BUTORPHANOL, AZAPERONE, AND MEDETOMIDINE ANESTHESIA IN FREE-RANGING EASTERN MOOSE (ALCES AMERICANUS).

Abstract

Fifty-three free-ranging moose (Alces americanus) cows were darted from a helicopter with 3-4 ml of a premix combination of butorphanol (27.3 mg/ml), azaperone (9.1 mg/ml), and medetomidine (10.9 mg/ml; BAM), equivalent to estimated dosages of: butorphanol 0.26 ± 0.08 (mean ± SD) mg/kg, azaperone 0.09 ± 0.03 mg/kg, and medetomidine 0.11 ± 0.03 mg/kg. After a mean chase time (from sighting to darting) of 6.1 ± 5.5 min, the mean induction time (from darting to recumbency) was 8.3 ± 2.6 min. This combination provided a safe and reliable sedation for minor procedures that lasted 30-60 min. Heart rate (50.4 ± 7.0 beats/min), respiratory rate (21.3 ± 11.1 breaths/minute), ETCO2 via nasal canula (43.2 ± 7.0 mmHg), and rectal temperature (38.5°C ± 0.7°C) mostly remained at expected values for wild cervid and bovid species anesthetized with this drug combination. SpO2 (90.0% ± 3.7%) was suggestive of moderate hypoxemia despite intranasal oxygen supplementation (1 L per 100 kg/min). The recovery time to standing was 6.7 ± 3.8 min after reversal with IM naltrexone (3 mg/mg butorphanol) and atipamezole (5 mg/mg medetomidine). Despite a larger volume to inject, this protocol offers an alternative to highly potent opioids, and should be considered for practical or staff safety reasons. On the basis of the results of this study, the use of 4 ml of BAM is considered a safe and effective protocol for immobilization of cow moose under comparable settings.