considered to be the most important players for carrying out organized breeding services, as the main objectives of breeding like development of foundation stock, increase in productive capacity and reproductive efficiency of the local stock through genetic upgradation cannot be achieved without them. They are the reservoirs of the required germplasm or genetic potentialities, which is transmitted to subsequent generations to their offsprings. Once it is established in the offsprings or progenies no extra cost is required to transmit these characters for further inheritance unlike in case of environmental components like the managemental practices, which needs constant investment.

On other hand selection of breeding bulls is an important factor for attaining the desired result. By observing only the body conformation, phenotypic characters or pedigree records, it is not accurate to judge the genetic potential of a bull. Progeny testing therefore, basing on the adequate information gives an accurate estimate of breeding value for assessing the genetic potentialities and is therefore preferred when the animal is used for breeding.

Milk yield is the most important trait considered in selection programmes for dairy cattle, though fat percentage is also measured routinely in some schemes. Since the negative genetic correlation between milk yield and fat percentage may result in the latter declining to low levels, it is usually monitored to eliminate undesirable animals. Bull fertility is important, particularly in AI bulls, while in the female reproductive performance is considered. Culling is being done more for economic reasons than for genetic improvement.

The principal method employed in progeny testing where the breeding

value of bulls is assessed on the performance of their daughters. The test depends for its efficiency on a

STEPS TO BE ADOPTED IN THE FIELD PROGENY TESTING PROGRAM

large progeny group per sire and on having each sire represented in several herds. AI is necessary to separate environmental from genetic effects. Milk yield records are usually restricted to those from first-calving heifers since this gives the largest group of unselected daughters. Young bulls that enter the progeny test are bred from the best progeny-tested sires and selected dams. Each young bull is used on about 500 cows in milk-recorded herds to ensure that first lactation records of at least 50 daughters are obtained. Matings are done at random to ensure that the dam contribution to progeny genotype is similar for all sire progeny groups.

Though this type of selection programme appears to require a great deal of infrastructural facilities, an efficient testing programme could operate even with a simpler organization if recording is limited to that required for progeny testing. Thus, we will operate the programme which tests 20 Crossbred bulls annually on approximately 50 daughters per bull out of which a minimum of 30 can attain motherhood.

1. Selection of Districts/Sub-Divisions/Blocks

It has to be performed where the adequate breedable populations are available in proposed area to carry out the programme. The farmers should actively participate in this programme.

2.Selection of bulls for testing

Several crossbred bulls (10 in first phase & 10 in next phase) of semen bank donating semen. 2000 doses of semen per bull totaling, 20000 doses is to be used in the field. The breedable crossbed cattle are to be identified for insemination at random by the veterinary officer in a contiguous patch.

3.Orientation programme

One orientation programme would be conducted at Head Quarters involving the fields staff.

4.Identification of clusters in each block

The chief district veterinary officers of the concerned districts in consultation with the Veterinary Officer and the Veterinary Assistant Surgeon has to identify some potential pockets for carrying out the test inseminations. The environmental factors like animal population, type of animals, availability of feed resources, farmers’ awareness, holding size etc. may be considered while selecting the clusters.

5.Farmers’ awareness programmes

Awareness for the farmers of the villages under the identified clusters of each block is to be conducted at block level to sensitize them regarding the programme for their involvement and cooperation to make the programme success.

6.Registration / Identification of dams (cows)

The crossbred cows of each cluster are to be registered and identified for test cross through AI with selected bulls. The detailed information of each dam like name of the owner with address, occupation, skin color, age, no. of calvings ,health condition, production status etc are to be recorded for future references.

7.Maintenance of records

Independent registers for the AI of the selected mothers and follow up and thereafter the progeny born is to be maintained at Veterinary Dispensary for monitoring of programme.

8.Follow up of inseminated cows

The follow up of the inseminations are to be taken up regularly on per rectal examination by the concerned Veterinarian. Periodic health control camps are to be conducted to address the reproductive disorders to create awareness. The database on the measures taken and insemination follow up should be maintained properly. The comprehensive health care package for pregnant cows covered under the programme will include vitamin, mineral supplement, dewormer and FMD vaccination. Special camps are to be conducted for health coverage of the inseminated cows. The monitoring reporting format and other stationeries are to be developed and supplied to the field.

9.Detection and follow up of the progenies

All the female calves born out of the inseminations are to be identified and registered within 25 days of their birth. Moreover, the female progenies born out of the insemination will be covered under special health care management upto calving (3 years).

10. Organization of calf rallies or shows

Rallies or shows are to be organized by the district authorities with support of the Government and NGOs for public consciousness.

11. Organization of infertility treatment/HI camps

In due course after attainment of the sexual maturity, the female progenies born out of the test cross are to be observed for coming to heat and efforts are to be made by the district authority to bring them into maturity for successful breeding for all the animals.

12. Breeding the female progenies attaining maturity

After attaining maturity the females are suitably out bred through AI with proven bull semen and normal follow up is to be taken out as in case of the mother cows till parturition.

13. Recording of milk

MODULE-26: SELECTION FOR COMBINING ABILITY

COMBINIG ABILITY

An educated youth of the village concerned is to be identified and trained for recording the milk yield of F1 mothers after 15 days of calving. The analysis of SNF, Fat and Milk yield is to be followed as per the test period method for judging the productive capability of the mothers.

14. Estimation of probable breeding value of sires

Based on the milk yield, heritability and progeny per bull the breeding value of each bull is estimated for its potentialities and ranked accordingly. Sires are to be evaluated on the basis of their daughters 305 day milk yield in single / multiple herds using the method as under.

Sire Index = m + { (2n / n+12)} x ( D – CD )

Where,

m = Overall average of daughters 305 days first lactation milk yield.

n = No. of daughters / sire. D= Daughters average 305 days first lactation milk yield and

CD = Contemporary daughters (over single or multiple herds ) average 305 days first lactation milk yield.

All the sires will be ranked on the basis of their sire index of which 20-30 % top ranking bulls shall be selected for future use as proven bulls for production of superior germplasm. This has ensured sustained maintenance and production of improved germplasm on a large scale for use in cattle and buffalo improvement programme and for establishing linkages with other institutions in India.

Learning objectives


combining ability, selection for general combining ability, selection for general and specific combining ability, recurrent selection and reciprocal recurrent selection.

At the present state of knowledge, performance of two or more breeds or lines in crosses is somewhat unpredictable. Some lines or breeds appear to "combine well" whereas others do not. This can be determined only by test crosses. There are two types of combining abilities viz., general combining ability (GCA) and specific combining ability (SCA). GCA is the mean performance of the F1 offspring of a line with other lines and it is due to additive genetic variance. SCA is the superiority of a particular cross over the

SELECTION FOR GENERAL COMBINING ABILITY

average GCA of the two lines and it is due to non-additive genetic variance. GCA and SCA are expressed as variance and not as values.

To estimate the combining ability of two or more lines, “diallel mating system” is followed. In this system of crossing, all possible combinations of the lines are produced. This mating scheme allows estimating the performance of the individual combinations. The diagram below explains the diallel mating system and the combining abilities of four lines, x1, x2, x3 and x4.

Line x1 x2 x3 x4 GCAx1 x

1x1x

1x2x

1x3x

1x4x1

x2 x2x1

x2x2

x2x3

x2x4

x2

x3 x3x1

x3x2

x3x3

x3x4

x3

x4 x4x1

x4x2

x4x3

x4x4

x4

SCA: The diagonals elements

In symbols, the performance of a combination of lines is composed as follows:

G(x1x2) = GCA(x1) + GCA(x2) + SCA(x1x2)

where,

G(x1x2) denotes the genotypic value of the cross “x1x2”.

For measuring the general combining ability, top crossing is followed. In top crossing, individuals from the inbred lines to be tested are crossed with individuals from the base population. The mean value of the progeny measures the general combining ability of the line because the gametes of individuals from the base population are genetically equivalent to the gametes of a random set of inbred lines derived without selection from the base population. This method is for comparing the general combining abilities of different lines and to choose the lines most likely to yield the best cross among all the crosses that would be made between the available lines.

SELECTION FOR GENERAL AND SPECIFIC COMBINING ABILITY

The specific combining ability of a cross cannot be measured without

making and testing that particular cross. To get SCA, two lines should be developed which differ in gene frequencies. Two methods of selection are available viz., recurrent selection and reciprocal recurrent selection.

Both these systems involve progeny testing. Due to the increased generation intervals, this would be expected to result in slower progress than other breeding systems for characters moderate to high in heritability. They would be expected to be more useful than other breeding systems only if overdominance or other non-additive types of inter- or intra-allelic gene action are important in heterosis.

