Published online by Cambridge University Press: 27 March 2009
1. The data used in this study were the estimated 210-day weights of 2351 calves born on eight farms in the years 1958–61. In each year data were only used from herds which recorded at least five calves of each sex in that year. One hundred such herd years were included in the study.
2. The mean 210-day difference in weight between male and female calves was 27 lb. 1202 male calves had a mean weight of 380 lb. and 1149 female calves had a mean weight of 353 lb.
3. The response of calf weight to age of dam was different in the two sexes. The weight of the female calf was found to increase with dam age in a linear fashion, whereas the response of male calves was best described by a quadratic relationship with the maximum response at a dam age of 8 years.