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UNIVERSITI PUTRA MALAYSIA
STUDIES ON THE UTILIZATION AND SUPPLEMENTATION OF SWEET CORN STOVER SILAGE AND ITS EFFECT ON
CARCASS COMPOSITION OF GROWING LAMBS
YACOB
FPV 1994 4
STUDIES ON THE UTILIZATION AND
SUPPLEMENTATION OF SWEET CORN STOVER
SILAGE AND ITS EFFECT ON CARCASS
COMPOSITION OF GROWING LAMBS
YACOB
MASTER OF SCIENCE UNIVERSITI PERTANIAN MALAYSIA
1 994
STUDIES ON THE UTILIZATION AND
SUPPLEMENT ATION OF SWEET CORN STOVER
SILAGE AND ITS EFFECT ON CARCASS
COMPOSITION OF GROWING LAMBS
By
YACOB
Thesis Submitted in Fulfillment of the Requirements
for the Degree of Master of Science in the Faculty
of Veterinary Medicine and Animal Science
Universiti Pertanian Malaysia
June 1994
ACKNOWLEDGEMENTS
The author expresses his sincere appreciation to Assoc. Prof. Dr. Hj.
Mohamad Hilmi Hj. Abdullah and Dr. Abdul Razak Alirrion for their guidance,
support, encouragement and patience throughout the author's period of graduate
studies and in the preparation of the thesis manusclipt.
Grateful thanks and appreciation are due to Drs. Abdul Razak, Abdul Malik,
MA. and Maman Ripai, MA. and the staff of the Agliculture Ministry of Indonesia
for their encouragement and support.
Deep appreciation is also due to the National Project of the Department of
Agriculture, Republic of Indonesia and U niversiti Pertanian Malaysia for providing
scholarship and technical support, respectively.
Sincere appreciation and gratefulness are also extended to the Animal
Nutrition and Meat Science Division, Department of Animal Science for the
facilities and technical support by their staff in particular, Mr. Ibrahim Mohsin, Mr.
Bakari Abdul Rahman, Mr. Saparin Demin and Mr. Sahri! Hassan, and also the staff
of Ladang Dua especially Mr. Sukri lusoh, Mr. Islahuddin, Mr. Bahron Utar and
Mr. lamiudin and Mr. Palaniappan for their assistance in conducting the
experiment.
Special thanks to my father, Mohd. Ali and mother Nuriah, for their support
and encouragement.
Finally, this manuscript and the work it represents could not have been
achieved without the patience and understanding of the author's loving wife,
Nuriaty, son, Aan and daughters, lin, Iyen and Vivi.
II
T ABLE OF CONTENTS Page
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . · . . . . . . . . ii
LIST OF TABLES · . . . . . . . Vll
LIST OF FIGURES • . . . . . . . IX
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X
ABSTRAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xu
CHAPTER
I INTRODUC1rION . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 1
II LITERATURE REVIEW . . . . . . . . . . . . . . . . . . . . . . . ..... 5
Crop Residues as Ruminant Feed . . . . . . . . . . . . . . . . . . . .5
Cultivation of Sweet Corn in Malaysia . . . . . . . . . . . . . . . . . 8
Corn Stover as Ruminant Feed . . . . . . . . . . . . . . . . . . . . . 10 Grazing System . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Cut and Carry System . . . . . . . . . . . . . . . . . . . . . . . 10
Nutritive Value of Corn Stover . . . . . . . . . . . . . . . . . . . . . 1 1 Chemical Composition . . . . . . . . . . . . . . . . . . . . . . 1 2
Rumen Degradability . . . . . . . . . . . . . . . . . . . . . . . 1 4 Voluntary Intake . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Digestibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Rumen Parameter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 9 Ammonia . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . 1 9 Volatile Fatty Acid . . . . . . . . . . . . . . . . . . . . . . . . . 20 Rumen pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Supplementation of Corn Stover . . . . . . . . . . . . . . . . . . . . 2 1
Growth Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Carcass Traits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Carcass Weight . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Dressing Percentage . . . . . . . . . . . . . . . . . . . . . . . . 24 Carcass Composition . . . . . . . . . . . . . . . . . . . . . . . 25
Longissimus dorsi muscle . . . . . . . . . . . . . . . . . . . . . . . . 26
111
In GENERAL MATERIALS AND METHODS . . . . . . ' . . . . . . . . . 27
Location of Experiment . . . . . . . . . . . . . . . . . . . . . . . . . 27
Processing of Sweet Corn S tover . . . . . . . . . . . . . . . . . . . 27 Collection of Sweet Corn Stover . . . . . . . . . . . . . . . . 27 Silo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Silage Making . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Animal . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 28
