Lifetime reproductive performance of Chokla sheep at an organized farm in semi-arid conditions

Abstract

The Chokla sheep, renowned as the finest carpet wool producer of India, plays an important role in supporting the rural economy of the arid and semi-arid regions of its native state of Rajasthan. This study was carried out to assess the lifetime reproductive efficiency of Chokla ewes by analyzing the records of 1,001 ewes bearing 3,541 lambs over a period of 22 years (1994-2016) to assess five traits, namely total lambs born (TLB; 3.38±0.11 lambs), total lambs weaned (TLW; 2.97±0.11 lambs), cumulative lamb weights at birth (TLBW; 9.59±0.37 kg), weaning (TLWW; 39.59±1.68 kg) and 12 months of age (TLAW; 50.15±2.51 kg) produced by an ewe in her lifetime. Period of birth of ewe had a significant effect on all the traits whereas season of birth, inbreeding coefficient and birth weight of ewe had no influence. REML procedures were employed to estimate the genetic parameters through an animal model. Analysis revealed low heritability estimates for the lifetime reproductive traits (TLB; 0.06±0.04, TLW; 0.05±0.04, TLBW; 0.09±0.05, TLWW; 0.05±0.04 and TLAW; 0.02±0.04), suggesting greater role of environmental and managemental factors. Positive correlation among cumulative lamb weights (0.51-0.92) suggested selection for birth weights would result in higher weights at subsequent life stages of lambs. The low heritability estimates and high CV% for all the traits suggest the suitability of a management focussed approach for improvement of lifetime reproductive performance of ewes.