Etorphine-Azaperone-Medetomidine Immobilization in Free-Ranging Plains Zebras (Equus quagga)
Wild equids are a challenging group of wild animals to immobilize since quality of anaesthesia is often unpredictable.1 Six plains zebras (Equus quagga) were anaesthetised using a combination of etorphine (0.018 mg/kg) (Captivon 9.8 mg/mL; Wildlife Pharmaceuticals, Karino, South Africa), medetomidine (0.016 mg/kg) (20 mg/mL, Kyron Laboratories, White River, South Africa), and azaperone (0.23 mg/kg) (50 mg/mL; ZooPharm, Windsor, CO, USA). Drugs were delivered in a 2 ml dart (Type ‘C’; Pneu-Dart, Inc., Williamsport, PA, USA) by means of a blank cartridge-fired projector (Model 196, Pneu-Dart, Inc., Williamsport, PA, USA). A descriptive score was used to assess the quality of immobilization, reaction to manipulation, maintenance, recovery, and physiological parameters were recorded at five-minute intervals for a total of 20 minutes. At the end of the procedure, the opioid antagonist naltrexone (Trexonil 50 mg/mL; Wildlife Pharmaceuticals, White River, South Africa) was administered IM (0.24 mg/kg). Immobilization was scored as profound (lateral recumbency, not rousable) in 5 animals, and moderate (rousable) in 1. Reactions to manipulation resulted to be excellent (no reaction) in all animals. Recumbency was achieved in 7.3±7.5 minutes. Heart rate (63.5±17.4 bpm), systolic (149±28.4 mm Hg), diastolic (91.9±19.1 mm Hg), and mean (111.3±20.6 mm Hg) blood pressure, respiratory rate (13.6±8.3), EtCO2 (57.9±5.7 mm Hg), SpO2 (94.1±5.1%), and temperature (38.7±1.5°C) had no significant variation over time. Maintenance was scored as good and recovery as excellent in all animals. All zebras recovered smoothly within 3.7±2 minutes.
1. Lance W. Exotic hoof stock anesthesia and analgesia: best practices. NAVC Congress; 2008:1914–1916.