Genetic analysis of lifetime fleece weight in Rayeni Cashmere goats

Fleece weight is an economic trait in Rayeni Cashmere goat and its genetic improvement is important. The study was carried out for genetic analysis of fleece weight measured at 1, 2, 3, 4, 5 and 6 years of age in this breed. 12083 records; measured on 5949 Raieni Cashmere goats that originated from 289 sires and 2426 dams born during 1994 to 2008; were used for the analysis. The importance of additional random effects in animal model, including maternal genetic effects, direct-maternal genetic covariance, maternal permanent environmental effects and sire by flock interaction, on genetic analyses of the fleece weights, using univariate animal models was studied. The additional random effects were not important for the genetic analyses of the fleece weights measured at the different ages. Then, in the final model, direct additive genetic effects as well as the significant fixed effect were fitted. The (co)variance components were estimated using a multivariate animal model. Direct heritability of fleece weight measured at 1 to 6 years of age were 0.18±0.03, 0.23±0.04, 0.14±0.04, 0.17±0.05,0.35±0.07, 0.21±0.07, respectively. The genetic correlations between fleece weight measured at one year of age and those measured at 1, 2, 3, 4, 5 and 6 years of age were 0.92, 0.76, 0.75, 0.57 and 0.54, respectively. Then fleece weight measured at one years of age can be used as a selection criterion for the later ages. The selection accuracy can be improved using the additional records after one year of age but it should be economically investigated.