Effect of interval from castration of bulls to slaughter on carcass characteristics and meat quality

A trial was conducted to see whether reducing the interval from castration to slaughter could produce steer-like carcasses but retain the weight advantage of bulls. Ninety Angus, Friesian x Hereford, and Friesian x Simmental bulls were allocated to nine groups. Four groups were castrated at 8 months of age (steers), and three groups were castrated on January 17 (Day 0) at 17 months of age (castrates). One group of bulls and one group of steers were slaughtered on Day 5, groups of steers and castrates were slaughtered on Days 62, 111, and 166, and the remaining group of bulls was also slaughtered on Day 166. On Day 0, bulls and steers were 455 +/- 6 and 426 +/- 5 kg liveweight, respectively. Liveweight gain of castrates was lower than that of steers for 106 days following castration and the carcass weight (CW) advantage of bulls over steers at 17 months of age was lost in castrates slaughtered at Day 62. The rate of change in carcass, meat, and fat characteristics varied with the attribute under consideration. For castrates the proportion of carcasses classified as steer at slaughter on Days 62, 111, and 166 was 20%, 60%, and 73%, respectively. We conclude that the loss of the weight advantage is faster than most other carcass attributes change and there is little opportunity to exploit postpubertal castration for economic advantage.