Do potent immobilising-opioids induce different physiological effects in impala and blesbok?

Authors

  • Silke Pfitzer Murdoch University
  • Michael Laurence Murdoch University
  • Liesel Laubscher University of Stellenbosch
  • Jacobus P Raath Wildlife Pharmaceuticals South Africa (Pty) Ltd
  • Kristin Warren Murdoch University
  • Rebecca Vaughan-Higgins Murdoch University
  • Leith R.C Meyer University of Pretoria

Abstract

Potent opioids are known to cause negative alterations to the physiology of immobilised antelope. How these effects differ between species has not been studied. This study aimed to compare time to recumbence and effects of opioid-based immobilisation on the physiology of impala (Aepyceros melampus) and blesbok (Damaliscus pygargus phillipsi). Eight animals of each species were immobilised, with 0.09 mg/kg etorphine and 0.09 mg/kg thiafentanil respectively, in a randomised two-way cross-over study. Variables measured and analysed by means of a linear mixed model included time to recumbence, heart rate, respiratory rate, arterial blood pressure, blood gases, lactate and glucose. In blesbok, mean time to recumbence was not
significantly different with either drug (2.5 minutes and 2.2 min, respectively), but in impala thiafentanil achieved a shorter time to recumbence (2.0 min) than etorphine (3.9 min). Mean heart rates of immobilised impala were within reported physiological limits, but lower in immobilised blesbok when both opioids were used (35 beats/min to 44 beats/min vs. 104 ± 1.4 beats/min resting heart rate). Impala developed severe respiratory compromise and hypoxaemia from both opioids (overall mean PaO2 values ranged from 38 mmHg to 59 mmHg over 30 min). In contrast, blesbok developed only moderate compromise. Therefore,
significantly different species-specific physiological responses to potent opioid drugs exist in blesbok and impala. Given that these different responses are clinically relevant, extrapolation of immobilising drug effects from one species of African ungulate to another is not recommended. Keywords: Blesbok; etorphine; immobilisation; impala; opioids; thiafentanil.

Author Biographies

  • Silke Pfitzer, Murdoch University

    School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia and School of Biology and Environmental Sciences, Faculty of Agriculture and Natural Sciences, University of Mpumalanga, Nelspruit, South Africa

  • Michael Laurence, Murdoch University

    School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia

  • Liesel Laubscher, University of Stellenbosch

    Department of Animal Science, University of Stellenbosch, Cape Town, South Africa

  • Jacobus P Raath, Wildlife Pharmaceuticals South Africa (Pty) Ltd

    Wildlife Pharmaceuticals South Africa (Pty) Ltd, White River, South Africa

  • Kristin Warren, Murdoch University

    School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia

  • Rebecca Vaughan-Higgins, Murdoch University

    School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia

  • Leith R.C Meyer, University of Pretoria

    Centre for Veterinary Wildlife Studies and Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa

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Published

2021-12-09

Issue

Vol. 91 No. 1 (2020)

Section

Original Research