Maternal effects on the genetic evaluation of Tabapuã beef cattle

José Elivalto Guimarães Campêlo,Robledo De Almeida Torres,Cláudio Vieira De Araújo,Luiz Otávio Campos Da Silva,Paulo Sávio Lopes,Carmen Silva Pereira,Ricardo Frederico Euclydes

doi:10.1590/s1415-47572004000400009

Abstract

The aim of this investigation was to study the influence of maternal effects on the genetic evaluation of sire production in Tabapuã beef cattle. Single and multiple trait analyses were done with adjusted animal weights at 120, 240 and 420 days of age. Antagonism was observed between additive direct and maternal genetic effects, with the maternal effect being higher until weaning. The inclusion of maternal effects in the models removed part of the additive variance only in single trait analyses and resulted in smaller means and standard deviations for the sire breeding values. The use of maternal effect associated with single or multiple traits may affect sire ranking. The contradictory results of the single and multiple trait analyses for additive direct and maternal effects indicate that caution is needed when considering recommendations about the importance of maternal effects in Tabapuã beef cattle.

Highlights

Mammalian growth during the suckling period is affected by the offspring whose growth is measured and by the dam that provides the developmental environment
The data were obtained from the body weight control program of the Tabapuã Beef Cattle Herd registered in the National Records of the breed belonging to the Brazilian Zebu Breeders Association (ABCZ) and were provided by Embrapa-Beef Cattle, in agreement with the Ministry of Agriculture
Pre-weaning and weaning weights were similar to those observed for the Nellore breed by Mercadante and Lôbo (1997), Ferreira (1999), Ferraz-Filho et al (2000) and Mercadante et al (2000), who reported the importance of maternal effects on beef cattle, mainly during the pre-weaning phase

Summary

Introduction

Mammalian growth during the suckling period is affected by the offspring whose growth is measured and by the dam that provides the developmental environment. The trait measured is generally the phenotypic value of the offspring and consists of at least two components, i.e., offspring growth and a maternal effect contributed by the dam. The maternal effect is strictly environmental relative to the offspring, but phenotypic differences for the maternal effect among dams are expressed in the phenotypic values of the offspring (Willham, 1972). According to Robison (1981), the importance of maternal influence on the growth of young mammals has been recognized since the earliest attempts to improve livestock production. Cundiff (1972) indicated that maternal effects are more important than direct gene effects during the early postnatal growth of young suckling their mothers. The maternal influence diminishes and direct effects of the genes that influence growth assume primary importance

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