Estimates of (co)variance components and genetic parameters of growth traits in Marwari sheep

The present investigation was undertaken to estimate the (co)variance components and genetic parameters for different growth traits in Marwari flock comprising records of 1649 animals distributed over a period of 12 years (1999–2010), maintained at Arid Region Campus of Central Sheep and Wool Research Institute, Bikaner, Rajasthan, India. The estimation was done by restricted maximum likelihood procedures, fitting six animal models with various combinations of direct and maternal effects. As per likelihood ratio test, direct heritability estimates from the best model for body weight at birth, weaning, 6, 9 and 12 months of age, and average daily gain during birth to weaning, weaning to 6 and 6–12 months of age were 0.28 ± 0.058, 0.27 ± 0.050, 0.28 ± 0.049, 0.30 ± 0.080, 0.29, 0.26 ± 0.050, 0.16 ± 0.040 and 0.31, respectively. Maternal genetic effect declined from 4% at 6 months weight to 1% at 9 months and was zero at 12 months of age. Maternal genetic effect on the post-weaning traits was a carryover eff...