The effect of slaughter weight and sexual status on performance characteristics of male Holstein-Friesian cattle offered a cereal-based diet

Abstract

AbstractA total of 180 Holstein-Friesian male calves, mean age and live weight (LW) at start of the study 112 (s.d. 26·0) days and 134 (s.d. 37·6) kg, respectively, were used to evaluate the effect of slaughter weight on food efficiency and animal performance. Animals were offered concentrates ad libitum and a restricted quantity of straw and slaughtered at one of six LWs as bulls: 300, 350, 400, 450, 500 or 550 kg. A further group of cattle were slaughtered as steers at 450 kg LW. Mean age at slaughter was 247 and 434 days for bulls slaughtered at 300 and 550 kg LW respectively. Neither rate of LW or carcass gain was influenced by weight at slaughter ( P>0·05), with mean values of 1·31 and 0·70 kg/day, respectively. Food conversion ratio, killing-out proportion, carcass conformation, fat classification and weight of internal fat depots increased ( P<0·001) as slaughter weight of the bulls increased. In the comparison of steers and bulls slaughtered at 450 kg, steers had lower ( P<0·001) rates of LW and carcass gains and had a higher ( P<0·001) food conversion ratio than comparable bulls. Steers had lower ( P<0·001) estimated carcass lean, and higher ( P<0·01) estimated carcass fat concentrations than bulls slaughtered at the same LW.