Effects of finishing strategy on performance of Belgian Blue x Friesian and Limousin x Friesian steers.

摘要

Belgian Blue and Limousin bulls are used for cross-breeding with Holstein Friesian dairy cows in Ireland. In beef winter-finishing enterprises, a preliminary feeding period sometimes precedes the finishing period. The optimum feeding level for this period has not been established. The objective of this study was to compare lifetime performance of Belgian Blue x Holstein Friesian (BB) and Limousin x Holstein Friesian (LM) steers and to determine the effects of three finishing strategies on performance and carcass traits. Fortyeight spring-born male calves (24 BB and 24 LM), the progeny of Limousin and Belgian Blue bulls out of Holstein Friesian cows, were reared together to slaughter. At about 19 months of age they were assigned to one of three finishing strategies involving grass silage ad libitum plus 0, 3 or 6 kg concentrates per head daily for 112 days (preliminary period) followed by concentrates ad libitum to slaughter at 610 kg live weight. Slaughter weight and carcass weight did not differ between the breed types but BB had a higher kill-out proportion, better carcass conformation and lower carcass fatness. Live-weight gains during the preliminary period were 431, 914 and 1134 g/day (s.e. 31.8; P<0.001) for the 0, 3 and 6 kg/day concentrate levels, respectively. Overall gains for the combined preliminary and finishing periods for the treatments in the same order were 945, 1101 and 1081 g/day (s.e. 36.1; P<0.01). There were few differences between the finishing treatments in slaughter weight, carcass weight or carcass traits. It is concluded that general productivity is similar for BB and LM but BB have superior carcass traits. Where a preliminary feeding period precedes a finishing period on ad libitum concentrates, animals fed a low level of supplementary concentrates require less feed energy to reach a fixed slaughter weight than those fed none or a higher level of supplementary concentrates.