THE BIRTH AND WEANING WEIGHTS OF HIGHLAND AND HEREFORD CATTLE AND THEIR RECIPROCAL CROSSES

Abstract

Birth and weaning data were collected from 1957 to 1960 on 219 calves of the Highland and Hereford breeds and their reciprocal crosses. Significant (P < 0.01) effects of breed of calf, age of dam, sex of calf, and date of birth on birth weight, and significant (P < 0.01) effects of breed of calf, year of birth, age of dam, sex of calf, and age of calf on weaning weight, demonstrated the importance of considering both genetic and environmental factors when undertaking comparative tests of breeds and crosses.Breed means and standard errors for birth weight were Hereford, 70.7 ± 0.9; Highland, 63.6 ± 1.0; Highland (sire) × Hereford (dam), 73.6 ± 0.9; and Hereford (sire) × Highland (dam), 70.1 ± 1.1 lb. Weaning weight means and standard errors were: Hereford, 360 ± 5.6; Highland, 339 ± 6.7; Highland × Hereford, 378 ± 6.0; and Hereford × Highland, 385 ± 7.0 lb.The average of the reciprocal crosses exceeded the average of the parental breeds by 7.0% in birth weight and 9.2% in weaning weight.Variability (sum of squares) in birth weight accounted for by breed of calf was about twice that accounted for by age of dam or sex of calf, and about 6 times that contributed by year of birth or date of birth within years. The influence of age of dam on the variability in weaning weight was about twice that accounted for by breed of calf, year of birth, or age of calf, and about 7 times that due to sex of calf.