Maternal influences from birth to yearling in Guzerá cattle. I. Genetic causal components of variance and covariance

Abstract

Data from 635 Guzerá calves collected at the Canoas Farm (State of Minas Gerais, Brazil) were analysed. The components of variance and covariance were estimated by intraclass correlation of paternal and maternal half-sibs, offspring-dam and offspring-sire pairs. The variance of maternal effects (σ²_Am) were 7.36, 81.34 and 15.76% of total phenotypic variance for birth, weaning and yearling weight, respectively. The estimated negative covariance of additive direct and maternal effects (σ²_AoAm) for weaning and yearling weights indicated genetic antagonisms between these effects. The results showed the importance in establishing the adequate age for selection practice in beef cattle.