RECURRENT SELECTION

RECIPROCAL RECURRENT SELECTION

The principle of recurrent selection is developed out of convergent improvement. In this a highly inbred line presumably homozygous at most loci is selected as a tester. A large number of individuals are crossed with this line and their progeny are evaluated. Those giving best progeny are subsequently inter mated and a large number of their progeny are tested in the crosses on the inbred tester. The cycle is repeated over and over. This is done to take greater advantage of the interaction of genes and the resultant overdominance by selecting inbred lines during their developmental process for the purpose of better complementing each other.

The success depends on the ability of the breeder to accumulate a greater number of genes having additive effects in two different parental lines that interact to greater advantage. If heterosis is largely dependent upon overdominance, this procedure should result in the line selected on cross performance becoming homozygous for different alleles than the inbred used as the tester. In other words when tester is aa, the selected line would become AA; the tester is BB, the selected line becomes bb etc.

The application of recurrent selection to animal breeding appears to be more difficult than its application to plant breeding because

o The overall effects of inbreeding are deleteriouso The degree of fertility is lacking. It depends on survivabilityo More number of animals are required and it involves longer

generation interval and make this selection

It is a system of selection for increasing the combining ability of two or more lines or breeds that nick or combine well. Individuals in two lines are not completely homozygous in opposite ways for all pairs of genes but that one allele may be present at a high frequency in one line and at a low frequency in other line. Crossing the lines and selecting the individual to reproduce each pure line on the basis of the performance of their crossbred progeny make the two lines more homozygous in opposite direction. It is a method of selection between lines or families or breeds to take advantages of overdominance, dominance, epistasis, or only additive effects.

In farm animals, selection is usually carried out for more than one trait, since one trait may be affected mostly by non-additive gene action and another by additive gene action or both. Hence, it is to select and improve the best and mating the best to best followed by crossing the improved lines or breeds to take the advantage of hybrid vigour due to non-additive gene action.

Randomly selected representatives of each of the non-inbred strains are progeny tested in crosses with the other. Those individuals of each strain having the best cross progeny are then intermated to propagate their respective strains. Offspring from these within strain mating are again progeny tested in crosses with the other and the cycle repeated.

These systems are useful in breeds or strains in which their performance is already high for highly heritable traits and in which it is desired to improve the potential performance of their crosses for the low heritable traits related to fertility and liveability e.g. litter size and early growth rate in swine.

MODULE-27: BREEDING METHODS FOR IMPROVEMENT OF DAIRY CATTLE AND BUFFALOES

IMPORTANCE OF CATTLE AND BUFFALO IN INDIA

Learning objectives


importance of cattle and Buffalo in India, production of crossbred bulls, progeny testing, milk recording, draught cattle and buffaloes improvement.

India possesses 27 acknowledged indigenous breeds of cattle and seven breeds of buffaloes. Various central and centrally sponsored schemes are being implemented for genetic improvement of cattle and buffalo with a view to enhance the per capita availability of consumption of milk through increased milk production. Efforts are also made to protect and preserve the indigenous cattle and buffalo in their native tract, which are facing threat of extinction. The elite animals are selected and registered on the basis of their performance for production of superior pedigree bulls, bull mothers, frozen semen and frozen embryos for future breeding improvements.

The National Project for Cattle and Buffalo Breeding envisages 100 per cent grant in aid to implementing agencies. At present 28 , States and one UT are participating in the project. Financial assistance to the tune of Rs. 398.36 crore has been released to these States upto 2007-08. During the financial year 2008-09 , against the RE of Rs. 89.70 crore, an amount of Rs. 87.37 crore has been released.

A Central Herd Registration Scheme for identification and location of superior germ plasm of cattle and buffaloes, propagation of superior germ stock, regulating the sale and purchase, help in formation of breeder's society and to meet requirements of superior bulls in different parts of the country is also being implemented. The Government of India has established Central Herd Registration Unit in four breeding tracts i.e. Rohtak, Ahmedabad, Ongole, Ajmer. A total of 92 Milk Recording Centres are functioning to register these breeds of cattle viz. Gir, Kankrej, Hariana and Ongole and in Buffalo Jaffrabadi, Mehsani, Murrah and Surti.

The seven Central cattle breeding farms at Suratgarh (Rajasthan), Chiplima and Semiliguda (Orissa), Dhamrod (Gujarat), Hessarghatta (Karnataka), Alamadi ( Tamil Nadu) and Andeshnagar (Uttar Pradesh) are engaged in scientific breeding programmes of cattle and buffaloes and production of high pedigreed bulls for National Project for Cattle/Buffaio Breeding Programme besides providing training to farmers and breeders. During 2008-09 , these farms produced 346 bull calves and supplied 245 high pedigreed bulls for use under Artificial Insemination Programme in various parts of the Country. 3 , 711 persons were trained in farm management practices and demonstration of scientific breeding. The CCBFS trained 2912 nos. of farmers in during farm management.

The Central Frozen Semen Production and Training Institute (CFSP&TI) located at Hessarghatta (Bangaluru) is producing frozen semen doses of indigenous, exotic and crossbreed cattle and Murrah buffalo bulls for use

in artificial insemination (A 1). The Institute also provides training in semen technology to technical officers of the State Governments and acts as a Centre for testing the indigenously manufactured frozen

PRODUCTION OF CROSSBRED BULLS

PROGENY TESTING

Milk recording has to be initiated for progeny testing and also to implement any meaningful genetic improvement programme. To start with about 2000 cows in different agroclimatic regions can be involved and the number can be increased

MILK RECORDING

semen and Al Equipments. The Institute produced 8.66 lakhs doses of frozen semen and provided training to 227 persons in field of frozen semen technology and andrology during the year 2008-09.

In dairy cattle improvement we should aim for genetic improvement as a priority. In dairy cattle, milk production and reproduction traits are sex-limited and expressed only in cows. But due to higher replacement requirements not much selection is possible among them. In the male, the breeding value for its milk production potential can be estimated only through female relatives such as dam, half sibs and daughters. Due to the requirement of lesser number of bulls (<2 per cent) through artificial insemination (AI), high intensity of selection can be achieved.

The crossbreds already generated have to be consolidated so that they become fairly homogeneous milk producing genotypes. The deterioration in performance in the second generation crosses can be compensated and productivity enhanced only through selection programs. Therefore, selective breeding using proven Jersey and Holstein Friesian half bred bulls and stabilizing the percentage of exotic inheritance around 50 is the immediate task.

In India, for the supply of frozen semen, there are limited number of sperm stations for cattle and buffaloes. In the cattle sperm stations Jersey, Holstein Friesian and Jersey and Friesian crossbreds are maintained. The exotic bulls have to be reduced and 50% Jersey crossbred bulls have to be substantially increased to meet the growing demand. There is only limited scope for sourcing Jersey crossbred bulls of high genetic merit from organized farms due to the shortage of elite cows. The other practical approach is to generate crossbred bull calves from the field by contract mating of elite crossbred cows to proven half bred Jersey bulls.

Crossbred bulls meant for natural service can be obtained by selecting bull calves born to crossbred cows yielding more than 2500 kg, preferably in the first lactation. Multiple ovulation and embryo transfer (MOET) can be taken up in respect of elite cows identified in the course of milk recording. This will facilitate production of superior bulls for AI in addition to faster multiplication of elite cows. For implementing all these programs, milk and performance recording are essential.

Sustained genetic improvement can be achieved only through continuous use of bulls of high genetic merit evaluated through progeny testing. Progeny testing is the estimation of breeding value of bulls by studying the average performance of a number of its daughters. It has been established that in a well run progeny testing programme the annual genetic gain is around one per cent. Progeny testing is expensive and time consuming but, at the same time it is the most accurate method for estimating the breeding value of the bull, which is half the herd.

IMPROVEMENT OF BUFFALOES

IMPORTANCE OF RECORDS

Though there is a decline in the demand for draught animals, they do have a critical role for ploughing (particularly in wet areas), transport of agricultural produce and manuring the fields. The scenario is unlikely to change for another decade or so and therefore the draught breeds have to be not only preserved but also improved. Selective breeding of indigenous breeds has to be resorted to. Wherever possible in addition to AI, natural service through licensed bulls may be adopted. Criteria for selection of draught cattle have to be developed and research on work physiology should be initiated. For the draught breeds Breeders’ societies may be organized and registered. Active patronage by the government and support of the non-government organizations is needed.

Majority of local cattle is grouped under the category “non-descript” since they are considered to have no distinct external features. They are found mostly in resource poor areas and meet the draught power of the region. Hence crossbreeding with exotics for increasing milk production may not be advisable. One approach is to select bulls locally based on phenotypic features for draught qualities and use them for natural service. The other approach is to introduce Tharparkar, a dual purpose hardy breed into southern states for upgrading the local cattle. This may improve milk production without affecting draught quality and disease resistance.

