Phenotypic and genetic analyses of wool weight trait in Iran Black sheep using different animal models

Wool weight is an economic trait affecting farm income for which phenotypic mean is expected to increase as the genetic selection is practiced. This research aimed to analyse phenotypic and genetic aspects of wool weight trait in Iran Black sheep using different animal models. A total of 13,175 wool weight records belonging to 3,763 Iran Black sheep breed (progeny of 104 sire and 1,122 dams) collected during 24 years (1983-2006) in Abbas Abad Breeding Centre, Mashhad was use. Genetic analysis was carried out through a set of animal models. Least square means of wool weight for male and female lambs were 864.21 and 678.95 g, respectively which were significantly different from each other (P<0.0001). Phenotypic trend was found to be 6.762 (±4.325) g per year which was statistically non-significant. Direct and maternal additive genetic variances, lamb and maternal permanent environmental variances, direct and maternal heritabilities, and repeatability of wool weight were found to be 16658.129, 6636.060, 6755.514, 3021.294, 0.142, 0.057 and 0.200, respectively. Mean predicted breeding value of wool weight for female lambs (8.09 g) was significantly (P<0.05) lower than male lambs (37.74 g). Based on model 4, direct and maternal changes were 13.1 (±0.192) and -7.15 (±0.092) g per year and were statistically significant (P<0.001). The findings of the present research indicate that selection has resulted in a positive and favorable genetic gain for the wool trait in the population under consideration.