AN EVALUATION OF GROWTH AND ADAPTIVE TRAITS OF DIFFERENT CATTLE GENOTYPES IN A SUBTROPICAL ENVIRONMENT

The ability of the large, late maturing, high grade Simmental (HCS), p urebred Hereford (H), Hereford x Shorthorn crossbred (HSH) and grade B elmont Red (BR) genotypes to withstand both tick and intestinal helmin th burdens and high ambient temperatures and to grow in a subtropical environment was investigated. Compared with the H, HSH and BR genotype s the HGS was the least heat tolerant and tick resistant, while there was no difference among genotypes in helminth resistance. The HGS had the heaviest weaning (228 kg v. average of 186 kg for the other breeds ) and 12 month of age (235 kg v. average of 210 kg for the other breed s) weights, however, by 18 months of age there was little difference i n the weights of the HGS and BR genotypes (323 v. 317 kg, respectively ), with the HSH intermediate (302 kg) and the H the lightest (288 kg). When compared with H, HSH and HGS genotypes, the BR genotype is the r ecommended breed for this subtropical environment because it demonstra ted superior adaptive trait performance and, as high, or higher growth performance at 18 months of age.