Since long Murrah has been recommended as the breed of choice for upgrading local buffaloes for increasing the milk production. In this process, no base-line data have been collected regarding the reproduction and milk production of local buffaloes. Progeny testing of Murrah bulls carried out by the Milk federations under Dairy Herd Improvement Plan Actions may be strengthened and expanded. Future bulls of Murrah for AI have to be generated from the field by inseminating the semen of Murrah bulls of high breeding value to elite local buffalo cows. This will facilitate incorporation of some favorable genes from the local population. Licensing of buffalo bulls for natural service has to be taken up on large scale since about 6 per cent of breedable females alone are covered through AI. Simultaneously, AI coverage of buffalo cows has to be increased by ensuring higher conception rate.

Breeding record is the registering of information available on reproduction of the animals. The record should be simple, accurate, complete, upto date, understandable and easy to maintain.

Detailed information regarding the performance and reproduction of individual animals and herd can be collected.

DRAUGHT CATTLE

in a phased manner. Individual animals have to be identified before starting the milk recording. Once a month, two - time milk (morning and evening) recording has to be done and 9 to 10 milk records are required for the entire lactation.Owner recording with periodical verification by official agents or contract recording through self-help groups may be done.

Useful in evaluation of post management practices adapted in the farm.

MODULE-28: OPEN NUCLEUS BREEDING SYSTEM

INTRODUCTION

Useful in long term planning. Very important for day to day decision making.

Records that are maintained in a farm

Pedigree and herd records Breeding record Production record Record for feed Health record Labour record Business record. Stock record Cow card

National Project for Cattle and Buffalo breeding (NPCBB)

The government of India initiated action in the beginning of IX Plan towards formulation of a comprehensive scheme for cattle and buffalo breeding in consultation with State governments and other concerned agencies with an aim to consolidate the gains achieved till VIII Plan period, to maximize returns on investments, and to ensure sustainability of operations as well as quality in breeding inputs and services. These efforts culminated in merger of the ongoing centrally sponsored schemes on cattle and buffalo breeding, namely Extension of Frozen Semen Technology & Progeny Testing Programmes (EFST & PTP) and National Bull Production Programmes (NBPP) into a new centrally sponsored National Project for Cattle and Buffalo Breeding (NPCBB) which aims at thorough re-organization and reorientation of the cattle and buffalo breeding operations in the country. The objectives of the project include establishment of appropriate institutional structures to channel and supply high quality breeding inputs and services; setting up national standards for bulls, semen, semen laboratories and AI services to guarantee quality assurance; training of inseminators and professionals based on nationally accepted curriculum and hands- on practices and regulating and strengthening breeding system in area covered by natural service as well as fostering breeders organizations. Most of the states have participated in implementation of the project.

Learning objectives


structure of ONBS, closed nucleus breeding system and cooperative group breeding system (CGBS).

STRUCTURE OF ONBS

Screening of population to identify superior individuals can be very helpful in establishing a central nucleus, where genetic improvement can be further generated by selection based on measured production. The nature of a group breeding scheme is such that it is the interest of all its members to secure the highest possible genetic level and the highest rate of genetic progress for the nucleus. This is a strong motive for the individual farmers to contribute superior females to the nucleus both at the initial screening and at later stages (Open nucleus system). The rate of genetic progress may thus be increased by a further 10 – 15%.

Open Nucleus Breeding Schemes (ONBS) should be effected in different regions to monitor and augment the production performances of different breeds of cattle and buffaloes in India. The ONBS concept comprises a nucleus herd established under controlled conditions to facilitate selection. The nucleus is established from the best animals selected from the base population. These are then recorded individually and the best animals are selected to from the elite herd of the nucleus. The elite females and superior sires are then mated and the resulting offspring are reared, recorded and the males among them are evaluated and such elite group of males with high breeding values can be used in the farmers herd for genetic improvement. By this, greater genetic improvement can be made in large population of cattle and buffaloes in their home tract.

The structure is in the form of a pyramid. It consists of three-tier multiplication systems, namely the nucleus tier, multiplier tier and the commercial tier.

Nucleus tier

It is composed of top parental breeding stock. It consists of 10 – 15% of total breed population and these are selected exclusively on their breeding value. This tier acts as selector and supplier of replacement male and female breeding stock for itself and for multiplier tier at farm level and commercial tier at field level. It is stationed at a particular place with all necessary inputs of land, feed, labour and favourable environment.

Multiplier tier

This is constituted by about 30-40 percent of breed population. It acts as multiplier and tester population. It exclusively receives stud males and sometimes breeding females from the nucleus herd with the sole purpose of producing sufficient number of breeding animals therby satisfy the demands of herds in the commercial tier.

Commercial tier

This is constituted by about 40 – 60 percent of breed population and generated using males and females that are produced under multiplier

herds with the intention of increasing the production and the genetic improvement. It acts as terminal tier of hierarchical breeding structure.

ONBS concept involves introduction of superior quality females to the sire breeding nucleus, like semen stations from other tiers of breeding. Although bulls are considered

CLOSED NUCLEUS BREEDING SYSTEM

COOPERATIVE GROUP BREEDING SYSTEM (CGBS)

MODULE-29: BREEDING METHODS FOR IMPROVEMENT OF SHEEP

as the chief architect genetic improvement in cattle and buffaloes due to high selection intensity and advent of AI and frozen semen technology the expected genetic gain is limited. This is overcome by ONBS to some extent where both males and females contribute to the total annual genetic gain in this system. The expected genetic gain may be increased by 10 – 15 per cent.

The direction of the gene flow in traditional system is always one sided i.e from nucleus tier to multiplier and then to the commercial tier. And never back to nucleus tier from commercial tier. This system is known as Closed Nucleus Breeding System (CNBS ).

Generally superior breeding females – daughters born to sires of nucleus tier in the multiplier or commercial tier are selected based on their genetic merit and breeding values and in turn transferred to the nucleus tier for breeding as replacer such that the nucleus tier is opened for the external source of superior genes and the system is called Open Nucleus Breeding System(ONBS). The gene flow occurs in both directions – from the nucleus tier to commercial tier via multiplier tier and back to the nucleus tier.

The nucleus tier consists of bulls selected based on their pedigree. Best bulls are selected based on their genetic superiority and used for producing best animals. The females from the commercial tier are selected based on their genetic merit and transferred to multiplier herd and nucleus tier for breeding. The nucleus tier is opened for the receipt of elite females from the downward tiers as replacer. Thus the ONBS raises the possibility of introducing commercially bred, non pedigreed animals into pedigree herds of nucleus.

The major disadvantage of this system is the disease control that have a major influence. So the breeders maitain their units under closed breeding system by adopting strict quarantine and biosecurity measures.

Majority of our farmers usually maintain only one or two cows or buffaloes and so keen interest is evinced in cooperative breeding systems especially in dairy sector. So that maximum selection intensity can be achieved. In this direction NDDB and state level Milk federations have already established bull mother farms and they are in the process of procuring young bull calves born to elite cows under field conditions and raising them as future breeding bulls.

In principle the CGBS adopted a sire breeding nucleus to breed replacement sires for itself and the associated field level herds. Cows or buffaloes replacements are reared in both the nucleus and associated herds at field level.

Genetic gain

Realization of actual genetic gain depends upon the high selection pressure, which is applied on initial screening of both cows and bulls besides, population size and continuation of selection of cows and bulls within the nucleus as well as exchange rate of females and males from the contributor herds and nucleus unit.

BREEDING METHODS FOR IMPROVEMENT OF SHEEP

Learning objectives


breeding methods for improvement of sheep, selelction and breeding, Open Nucleus Breeding Scheme (ONBS) and economic traits in sheep to be considered for improvement.

Sheep rearing is a traditional occupation of rural people in desert, hilly and mountain regions of the country, where agriculture farming is limited due to harsh climatic conditions. The ability of sheep to thrive on sparse vegetation of community grazing lands and convert into meat and wool on least input make favourable venture for livelihood security and source of income among socio-economic weaker sections of society in the country. In situation of drought and famine sheep act as liquid assets, which can be cashed easily to meet financial requirement. India possesses 59.0million sheep, they contribute 229 million kg mutton, 51 million kg wool and 56.3million kg of skin beside 29 million kg of manure. Sheep husbandry is contributing an income of Rs 1200crore in form of meat, wool, skin, milk and manure to the nation. At present 100million kg wool is required for manufacturing of carpet and woollen garments in the organized sector.

The country is importing 50 million kg wool from Australia and New Zealand to meet the demand of industry. Mutton is an important produce from sheep has great demand in the country especially in the Jammu and Kashmir and Himachal Pradesh states. About 70% of earning in sheep rearing comes from meat. To meet the growing demand of meat and wool in the country, there is an urgent need to increase the productivity per sheep by better feeding, breeding and health management. There is ample scope of increasing meat and wool production from sheep owning to availability of vast genetic diversity and population distributed in different regions of the country.

