The hairy lizard: heterothermia affects anaesthetic requirements in the Arabian oryx (Oryx leucoryx)

Mads F. Bertelsen*, Osama Mohammed, Tobias Wang, Paul R. Manger, David Michael Scantlebury, Khairi Ismael, Nigel C. Bennett, Abdulaziz Alagaili

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Objective: To study the effect of heterothermia on anaesthetic drug requirements in semi-free ranging Arabian oryx and to assess the temperature quotient (Q10) of oxygen consumption. Study design: Prospective observational study and controlled metabolic experiment. Animals: Sixty-eight anaesthetic events in 59 Arabian oryx from Mahazat As-Sayd protected area, Saudi Arabia Methods: Anaesthesia was induced by remote injection of 25 mg ketamine, 10 mg midazolam and 0.5 mg medetomidine with a variable amount of etorphine based on a target dosage of 20 μg kg–1 and subjective assessment of body mass. Animals not recumbent within 15 minutes or insufficiently anaesthetized were physically restrained and administered supplementary etorphine intravenously depending on the anaesthetic depth. Body temperature (Tb) was measured rectally immediately upon handling of each animal. From six anaesthetized oryx, expiratory gasses for oxygen analysis and metabolic rate calculation were collected at two Tbs; before and after submersion in ice water for approximately 30 minutes. Results: Forty-two animals (62%) became recumbent with the initial dose, with a mean induction time (± standard deviation) of 9 ± 2 minutes. The remaining animals could be handled but needed 0.3 ± 0.1 mg etorphine intravenously to reach the desired level of anaesthesia. There was a significant positive correlation between Tb and effective etorphine dosage (R2 = 0.48, p < 0.0001). Average Tb of the six animals in which metabolic rate was measured decreased from 40.0 ± 0.5°C immediately after induction to 35.5 ± 0.5°C after cooling. This reduction was associated with a reduction in oxygen uptake from 3.11 ± 0.33 to 2.22 ± 0.29 mL O2 minute–1 kg–1, reflected in Q10 of 2.17 ± 0.14. Conclusions and clinical relevance: Tb significantly affects anaesthetic requirements in Arabian oryx and should be considered when selecting dosages for anaesthetic induction for species showing diurnal heterothermy.

Original languageEnglish
Pages (from-to)899-904
Number of pages6
JournalVeterinary Anaesthesia and Analgesia
Issue number4
Early online date06 Mar 2017
Publication statusPublished - Jul 2017

Bibliographical note

Funding Information:
The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding the work through the research group project no. RGP-VPP-020. The authors are grateful to Prince Bander bin Saud Al-Saud, President of the Saudi Wildlife Authority (SWA) for his unlimited and enthusiastic support to undertake these studies on the Arabian oryx managed by the SWA. We are also grateful for the tremendous help provided by our colleagues at the National Wildlife Research Center in Taif, Saudi Arabia, especially Mr. Ahmed Boug, Dr. Saud Anagariyah, Mr. Ghazi Raziman, Mr. Raed Aljuaid and Mr. Ali Aljuaid.

Publisher Copyright:
© 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia

Copyright 2018 Elsevier B.V., All rights reserved.


  • anaesthesia
  • body temperature
  • etorphine
  • heterothermy
  • Oryx leucoryx

ASJC Scopus subject areas

  • General Veterinary


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