Hot-iron disbudding: stress responses and behavior of 1- and 4-week-old calves receiving anti-inflammatory analgesia without or with sedation using xylazine

Cattle are often disbudded in a procedure that is painful to them. In an effort to find practical ways to reduce poor welfare due to hot-iron disbudding, we tested a combination of sedation and nonsteroidal anti-inflammatory analgesia (NSAID) that farmers themselves can apply to calves at two different postnatal ages. We compared Prim’Holstein and Charolais calves, male or female, aged 1 or 4 weeks, subjected to hot-iron disbudding without (vigil calves), or with sedation (xylazine calves, 0.2 mg/kg xylazine 2%), and to sham-disbudded calves without sedation or analgesia (control calves). Both groups of disbudded calves received NSAID (3 mg/kg Ketoprofen 10 %®). Calf behavior was observed during disbudding and the following 15 min, and then between 2 h and 7 h post-disbudding. Salivary cortisol and heart rate were measured from 20 min before to 240 min after disbudding. Compared to control and xylazine calves, vigil calves reacted strongly to disbudding by vocalizing (mean vocalizations during the 15 min post-disbudding: vigil calves, 1.95; control calves, 0.2; and xylazine calves, 1.30, a value that was not significantly different from the other two), and higher salivary cortisol concentrations 30 min post-disbudding (vigil calves, 4.08 ng/mL; control calves, 1.59 ng/mL; and xylazine calves, 1.18 ng/mL). An increase in heart rate of 17 bpm above baseline was observed in vigil calves during the 10 min post-disbudding, whereas the heart rate of control calves did not vary and that of xylazine calves decreased by 39 bpm. Significant differences in salivary cortisol concentration and heart rate were observed at 45 min and 30 min post-disbudding, respectively. Vocalizations were observed between 2 and 7 h after disbudding in both vigil and xylazine calves. Responses to disbudding were the same whatever the age, sex, or breed of the calves. The results suggest that sedation with xylazine can reduce the stress calves experience right after disbudding but not after 2 h, and that the pain produced by disbudding is the same at 1 or 4 weeks of age.