Evaluation of environmental effects and estimation of genetic parameters for growth traits in Moghani sheep

In this study the data of birth weight (BW)، three months (3MW)، six months (6MW)، nine months (9MW) and yearling weights (YW) of Moghani sheep breed were used to estimate effects of environmental factors and genetic and phenotypic parameters. The data were collected from Jafar-Abad sheep breeding research station during twelve years period (1995 to 2006). Estimates of (co) variance components and genetic parameters were obtained using single and multiple trait models. The fixed effects were Year birth، month birth، sex of lamb، birth type and age of dam. The age of lamb at weighting was also used as covariate. Direct heritability estimates from five traits analyses were 0. 2±0. 03 for BW، 0. 18±0. 04 for 3MW، 0. 19±0. 04 for 6MW، 0. 29±0. 04 for 9MW and 0. 21±0. 04 for YW. Estimates of maternal heritability were 0. 18±0. 04 and 0. 18±0. 04 for BW and 3MW، respectively. Estimates of genetic correlations among growth traits were positive and ranged from 0. 48 to 0. 98.