Laboratory Chemical Analyses . . . . . . . . . . . . . . . . . . ... 29
Dry Matter (DM) . . . . . . . . . . . . . ... . . . . . . . . .. 29
Ash and Organic Matter (OM) . . . . . . . . . . . . . . . . . . 30
Crude Protein (CP) . . . . . . . . . . . . . . . . . . . . . . . . . 30 Ether Extract (EE) . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 Crude Fibre (CF) . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 Neutral Detergent Fibre (NDF) . . . . . . . . . . . . . . . . . 32 Acid Detergent Fibre (ADF) . . . . . . . . . . . . . . . . . . . 33
Acid Detergent Lignin (ADL) . . . . . . . . . . . ....... 33
IV CHEMICAL COMPOSITION AND DEGRADABILITY OF SWEET CORN STOVER, ITS PARTS AND ITS SILAGE . . . . . . 34
Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . 35 Sampling of Sweet Com Stover . . . . . . . . . . . . . . . . . 35 Preparation of Com Stover Silage . . . . . . . . . . . . . . . . 35 Chemical Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 38 Degradibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
S tatistical Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Nutritive Value of Sweet Corn Stover and Its Parts . . . . . . 39
Nutritive Value of Sweet Corn Stover Silage ......... 44
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Chemical Composition . . . . . . . . . . . . . . . . . . . . . . 48 Degradibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
V THE EFFECT OF SOURCES AND LEVELS OF PROTEIN SUPPLEMENTATION OF SWEET CORN STOVER SILAGE BASED DIET ON INTAKE, DIGESTIBILITY AND RUMEN PARAMETER OF GROWING LAMBS . . . . . . . . 55
IV
Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . 58 Preparation of Sweet Com Stover Silage (SCSS) . . .. . . . 58 Animals . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . 59 Feeding Management . . . . . . . . . . . . . .. . . . . . . . . 59 Sample Collection and Chemical Analysis . . . . . . . . . . . 60
Statistical Analysis . . . . . . . . . . . . . . . . . . . . . . .. . . . . 62
Results . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . ... 63 Chemical Composition of SCSS and Concentrates. . . . . . 63 Experiment 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Experiment 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Dry Matter and Organic Matter Intakes . . . . . . . . . . . . . 72
Digestibility . . . . . .. . .... . .. . . . . . . . . . . .. . . 72
Rumen Ammonia . . . . . . . . . . . . . . . . . . . . . . . . . 73
Rumen VFAs . . . . . . .. . .. . . . . .. . . . . . . . . . . . 74 Rumen pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
VI THE EFFECT OF SOURCES AND LEVELS OF PROTEIN SUPPLEMENT A TION OF SWEET CORN STOVER SILAGE BASED DIET ON GROWTH, CARCAS S COMPOSITION AND LEAN CHEMICAL COMPOSITION OF GROWING LAMBS . . . . 77
Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . 78 Animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Diets and Management . . . . . . . . . . . . . . . . . . . . . . 78 Determination of Dry Matter Intake . . . . . . . . . . . . . . . 79 Feeding Behaviour. . . . . . . . . . . . . . . . . . . . . . . . . 79
Growth Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Slaughter Procedure . . . . . . . . . . . . . . . . . . . . . . . . 80 Carcass Composition . . . . . . . . . . . . . . . . . . . . . . . 8 1 Shear Force Measurement . . . . . . . . . . . . . . . . . . . . 8 1 Chemical Composition . . . . . . . . . . . . . . . . . . . . . . 82
S tatistical Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Results . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 83
Nutrient Intake . . . . . . .. . . . . . .. . . . . . . . . . . . . 83
Feeding Behaviour . . .. . . . . . . . . . . . . . . . . . . . . . 84
Growth Rate and Carcass Composition . . . . . . . . . . . . . 85
v
Discussion . . . . . . . . . . . . . . . . . ........ ........ 89
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
VII GENERAL DISCUSSION AND CONCLUSION . . . . . . . . . . . . . 93
Chemical Composition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Effect of Protein Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Effect of Protein Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
APPENDIX : Additional Tables .. . . . . . . . . . . . . . . . . . . . .. . . . 113
CURRICULUM VITAE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
PUBLISHED PAPERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
vi
Table
1
2
LIST OF TABLES
Utilization of Corn Stover as Animal Feed . . .
