Caribou (Rangifer tarandus) are frequently captured for research and management, often using drug combinations that include potent opioids. We evaluated an alternative combination of butorphanol-azaperone-medetomidine (BAM) plus ketamine (KBAM) for helicopter-based captures of free-ranging caribou. The study included 61 animals from four herds captured between October 2024 and April 2025: 30 female calves and 31 adult cows. Initially, 11 calves were immobilized with 1 mL BAM and 50 mg ketamine; subsequently, the ketamine dose was reduced to 30 mg for the remaining calves. Adult cows received 1.75-2.25 mL BAM with 50 mg ketamine. Overall, 22/30 calves were weighed, and doses (mean ±SD range) were 0.51±0.04 (0.43-0.60) mg/kg for butorphanol, 0.17±0.01 (0.14-0.20) mg/kg for azaperone, and 0.21±0.01 (0.17-0.24) mg/kg for medetomidine. Mean ketamine doses were 0.96±0.08 (0.85-1.10) mg/kg for calves receiving 50 mg and 0.55±0.04 (0.48-0.63) mg/kg for calves receiving 30 mg. Mean time from darting to recumbency was 4.1 min (range 2-8 min) for calves and 6.3 min (range 3-16 min) for adults, and mean time from intramuscular reversal with atipamezole and naltrexone to standing was 5.4 min (range 1-12 min) for calves and 6.0 min (range 1-38 min) for cows. No capture-related mortalities were observed within 1 mo post-release. All animals experienced hypoxemia, which improved with intranasal oxygen administration. These results suggest that KBAM is an effective alternative to potent opioids for helicopter-based capture of caribou, providing reasonably rapid induction and recovery while minimizing mortality risk.
Roug et al. (Fri,) studied this question.