Abstract

The effects of surgical castration of pre- and post-pubertal bulls on measures of stress and growth were investigated in two separate experiments. In Experiment 1, 17-month-old Friesian bulls (n = 6 per treatment) were either left untreated (Controls), handled and administered local anaesthetic (Handled), or handled, administered local anaesthetic and surgically castrated (Castrates). In Experiment 2, 5-month-old Friesian bulls (n = 10 per treatment) were either left untreated (Controls) or surgically castrated without local anaesthetic (Castrates). Castrates in Experiment 1 had higher (P<0.05) plasma cortisol concentrations 7 and 14 days after treatment compared with Handled bulls and lower (P<0.01) gains in body weight for 14 days compared with Controls. There were no effects of treatment on plasma non-esterified fatty acid, b-hydroxybutyrate and urea concentrations. Castrates in Experiment 2 had higher (P<0.05) plasma concentrations of cortisol and the inflammatory protein haptoglobin for 7 days after treatment compared with Controls. The feed intake and weight gain of Castrates were also lower (P<0.05) than that of Controls during the week following treatment. It is concluded that the castration of cattle causes stress, resulting in a check in growth which is possibly mediated via a reduction in feed intake.

JF, Carragher, TW Knight, AF Death, JR Ingram, and LR Matthews

Proceedings of the New Zealand Society of Animal Production, Volume 57, , 100-104, 1997