Area Under Sweet Corn Cultivation (hectares) According to S tates and Years in Peninsular Malaysia
3 Division of Forages Organic Matter by System of
Page
. . . . 7
· . . 9
Analysis Using Detergent . . . . . . . . . . . . . 13
4 Chemical Composition of Crop Residues . . . . 14
5 Live Weight and Dry Matter Intake (DMI) of Sweet Corn Stover by Sheep, Cattle and Buffalo . . . . . . . . . .. . . . . 1 6
6
7
Dry Matter Digestibility and Nitrogen Contents of Crop Residues . . . . . . . . . . . . . . . . 1 8
Ratio of Concentrate and Silage During Adaptation Period of Growing Lambs . . . . . . . . . . . . . . . . . 29
8 The Chemical Composition of Sweet Corn Stover and Its Parts on Dry Matter B asis .. . . . . . . . . . . 40
9 Dry and Organic Matter Degradability of Sweet Corn Stover and Its Parts at 72 hours Incubated on Sheep, Cattle and Buffalo . . . . . . . . . . . . . . . . . . . . . . . . 42
1 0
1 1
The Soluble (a), the Potential Degradation (a+b) and the Degradation Ratelhours (c) of S weet Corn Stover and Its Parts on Sheep .... . . . . . . . . .
The Chemical Composition of Sweet Corn Stover and Its Silage at 4 and 16 Weeks of Storage ... ..
12 Dry Matter and Organic Matter Degradability of Sweet Corn Stover Silages at 72 hours Incubated on S heep,
· . 43
· .44
Cattle and Buffalo . . . . . . . . . . . .. . . . .. . . . .. . .. . ... 46
1 3
14
The Soluble (a), the Potential Degradation (a+b) and the Degradation Rate/hours (c) of Sweet Corn Stover and Its Silage on Sheep . . . . . . . . . . . . . . . . . . . .
Composition of Concentrate . . .... . . .. . . . .. . .
Vll
. 47
. 58
1 5 Sweet Corn Stover Silage (SCSS) and Concentrate Offered ........... .
1 6 Chemical Composition of Sweet Corn Stover Silage and Concentrates .............. .
1 7 The Effect of Sources and Levels of Protein Supplementation of Sweet Corn Stover Silage (SCSS) Basal Diet on Dry Matter and Organic Matter
. 60
. 63
Intake by Growing Lambs . . . . . . . . . . . . . . . . . . . . . . . . . .65
1 8 The Effect of Sources and Levels of Protein Supplementation of Sweet Com Stover Silage (SCSS) Basal Diet on Nutlient Digestibility, TDN and Metabolizable Energy (ME) by Growing Lambs. . . . . . . . . . . . . 67
19 The Effect of Sources and Levels of Protein Supplementation of Sweet Com Stover Silage (SCSS) Basal Diet on DIy Matter Intake(DMI), Rumen pH, Rumen Ammonia and Rumen VF As of Sheep . . . . . . . . . . . . . . . . . . . 68
20
2 1
The Effect of Protein Levels and Sources on Dry Matter, Organic Matter and Crude Protein Intake by Growing Lambs Fed SCSS .....
The Effect of Dietary Treatment on Feeding Behaviour by Growing Lambs Fed SCSS ...
