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Effects of hot-iron branding on heart rate, breathing rate and behaviour of anaesthetised Steller sea lions
  1. K. A. Walker, BSc, MSc, PhD1,
  2. J. E. Mellish, BSc, PhD2 and
  3. D. M. Weary, BSc, MSc, PhD1
  1. Animal Welfare Program, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
  2. School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
  1. E-mail for correspondence kristenw3{at}

This study assessed the heart rate, breathing rate and behavioural responses of 12 juvenile Steller sea lions during hot-iron branding under isoflurane anaesthesia. Physiological and behavioural measures were recorded in four periods: baseline (five minutes), sham branding (one minute), branding (approximately 2.7 minutes) and postbranding (five minutes). No difference in heart rate was noted from baseline to sham branding, but heart rate increased from mean (sem) 78.3 (2.4) bpm in the baseline period to 85.6 (2.5) bpm in the branding period. Heart rate remained elevated in the postbranding period, averaging 84.7 (2.5) bpm. Breathing rate averaged 2.5 (1.0) breaths/minute in the baseline and sham branding periods increased to 8.9 (1.0) breaths/minute during branding, but returned to baseline by the postbranding period. Behaviourally, half of the sea lions exhibited trembling and head and shoulder movements during branding.

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  • Dr Mellish is also at the Alaska SeaLife Center, 301 Railway Avenue, PO Box 1329, Seward, AK 99664, USA

  • Provenance not commissioned; externally peer reviewed

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