تاثیر عوامل مادری بر افزایش وزن روزانه و ضریب کلیبر گوسفند نژاد قزل در سیستم پرورش روستایی

Background: estimation of genetic parameters of economic important traits are necessary for determining breeding goal and selection index. objectives:in present study, the genetic parameters of average daily gain from birth to weaning (adga), from weaning to 6 month of age (adgb) and from 6 to 9 month of age (adgc) and kleiber ratio at weaning (kra), at 6 month of age (krb) and at 9 month of age (krc) were estimated. methods:the data set included 12701 records of rural flocks under supervision of ghezel sheep breeding station located in western azerbaijan province and collected over the period from 1994 to 2009 were analysed by restricted maximum likelihood (reml) procedure using wombat software.results:fixed effect of herd - year of birth (hy) was significant on all traits. effect of sex was significant on all traits except for kra and effect of litter size was significant for all traits except for krb. effect of dam age was significant on adgc, krb, only. model 1 (contains direct additive genetic effect) was the best model for adgc and krc and model 7 (contains direct additive genetic and maternal common environmental effects) was the best model for the other traits. direct heritability of the adga, adgb, adgc, kra, krb and krc based on the best model were 0.27, 0.18, 0.14, 0.22, 0.13 and 0.16, respectively. the proportion of maternal common environmental variance to phenotypic variance (c2) for adga, adgb, kra and krb were 0.52, 0.16, 0.52 and 0.19, respectively.conclusions:direct heritability of average daily gain and kleiber ratio in studied rural flocks were moderate. therefore selection specially based on kra will be effective for these traits. moreover, including maternal common environmental effect in animal models for accurate estimation of direct heritability in this breed is recommendable.