22 The Effect of Sources and Levels of Protein Supplementation of Sweet Com Stover Silage Basal Diet on Growth Rate, Carcass
. 83
. 84
Composition of Growing Lambs . . . . . . . . . . . . . . . . . . . . . . 86
23
24
The Effect of Sources and Levels of Protein Supplementation of Sweet Com Stover Silage Basal Diet on Rib-Eye Area and Its Chemical Composition of Growing Lambs . . . . . . . . .
Average Growth Rate of Individual Lamb in Each Group with Group Mean and Standard Deviation
25 Component of the Live Lamb as Percentage of
. . 88
. . . . . . . . 114
Live Body Weight. . . . . . . .. .. . . . . . . . . . . . . ... . . . . 1 15
26 Degradibility of Sweet Corn Stover Silage and Its Component in Sheep ... . . . . .... . ... . . . . . .. . . 1 16
27 Ammonia, pH and Volatile Fatty Acids in S heep Fed Sweet Corn Stover Silage . . .. . . . . . . .. . . . . . . . ... . . . 1 18
Vlll
Figure
1
2
LIST OF FIGURES
Ensiling Process of Sweet Com Stover.
Dry Matter Disappearance of Sweet Corn Stover and Its Parts on Sheep .
3 Organic Matter Disappearance of Sweet
Page
. . 37
. . . . . . 5 1
Corn Stover and Its Parts on Sheep . . .. . . . . . . . . . . . 52
4 Dry Matter Disappearance of Sweet Corn Stover Silage on Sheep . . . . . . . . . . . . . . . . . . . 53
5
6
7
8
Organic Matter Disappearance of Sweet Corn Stover Silage on Sheep . . . . . . . .
Concentration of Rumen Ammonia ....
Concentration of Rumen VF As
Concentration of Rumen pH ..
IX
53
69
70
. 7 1
Abstract of the thesis presented to the Senate of Universiti Pertanian Malaysia in fulfillment of the requirements for the Degree of Master of Science
STUDIES ON THE UTILIZATION AND SUPPLEMENTATION OF SWEET CORN STOVER SILAGE AND ITS EFFECT ON CARCASS
COMPOSITION OF GROWING LAMBS
by
Yacob
June 1994
Chairman: Assoc. Prof. Dr. Mohamad Hilmi. Hj. Abdullah
Faculty: Veterinary Medicine and Animal Science
The main objectives of this study are to detennine the growth performance
and carcass composition of growing lambs raised on sweet corn stover silage.
The sweet com stover can be considered to be a better quality animal feed as
indicated by its high crude protein content and its low neutral detergent fibre, acid
detergent fibre and acid detergent lignin as compared to other cereal crop straws.
The nutrient content of the sweet com stover could be maintained by ensiling. The
ensiling process takes four weeks and the silage can be stored for 16 weeks without
any change to its nutritive value. When rice bran is added to the ensiling, the crude
protein and the potential degradability increase. However, addition of molasses
only increased potential degradability but decreased crude protein content.
The total intake of sweet com stover silage by growing lambs was 24.2 g dry
matter/kg body weight. The concentration of rumen ammonia was 229.2 mg Nil and
the total volatile fatty acids was 63.1 mM/i. With concentrate supplementation
(200 g/animal/day; 20 - 30% crude protein, fish or soybean meals as source of
x
protein) on the sweet corn stover silage basal diet, the total dry matter intake
increased (29.0%), however, dry matter intake of sweet corn stover silage decreased
( 1 3 .6%). The concentrate supplementation also increased rumen ammonia (28. 1 %)
and total volatile fatty acids (5 .5%).
Providing 100% of the sweet corn stover silage to the lambs was sufficient
for maintenance as well as for a little average daily gain (10.7 g/day) with a dressing
percentage of 42.5%, carcass fat of 3.3% and lean to bone ratio of 1 . 86: 1 . The
concentrate supplementation increased the average daily gain to 7l.6 g/day, the
dressing percentage to 47 .7%, the carcass fat to 8 .3% and the lean to bone ratio to
2 .8 : l .