In near future sheep husbandry will continues to play an important role in ensuring nutritional security and economic sustenance of people either as main or subsidiary occupation. The need of an hour is to maintain sustainability in production with ecosystem conservation. The major challenges before sheep husbandry are shrinkage of grazing land, declining genetic resources, increasing disease risk, pollution and human health issues, emerging infectious and non-infectious diseases due to changing agroclimatic and social perspective, lack of infrastructure for production and processing of animal produce and inadequate market and transport facilities for animals and animal produce in the rural areas. Biotechnological approaches for conservation of genetic resources, improvement of feed and fodder resources and its utilization, disease diagnosis and control organised marketing structure and organic farming for achieving eco-friendly sustainable production and ensuring safer meat and wool for human consumption are some of the issues need focus in research programmes. The institute has developed low input technologies suitable for enhancing flock productivity in the rural areas for sheep farmers. These technologies should be made available to end users through effective extension network involving government, NGO’s and development agencies.

SELECTION AND BREEDING

OPEN NUCLEUS BREEDING SCHEME (ONBS)

As there is existence of distinct breeds of sheep, selection within local breeds preserve the essential adaptation characteristics to the environment. Breeding programmes in sheep are to be concentrated on growth, body weight and improved reproductive efficiency. Tropical breeds acquired the adaptability characters through natural selection and hence the selection and breeding programmes should rely mainly on the improvement of adapted breeds. Hence, only pure breeding/Selective breeding should be carried out in the breeding tract to improve the performance.

Screening of population to identify superior individuals can be very helpful in establishing a central nucleus, where genetic improvement can be further generated by selection based on measured production. The nature of a group breeding scheme is such that it is the interest of all its members to secure the highest possible genetic level and the highest rate of genetic progress for the nucleus. There is a strong motive for the individual farmers to contribute superior females to the nucleus both at the initial screening and at later stages (Open nucleus system). The rate of genetic progress may thus be increased by a further 10 – 15%.

Open Nucleus Breeding Schemes (ONBS) should be effected in different regions to monitor and augment the production performances of different breeds of sheep in Inida. The ONBS concept comprises a nucleus herd established under controlled conditions to facilitate selection. The nucleus is established from the best animals selected from the base population. These are then recorded individually and the best animals are selected to form the elite herd of the nucleus. The elite females and superior sires are then mated and the resulting offsprings are reared, recorded and the males among them are evaluated and such elite males with high breeding values can be used in the farmers flock for genetic improvement. Already an all India Coordinated scheme on “Network Project on Sheep Improvement” is in the field for genetic improvement in large population of sheep in their home tract.

For development of sheep in the field, breed registries or breed societies for sheep in key areas of the breeding tract and / or co-operatives can be started and strengthened and linked to the organisations. This kind of participatory sheep Development Programme would cover larger area and population, there by bringing the benefit and achieving the goal of sustainable production. Various co-operative Zones can be created and the small ruminant population can be improved through Open Nucleus Breeding Scheme (ONBS).

Some sheep flocks are often small in size and that limits the speed of genetic improvement they can achieve. However, this constraint can be overcome through co- operative breeding schemes such as sire referencing schemes where flocks are linked together genetically by sharing a few rams in common. With these links established, the genetic merit of sheep in separate flocks can then be directly and accurately compared. This is one of the best strategies to select and use those “reference rams” shared across flocks to facilitate quick rates of genetic gain while minimizing inbreeding.

Under nucleus breeding system, the nucleus flock should be maintained in the home tract of the respective breed of sheep. The nucleus may contain either the farm bred rams or the elite rams chosen from among the farmers flocks. The nucleus (either a Government District Farm or University Farm)

should have sufficient breeding stock to satisfy the demands from the herds or farmers flocks.

Under the nucleus (for a particular breed improvement), 3 to 5 cooperating units (Government Institutions / University Centres/ NGOs/ Self help groups) are to be engaged in monitoring the breeding and improvement plans, depending up on

ECONOMIC RAITS IN SHEEP TO BE CONSIDERED FOR INPROVEMENT

MODULE-30: BREEDING METHODS FOR IMPROVEMENT OF GOAT

BREEDING METHODS FOR IMPROVEMENT OF GOAT

distribution of flocks and feasibility in coverage. Each cooperating unit should have a large sizeable farmers flocks (100 farmer’s units) covering wide area in the breeding tract. Under this scheme, a total of 300 to 500 farmer flocks are covered and genetic improvement could be made in larger populations. In addition, the cooperating centres have to make detailed recording of performance to study the impact of the programme and change the rams among the farmers flock once in a year to avoid inbreeding.

Recommendations

Pure breeding/selective breeding of sheep breeds in their respective breeding tract. Genetic improvement of field stock through network project/Open

Nucleus Breeding Scheme (ONBS)/participatory sheep breeding programme.

Critical documentation of distinct populations for their identity and for recognising them as breeds. Conservation of vulnerable breeds based on population dynamics, establishment of elite nucleus stocks of sheep and in-situ preservation in organized farms.

Marketing of products through village cooperatives in an organized manner.

Tupping % = (Number of ewes mated / Number of ewes allowed to ram ) x 100 Lambing% = (Number of ewes lambed / Number of ewes allowed to ram) x 100 Weaning% = (Number of lambs weaned / Number of lambs born) x 100 Twinning% = (Number of twin births / Number of births) x 100 Preweaning mortality% = (Number of lambs died till weaning / Number

of lambs at birth) x 100

Learning objectives


breeding methods for improvement of sheep, selelction and breeding and Open Nucleus Breeding Scheme (ONBS)

.

Goats play vital role by significantly contributing to the production of meat, skin and manure, also to the provision of rural employment, especially in ecologically difficult areas. India is having highly diversified physical features and agro ecological conditions. Based on rainfall, irrigation pattern and other physical, ecological and social factors, the state is classified into several distinct agroclimatic zones and each possessing distinct breed/breeds of goat.

SELECTION AND BREEDING

OPEN NUCLEUS BREEDING SCHEME (ONBS)

As there is existence of distinct breeds of goat, selection within local breeds preserve the essential adaptation characteristics to the environment. Breeding programmes in goats are to be concentrated on growth, body weight and improved reproductive efficiency. Tropical breeds acquired the adaptability characters through natural selection and hence the selection and breeding programmes should rely mainly on the improvement of adapted breeds. Hence, only pure breeding/Selective breeding should be carried out in the breeding tract to improve the performance.

Open Nucleus Breeding Scheme (ONBS)

Screening of population to identify superior individuals can be very helpful in establishing a central nucleus, where genetic improvement can be further generated by selection based on measured production. The nature of a group breeding scheme is such that it is the interest of all its members to secure the highest possible genetic level and the highest rate of genetic progress for the nucleus. There is a strong motive for the individual farmers to contribute superior females to the nucleus both at the initial screening and at later stages (Open nucleus system). The rate of genetic progress may thus be increased by a further 10 – 15 per cent.

Open Nucleus Breeding Schemes (ONBS) should be effected in different regions to monitor and augment the production performances of different breeds of India. The ONBS concept comprises a nucleus herd established under controlled conditions to facilitate selection. The nucleus is established from the elite animals selected from the base population. These are then recorded individually and the best animals are selected to form the elite herd of the nucleus. The elite females and superior sires are then mated and the resulting offsprings are reared, recorded and the males among them are evaluated and such elite males with high breeding values can be used in the farmers flock for genetic improvement.

For development of goat in the field, breed societies for goat in key areas of the breeding tract and / or co-operatives can be started and strengthened and linked to the organisations. This kind of participatory goat Development Programme would cover larger area and population, there by bringing the benefit and achieving the goal of sustainable production. Various co-operative zones can be created and the small ruminant population can be improved through Open Nucleus BreedingScheme (ONBS).

Some goat flocks are often small in size and that limits the speed of genetic improvement they can achieve. However, this constraint can be overcome through co-operative breeding schemes such as sire referencing schemes where flocks are linked together genetically by sharing a few bucks in common. With these links established, the genetic merit of goat in separate flocks can then be directly and accurately compared. This is one of the best strategies to select and use those “reference bucks” shared across flocks to facilitate quick rates of genetic gain while minimizing inbreeding.

There is considerable opportunity for greater use of improved breeding stock through:

Increasing the number of recorded flocks Improving the dissemination of high merit breeding stock through wider use of AI Further use of comprehensive recording and sire referencing schemes Establishment of elite nucleus stock of goat breeds in their respective breeding tract

Exotic breed generally show poor adaptability and require major alterations of the management and feeding systems to produce satisfactorily. Although there are many examples of failure, the possibility of utilizing some of their genes in suitable crossbreeding programmes should not be entirely ruled out.

