Effect of some environmental and genetic factors influencing wool weight trait of Baluchi sheep in Abbas¬abad breeding station of Mashhad

In this research a total of 46،563 wool weight records belonging to 12،842 Baluchi sheep (represented 414 sires and 4892 dams) collected during 24 years (1983-2006) from two herds of Abbas Abad breeding centre، Mashhad were utilized to study the effects of some environmental and genetic factors. A linear mixed model was used to evaluate fixed environmental factors using SAS software. The year and month of shearing، sex، birth type، age and shearing order of lamb had statistical significant effect on wool weight. Phenotypic trend estimation was 13. 12 g per year which was statistically significant. Genetic analysis of the trait was undertaken by a repeatability animal model using DMU software. The estimates of additive genetic and permanent environment variances، heritability and repeatability were 9293. 58، 6758. 45، 0. 092 and 0. 159، respectively. The estimation of genetic trend for wool weight was 3. 49 g per year which was statistically significant. Mean breeding value for wool trait was significantly lower in male (24. 67 g) than female (32. 11 g) lambs