Fish meal or soya bean meal as a source of protein supplementation had a
similar effect on the nutritive values, growth rate and carcass composition.
Xl
Abstrak tesis yang dikemukakan kepada Senat Universiti Pertanian Malaysia sebagai memenuhi syarat keperluan untuk Ijazah Master Sains
KAJIAN KE AT AS PENGGUNAAN DAN SUPPLEMENTASI SILAJ JERAMIJAGUNG MANIS DAN KESANNYA KE ATAS KOMPOSISI
KARKAS BEBIRI YANG SEDANG MEMBESAR
Oleh
Yacob
Jun 1 994
Pengerusi: Prof. Madya. Dr. Mohammad Hilmi. Hj. Abdullah
Fakulti: Kedoktoran Veterinar dan Sains Peternakan
Objektif utama kajian ini adalah untuk menentukan prestasi pertumbuhan
dan komposisi karkas bebiri yang sedang membesar dan diberi pemakanan silaj
jerami jagung manis
Jerami jagung manis boleh dianggap sebagai makanan ternakan yang
mempunyai kualiti yang baik, iaitu tinggi dalam kandungan protein kasar dan
rendah dalam e kandungan neutral detergen fiber, asid detergen fiber dan asid
detergen lignin berbanding kepada jerami tanaman bijirin lain. Kandungan nutrien
daripada jerami jagung manis ini dapat dipertahankan dengan proses fermentasi.
Proses pemasaman adalah empat minggu sahaja dan silaj ini dapat disimpan da1am
selama 16 minggu tanpa sebarang perubahan pada nutriennya. Jika dedak padi
ditambahkan pada masa fermentasi, kandungan protein kasar dan keupayaan
pendegradan akan meningkat, manakala penambahan molases hanya meningkatkan
keupayaan pendegradan sahaja sedangkan kandungan protein kasar menurun.
xii
Jumlah pengambilan silaj jerami jagung manis oleh bebiri yang sedang
membesar adalah 24.2 g bahan keringlkg berat badan . Konsentrasi rumen ammonia
dan asid lemak meruap keseluruh'l:nnya masing-masing adalah 229.2 mg N/l dan
63. 1 mM/l. Dengan penambahan makanan tambahan (200 g/ekor/l1ari, kandungan
protein kasar antara 20 - 30%, tepung hampas kacang soya atau tepung ikan sebagai
sumber protein) kepada makanan asas, pengambilan bah an kering meningkat
(29.0%). Walau bagaimana pun ianya menurunkan pengambilan bahan kering dari
silaj ( 1 3.6%). Konsentrasi dari pada rumen ammonia dan jumlah asid lemak
meruap juga meningkat dengan makanan tambahan masing-masing sebanyak 28. 1 %
dan 5.5%.
Pemberian 100% silaj jerami jagung manis hanya mencukupi keperluan
saraan dan meningkatkan sedikit purata pertambahan harian ( 10.7 g/hari) dengan
peratusan karkas (42.5%), lemak karkas (3.3%) dan nisbah daging dengan tulang
( 1 .86: 1 ) . Penambahan dengan konsentrat, meningkatkan purata pertambahan harian
kepada 7 1 .6 g/hari) , peratusan karkas kepada 47.7%, lemak karkas kepada 8.3% dan
nisbah daging dengan tulang kepada 2.8 : 1 .
Tepung hampas kacang soya dan tepung ikan sebagai sumber protein
tambahan mempunyai kesan yang sarna ke atas nilai pemakanan, pertumbuhan dan
eiri-eiri karkas daripada bebiri yang sedang membesar yang memakan silaj jerami
j agung manis.
Xlll
CHAPTER!
INTRODUCTION
Efficiency of livestock production depends greatly on sufficient feed of the
right quality and its availability throughout the year. The potential of animal
production depends critically on feed energy and protein resources (Sykes, 1992).
Devendra (1991) reviewed the availability of feed resources in the Asian region and
identified the importance of permanent pasture and crop residues.
