The Effect of Birth Weight, Age of Dam and Time of Birth on Suckling Gains of Beef Calves

One hundred three purebred Hereford and Aberdeen Angus calves were used in this study. The data included two years—1953 and 1954. Time of birth was broken down, arbitrarily, into 20-day periods beginning with March 1. The other variables were used in the usual manner. The data were analyzed using the method of least squares. Lines, time of birth, and birth weight all affected rate of gain during the suckling period. There was a difference of 0.115 lb. per day in rate of suckling gains associated with each difference of 10 lb. in birth weight. There was little or no effect of age of dam even though large differences appeared to exist between two-year old and older cows. There was apparently no direct effect of sex on rate of suckling gain. This would indicate that on removal of the birth-weight effect, the females approached the males in suckling gains.