Genetic and environmental effects for growth traits in Santa Inês hair sheep at Ceará State

Abstract

Files from 1,335 sheep of Santa Inês breed, born between 1984 and 1998, in the experimental herd of the National Goat Research Center – Embrapa caprinos and raised under semi intensive pasture condition were used to estimate direct and maternal heritability for body weight at different ages. Variance components and heritability were estimated by Restricted Maximum Likelihood methodology using a single trait animal model and the software MTDFREML. The statistical model included direct and maternal genetic effects and permanent environmental random effects, as well as the fixed effects of sex, season and year of birth, birth type and covariate weight of the dam. The direct and maternal heritability, varied from 0.11 to 0.21. The direct and maternal heritability suggest small genetic variability and indicate a necessity of inserting new rams for genetic improvement of the herd.