Sheep - AgRIS

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infarm flocks. Twinning in sheep often is desirable, because a ewe that weans twins produces from 10 to 15 kg more lamb than the ewe that weans a single lamb. Fertility in sheep is lowly heritable, with an average heritability and repeatability estimate of 7 to 13 per cent. These estimates are in agreement with those for other classes of livestock. This indicates that fertility in sheep is not greatly affected by additive gene action and could be improved very little by selection. Most of the phenotypic variation, therefore, is due to environmental factors and attention to these should improve the lamb crop. 13.2.2 Growth rate & feed conversion efficency The age at which lambs are weaned varies under different conditions, but the age of 180 days is often used for selection purposes. Lambs can be weighed as they reach 180 days, or can be corrected to this age. the correction is done by multiplying the average daily gain from birth by 180 and adding this product to the birth weight. The age of the ewe may have considerable influence on the weaning weight of her lambs. Two-year-old ewes wean lambs that are from 2 to 4 kg lighter than those from mature ewes. Production of ewes usually increases to four or five years of age. Probably the most important adjustment is that for weaning weights of lambs from ewes that are two years of age. This adjustment can be made by comparing the production of the two-year-old ewes with that of mature ewes in the same herd and then adding the difference to the weaning weights of lambs from the younger ewes. If this is not possible, an adjustment may be made by adding 3.1 kg to the weight of the lambs. 13.2.3 Type and Conformation Desirable type and conformation have also recieved attention in sheep as in other classes of farm animals. With this species, however, attention must also be paid to selection for wool production in addition to mutton quality and rate and efficiency of gains. Animis possessing vesry obvious defects, such as over-shot jaws, undershot jows, black wool, wool-blindness, skin folds, shallow bodies, and poor mutton qualities, should be culled from the flock. If animals with these defects are eliminated from the breeding flock and selections are made on the basis of body weight and quantity and quality of wool, especially in the selection of rams, perhaps this will be sufficient attention to type. 13.3 Factors affecting mutton Production 13. 3.1 Body weight Body growth affects the composition of the lamb. It has been observed by many research workers (Reid et al., 1968) that the 63 percent, 95 percent and 88 percent of variation in ash, protein and fat, respectively are due to changes in body weight at slaughter. 13. 3.2 Heredity The rate of growth varies from breed to breed, even if given same type of fodder and concentrate to all the breeds. The growth rate is affected by the adult body weight (Dackson, 1974). 13.3.3 Sex The sex hormones of males and females affect their growth rate. The ewe differ from the ram in that it has slower growth rate, a more early maturing carcass and reaches a lower mature size due to the effect of oestrogen in restricting the growth of long bones of the body. 13.3.4 Castration The castration of male decreases their growth rate and they mature at an early age. The appreciation of the central role of the sex hormones in growth and development as manifested in the consequences of castration have led to extensive study of the effects of the administration of natural or synthetic hormones to meat animals in order to influence performance. 471
Table 13.1 Mutton (sheep) production potential Year Total population (m) Lambs Adults Total Disposable No. (m) Meat prod. (000MT) Value Rs. (m) Disposable No. (m) 472 Meat prod. (000MT) Value Rs. (m) Meat prod. No. (m) Value (000MT) 1987 44.84 13.96 126 7560 6.5 91 4095 217 11655 1994 47.91 15.03 135 8100 6.94 97 4365 232 12465 2001 51.19 15.97 144 8640 7.42 104 4680 248 13320 2015 68.29 21.26 191 11460 8.86 139 6255 330 17715 Lambing percentage is assumed at 130% Breedable females are estimated at 80% of females of one year and above age group Mortality in lambs at 10% Carcass yield of lambs 9 kg and adults 14 kg Value is taken at Rs. 60 per kg lamb meat and Rs. 45 per kg of mutton from adult sheep.
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1. Introduction ANNEXURE - IX-C SHE
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2. Classification, Origin and Domes
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Nadu, Andhra Pradesh and Karnataka,
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different states it is estimated th
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Table 3.3 continued...... Country N
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een possible because of its substan
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(USA). The Rambouillet as purebreds
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ii) Marwari Deriving its name from
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Pradesh and Bihar, Bijapur, Gulbarg
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elatively tall with little hair exc
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4.2 Distribution of type breeds in
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Table 4.1 continued...... Region/Br
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Table 4.2 continued....... SI. Bree
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5. Genetics 5.1 Chromosome Profile
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esponsible for the formation of one
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the exercise these animals did not
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For understanding the inheritance o
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with a dense growth of relatively l
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produced on rations which contain i
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The Coefficient of Variation The co
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5.6.3 Wool Production/Wool yield an
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6. Breeding 6.1 Components of Sheep
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elationships. Certain coat colors a
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Selection on this basis means that
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ii) Independent Culling Method In t
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eflected by increase in average fle
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at 75 or 8-4 monthly intervals comp
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Based on the crossbreeding results,
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Table 6.8 Means and standard errors
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month post-weaning individual feedl
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ams) in November, 1975 for evaluati
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een heavily fed and therefore may h
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need for one or more "teasers" to d
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ii) Consistency The normal consiste
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collection frequencies per day in 3
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iv) Altitude High altitude and poor
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containing diluents enriched with a
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6. Nutrients Although spermatozoa u
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7. 3.1 Puberty Puberty in the femal
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Estrogen in large quantities inhibi
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The udder becomes firm and enlarged
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7. 3. 8 Interlambing interval It is
Page 85 and 86: 8. Nutrition 8.1 Components of Shee
Page 87 and 88: allied to the various amino acids o
Page 89 and 90: animals. A deficiency of salt is sh
Page 91 and 92: seem to have most significance in s
Page 93 and 94: Table 8.2 Chemical composition of g
Page 95 and 96: Table 8.3 Nutritive value of fodder
Page 97 and 98: Mineral and vitamin Requirement If
Page 99 and 100: Table 8.5 Total digestible nutrient
Page 101 and 102: Table 8.7 continued....... c) Lacta
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Page 105 and 106: Sorghum-Berseem-Maize Improved vari
Page 107 and 108: 9. Housing and Management 9.1 Syste
Page 109 and 110: ) Shearing, skirtng and primary cla
Page 111 and 112: The availability of pastures which
Page 113 and 114: fodder as green or hay, concentrate
Page 115 and 116: 9.2.2 Lambs Efforts should be made
Page 117 and 118: Mortality in young lambs and other
Page 119 and 120: land and they depend on the forest
Page 121 and 122: age and fed intensively till they a
Page 123 and 124: Overnight teasing and drafting ridd
Page 125 and 126: The secretion of milk takes place d
Page 127 and 128: with coarse and hairy breeds showed
Page 129 and 130: 11. Sheep Production System in Diff
Page 131 and 132: 12. Wool Production and quality 12.
Page 133 and 134: crosses with Dorset and Merinos, Pa
Page 135: 13. Meat Production 13.1 MeatProduc
Page 139 and 140: 14.4 Utilization of milk Sheep are
Page 141 and 142: one crushing mills and about 360 bo
Page 143 and 144: 16. Sheep Records It is essential t
Page 145 and 146: 17. Diseases and their Control Morb
Page 147 and 148: Atropin sulphate 2.0 mg/kg. body we
Page 149 and 150: contents by neutralization tests wi
Page 151 and 152: prophylactic, foot and mouth vaccin
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Sheep - AgRIS

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