Alternative animal models to estimate (co) variance components and genetic and phenotypic parameters for birth weight in Nellore cattle

Revista Brasileira de Zootecnia

Lôbo, Raysildo Barbosa²  Scarpati, Márcia Tereza Vieira¹ 

[1] CNPq;USP, Ribeirão Preto

关键词: beef cattle;    maternal effects;    restricted maximum likelihood;    selection    Introdução O peso ao nascer (PN) é a primeira informação após o nascimento do animal que indica seu vigor e desenvolvimento pré-natal;    fortemente influenciado por fatores ambientais que influenciam a mãe;    antes e durante a gestação;    e pelo próprio período de gestação;   

DOI  :  10.1590/S1516-35981999000300011

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

The objective of this work was to study the genetic-quantitative aspects of birth weight (BW), in animals of Nellore breed, in the herd from the Nellore Cattle Genetic Improvement Program, conducted by the Department of Genetics of the University of São Paulo. Only the weights of sound calves, born alive and from births, obtained by artificial insemination were considered. The (co) variance components were estimated under four different animal models where direct and maternal genetic and permanent environmental were taken into account by including the appropriate random effects, as well as contemporary groups and age of cow at calving effects, in the statistical model. This procedure allowed the quantification of the contribution of different random effects, especially maternal effects. The number of records was 6511; the overall means 31 kg, and the standard deviation 4,1 kg. The direct, maternal and total estimated heritability ranged from 0.20 to 0.37, 0.11 to 0.13 and 0.22 to 0.37, respectively. The correlation's between genetic direct and maternal effects were negative (-0,14 to ¾0,16). The BW is a trait greatly determined by direct additive genic action, insignificantly affected by maternal phenotype, and with antagonism between the genetic effects. Response to selection for BW would be maximized if based on the parameters obtained by the analysis fitting animal models with direct and maternal effects.

【 授权许可】

CC BY-NC