Discipline: Animal Science
Linear and non-linear (quadratic, cubic and logarithmic) models were fitted to describe the post-weaning growth of 51 American Brahman bulls at ANSA Genetics, Inc. cattle breeding farm, Lipa City, Batangas. The final model consisted of the live weight of bulls as a linear function of age (i.e., at least 270 days old) and adjusted for the significant effects (P<0.01) of their sire and the number of calving by their dam (P<0.01). The post-weaning data represented the second phase (linear) of the sigmoid growth curve in beef cattle. Based on 429 monthly live weight records, the sire effects on the post-weaning live weight of young bulls (also estimated breeding values) were highest for sires #322, #108 and #344. Selection of sires based on the superior post-weaning growth of its sons may thus provide the practical basis to improve efficiency of local beef production. Post-weaning growth was also highest in bulls with dams on their fifth calving.