Evaluation of Brahmans and tropically adapted crossbreds and composites for economically important beef cattle traits

Abstract

This thesis compared straightbred Brahmans to tropically adapted composites for carcass quality, objective and sensory meat quality, feed efficiency, feeding behaviour and reproductive performance under tropical and subtropical conditions in northern Australian using typical commercial beef production practices. Straightbred Brahmans had carcasses up to 160% lighter than Continental (Charolais, Limousin) and British (Angus, Hereford, Shorthonl) sired crosses by Brahman dams (P<0.001), intermediate subcutaneous fat cover, retail beef yields and kilograms of retail primals, and low marbling. British and Belmont Red sired crossbreds had the highest marbling, while British and Santa Gertrudis sired crossbreds had the fattest carcasses. Continental crossbreds had the leanest, highest yielding carcasses with intermediate marbling. There was little difference between sire breeds for most objective and sensory meat quality traits. The exception was straightbred Brahmans with the highest LT shear force (5.39±0.07; P<0.001), LT instron compression (1.89±0.02; P<0.05) and LT and ST cooking loss (P<0.05). Straightbred Brahmans were the only breed that failed to meet minimum MSA (sensory) grading (CMQ4 = 38.3; P<0.001). Crossbreds with up to 75% Brahman content had acceptably tender beef (shear force < 5.0 kg, instron compression < 2.2 kg, CMQ4 score> 46.5). All measures of instron compression were below 2.2 kg indicating connective tissue toughness was not important in these animals slaughtered by an average of 24 months of age. There was little evidence of breed x finish and breed x market interactions.