Influence of energy and protein levels on growth rate, feed efficiency, carcase and meat quality of steers

Abstract

The growth pattern of full fed Friesian steers was one of initial increasing rate of gain followed by a declining rate of gain with increasing bodyweight. Differences in ration energy level which had a significant effect on performance had little influence on efficiency or carcase composition of large breed type steers. In a serial slaughter experiment with Friesian steers, the carcases of animals grown on a grass silage/barley diet had more fat and less meat than those grown on a concentrates/chopped straw diet even though both diets were similar in energy content and supported similar levels of performance. There was an interaction between the effects of diet and slaughter weight. At low carcase weights there was no effect of diet on composition but with increasing carcase weight, the diet effect emerged. A restriction of 20 per cent in feed intake reduced performance, efficiency and carcase fat content.

Carcass composition of serially slaughtered Friesian, Hereford × Friesian and Charolais × Friesian steers finished on two dietary energy levels

“…Bone and fat proportions were reduced and muscle proportion was increased on the M diet. This is in agreement with a number of reports in the literature (Andersen, 1975;Smith, Crouse, Mandigo and Neer, 1977;Keane and Harte, 1980) which indicate that animals reared on a higher feeding level tend to have more fat and less bone and muscle than those reared on a lower feeding level. However, the effects of feeding level on composition may vary with breed type and there may be differences in chemical composition which are not evident in physical composition (Prior, Kohlmeier, Cundiff, Dikeman and Crouse, 1977;Fortin, Reid, Maiga, Sim and Wellington, 1980a).…”