Genetic factors affecting pre-weaning growth of crossbred Santa Inês in Ceará state

Abstract

Data of 1,474 cross-bred Santa Inês lambs sired by 48 Santa Inês rams in eight private farms located at Quixadá, Quixeramobim, Morada Nova, Crateús and Independência, CE, Brazil, were analysed and provided estimates of the genetic parameters for the weights on the pre-weaning phase. The heritability estimates were of 0.48 ± 0.10 for weights and birth, of 0.36 ± 0.09 for weights at 56 days, of 0.51 ± 0.10 for weights at 84 days, of 0.53 ± 0.11 for weights at 112 days for age, of 0.37 ± 0.09 for the weight gains from birth to 56 days, of 0.54 ± 0,11 for the weight gains, from 56 to 84 days, and of 0.56 ± 0.12 for the weight gains from birth to 112 days of age. The heritability estimates were high, meaning that selection may promote a genetic change on pre-weaning weights in the population. The genetic correlations were also midium or high and positive, suggesting that the selection for a particular weight results in improvement on the other weights as well, except the genetic correlation between birth and the weight daily gains. The phenotypic and environmental correlations were higher than the genetic and also positive.