Genetic parameters for growth traits of the Moroccan Timahdit breed of sheep

Data from 522 lambs of the Timahdit breed representing 13 sires were used t o estimate genetic parameters. Traits analyzed were weights at birth (BW), 30 days (W30), 70 days (W70) and 90 days (W90), average daily gains from 10 to 30 days (ADG10-30), 30-70 days (ADG30-70) and 30-90 days (ADG30-90). RE ML estimates of variance and covariance components were obtained assuming a nimal models that included the fixed effects of sex, age of dam and the com bined effect of year and types of birth or rearing, and the animal random e ffects for the direct and the maternal genetic effects.. Genetic correlatio ns were estimated with the same fixed effects and only additive direct gene tic effects. Results showed that an important direct additive and maternal genetic effects were observed. Estimates of the direct heritability and mat ernal heritability were respectively 0.18, 0.59 (BW); 0.31, 0.34 (W30); 0.5 0, 0.24 (W90); 0.42, 0.08 (ADG10-30), and 0.31, 0.22 (ADG30-90). Estimates of additive direct-maternal correlations were important and ranged from -0. 94 to -1.0 for live weights, and from -0.70 and -1.0 for daily gains. The e stimates of genetic and phenotypic correlations were high and showed no gen etic antagonisms among the growth traits. (C) 2000 Elsevier Science B.V. Al l rights reserved.