عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Genetic analysis of growth traits including body weight recorded at birth (bwt), 3 (3bwt), 6 (6bwt), 9 (9bwt) and 12 (12bwt) months of age was carried out using 4107 records on Raieni Cashmere goats born from 206 sires and 1402 dams, during years 1992 to 2006. The records were collected from a resource flock in Baft Research Station, situated in Kerman Province, Iran. The importance of additional random effects including maternal genetic effects, maternal permanent environmental effects as well as direct-maternal genetic covariance on genetic analyses of the growth traits were studied using univariate animal models. Significant maternal genetic effects were found for bwt, 3bwt, 6bwt and 9bwt. Estimates of heritability were upwardly biased when maternal effects ignored. The maternal heritability estimates for bwt, 3bwt, 6bwt and 9bwt were 0.17, 0.09, 0.08 and 0.08, respectively. The maternal permanent environmental effects were pronounced only for 12bwt. The (co)variance components were estimated using a multivariate animal model. Yearling weight was excluded from the model because of its limited number of records. Accordingly direct heritability of bwt, 3bwt, 6bwt and 9bwt were estimated to be 0.26±0.05, 0.30±0.04, 0.33±0.05 and 0.30±0.05, respectively. The genetic correlations among the body weights were high and positive (0.66 to 0.96), which is promising. The respective genetic correlation between 3bwt and the later ages were 0.95 and 0.92. Accordingly, the body weight observed at at weaning age could be employed as a selection criterion for BW genetic improvement in Raieni Cashmere Goat.