However, efforts are still going on to upgrade the local non-descript goats using improved breeds in their locality. “At no point, crossbreeding of goat should beresorted”. Introduction of exotic breed should be avoided to prevent the genetic dilution and uniqueness of the specific breeds rather up gradation of local goats can be done using improver breeds.

Benefits of the co-operating units

To monitor breeding activities To record the performance characteristics in detail To monitor the health and surveillance of the disease Further, village co-operative can hold control over marketing and organize

the farmers collectively to fetch better price for their stock

MODULE-31: BREEDING METHODS FOR IMPROVEMENT OF SWINE

BREEDING METHODS FOR IMPROVEMENT OF SWINE

Marketing should be promoted only through the co-operative societies in order to avoid the problems of middlemen, thereby increasing the profit to the produces/farmers.

Recommendations

Pure breeding/selective breeding of goat breeds in their respective breeding tract. Upgrading the non-descript goat population using improver breeds. Genetic improvement of field stock through network project/Open

Nucleus Breeding Scheme (ONBS)/participatory goat breeding programme.

Critical documentation of distinct populations for their identity and for recognising them as breeds. Conservation of vulnerable breeds based on population dynamics, establishment of elite nucleus stocks of goats and in-situ preservation in organized farms.

Marketing of products through village cooperatives in an organized manner.

Learning objectives


breeding methods for improvement of swine and reproductive and growth traits in swine.

As per Livestock census 200 7, the pig population in the country was 11 . 60 million of local and cross bred/exotic pigs. Exotic breeds like white Yorkshire, Hampshire and Landrace are maintained at these farms. There are about 158 pig breeding farms in the country run by the State Governments/UTs. Efforts are being made in consultation with Planning Commission and other appraisal agencies to initiate Integrated Piggery Development Scheme under Macro Management Scheme during 11 th Five Year Plan.

Pig production, among other species has a high potential to contribute to high economic gain. The pigs have high fecundity, high feed conversion efficiency, early maturing, short generation interval and relatively small space requirement. They are providing about 40% of meat consumed in the world market, and by-products like pig dung as manure and bristle for brush industry. It is produced under a variety of production systems ranging from simple backyard pigs, pigs living on garbage belts to family operated farms or large scale integrated pig industries with sophisticated bio-safety measures.

Pigs are widely distributed in all the eco-regions of the country and is an important occupation of the rural society especially the tribal masses. People of certain ethnic groups prefer to keep pigs, especially black ones, for festivals and ceremonial purposes. Interestingly, these ethnic groups are mainly concentrated in the North-Eastern Region where almost 28% of the country's total pig population exists. According to FAO records, India's pig population is 13.84 million (FAOSTAT, 2009) and it constitute 1.47% of

world pig population and our piggery sector is gaining slow but steady momentum during the past years. Majority of our pig population is held by marginal and small farmers . Further, the average pig population per thousand human populations is about 11.5. Among Indian states, Uttar Pradesh has the maximum number of pigs with about 17% of

REPRODUCTIVE AND GROWTH TRAITS IN SWINE

the total pigs followed by Assam (~12%), West Bengal (~10%) and Jharkhand (~8%). In south India, Kerala is having maximum population. Nowadays, pig husbandry is developing fast near metropolitan cities because of multi-ethnic population lives in concentration having urge to take pork in their menu. Hence, development of piggery should be concentrated more for proving quality protein to the needy people.

Even though, pig rearing is an important occupation of the rural society specially to the tribal people of the country and 13.84 million (FAO stat, 2009) of pigs which constitutes 1.47% of world’s pig population but still there exists a high demand of the pork in the tribal area of the country in general and NE Region in particular where 28% of country’s pig population is available. In spite of aptitude of the people towards pig rearing and the sizable pig population, the NE Region has to procure pork from outside the region valued roughly at 20 crores every year. This scenario is basically due to the bulk of the pig population (~75%) being from non-descript type known for their stunned growth and poor production.

In the present era of globalization, the country needs to concentrate on systematically exploring its strength so that it could become a player in global trade of agriculture and allied sector. This upcoming need could perhaps be fulfilled by revolutionizing pork production in the country encasing the positive aptitude of the people towards quality and profitable pig farming. This again could only be done through skill up-gradation of the pig farmers on quality, quantity and profitable mode of production.

The potential of the piggery sector needs to be exploited as this can play a key role in providing sustainable employment and livelihood security to the farmers in their own locations and preventing migration of people to urban areas. It is necessary to take efforts to minimize the cost of production through nutritional interventions. Micro environment needs to be taken care of to protect them against thermal stress under tropical climate. Incidence of diseases due to improper management at different stages is another problem to be countered. Moreover organized marketing is not yet well established in our country. Pig industry is following Western technology which is not cost effective. The farmers are in need of innovative technological interventions to improve the productive performance of pigs. Hence, exploring and identifying different management techniques with regard to breeding, housing, feeding, health care, post harvest technology and marketing to bring about sustainable pig farming both in rural and commercial units is need of the hour.

MODULE-32: BREEDING METHODS FOR IMPROVEMENT OF POULTRY

BREEDING METHODS FOR IMPROVEMENT OF POULTRY

Learning objectives


breeding methods for improvement of poultry, scope of poultry farming in India.

Poultry egg and meat are important sources of high quality proteins, minerals and vitamins to balance the human diet. Specially developed breeds of egg type chicken are now available with traits of quick growth and high feed conversion efficiency. Depending on the farm-size, layer (for eggs) farming can be main source of family income or can provide income and gainful employment to farmers throughout the year. Poultry manure has high fertilizer value and can be used for increasing yield of all crops

Breeding methods for improvement of poultry

The term poultry although very often used as synonymous to chicken, includes a number of avian species such as chicken, turkey, geese, guineafowl, peafowl etc., Poultry development in the country has shown steady progress over the years, primarily due to research and development schemes of Government as well as effective marketing & management by organized private sector.

India, with poultry population of 489 million and estimated more than 532 billion eggs production, ranks among the top three countries in egg production in the world. During 1980-81 , egg production reached double-digit billion figures ( 10 billion numbers) and has increased over 5 times currently. Per capita availability has, during this period, also increased nearly 3 times from a mere fifteen numbers per person per annum to forty-two per annum.

The broiler production is growing at the rate of nearly 8-10% every year and growth in production of poultry/chicken meat increased from mere 0.12 million metric tonnes in 1981 to 2.2 million metric tonnes presently. The annual per capita availability of eggs and chicken meat has also increased from a mere 10 eggs and 146 grams in 1970 s to around 42 eggs and 1.6 Kgs respectively presently.

India's share of the world trade in poultry and poultry products is very small. However, the country has come a long way during the last decade increasing its value of exports from nearly Rs. 11 crores in 1993-94 to around Rs. 441 crores during 2007-08. Poultry Sector, besides providing direct or indirect employment to nearly 3 million people is a potent tool for subsidiary income generation for many landless and marginal farmers and also provides nutritional security especially to the rural poor.

To provide necessary services to the farmers of the country region-wise, four regional centres have been restructured on the principle of one-window service to the farmers. In these regional Central Poultry Development Organizations ( CPDOs) located at Chandigarh, Bhubaneswar, Mumbai and Hessarghatta, training is also being imparted to the farmers to upgrade their technical skills. To monitor the production potential of various stocks in the country, the Central Poultry Performance Test unit at Gurgaon is conducting one layer and two broiler tests in a year.

Recently Cabinet Committee on Economic Affairs approved the Centrally Sponsored Scheme. "Poultry Development" from third year of XI Five Year Plan i.e. 2009-10 , at a total outlay of Rs. 150 crore. The Centrally Sponsored Scheme combines three components viz., 'Assistance to State Poultry Farms', (which is a continuing component) and two new components 'Rural Backward Poultry Development and 'Poultry Estates'. The administrative approval and scheme guidelines are being issued.

The Scheme through its 'Assistance to State Poultry Farms' component aims at strengthening existing State poultry farms so as to enable them to provide inputs, mainly in terms of providing improved stocks suitable for rural

backyard rearing. The 'Rural Backyard Poultry Development' component is expected to cover the needy Below Poverty Line section of society to mainly enable them to gain supplementary income and nutritional support. Entrepreneurship skills are expected to be improved through pilot component of 'Poultry Estates' which is meant primarily for educated, unemployed youth

SCOPE OF POULTRY FARMING IN INDIA

and small farmers with some margin money, for making a profitable venture out of various poultry related activities in a scientific, and bio-secure cluster approach.