In South East Asia, the productivity of ruminant livestock is extremely low
due to its traditional management system, poor nutritional status and, to some
extent, poor disease control especially in the rural areas. In Malaysia, as in most of
the Asian counuies, ruminants are still raised under u'aditional system. The animals
are let to graze on the forages growing along the road sides, on unused lands, and
sometimes in the rice fields after the harvesting period. During the rainy season, the
supply of green forages are generally sufficient, but dUling dry season the supplies
are limited. The success or failure of livestock enterprise in Malaysia depends
mainly on the availability of feed, particularly during dry season, when little or no
grass grows.
With the advancement of agricultural technology, most of the arable
agricultural lands are fully utilized. In modern rice production systems, the rice
fields are not left idle but are cultivated with other cash crops such as corn, sweet
p otato and tobacco. With limited areas available for grazing, more and more
1
2
farmers are forced to practice cut and cany system or to feed their animals with
commercial feeds. However, the cost of commercial feeds is high. Since most of
the ingredients are imported, the cost of the commercial feed becomes too
expensive and is not economically viable for smallholder faImers. Therefore, a
cheaper ruminant feed as an alternative, which is not directly in competition with
human consumption is necessary. Since most of agricultural activities in Malaysia
aI'e based on intensive crop production, a variety of crop residues are available as
feed for ruminants. These by-products include rice straw, corn stover, sugar cane
bagasse, sugar cane tops, etc. Some of these feeds, such as rice straw, are
traditionally used by faI'mers to feed their animals.
Generally, fibrous crop residues are characterized by extensive lignification
of cellulose and hemicellulose, and by low level of protein, soluble carbohydrates
and mineral (Dixon, 1 986) . These characteristics are caused by the changes in cell
wall content due to the increase in maturity. Weaver (1978) stated that increasing
maturity will not only increase cell wall percentage, but also decreases the
digestibility of cell wall. McManus (1983) determined that the decrease in
digestibility of cell wall was caused by substances masking cell wall structures
which prevented the action of microorganisms and enzymes upon the substrates
within the cell. Moreover, McManus (1983) said that masking substances were
lignin, hemicellulose and certain protein. He showed that the masking substances
are enhanced by mineralization of silica in external layers of the cell wall. Some of
the crop residues like corn stover, although abundantly available, are unused and
left in the field. According to Carangal and Calub (1987), and McDonald et al.
(1987), the corn stover has a high nutrient content and is more digestible than other
cereal crop residues. McDonald et al. (1987) repOlted that com stover has crude
3
protein of about 60 g/kg DM and a metabolizable energy (ME) value of about
9 MJ/kg DM. Rivera et al. ( 1989c) reported that the average daily gain of calves
grazing on com stover field at 2.7 1 stocking rate (headlha) was 0.5 13 kg/day.
Com stover is one of the major crop residues in Malaysia. Sweet com was
first introduced to small farmers by Malaysian Agricultural Research and
Develpoment Institute (MARDI) in 1 98 1 . It replaced most of the traditional cultivar
of boiling com (Ramli and Zameri, 1 983). As a result, the area of sweet com
cultivation in Peninsular Malaysia in 1989 increased to 7,116 ha (Kementerian
Pertanian Malaysia, 1 989). In harvesting sweet corn, ears are picked before they are
fully ripe and the partly green stover are left in the field to decompose or are cut
down and removed from the field. The land may be prepared for other crops.
Approximately, 40 to 50% of com plant dry matter remains in the residues after
harvesting (Berger et aI. , 1979). Like many bulky crop residues in Malaysia, the
collection and storage of com stover are major constraints in their utilization for
livestock feeds. The storage of dry stover requires a large area and space because of
its bulkiness and requires care because they present a high fire hazard. The other
method of preserving com stover is by ensiling (Isarakul, 1 982; Castillo, 1983).
The efficiency of animal production raised on crop residues is not only
detennined by availability and continuity of their supply, but is also basically
detennined by its nuuitive values, digestibility and their effect on growth
performance and carcass composition. Even though a lot of research on com stover
as animal feed has been done, the local work on the use of sweet com stover silage
as feed are few. The nutritive value, intake, digestibility of sweet com stover silage
and its effect on growth performance and carcass composition of growing lamb are
still not fully established.
