Inbreeding Effect on Genetic Parameters of Economic Traits in Moghani Sheep Breed

The aim of this study was to investigate the effect of inbreeding on the estimation of genetic parameters of weight traits at different ages in Moghani sheep. In the present study, the information of 11721 Moghani sheep in Jafarabad Moghan breeding station from 1987 to 2011 was used. Genetic parameters were estimated using single trait model with covariate and classification and without inbreeding. CFC and WOMBAT software were used to estimate the inbreeding coefficient and the effect of inbreeding on traits, respectively. The results of analysis of variance showed that the random effect of the animal and the fixed effects of year-season, sex and age had a significant effect on all the studied traits (P <0.05). The mean inbreeding for all animals and inbreed animal were 0.4% and 1.67% respectively. Totally, 26.1 % of all the animals were inbred. The inbreeding depression for body weight traits at birth, 3, 6, 9, 12, 24, 36, 48 and 60-months of age was respectively, -1.06, 0.113, 0.126, -0.089, 0.817, -0.054, -0.687, 2.717 and -0.139 kg, per 1% increase in individual coefficient. Direct heritability for birth weights, 3, 6, 9, 12, 24, 36, 48 and 60 months were calculated 0.17, 0.14, 0.10, 0.27, 0.16, 0.21, 0.20, 0.02 and 0.23 respectively. The results showed that the inclusion of inbreeding in models for estimating genetic parameters had a low to moderate effect on the estimation of heritability. The results also showed that the harmful effects of excessive inbreeding could be prevented by increasing the use of distant crosses with superior males and proper genetic management in herds.