India and the neighbouring countries in the east are considered to be the original home of the well-known Red Jungle Fowl (Gallus gallus) from which the present day domestic birds have descended. The fowl population of India can be classified into two types - desi/indigenous and improved/exotic.The birds are raised mostly by the rural folks as a backyard enterprise. About 18 breeds of fowl have been documented. The status of most of these breeds except Aseel, Kadaknath,

Kashmir Faverolla, Miri and Nicobari is not known. Most of the present day populations are commercial hybrids involving

White Leghorn, Cornish, Barred Plymouth Rock, Rhode Island Red and Black Australorp. Some crossbred strains of fowl have been developed to use them for rural poultry production. Some of these are Giriraja, Vanaraja, Krishna–J, Yamuna, Kalinga Brown, Dhanraja, Mrityunjay, Cari Gold, Debendra, Nandanam-I, Girirani, Athula, Gramalakshmi, Gramapriya. Vanaraja.

Poultry industry which provides cheap source of animal protein has taken a quantum leap in the last three decades evolving from a near backyard practice to a venture of industrial promotion. Poultry is one of the fastest growing segments of the agricultural sector in India today. While the production of agricultural crops has been rising at a rate of 1.5 to 2 percent per annum that of eggs has been rising at a rate of 8 percent per annum. India is on the world map as one of the top five egg producing countries with55.6 billion eggs produced during 2008.

The poultry sector in India has undergone a paradigm shift in structure and operation. This transformation has involved sizable investments in breeding, hatching, rearing and processing. Farmers in India have moved from rearing non-descript birds to rearing hybrids which ensures faster growth, good liveability, excellent feed conversion and high profits to the rearers. High quality chicks, equipment, vaccines and medicines are available. Technically and professionally competent guidance is available to the farmers. The management practices have improved and disease and mortality incidences are reduced to a great extent. The industry has grown largely due to the initiative of private enterprise, minimal government intervention, considerable indigenous poultry genetic capabilities and adequate support from the complementary veterinary health, poultry feed, poultry equipment and poultry processing sectors. The industry has created direct and indirect employment for 3 million people.

Duck

Duck rearing is prevalent among weaker sections of rural population which provides them supplementary and steady income on daily basis besides providing them nutrition duck eggs for family consumption and engaging family labour in their leisure hours to look after Duck unit thus, generates rural employment.

Gujarat State has several hectares of land under in land water ponds or water holes particularly in South Gujarat region and tribal communities keep duck for

production of duck eggs and duck meal, which are considered to be poorman’s poultry productions available at affordable prices.

Over 10 million duck population exists in the country and ranks 2nd in the world after Indonesia. Around 600 million duck eggs valued at Rs. 180 crore are being produced and are being consumed in the rural area, Kerala, West-Bengal, Orissa, Andhra Pradesh are the Staes where duck are predominant.

Ducks suppliment their feed by foraging. They eat fallen grains in harvested paddy fields, insects, shails, earth worms, small other fishes etc.

Duck rearing does not require elaborate housing like poultry. Ducks are more hardy well suited for weaker section where level of management is moderately scientific.

Marshy, riverside, wet land and barren moors are excellent areas for duck farming. Duck cum fish farming can be integrated.

Ducks lay 95% to 98% eggs in early morning before 9.00 am after which the flock can be taken for foraging to nearby ponds by the duck farmer or his family members.

Khaki Campbell is best egg producing breed in ducks. Animal Husbandry Department of Govt of Gujarat from their Duck breeding farms at Mandvi in Surat district can supply 3 months old duck lings at Rs. 130 per duck ling.

Indian breeds of ducks are Indian Runner, Nageshwari, Sythetemete, Kuttanadu Chara and Chemballi. Khaki Campbel – a synthetic breed is being used as an improver breed.

Quail

Japanese quail (Coturnix coturnix japonica) is the domesticated version of common wild quail (Coturnix coturnix). Indian subspecies of quail, viz. Rain, Grey and Button quail collectively known as ‘Bater’ has distinct popularity as game bird. Quails are seen in diversified colour varieties. Commonly seen plumage is a mixture of different shades of brown with some black patterns. Besides the cultural and religious considerations for animal keeping, all the breeds of different domestic livestock and poultry species are contributing significantly to food and agriculture in terms of milk meat, wool, fibre, egg, manure, fuel and draft power. Variations in regional demand for animal products have influenced the use of different AnGR.

Economic traits in poultry

Egg production

MODULE-33: CONSERVATION OF GERMPLASM

CONSERVATION OF GERMPLASM

Learning objectives


conservation of germplasm, reasons and motives for conservation, categories of domestic population, status of Animal Genetic Resources (AnGR) in India, breeds requiring conservation, In-situ and Ex-situ conservation, Ex-situ / Cryogenic preservation.

Indian subcontinent is globally recognized as one of the Mega Centre of biodiversity of animals and plants. India is bestowed with rich domestic animal genetic resources at present which are intricately associated with the social, cultural and traditional values of the region to which they belong and serve as vital source for food, fibre, draught power, manure and provide much needed self employment to small and marginal farmers and weaker sections of the society.

Historical perspective of conservation

REASONS FOR CONSERVATION

The need for conservation of animal genetic resources was expressed for the first time in 1959 in Chicago in a joint symposium on germplasm for plant and animal breeders. Conservation of poultry genetic resources was a major issue at second European Poultry Conference held at Bolagna in 1964. The FAO organized several study groups to discuss problems of animal genetic resources especially for cattle, pigs and poultry in Rome (1966, 1968), Copenhagen (1971), Nouzilly (1973) and a pilot study in 1975.

In 1985 FAO, under the responsibility of the Commission on Genetic Resources for Food and Agriculture, introduced an expanded Global Strategy for the Management of Farm Animal Resources. In 1992, it launched a special action programme for the Global Management of Farm Animal Genetic Resources (AnGR) with a framework to stimulate national participation in the global effort to implement conservation activities. National and regional focus points played an important role in stimulating and coordinating these actions. The Domestic Animal Diversity Information System (DAD-IS) is used to collect information on breeds and conservation activities and it offers the opportunity to retrieve guidelines for conservation activities.

In 1992, the Second United Nations Conference on the Environment in Rio de Janeiro recognised the importance of farm animal genetic resources in Agenda 21 and in the Convention on Biological Diversity (CBD). Nearly all countries have signed this convention, bringing about political and social awareness of national animal genetic resources and activities to conserve them in several countries. The CBD included farm animal genetic variation as a component of overall biological diversity and also recognized the sovereignity of each country on its own genetic resources, which implied also the obligation to conserve the AnGR.

In 1998, this programme got a new impetus in the first session of the Inter- Governmental Working Group on Animal Genetic Resources for Food and Agriculture. This working group recommended to the Commission on Genetic Resources for Food and Agriculture that FAO should continue to shape more clearly the framework and further develop the framework and that it should co-ordinate the development of a country-driven Report on the State of the World's Animal Genetic Resources.

Conservation

It is defined as the management of human use of the biosphere for the greatest sustainable benefit to present generation while maintaining its potential to meet the needs and aspirations of future generations. Thus, conservation is positive embracing preservation, maintenance, sustainable utilization, restoration and enhancement of the natural environment.

Preservation

Preservation is the part of conservation by which a sample of animal genetic resource population is designated to an isolated process of maintenance, by providing an environment free of human forces which might bring about genetic changes.

Breeds with specific qualities like disease resistance, heat tolerance, etc.

Future requirements of type and quality of animal produce ( meat, milk, skin, draught power).

MOTIVES SFOR CONSERVATION

CATEGORIES OF DOMESTIC POPULATION

Breeds with unique physiological traits are of great values as they provide missing links in the genetic history, eg. study of blood group, biochemical polymorphism etc.

To evaluate magnitude of genetic change due to selection, maintenance of sample as controlled population is very much essential.

Variety of population is an asset for research workers in biologiacal evaluation, behavioural studies, etc.

Diverse population for excellent teaching materials. To take care of existence of different creation of the nature of posterity. Valuable material of nature and culture. Preservation with diverse sizes, colors and other morphological features,

for aesthetic reason.

To avoid the loss of genetic materials which would be valuable for future production requirements (historical, socio-economic status)

To avoid the loss of genetic material viz., breeds before adequate evaluation has been carried out.

Each breed may have valuable genes. The gene bank materials are to be studied as reference points such as blood types and enzyme proteins. The most common conservation methods in use are frozen semen banks and frozen embryos. The live conservation of herds is also adopted.

EXTINCT: No possibility of restoring the population, no purebred males or females can be found.

CRITICAL: Close to extinction, genetic variability reduced below that of ancestral population.

ENDANGERED: In danger of extinction, because of the number is too small to prevent genetic loss through inbreeding. Preservaion must be enacted.

