Genetic Analysis of Reproductive and Fitness Traits of Malpura Sheep in Semi-arid Tropics of India

Abstract

Malpura sheep is one of the well adapted and heavy breeds of sheep in semi-arid region of India, which is primarily reared for mutton production. Present study was carried out to evaluate the reproductive parameters and selective value and also to estimate (co)variance component for these traits in the Malpura sheep on the data spread over 35 years (1975–2009). Study revealed the age at first service (AFS; 632.52 ± 4.47 days), weight at first service (WFS; 26.05 ± 0.08 kg), age at first successful service (ASS; 689.48 ± 5.28 days), weight at first successful service (WSS; 26.74 ± 0.09 kg), age at first lambing (AFL; 838.55 ± 5.34 days), ewe weight at lambing (WL; 27.94 ± 0.10 kg) and lambing interval (LI; 439.18 ± 4.84 days). Survivability of female lambs born in herd was found to be 91.8 % till weaning and 71.8 % till they reached maturity at 12 month. The study also determined fitness traits (lifetime) such as total lambs born per ewe (TLB; 3.85 ± 0.05), total female lambs born per ewe (TFLB; 1.95 ± 0.04,), lambs weaned by a ewe (LW; 3.37 ± 0.05), total female lambs weaned by a ewe (TFLW 1.79 ± 0.04) and selective value or females reached reproductive age per ewe (SV 1.40 ± 0.04). Estimates of additive genetic variance (h2) for reproductive traits were 0.09 ± 0.05 for AFS, 0.39 ± 0.06 for WFS, 0.18 ± 0.06 for ASS, 0.34 ± 0.06 for WSS, 0.11 ± 0.05 for AFL, 0.25 ± 0.06 for WL and 0.00 ± 0.04 for LI. Similarly, h2 estimates were 0.13 ± 0.05 for TLB, 0.00 ± 0.03 for TFLB, 0.14 ± 0.05 for TLW, 0.02 ± 0.04 for TFLW and 0.02 ± 0.04 for SV. Study revealed that for reproductive traits, there was moderate direct additive variance, and thus, scope of further improvement in the traits, however, for SV maximum variance was attributed to the environmental sources of variation. Maternal effect was found to have very little or no effect on the reproductive traits as well as SV in Malpura sheep.