Reproductive performance of native and crossbred ewes under semi arid climate

Data spread over 12 years, comprising reproductive and productive traits of native (Chokla and Nali) and crossbreds (Chokla synthetic, Nali synthetic and Fine wool synthetic) was used to study the effects of year, breed of ewe, age of ewe, age of ram and ewe weight at mating on oestrous cycle length (OCL), number of service /conception (NSPC), number of ewes lambing/ewe mated (ELEM), number of lambs weaned/ewe mated (LWEM), kg weaned lambs/ewe mated (KGWEM). The overall means of OCL, NSPC, ELEM, LWEM and KGWEM were 17.68 days, 1.30, 0.64, 0.58, and 7.36 kg, respectively. Breed of ewe had significant effect on all the traits. Native breeds were superior to the crossbreds in terms of ELEM, LWEM and KGWEM but inferior to OCL and NSPC. All the traits except OCL were significantly affected by year. Age of ewe had significant effect on LWEM and KGWEM. Age group of 4–5 years of ewe was observed best for all the traits studied. Age of ram had significant effect on NSPC. For lower NSPC, rams 2–4 years of age were best. Weight of ewe at mating had significant effect on NSPC and KGWEM. For lower OCL and minimum NSPC 22–24 kg and ≤21 kg ewe weight at mating, respectively, was found suitable. For maximum ELEM and LWEM, 31–33 kg body weight of ewes was found best but ≥33 kg ewe weight for maximum KGWEM. Positive correlation of all the traits, except OCL, with ewe weight at mating indicated that efforts should be made to achieve higher/optimum body weight at an early age through improved environment.