4
The main objectives of this study are to determine growth performance and
carcass composition of growing lambs raised on sweet corn stover silage. The
specific objectives are as follows:
1. To determine the chemical composition of sweet corn stover fraction and
sweet corn stover silage.
11. To determine the degradability of sweet corn stover fraction and sweet corn
stover silage.
111. To determine the intake and digestibility of sweet corn stover silage
supplemented with different sources and levels of protein.
IV. To determine the effect of different sources and levels of protein
supplementation of sweet corn stover silage basal diets on rumen pH,
ammonia and VFAs concentration.
v. To determine the effect of different sources and levels of protein
supplementation of sweet corn stover silage basal diets on growth
performance of growing lambs.
VI. To determine the effect of differen t sources and levels of protein
supplementation of sweet corn stover silage basal diets on carcass
composition of growing lambs.
CHAPTER II
LITERATURE REVIEW
The majority of farmers in the Asian region are involved in mixed farming
system. In general, smallholder farmers have small area of land (1-2 ha). They
usually diversify their activities to maximize income from the land. Many farmers
keep livestock as integral part of the frum. The animals are kept for home
consumption, insurance against crop failure and for the production of manure. The
majority of ruminants in Malaysia are raised under traditional management system.
The animals are allowed to graze on waste or unused land during the day and are
kept at night in simple pens or sheds. During the dry season green forages are
limited and most farmers feed their ruminant with crop residues such as rice straw,
sugar cane tops, etc.
Crop Residues as Ruminant Feed
Ruminant animals have a stomach with four compartments, namely rumen,
reticulum, omasum and abomasum. The rumen acts as a large fermentation vat and
has a very high population of microorganisms (Church and Pond, 1 978) . Unlike
monogastric animals, ruminant animals are able to digest low quality roughage to
volatile fatty acid as source of energy by using microorganisms (McDonald et al.,
1987). By fermentation, the ruminant converts the crop residues, which are not
digestible for human, to very nutritious and palatable human foods, meat and milk.
5
6
Crop residues are major source of feeds for ruminant in S outh East Asia,
particularly in area where land for grazing is limited and pasture growth is seasonal
(Dixon and Egan, 1 988). Carangal and Calub (1 987) mentioned that the most
common crop residues used as ruminant feed are rice straw, corn stover, barley
straw, soybean straw and peanut straw. In most Asian countries, r ice straw and corn
stover are the most importance crop residues for animal feeding particularly during
the dry season (Castillo, 1983; Carangal and Calub, 1987). Among the cereal
straw, corn stover has a higher crude protein content than the other cereal straw
(McDonald et aI . , 1 987; Carangal and Calub, 1 987; Castillo, 1 983). Currently,
utilization of corn residues as animal feed are on the increase. For instance in the
United State, residues from corn cultivation, such as stover is half of the total
available residue supply. These materials can be a useful source of winter feed for
beef cattle (National Research Council (NRC), 1983). Table 1 summarizes some
studies carried out on the utilization of corn stover.
There are many corn varieties frequently planted by farmers to produce
grain , young cob and baby corn. Gebencsikop ( 1949) as cited by Singh (1987)
introduced the telm corn varieties (varieties groups) to designate the maize type viz:
Flint maize, Dent maize, Pop maize, Floury maize, Pod maize, and sweet maize
(Zea mays cornvar. Saccharata Koern.).
7
Table 1
Utilization of Corn Stover as Animal Feed
Reference Level Suppi. Com stover Digestibility Live weigh Animal
status intake gain (kg/d)
Rivera et al., gazmg n.a. n.a. n.a. 0.513 cattle
1989a 2.71 h/ha
Rivera et al., grazing
1989b 2 week n.a. n.a. DMO 57-75% n.a. cattle
8 week n.a. n.a. DMD41-58% n.a. cattle
Van der Liden ad lib. pelleting 21.9 gJkg W. OMD 14.0 g n.a. sheep
et aI., 1984 protein
ad lib. pelleting 16.3 gJkg W. OMD 13.9 g n.a. sheep
protein+
com grain
Colenbrander ad lib. supple- 4.25 kg/d n.a. 0.508 dairy
et al., 1971 mented heifer
Isarakul and n.a. n.a. 0.40 kg/d OMD 59.0 % n.a. sheep
Isarakul 1984 n.a. n.a. 3.13 kg/d OMD 64.2 % n.a. cattle
n.a. n.a. 3.12 kg/d OMD62.5 % n.a. buffalo
n.a = not available
8
Cultivation of Sweet Corn in Malaysia
The sweet corn (sweet maize) crop is primarily grown for its tender green
ear which is harvested at the milk stage. It is commonly consumed after boiling,
however, it can also be canned or frozen for later consumption (Singh, 1987).
