Studies on factors in beef cattle production in a subtropical environment. 2. Growth to weaning.

Data from 973 calves from 259 cows during the years 1955-1960 at "Brian Pastures" Pasture Research Station in south-eastern Queensland were analysed. The inter-relationships between birth weight, weaning age, daily gain to weaning, weaning weight and weaning score were studied and the effects of sex, year of birth, age of dam, weight of dam and time of birth on them. were evaluated. \nThe mean 1birth weight of all calves was 72·3 lb, with very significant sex and year differences. The mean suckling gain was 1·52 lb per day but was the most variable character studied, year differences, age and precalving history of the cow having significant effects. The repeatability of suckling gain was high. Weaning. weight averaged 339 lb at 172. days, with significant year, sex and dam influences. Weaning score was not nearly so variable as the other characters measured and was only influenced by whether a cow had had a calf the previous year or not. \nBirth weight exerted its major effect on weaning weight, which in tum was closely associated with suckling gain and weaning score.