Abstract
The relationships between direct genetic effects and genetic maternal effects on preweaning growth traits (body weight, withers height, body length, chest depth, rump length, hip bone width, heart girth) in Hereford cattle at the TOKACHI National Livestock Breeding Station were examined. 1) The figures for covariance between direct genetic effects and genetic maternal effects were negative for almost all body measurements. 2) Heritability figures for maternal effect were higher than those of the direct effect for body weight, chest, depth, rump length, hip bone width, and heart girth at 3 and 6 months of age. Heritability figures for maternal effect for body weight, rump length, hip bone width, and heart girth at 3 months of age were 0.67 to 0.76. 3)Total additive genetic contribution accounted for less than 30% of variation in almost all body measurements. 4) The figures for the phenotypic correlation coefficient between the preweaning body measurements of cows and their calves were lower than 0.30 for almost all the traits.