B oiled corn cob Uagung) is a popular vegetable in the markets and r oadside stalls in
Malaysia. In 1981, the Thai super sweet cuitivar was introduced in Malaysia by
Malaysian Agricultural Research and Development Institute (MARDI). This
cultivar has a soft and sweet kernel and it can be harvested 70 days after planting.
The Thai super sweet has also replaced most of all the traditional cultivars (Ramli
and Zameri, 1983). Statistical data issued by Kementerian Pertanian Malaysia
showed that the hectares of sweet corn in 1989 was 7116 ha or about 84% of the
total area of corn cultivation in Peninsular Malaysia. The distribution of sweet corn
cultivation in this area is presented in Table 2.
Sweet corn is one of the impo11ant resources of fibrous crop residues in the
tropical and sub tropical areas. In Thailand, sweet corn is often integrated with
many cropping systems and grown in the dry season (Isarakul and Isarakul, 1984).
The purpose of the corn cultivation is to produce young cobs. The cobs are usually
picked up at the milky stage. At this stage, most of leaves and stalks are still green,
which are good as a source of ruminant fodder.
Table 2
Area under Sweet Corn Cultivation (hectares) According to States and Years in Peninsular Malaysia
State
lohor Darul Takzirn
Kedah Darul Arnan
Kelantan Darul Nairn
Melaka
Negeri Sernbilan Darul Kusus
Pahan g Darul Makmur
Pulau Pinang
Perak Darul Ridzuan
Perlis Indra Kayangan
Selangor Darul Ehsan
Terenganu Darul Iman
S ernenanjung Malaysia (Total)
Fresh Com stover weight (rnt)*
Com stover DM (rnt) *
*Estirnate
Years -------------------------------------------------------
1 986 1987 1 988 1 989
633 742 1 288 1266
325 373 489 654
67 8 1 9 1 1 17 1082
1 3 1 1 85 1 23 120
37 104 52 141
327 578 396 7 14
60 123 88 1 97
926 1207 832 987
6 1 289 334 178
357 398 43 1 987
575 807 867 790
3599 5625 6017 7 1 16
67 104 1 12 1 32
1 6 25 27 32
S ource: Kernenterian Pertanian Malaysia (1986, 1 987,1988,and 1 989).
9
10
Corn Stover as Ruminant Feed.
There are two systems in which forages are utilized as animal feed, namely,
grazing system and cut and carry system.
G razing System
In this system, animals are allowed to graze com stover in the field. This
system is an economical method of utilizing corn stover, because it does not require
the use of machine in harvesting and no material in removed from the soil (NRC,
1 983). The grazing system can be profitable if the animal and corn stover are in the
same location especially if they are within the same farm (Klopfenstein et al., 1 987).
Undoubtedly, the grazing system is the simplest and cheapest form of utilizing com
stover, but it has certain limitation. It was shown the com stover tend to lose its
nutritive value rapidly (Parra and Escobar, 1 985). The reduction in nutritive value
was caused by selected grazing (Rivera and Klopfenstein, 1 989ab) and under
grazing system, loss of soluble sugar and protein is related to the time the com
stover is left in the field.
Cut and Carry System
Another important method by which corn stover"is utilized as an animal feed
is by the cut and cany system. The stover is collected, transported, processed and
finally fed to animals. This system is more costly, compared to t he grazing system,
but it is useful for animals under intensive system and has the advantage that its
nutritive value is maintained.