Evaluation of Genetic Progress of Growth Traits in Kermani Sheep Breeding Station

For genetic analyses of growth traits of Kermani sheep including body weight at birth, three, six, nine and twelvemonths of age, 10, 459 body weight records measuredon 3132 animals originated from 78 sires and 1163 dams were used. The data were collected at Kermani sheep breeding station during 1988 to 2010. The data were analyzed using a multivariate animal model. In the model, animal age, sex, type of birth, year and season of birth were fitted as fixed effects. Maternal genetic effects as well as the direct additive genetic effects were fitted as the random effects. Heritability estimates of the body weight measured at birth, 3, 6, 9 and 12 months of ages were 0.14, 0.33, 0.34, 0.12, and 0.16, respectively. The genetic correlations between the growth traits were in a range of 0.78 to 0.98. These results show that the growth traits can be improved genetically. In the station, the genetic trends of the traits investigated were generally erratic and the genetic progress was low which were mostly due to the lack of an efficient breeding program. The genetic progress can be achieved if the animals are genetically evaluated based on their individual performance records and pedigree information.