Study on the influence of genetic and environmental maternal effects on body weight trairs in Ghezel sheep breed in rural breeding system

In this study, variance components and genetic parameters of birth weight (BW), weaning weight (WW), 6 month weight (W6), 9 month weight (W9) and 12 month weight (W12) were estimated with Restricted Maximum Likelihood (REML) method using WOMBAT software. The data set was included 12701 records of rural flocks under supervision of the Ghezel sheep breeding station is located in Western Azerbaijan province and collected over the period from 1994 to 2009. Effect of herd- year, lamb sex and litter size were significant on all traits. Effect of dam Age was only significant on BW, W6. Model that contains direct additive genetic and maternal common environmental effects was the suitable model for all mentioned traits except W12.Direct heritability of the BW,WW,W6,W9 and W12 based on the suitable model were 0.29, 0.26, 0.25, 0.56 and 0.34 respectively. The proportion of maternal common environmental variance to phenotypic variance (c2) for BW,WW,W6 and W9 were 0.66, 0.52, 0.34 and 0.18 respectively. The results of this study showed that direct heritability for body weight in studied rural flocks were high. Therefore genetic improvement through selection is possible for these traits. Moreover including maternal common environmental effect (c2) in analysis models for accurate estimation of direct heritability in this breed is recommendable.