developments in genetics and welfare in broiler chickenfjaderfa.se/attachments/91/1540.pdf ·...

Developments in genetics and

welfare in broiler chicken

W. Bessei

Universität Hohenheim

Stuttgart-Hohenheim, Germany

Seminar

Svensk kyckling – framtida utmaningar och möjligheter

Uppsala-Lövsta, 9 – 10/ 2 2012

The Red Jungle Fowl (Gallus bankiva)

Commercial broiler 35 days of age

Body weight of male broilers at 42 days of age

(Havenstein al., 2003)

Diet

(g)

Feed conversion rate of male broilers at 42 days of age

(Havenstein al., 2003)

Diet

(1: )

Welfare problems related to genetic selection

for growth in broilers

• Leg problems

– Tibial Dyschondroplasia (TD)

– Bone deformation (Varus-Valgus)

– Reduced locomotor activity /irregular gait

– irregular posture

– Footpad dermatitis

• Problems of the cardiovascular system

– Sudden Death Syndrome (SDS)

– Ascites

Fast, intermediate and slow growing broilers 3 weeks

of age (Lorenz, 2010)

ROSS 708 ISA 657 ISA 757

Male broiler

Male layer

(medium

heavy, LB)

Male layer

(light, LSL)

Fast growing broiler, intermediate and light layer

strain males (Gerken et al., 2003)

Raising males of commercial layer lines in Italy

Body weight development in fast and slow growing

broilers (Schmid, 2007)

Age of

slaughter

The problems in meat producing poultry

Rapid early growth rate

Lighting

programmesGenetic

selection

Intensive

Feeding



• Leg problems








– Ascites

Heritabiliy estimates for Troponin-T levels (native

Troponin-T x 10.000) (Grashorn et al., 1998)

Model h² s.e.

Harvey

Full sibs 0.20 0.03

Patern. Half sibs 0.39 0.16

Matern. Half sibs 0.01 0.11

REML 0.23 0.05

Mean

(%S

aO

2)

Age (days)

a bab

RS RS RS RS RS

Mean % saturation of hemoglobin with oxygen (SaO2) in S4

chicks from AS-S and AS-R lines, measured during regular

brooding conditions (from day of hatch to Day 19), and under

ascites-inducing condition (Druyan et al., 2010)

Oxigen saturation in the blood of broiler Grand Parent

stocks after 12 years of selection (1989 – 2011)

(Source: Aviagen)

Mortality in commercial broilers in the UK from 1989

(Source: Aviagen)

Commercial Broiler Mortality UK

Ross 308 Breed

2.00

2.50

3.00

3.50

4.00

4.50

5.00

1998 2000 2002 2004 2006 2008 2010 2012

Mortality %

Mortality reducing at 0.08% per year

Development of mortality in commercial broilers from

2003 in the USA

Commercial Broiler Mortality USA

Ross 708 Breed

2.00

2.50

3.00

3.50

4.00

4.50

5.00

5.50

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Mortality %

Mortality reducing by 0.11% per year

Danish Industry Performance Data

Liveweight

1500

1700

1900

2100

2300

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012


FCR

1.500

1.600

1.700

1.800

1.900

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012


Mortality

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012


37 Day Liveweight

1500

1700

1900

2100

2300

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012


Killing Age

35.0

36.0

37.0

38.0

39.0

40.0

41.0

42.0

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012


EPEF

200

220

240

260

280

300

320

340

360

380

400

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012

Long-term Biological Trends of mortality and growth rate of broilers in Denmark

Broiler Processing Defect Trends

Ascites Condemn rates in birds per 10,000 as reported by the Canadian Food

Inspection Agency

0

5

10

15

20

25

30

35

40

45

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Condems/ 10,000



• Leg problems








– Ascites

Results of a one generation selection for reduced and increased

frequency of Tibial Dyschondroplasia (TD) by Lixiscope

measurements (after Soerensen, 1982)

Line Freq. of TD (%)

male fem.

Body

weight (g)

Control 20,0 14,4 2134

High TD 53,9 44,6 2163

Low TD 10,1 6,0 2126

Results of selection over three generations against

leg problems (Sörensen, 1992)

Linie Tibia Proximal Tibia distal

Low leg problems

High leg roblems

control

25,6 o

34,6 o

28,4 o

0,4 o

1,1 o

0,6 o



• Leg problems




– Irregular posture




– Ascites

Body weight, locomotor activity and leg conditions are

closely interrelated

Body weight

Locomotor activity Leg conditions

Walking and sitting (resting) behaviour of fast

growing broilers in response to age(Reiter und Bessei, 1996)

1 2 3 4 5

Age (weeks)

0

4

8

12

16Walking (%)

70

75

80

85Sitting (%)

walking sitting

Lebenswoche

Distance walked (m per hour ) of fast and slow growing

broilers (Lohmann Meat; Label Rouge) (Reiter and Bessei;…)

Gelaufene Strecken (m/h)

What do we know?