INSECURE: Population number is decreasing rapidly VULNERABLE: Some disadvantages effects endanger the existence of the population. NORMAL : Population not in danger of extinction.

Vulnerability of uniparous populations

S. No.

Status No. of Breeding females

1 Normal more than 100002 Insecure 5000 to 100003 Vulnerable 1000 to 50004 Endangere

d100 to 1000

5 Critical less than 100

Population size of a breed for its status (thousands)

Species

Normal Insecure Vulnerable Endangered Critical

Cattle 25 15-25 5-15 2-5 <2.0Buffalo 30 20-30 10-20 5-10 <5.0

STATUS OF ANIMAL GENETIC RESOURCES (AnGR) IN INDIA

India possess a total of 30 breeds of cattle, 10 buffalo breeds, 42 sheep, 20 goats, 8 camel, 6 horse and 18 poultry breeds in addition to other species like pigs, donkey, mithun, yak, turkey, ducks, etc. A wide variety of agro-ecological zones (20 nos. and 60 sub-zones) existing in India has helped to develop these large number of breeds of various livestock species including poultry for the benefit of local people under different farming systems. This genetic diversity of domesticated livestock and poultry breeds was the net result of the evolution over millions of years in association with man’s intervention within specific ecological niche to suit the local needs and they are well adapted to their native ecology.

The share of India in terms of number of breeds is 7.75 per cent of the total world cattle breeds, 26.39 per cent of buffalo breeds and 8.26 per cent of goat breeds (FAO, 1995), while the population size was to the tune of 16.25 percent of the total world cattle population, 56.88 percent of buffaloes, 16.69 per cent of goats and 5.71 per cent of sheep (FAO, 2002). Around 58.64 percent of total buffalo population, 46.83 per cent of cattle,26.38 per cent of goat and 22.50 per cent of camel’s population of Asia are found in India (FAO, 2002).

All these livestock species are generally large but contain (i) a small percentage of recognized indigenous breeds with specific breed characteristics and (ii) a very large proportion of non-descript native animals, which do not conform to any specific breed characteristics in the native ecology and constitutes around 80% of total livestock population. The last category of animals have been found to utilize all available natural resources (pasture lands, barren and uncultivable waste lands), crop residues and low quality grains to a greater extent in comparison to the recognized indigenous breeds of livestock including poultry, but with low input and low output relationship.

Number of breeds of livestock species including poultry

Species

World Asia & Pacific

India (FAO)

India ICAR

% of World *

% of Asia*

Cattle 787 190 61 30 7.75 32.11Buffalo 72 57 19 15 26.39 33.33Sheep 920 226 59 42 6.41 26.11Goat 351 126 29 20 8.26 23.02Pig 353 157 3 3 0.85 1.91

Ass 77 17 3 3 3.90 17.64Horse 384 72 9 6 2.34 12.50

BREEDS REQUIRING CONSERVATION

Camel 56 14 8 14.29 57.14Chicken

606 72 18 2.97 25.00

(Source: World Watch List, FAO, 1995); * with respect to FAO number.

Current status of indigenous animal germplasm in the country

In the absence of planned efforts to conserve and maintain pure breed populations, indiscriminate breeding within the native stocks as well as crossbreeding of native with exotics has been continued over the last four decades resulting in production of crossbreds, hybrids and graded ones of unknown genetic makeup. It has been estimated that nearly 80 per cent of indigenous animals are non-descript and practically useless for resource development. Animal Genetic Resources in the country have not been properly documented and created databases in order to evaluate their total utility vis-a-vis sustainability in the respective agro-ecological and production systems.

The livestock census is being carried out breed-wise and not breed wise. It is, therefore, extremely difficult to know the exact number of animals of a particular breed in the native tract except the number of animals of a species in the area. A large proportion of animals are non-descript even in the breeding tract of a descript breed which has created problems in determining the numbers of animals of a particular breed. On the basis of the information gathered from various sources, the breeds of different livestock species showing serious decline in their numbers and needing urgent conservation efforts are presented below:

Breeds requiring immediate conservation

Species

Breed

Population (Approx.)

Breeding Tract

Cattle Punganur 75 Chittor (A.P.)Vechur < 150 Kottayam (Kerala)

Buffalo Toda 3530 Nilgiri (Tamil Nadu)Goat Jamnapari < 10,000 Uttar Pradesh and

Madhya PradeshSheep Nilgiri < 1000 Nilgiri (T.N.)

Bhakarwal < 1000 Jammu & KashmirPoonchi < 1000 Jammu & KashmirGurej < 1000 Jammu & KashmirKarnah < 1000 Jammu & Kashmir

IN-SITU CONSERVATION

Horse Zanskari < 1000 LadakhSpiti < 1000 Spiti (H.P.)

Camel Bacterian (Double humped)

72 Ladakh

Poultry All indigenous breeds < 1000 each

Concept of conservation

The concept of conservation has developed from increasing consciousness of the human interference with his environment and its adverse affect on the natural flora and fauna resulting in a number of wild species becoming extinct and disappearing from their habitat on earth. In the case of farm livestock, the situation is not so severe. However, there is a concern about reduction in genetic variability of the existing number of species, number of breeds within species and genetic variability within breeds. It is aimed at maintaining the genetic variability for high productivity to meet the needs and aspirations of future generations.

Mechanism of conserving livestock genetic resources

Conservation is an effective process initiated by man in preventing the total loss or in arresting the mutilation of endangered species of animals / plants in their natural habitat. Once genetic resources have been identified and characterized, two basic conservation methods are followed viz., in- situ and ex-situ conservation.

In-situ conservation requires establishment of live animal breeding farms and their maintenance within their production systems and native ecology. In-situ conservation strategies emphasize use of indigenous cattle genetic resources by establishing and implementing breeding goals and strategies for animal sustainable production systems. In any such programme, the success depends upon the participation of the farmer for which he needs support and incentives. However, it is difficult to organize the farmers for conserving the breeds that are no more economical to them. In the case of breeds that are no more economically viable but their conservation is necessary for future generations, under such circumstances, the only alternative would be to bring them under government farms.

The major limitation of live animal conservation (in-situ) is the number of animals selected and maintained in its environment. While fixing the number for preservation of a breed, the cost of maintenance, availability of animals and rate of inbreeding should be taken into account. With small population size, the effective population size decreases and the genetic structure of the population is affected due to inbreeding and random drift. Many models are now available which reduce inbreeding to a minimum, but random drift over long periods may lead to a population very different in genetic composition from the initial one. Besides, genotype x environment interaction also poses a serious threat on genetic structure of the population, which needs to be taken care of effectively.

EX-SITU CONSERVATION

In-situ conservation involves a large infrastructure of land, buildings, feed and fodder resources, water supply, labour, technical and supervisory manpower, etc. Therefore, a new establishment for in-situ conservation of farm cattle genetic resources are quite costly and even the maintenance of existing ones is cumbersome. It is useful to evaluate different options for self-sustaining population. However, economic incentives are essential in the period of in-situ conservation to reach self-sustainability. Therefore the costs need to be estimated for each ecosystem separately.

In case of preservation of small populations, to prevent undesirable effects of inbreeding and random drift, FAO suggested a mating ratio of 5 males and 25 females, but a ratio of 50 males and 250 females is recommended in case of traits with low heritability. When preservation is through cryogenic methods, semen from 25 unrelated males should be frozen and embryos from 35 different matings must be ensured for embryo freezing.

Advantages

Live animals can be evaluated and improved over years. Genetic defects, if any, could be eliminated Live animals are always available for immediate use. The expenditure of live animal maintenance is compensated from its produce.

Disadvantages

Many no. of animals are to be maintained If small population is to be maintained considering cost of maintenance,

inbreeding may result.

Ex-situ conservation techniques are further categorized into two groups viz.,o Ex-situ cryopreservation of genetic materials: In the form of haploid

cells (spermatozoa, oocytes), diploid cells (in-vivo and in-vitro embryos, somatic cells) and DNA

o Ex-situ live: The maintenance of live animals of a breed outside its production system and native ecology (herds maintained in naturally protected / reserved areas and farms, in zoos).

Ex-situ live method excludes the present socio-economic value, because in this conservation strategy the breed is removed totally from its socio economic considerations. Besides it will also not attract cultural and historical value as well as ecological value. Ex-situ conservation however, continues to provide powerful and safe tools for conserving the AnGR being threatened / endangered and facing extinction. It is the storage of genetic resources, which the farmers are currently not interested in using.

Ex-situ conservation is based on the use of live animal populations wherever practicable, supported by cryo-preservation where technology exists or can be developed and combining within-country gene banks with global repositories. Interested governments, non-governmental organizations, research institutions and private enterprises should be encouraged to maintain in-vivo samples of breeds at risk, with national inventories being established and kept up to date so that the genetic resources are readily available for use and study.

