Assessment of the effect of castration upon arrival on long-term growth performance of stocker cattle

Existing records were used to quantify the effect of castration and dehorning of calves upon arrival at a stocker unit on long-term growth performance and morbidity. Male calves (n = 1,105; BW = 186 ± 24 kg) received over 3 yr were used to assess the effects of castration and dehorning on receiving health and ADG, as well as subsequent grazing performance. Data were compiled from 9 studies in which the protocols used were similar. All bulls (n = 672) were castrated upon arrival, and their ADG and morbidity over the course of the receiving (22-69 d) and grazing (44-217 d) phases were compared with calves received as steers (n = 433). During the receiving phase, bulls gained 0.12 kg/d less than steers (P < 0.01), and polled calves gained 0.09 kg/d more than dehorned calves (P < 0.01). During the grazing phase no differences (P ≥ 0.39) in ADG were noted between castrated bulls and steers or polled and dehorned calves. For the combined receiving and grazing phases, steers tended (P = 0.09) to gain BW faster (0.67 kg/d) than castrated bulls (0.62 kg/d) and polled calves tended (P = 0.11) to have greater ADG (0.65 kg/d) than dehorned calves (0.61 kg/d). This study suggests that purchasing bulls over steers, or horned calves over polled calves due to lower initial costs, would have a negative effect on receiving ADG and overall ADG, but would not affect performance during the grazing phase.