Estimation of Genetic Parameters and Trends for Additive Direct and Maternal Genetic Effects for Birth and Calf-market Weights in Japanese Black Beef Cattle

Abstract

Heritabilities and genetic correlations between additive direct and maternal genetic effects for birth and calf-market weights in Japanese Black beef cattle were estimated by two-trait restricted maximum likelihood (REML) under animal models and the genetic trends were investigated. The data were collected from field in Iwate, Gifu and Kagoshima prefectures. Heritabilities of direct effects for birth and calf-market weights were estimated to be from 0.19 to 0.39 and from 0.25 to 0.30, respectively. The estimates of maternal heritabilities were smaller than those of direct heritabilities and ranged from 0.16 to 0.28 for birth weight and from 0.10 to 0.18 for calf-market weight. Genetic correlations between direct and maternal effects were estimated a range of -0.07 to 0.74 for birth weight and 0.03 to 0.53 for calf-market weight. There were no serious antagonistic genetic relationships between them. However, genetic trends of maternal effects showed decreased and steady changes in all analyzed prefectures. The results indicate that selection for maternal effects on early growth is possible but more attention must be paid on maternal ability to improve beef production efficiency.