Genetic and phenotypic parameter estimates of live weight and daily gain traits in Malpura sheep using Bayesian approach

Estimates of (co)variance components and genetic parameters were calculated for birth weight (BWT), weaning weight (WWT), 6-month weight (6WT), 9-month weight (9WT), 12-month weight (12WT), average daily gain (ADG) from birth to weaning (ADG1), weaning to 6 months (ADG2) and 6-12 months (ADG3) for Malpura sheep. Data were collected over a period of 25 years (1985-2010) with records for economic traits on total of 4549 lambs descended from 234 sires and 1541 dams of Malpura sheep maintained at Central Sheep & Wool Research Institute, Avikanagar, Rajasthan, India. Analyses were carried out by Bayesian approach using Gibbs sampler Animal model. Total heritability estimates for BWT, WWT, 6WT, 9WT, 12WT, ADG1, ADG2 and ADG3 were 0.21, 0.15, 0.17, 0.11, 0.28, 0.15, 0.22 and 0.19, respectively. Maternal genetic effects contributed significantly for total variance in the traits except 12WT and ADG3. Maternal permanent environmental effects contributed 9% of the total phenotypic variation for BWT and thereafter declined significantly for all the traits. A moderate rate of genetic progress seems possible in the flock for live weight traits by mass selection. Direct genetic correlations between body weight traits were positive and high and ranged from 0.37 for WWT and 12WT to 0.96 between 9WT and 12WT. Genetic correlations between different daily gain traits were negative due to kin and contemporary competition effect. Results suggest that genetic progress in the growth traits can be achieved if the selection is carried out for higher 6-month weight. (C) 2015 Elsevier B.V. All rights reserved.