• Any means which reduce early growth

increase the locomotor activity and

improve the leg conditions of broilers

• However, it is difficult to reduce growth

rate under competitive market conditions

• This raises the question on the role of

locomotor activity in the development of

leg problems

The treadmill

Videotracking for measuring the sponaneous

locomotor activity of broilers

Deformation of Tibial bones of slow (left)

and fast (right) growing broilers

Analysis of bone characteristics by computer-

tomography

Mean values of the distance walked by broilers of a fast (FG) and a

slow growing (SG) broiler strain in walking test on a treatmill with

a max. distance of 100 m (Reiter, 2002)

0

20

40

60

80

100

120

2 3 4 5 6

FG

SG

The influence of locomotor exercise on bone

characteristics as measured by CT (Reiter, 2002)

Treatment Tibial

Angulation

Tibial

Torsion

(°)

Corticalis

area (mm²)

Corticalis

thickness

(mm)

FG

without

exercise

28,5a 25,4 10,5 0,38b

FG with

exercise

23,9b 21,5 17,7 0,99a

SG

without

exercise

25,7 21,7 13,6 0,42

SG with

exercise

24,6 19,0 10,8 0,36

Conclusions

• When tested or trained on a treadmill, broilersare able to fast growing broilers are able to walk more than they do in their home range

• Increased locomotor activity improves the boneconditions

• This raised the question whether the low activityof broilers under practical conditions is causedby the high weight load or lack of motivation

• To answer this question is was necessary to change the weight load independently from thegrowth rate

Body weight, locomotor activity and leg conditions are

closely interrelated: Effect of reduced weight load at

the same growth rate

Body weight

Locomotor activity Leg conditions

Weight load

Device to alleviate the

weight load

on the legs (Djukic, 2002)

Harness

Balance

Triples of slow growing broilers loaded and fast growing

broilers unloaded and two control birds each (Djukic

2002)

Body weight development of untreated fast growing

(Ross) and medium growing (ISA) broilers (Djukic,

2002)

0,0

500,0

1000,0

1500,0

2000,0

2500,0

1 2 3 4 5 6

ISA Mean ROSS

Locomotor activity of slow (ISA) and fast (Ross) growing broilers

when brought to the same weight load (after Djukic, 2007)

0

0,5

1

1,5

2

2,5

Control Modified BW

ROSS ISA

Activity

Angulation of the tibiotarsus (proximal) (°) (Djukic, 2007)

15

20

25

30

35

40

Isa loaded Isa Kontr. 1 Isa Kontr. 2 Ross unloaded Ross Kontr. 1 Ross Kontr. 2

ISA ROSS

a a a b a a

Development of leg defects in Ross 308 broiler Grand

Parent Stocks (Source: Aviagen)

Trend in leg defects in BUT Big 6 Turkey Grand Parent

Stocks (Source: Aviagen)

Broiler Processing Defect Trends

Leg Condemn rates in birds per 10,000 as reported by the Canadian Food

Inspection Agency

0

1

2

3

4

5

6

7

8

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Condems/ 10,000

Change in Reporting -

all leg condemns



• Leg problems








– Ascites

Fußballendermatiden

Foot pad dermatitis (by courtesy J. Kjaer)

Country Frequency Referenceof flocks

Sweden 88% Ekstrand et al., 1998

UK 94% Pagazaurt. and Warriss, 2006

Country Prevalence ReferenceD, Standard 95% Wolf-Reuter, 2004

D, Free range 80% Wolf-Reuter, 2004

D, Organic 48% Wolf-Reuter, 2004

UK, Standard 16% Pagazaurt. and Warriss, 2006

UK, Standard 14% Pagazaurt. and Warriss, 2007

UK, Freedom F. 10% Pagazaurt. and Warriss, 2007

UK, Organic 98% Pagazaurt. and Warriss, 2007

Foot pad dermatitis(by courtesy J. Kjaer)

• A genetic investigation on pedigreed

populations:

– A fast growing commercial broiler hybrid,

N=960

– A slow growing experimental broiler line,

N=960

– 35 Sires per line

Foot pad dermatitis(by courtesy J. Kjaer)

Conclusions

• Most welfare problems of broilers are related to rapid

early growth rates

• The longterm development of the incidence of

ascites, SDS, TD has shown, that the problems can

be reduced even with further increase of growth rate

• The control of these problems has led to a lower

mortality and condemnation rate

• The problems which are being adressed at present

are gait problems (angulation and torsion of the leg

bones) and footpad dermatitis.

• There is sufficient genetic variation within the broiler

lines which indicate ways for improvement

developments in genetics and welfare in broiler chickenfjaderfa.se/attachments/91/1540.pdf ·...

Documents