Because of random drift and possible gene x environment interactions, ex-situ methods are generally preferred over in-situ. Ex-situ conservation is

comparatively more

EX-SITU / CRYOGENIC PRESERVATION

MODULE-34: CURRENT LIVESTOCK AND POULTRY BREEDING PROGRAMMES IN STATE AND COUNTRY

convenient, economical and easy with the application of modern reproductive technologies.

It includes semen preservation, oocyte preservation, embryo preservation, preservation of ovaries, embryonic stem cell and nuclei, production of embryos in-vitro, embryo-splitting, transgenesis, DNA libraries. In-situ and ex-situ conservation schemes are complementary and not mutually exclusive, with their application for a particular animal genetic resource depending on farmers’ current use of it and its comparative uniqueness. Furthermore, frozen germplasm can play an important role in the support of in-situbreed development schemes.

Advantages

Easily done without any change in the genetic structure. Resource requirement for in-situ preservation is quite large as compared

to cryogenic methods.

Limitations

Ex-situ preservation using frozen semen delays the restoration of a breed. An important danger faced by a breed restored from cryogenic is from the

important changes in the environment like germs , climate, etc. that have taken place over the years.

Future strategies

There is need to cope with the diversity of agro-ecological settings and socio-economic resource endowments of the producers and to resolve the location specific livestock conservation and propagation. With this objective in view research programmes specific to agro-ecological zones for characterization and evaluation of livestock and poultry breeds are to be planned and refinement in production system need to be proposed. We should ensure stability and sustainability on war footing, besides containing potentially adverse impacts on the natural resource base and environment. There is also need to promote the multi-disciplinary location specific and participatory modes of operation through enhanced linkages between research institution and in all network and conservation programmes.

Learning objectives


livestock policy objectives of india, cattle and buffalo breeding policy of india and cattle breeding policy in different states.

LIVESTOCK POLICY OBJECTIVES OF INDIA

CATTLE AND BUFFALO BREEDING POLICY OF INDIA

To augment production of milk, eggs, chicken meat and other animal foods and increase availability of animal proteins in human diet.

To encourage livestock production through small holders with low input system. To expand organised dairying through synergisation of co-operative and

private sector efforts with a focus on quality and hygienic control. To increase production of quality carpet and coarse wool while

making efforts for developing fine wool. To enhance participation of women in livestock development programmes

and increase nutritional support and supplementary income to rural farmers.

To encourage conservation of animal bio-diversity and protection of indigenous breeds of livestock and poultry while restricting cross breeding to low producing stock.

To promote avenues for export of livestock and livestock products by adopting measures towards supportive fiscal policy as well as hygiene and quality standards consistent with global trade regime.

To control and eradicate communicable animal diseases pests and to increase health cover facilities for optimizing livestock production.

To augment feed and fodder resources for sustaining livestock and increasing production.

A reorientation of cattle and buffalo breeding policy would be attempted with area specific approach backed up by appropriate programs addressing our concerns for indigenous cattle breeds and draught animal power. A similar approach has been adopted in the National Project on Cattle and Buffalo Breeding.

Indigenous cattle breeds accepted by common farmers shall be further developed through region specific and breed specific programs aimed at selection in the breeding tracts and supply of improved quality germplasm on demand by farmers. The states shall be directed to specifically delineate the areas of native breeds of cattle, record their numbers breed wise and sex wise and encourage farmers to conserve them in their home tracts.

Formation of breed associations for improvement of indigenous breeds shall be encouraged. Such associations shall be involved in production of quality male stock. An effective mechanism for providing disease free quality breeding bulls and quality semen for artificial insemination will be put in place. Breeding services would be provided at the farmers’ door.

For sheep breeding also an area specific approach shall be adopted for effecting qualitative and quantitative improvement in carpet and coarse wool and developing fine wool. Breeding of sheep and goats will aim at increasing body weight, reproductive efficiency and control of mortality, besides improvement in milk yield in goats. Main focus will be on selection of rams and bucks and their distribution with backup by suitable programs. In high altitude areas support for breeding of Yaks and mithuns shall continue. Breeding of rabbits for fur and broiler purpose shall be encouraged in suitable areas. Preservation and development of pack animals – horses, mules, donkeys and camels - shall also be considered.

The indigenous breeds of livestock and poultry are essentially the products of long term natural selection and are better adopted to withstand tropical diseases and perform under low and medium input. Many of these breeds may have useful genes for fast growth, prolificacy and small size. Such

utility genes and breeds shall be identified,

CATTLE BREEDING POLICY IN DIFFERENT STATES

conserved and utilized. In recent time, international actions have been oriented towards conservation of animal genetic resources. India being a signatory to many such international agreements, the country will have specific policy focus on conservation of indigenous breeds of livestock and poultry. State will take up the responsibility of conserving such threatened breeds through appropriate programmes.

tate/UT Breed Breeding Policyra Pradesh Ongole Selective breeding in Ongole: grading up, non–descript with Ongole

Malvi Selective breeding Malvi in pockets, grading of Malvi with Tharparkar and Deoni Hallikar Selective breeding in Hallikar; grading up of nondescript with HallikarNon-descript Grading up, with Ongole, Tharparkar and Deoni cross breeding with Jersy and Holstein

achal eshm r

Local cattle

Local cattle Local cattle

Grading up, with Hariana and Redsindhi cross breeding with Jersy

Grading up, with Hariana and Redsindhi; cross breeding with JersyGrading up, with Tharparkar Hariana and Redsindhi; cross breeding with Jersy

tisgarh

Local cattle

Grading up, with Tharparkar Hariana and Shaiwal; cross breeding with Jersy and Holst

rat

ana

Gir, Kankrej

Local cattle Hariana Shaiwal

Selective breeding in Gir and Kankrej; grading up, non–descript with Gir and Kankrej; breeding with Jersy and Holstein-FriesianGrading up, with Redsindhi; cross breeding with Jersy Selective breedingSelective breeding

Non-descripit grading up, non–descript with Hariana, Shaiwal, Tharparkar; cross breeding with Jersy Holstein-Friesian.

achal Local

cattleGrading up, with Hariana and Redsindhi; cross breeding with Jersy

eshmu & Local

cattleGrading up, with Hariana and Redsindhi; cross breeding with Jersy

mir khand

atakaLocal cattle DeoniKrishna Valley

Khillari Amrit Mahal HallikarNon-Descript

Grading up, with Tharparkar Hariana and Redsindhi; cross breeding with Jersy

Selective breedingSelective breeding

Selective breeding Selective breeding Selective breedinggrading up, non–descript with Redsindhi; cross breeding with Jersy and Holstein-Fries

la Local cattle grading up, non–descript with Redsindhi, Kangayam and Tharparkar; cross breeding w

hya Pradesh

Crossbreds

Nimari Malvi Kenkatha

and Holstein-Friesian.Selective breeding with F1 cross bred bulls obtained from progeny tested either jersy or bullsSelective breeding Selective breeding Selective breeding

Non-descript Grading up, with Gir, Tharparkar, Hariana Shaiwal and Ongole; cross breeding with Jer

arashtra

Khillari Dangi Gaolao Nimari

HolsteinSelective breeding Selective breeding Selective breeding Selective breeding

Non-descript Grading up, with the breeds of the region and Hariana; cross breeding with Jersy and H

ipur Local

cattleGrading up, with Red sindhi; cross breeding with Jersy

halaya

Local cattle

Grading up, with Red sindhi; cross breeding with Jersy

ram

Local cattle

Grading up, with Hariana; cross breeding with Jersy

aland Local

cattleGrading up, with Hariana; cross breeding with Jersy

sa Local cattle Grading up, with Red sindhi and Hariana; cross breeding with Jersy and Holsteinab sthan

Local cattle Nagori Malvi Rathi

Grading up, with Shaiwal and Hariana; cross breeding with Holstein Friesian and Jersy Selective breedingSelective breeding Selective

b r eedingNon-descript Grading up, with Hariana, Gir, Tharparkar and Rathi; cross breeding with Jersy and Ho

Friesianim Siri Selective breeding

ilnadu

Local cattle Kangayam Umblachery BargurNon-descript

Grading up, with Hariana; cross breeding with Jersy Selective breedingSelective breeding Selective breedingGrading up, with Native breeds; cross breeding with Jersy in plains and Holstein Friesi areas

ura

Local cattle

Grading up, with Tharparkar; cross breeding with Jersy

r pradesh

Kenkatha

Selective breeding

Non-descript Grading up, with Hariana, Shaiwal, Tharparkar and Red sindhi; cross breeding with Jer

Holstein Friesian

learning objectives€¦ · web view2021. 2. 1. · the mohenjo-daro seal with a bull known...

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