Genetic parameters for pre-weaning growth traits of Mehraban Iranian fattailed sheep

Abstract

Data corresponding to 975 lambs, progeny of 18 rams, born during the 1984-1990 lambing seasons, were used to estimate genetic parameters for birth weight, weaning weight, pre-weaning daily gain, and body weight at 30, 60 and 90 days of age. Genetic parameters were estimated from paternal half-sib correlations. Heritabilities for birth weight, weaning weight, pre-weaning daily gain, and body weight at 30 and 60 days of age were 0.35, 0.44, 0.33, 0.36, 0.39 respectively. Genetic correlations were mostly high and all positive, especially between weaning weight and weight at 60 days of age (0.77). The corresponding phenotypic correlations were mostly high and positive (0.80). No genetic antagonisms were found among the characteristics that were studied. Response to selection for weight at 60 or 90 days of age should be effective.