An analysis of beef cattle growth records available in south-eastern Australia

Abstract

Records of growth to weaning of 1812 calves from seven herds in Victoria and one herd in New South Wales were analysed. The results of the analysis were : 1. Preweaning growth rate of heifers decreased significantly with age at weaning. That of bulls and steers did not. 2. Age of dam had a large effect in all three sexes. Environmental factors (properties, years) affected bull calves more than heifer calves. There were fewer degrees of freedom at these levels of the analysis for steers. 3. Adjustments for age of dam were calculated and are presented (table 3). 4. Heritability estimates were obtained from dam-progeny regressions and intra-class correlations. The heritability of adjusted preweaning average daily gain was about 0.25. Clearly many more records need to be analysed to provide further estimates of heritability.