Research in sheep and goat production

Research in sheep and goat production

The results of research in sheep-breeding were recently reviewed by Acharya in a discussion paper on breeding strategy for sheep in India. In addition to reviewing the performance of important pure-bred native breeds with respect to body weight, wool production and quality, lamb and adult survival, reproductive performance, etc., the author reviewed the effect of non-genetic and genetic factors on these traits, estimates of genetic and phenotypic parameters and the results of selection and cross-breeding experiments. Through selection within indigenous breeds (Deccani: Khot et al., Amble et al., ; Bikaneri & Lohi: Nanda & Singh, ; Khot et al., ; Patanwadi: AHD Gujarat, ; Bellary: Dass & Rajagopalan,), an improvement in fleece quality has been reflected by a decrease in the percentage of medullated fibres and average fibre diameter, but in some cases a decline in fleece weight and reproductive performance was reported.

Body weight at six months is the genetic and phenotypic parameter which should be utilized in work on improving market weight and ewe productivity, while an index combining greasy fleece weight and medullation percentage (weighed negatively) should be used as a reference for improving wool production and quality in carpet-wool breeds.

Cross-breeding among indigenous breeds has been extensive in Andhra Pradesh, Karnataka, Tamil Nadu and Uttar Pradesh for improving wool production and quality and, to some extent, for improving mutton production. Most of the wool breeds involved were from Rajasthan (Bikaneri, Magra and Nali). This programme was not fully successful in the southern States, since the Bikaneri rams did not survive long, presumably because, except in Uttar Pradesh, they adapted poorly to the hot humid climate. There was however an improvement in wool production and quality, reflected in an increase in staple length and a decrease in medullation percentage and average fibre diameter.

Cross-breeding work carried out in the country in general indicated the superiority in body weight, greasy fleece weight and fleece quality of half-breds over the indigenous pure-breds involved in crosses, except for Polwarth crosses with Rampur Bushair in Uttar Pradesh. The survival of half-breds was similar to that of indigenous breeds involved in the crosses, but crosses containing higher exotic inheritance did show problems of survival. Rambouillet appeared to be superior to other exotic breeds in cross-breeding experiments. When more than one indigenous breed was used with the same exotic breed, carpet-wool breeds - particularly Magra (Bikaneri) - showed superiority.

Sheep-breeding work under AICRP for fine wool, involving exotic fine-wool breeds (Soviet Merino and Rambouillet) and indigenous breeds (Gaddi, Nali, Chokla, Patanwadi, Nilgiri and Bonpala), yielded improvement in greasy wool production and fleece quality in the half-breds over the native breeds involved in crosses, but the improvement in greasy wool production was minimal where the native breed was already producing relatively high quantities of fleece (e.g. Nali and Chokla). Similarly, the improvement in fleece quality was minimal in breeds with already reasonably fine fleece, such as Nilgiri.

Cross-breeding experiments for improving mutton under AICRP involve exotic mutton breeds (Suffolk and Dorset) and indigenous breeds (Muzzafarnagri, Malpura, Sonadi, Deccani, Mandya and Nellore). The results available indicate improvements in weight gains and feed conversion efficiency under individual feed-lot conditions. Suffolk x Sonadi and Dorset x Nellore half-breds gave the best performance: the lambs attained 30 kg live weight at six months in individual feed-lot trials with ad libitum feeding of a ration consisting of 30% roughage and 70% concentrate ration from weaning (90 days) to 180 days.

At CSWRI, in a breeding experiment involving Rambouillet and three different indigenous breeds, Chokla (a superior carpet-wool breed), Jaisalmeri (a medium carpet-wool breed) and Malpura (an extremely coarse and hairy wool breed), the half-breds were substantially superior in body weight, greasy fleece production and fleece quality, but beyond 50% exotic fine-wool inheritance, there was little improvement in body weight and greasy fleece weight, though there was some further improvement in wool quality. The performance of progeny produced from inter-breeding half-breds was not much inferior to that of the first generation (F₁) half-breds. The half-breds pose no more serious management and disease problems under farm conditions than do native breeds. The Chokla crosses came close to desired apparel wool, and the Jaisalmeri and Malpura crosses came closer to ideal carpet wool. The improvement in Malpura was very substantial (almost 200%) in greasy wool production and in fleece quality.

More recently, research has been undertaken at CSWRI for breeding sheep for pelt, and Karakul is being crossed with indigenous extremely coarse carpet-wool breeds. The results achieved have been very encouraging.

Like development, research for improving goat production has been seriously lacking (AICRP, GB). Cross-breeding indigenous goats with exotic dairy goats (Alpine and Saanen) resulted in improved milk production and reproductive performance, but with a slight loss in prolificacy. Some work on improving meat production by crossing small and large indigenous breeds is in progress, but the results so far available show only limited promise. After cross-breeding indigenous goats with Angora for mohair production, it appeared that with 7/8 Angora inheritance, the crosses produce a similar quantity of relatively finer quality mohair than that of the Angora controls. Some research in improving pashmina production has also been undertaken