The aim of this study was to rank diverse beef cattle genotypes for meat quality characteristics and to determine whether that ranking changed depending on the environment in which the animals were finished. Breed groups, ranging from 100% Bos indicus to 100% Bos taurus content, were derived from Indian zebu (Brahman), African zebu (Boran), British breeds (Hereford-Shorthorn), continental breeds (Charolais and Simmental) and Sanga (Tuli and Belmont Red). Heavy steers (>600 kg) were raised in a tropical environment and finished either on pasture or in a feedlot.
For striploins (longissimus) from feedlot finished steers, cooking loss was greatest for zebu (Z) steaks, least for British (B) steaks (P < 0·001), and intermediate for the other breeds. For striploins from pasture finished steers and eye rounds (semitendinosus) from both pasture finished and feedlot finished steers, there were no breed differences in cooking loss.
For both feedlot finished and pasture finished steers, striploin steaks from B steers were most tender, and Sanga (S) and zebu × continental cross (ZC) steaks were more tender than Z steaks. Warner-Bratzler initial yields suggested that the lower toughness of these breeds was due to lower myofibrillar toughness. Peak force minus initial yield suggested a smaller, opposite effect of increasing connective tissue toughness associated with increasing Bos taurus content. This breed effect on connective tissue toughness was more prominent in the eye round samples. In the feedlot finished steers, Z eye round was as tender as B eye round. In pasture finished steers, Z eye round had a peak force 1·3 kg lower than B in contrast to the results for striploin where Z was 1·2 kg higher than B. Sanga eye round followed the same trend as B relative to Z but to a lesser extent. From the feedlot, S eye round was more tender than Z eye round and from pasture, S eye round was the same as Z eye round. There was no evidence of heterosis f or any meat quality attribute.
These results are best explained in terms of a model incorporating differential effects of breed on the myofibrillar and connective tissue components of toughness. The implications of this study are that the tenderness of grilling and roasting cuts of meat from the predominantly Brahman-based beef herd of northern Australia can be improved through crossbreeding with any of the taurine breeds studied.