Genetic relationship between birth weight and adult weight in Holsteins

Records of body weight for 1026 Holstein females from two herds included birth weight and all available subsequent calving weights for the first six parities. Birth weight differed between herds and between sires within herds. Years also differed; however, partial nesting of sires within years could account for part of this. Month of birth had no influence on birth weight. Calving weights differed between herds only at the second and fifth parities. Calving weights differed between sires within herds for the first five parities. Intraherd correlations between the birth weight of a heifer calf and later calving weights for her first six parities ranged from .22 to .34. Correlations between the birth weight of a calf and the average birth weight of her paternal half-sibs were .37 and .48 in the two herds. Heritabilities for birth and calving weights were of the same magnitude within herds but differed between herds. Genetic correlations between birth and adult weights were above .5 in one herd but erratic in the other herd.