Influence of environmental factors on production traits and heritability estimates of magra sheep in Arid region

Abstract

The aim of the present study was to examine the effect of non-genetic factors on growth and wool traits of 1482 Magra sheep spread over a period of five years (2008–12) maintained at the Arid Region Campus, ICAR-Central Sheep and Wool Research Institute, Bikaner. The least squares means for body weight at birth, 3, 6, 9 and 12 months of age were 3.18±0.02, 16.12±0.14, 23.72±0.20, 28.37±0.21 and 31.88±0.25 kg, respectively. The average daily gain in body weights during 0–3, 3–6 and 6–12 months of ages were 143.45±1.43, 84.23±1.35 and 40.22±1.13 g, respectively. For greasy fleece weight at first, second and third clips, least squares means were 567.18±5.16, 628.08±4.97 and 640.01±5.45 g, respectively. Least squares analysis of variance revealed significant (P<0.01) effect of year of birth and sex on all the traits. The fixed effect of parity had significant (P<0.01) effect only on birth weight. Dam's weight at lambing was a significant (P<0.01) source of variation for all the body weight traits, except average daily gains during 3–6 and 6–12 months of age. Greasy fleece weights at first, second and third clips were affected significantly (P<0.01) by lamb's age at shearing. Heritability estimates for body weight at birth, 3, 6, 9 and 12 months of age and average daily gain during 0–3, 3–6 and 6–12 months of age and greasy fleece weight at first, second and third clips were 0.17±0.06, 0.31±0.08, 0.33±0.09, 0.35±0.10, 0.59±0.14, 0.28±0.08, 0.23±0.07, 0.62±0.14, 0.52±0.11 and 0.32±0.10 and 0.11±0.09, respectively. Heritability estimates for all the growth traits was moderate to high, suggesting further scope for genetic improvement in the flock.