Abstract

The combination of medetomidine, butorphanol, and midazolam (BMM) has been used successfully to immobilize domestic and exotic carnivore species such as red wolf (Canis rufus), African wild dog (Lycaon pictus), and cheetah (Acinonyx jubatus).^1-4 The aim of this study was to evaluate the effects of BMM and its reversibility using naltrexone, atipamezole, and flumazenil in free-ranging lions.

Thirty lions, 10 male and 20 female, were anesthetized using 0.31±0.034 mg/kg butorphanol (butorphanol 50mg/ml; Kyron Laboratories (Pty) Ltd, Benrose, South Africa), 0.052±0.006 mg/kg medetomidine (medetomidine 20mg/ml; Kyron Laboratories (Pty) Ltd, Benrose, South Africa), 0.21±0.024 mg/kg midazolam (midazolam 50mg/ml; Kyron Laboratories (Pty) Ltd, Benrose, South Africa) and 1250 IU hyaluronidase (hyalas; Kyron Laboratories (Pty) Ltd, Benrose, South Africa) administered intramuscularly with a dart gun. Once recumbent, physiologic parameters and anesthetic depth were monitored, and arterial blood gas analyses were performed. Anesthesia was reversed 45–60 minutes after initial darting with 0.68±0.082 mg/kg naltrexone (naltrexone, 50 mg/ml; Kyron Laboratories, Benrose, South Africa), 0.26±0.031 mg/kg atipamezole (Antisedan; Orion Pharma, Espoo, Finland) and 0.0032±0.0007 mg/kg flumazenil (Anexate; Roche Products, Isando, South Africa) administered intravenously and subcutaneously.

The drug combination provided safe and reliable immobilization with minimal cardio-respiratory changes in healthy lions of both sexes. Blood gas analyses revealed a mean pH of 7.333, PaCO₂ of 33 mm Hg, and PaO₂ of 87 mm Hg. Mild to moderate hypoxemia was seen in four lions. Induction and recovery phase were both rapid (less than 10 minutes) and smooth, making the combination ideal for field work.

Literature Cited

1.  Fleming GJ, Citino SB, Bush M. Reversible anesthetic combination using medetomidine-butorphanol-midazolam in in situ African wild dogs (Lycaon pictus). In: Proceedings from the American Association of Zoo Veterinarians AAWV Joint Conference. 2006. Tampa, FL. Pp 214.

2.  Lafortune M, Gunkel C, Valverde A, Klein L, Citino SB. Reversible anesthetic combination using medetomidine-butorphanol-midazolam (MBMZ) in cheetahs (Acinonyx jubatus). In: Proceedings from the American Association of Zoo Veterinarians, AAWV, AZA/NAG Joint conference. 2005. Omaha, NE. Pp 270.

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4.  Verstegen J, Petcho A. Medetomidine-butorphanol-midazolam for anesthesia in dogs and its reversal by atipamezole. Vet Rec. 1993;132:353–357.