Date of Graduation
Master of Science in Animal Science (MS)
Second Committee Member
Third Committee Member
Angus-sired (n = 30) and Hereford-sired (n = 32) bull calves were assigned randomly to 1 of 4 treatments. Treatments were 1) surgical castration near birth, 2) oral administration of the analgesic meloxicam (1 mg/kg of body weight) followed by surgical castration near birth, 3) surgical castration at weaning, or 4) surgical castration at weaning with oral administration of the analgesic meloxicam (1 mg/kg of body weight). Data was recorded for behavior, hematology, and growth at birth and weaning. Calf standing and lying activity was monitored at both stages by recording x and y axis positions of a data logger accelerometer attached to the metatarsus of the right leg for 7 d. At birth, blood was collected on d 0 (birth), 1, 3, and 7 from a subset of calves, and post-weaning blood samples were collected on d 214 (weaning), 214 + 6 h, 215, 217, 221, and 228. Body weight was recorded on all calves on d 4, 33, 66, 116, 162, 199, and 214 (weaning). Body weight was recorded on all weaned calves on d 214 (weaning), 228, 246, and 270. Average daily gain did not differ between treatments (P ¡Ý 0.88) through weaning. The neutrophil to lymphocyte ratio at birth decreased with day (P < 0.0001). Following castration at birth, there were no differences in treatments for any of the three observed positions. Overall, post-weaning ADG was greater (P = 0.02) in steers compared to bulls castrated without meloxicam. At weaning the neutrophil to lymphocyte ratio displayed a d effect (P < 0.0001), with an increase at 6 h post castration, and then decreasing. Post-weaning behavior following castration resulted in steers spending the least proportion of time standing, and bulls castrated with analgesia tended to spend less time, numerically, lying on sternum compared to steers.
Brown, April C., "Timing of Castration, with or without Analgesia, on Growth Performance, Hematology, and Behavior of Beef Calves" (2012). Theses and Dissertations. 663.