Environmental and genetic effects on yearling and post-yearling weights of Nellore calves in Northeast Brazil

[摘要] Data growth records relative to 2004 Nellore breed calves, from Ceará and Piauí states, were used to study the influence of environmental effects and to estimate the heritability of the weight traits at the 365 days (yearling) and 550 days (post-yearling) of age. The variance components were estimated by the restricted maximum likelihood method. In the analysis of variance a model that included the fixed effects of sex, year and season and herd of birth, and the age of dam as covariant and the random effect of sire within the herd, was used. The fixed effects of classification were significant for all evaluated traits. Least square means were 186.16 ± 2.74 kg and 244.06 ± 5.23 kg, for yearling and post-yearling weight respectively. Age of dam at calving influenced only the yearling weights, with estimated maximum weight of 187.29 kg and ages around nine years. Heritability estimates were .56 ± .09 and .64 ± .12, for yearling and post-yearling weight, respectively.

[学科分类] 兽医学

[关键词] corporal weight;heritability;genetic correlation    Introdução A raça Nelore compõe quase 70% do rebanho zebuíno do Brasil;apresentando grandes diferenças no potencial do crescimento entre as várias regiões do país e também entre os vários sistemas de criação (ELER et al