Chemical immobilisation of lions: weighing up drug effectiveness versus clinical effects

Authors

Keywords:

butorphanol, cardiorespiratory, induction, ketamine, medetomidine

Abstract

Selection of an effective drug combination to immobilise African lions (Panthera leo) requires balancing immobilisation effectiveness with potential side effects. We compared the immobilisation effectiveness and changes to physiological variables induced by three drug combinations used for free-ranging African lions. The lions (12 animals per drug combination) were immobilised with tiletamine-zolazepam-medetomidine (TZM), ketamine-medetomidine (KM) or ketamine-butorphanol-medetomidine (KBM). Induction, immobilisation, and recovery were timed, evaluated using a scoring system, and physiological variables were monitored. The drugs used for immobilisation were antagonised with atipamezole and naltrexone. The quality of induction was rated as excellent for all drug combinations and induction times (mean ± SD) did not differ between the groups (10.54 ± 2.67 min for TZM, 10.49 ± 2.63 min for KM, and 11.11 ± 2.91 min for KBM). Immobilisation depth was similar over the immobilisation period in the TZM and KBM groups, and initially light, progressing to deeper in lions administered KM. Heart rate, respiratory rate and peripheral arterial haemoglobin saturation with oxygen were within the expected range for healthy, awake lions in all groups. All lions were severely hypertensive and hyperthermic throughout the immobilisation. Following antagonism of immobilising drugs, lions immobilised with KM and KBM recovered to walking sooner than those immobilised with TZM, at 15.29 ± 10.68 min, 10.88 ± 4.29 min and 29.73 ± 14.46 min, respectively. Only one lion in the KBM group exhibited ataxia during recovery compared to live and four lions in the TZM and KM groups, respectively. All three drug combinations provided smooth inductions and effective immobilisations but resulted in hypertension. KBM had an advantage of allowing for shorter, less ataxic recoveries.

Author Biographies

  • AC Donaldson, University of Pretoria

    Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, South Africa, Center for Zoo and Wild Animal Health, Copenhagen Zoo, Denmark and Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, South Africa

  • A Fuller, University of Pretoria

    Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria and Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, South Africa

  • LCR Meyer, University of Pretoria

    Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, and Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, South Africa

  • PE Buss, University of Pretoria

    Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Veterinary Wildlife Services, South African National Parks, Kruger National Park and Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, South Africa

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Published

2023-03-10

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Section

Original Research