Research Paper| Volume 47, ISSUE 4, P528-536, July 2020

Download started.


Immobilization quality and cardiopulmonary effects of etorphine alone compared with etorphine–azaperone in blesbok (Damaliscus pygargus phillipsi)

Published:April 01, 2020DOI:



      To evaluate the immobilization quality and cardiopulmonary effects of etorphine alone compared with etorphine–azaperone in blesbok (Damaliscus pygargus phillipsi).

      Study design

      Blinded, randomized, crossover design.


      A total of 12 boma-habituated female blesbok weighing [mean ± standard deviation (SD)] 57.5 ± 2.5 kg.


      Each animal was administered etorphine (0.09 mg kg–1) or etorphine–azaperone (0.09 mg kg–1; 0.35 mg kg–1) intramuscularly with 1-week intertreatment washout period. Time to first sign of altered state of consciousness and immobilization time were recorded. Physiological variables were recorded, arterial blood samples were taken during a 40-minute immobilization period, and naltrexone (mean ± SD: 1.83 ± 0.06 mg kg–1) was intravenously administered. Recovery times were documented, and induction, immobilization and recovery were subjectively scored. Statistical analyses were performed; p < 0.05 was significant.


      No difference was observed in time to first sign, immobilization time and recovery times between treatments. Time to head up was longer with etorphine–azaperone (0.5 ± 0.2 versus 0.4 ± 0.2 minutes; p = 0.015). Etorphine caused higher arterial blood pressures (mean: 131 ± 17 versus 110 ± 11 mmHg, p < 0.0001), pH, rectal temperature and arterial oxygen partial pressure (59.2 ± 7.7 versus 42.2 ± 9.8 mmHg), but lower heart (p = 0.002) and respiratory rates (p = 0.01). Etorphine–azaperone combination led to greater impairment of ventilatory function, with higher end-tidal carbon dioxide (p < 0.0001) and arterial partial pressure of carbon dioxide (58.0 ± 4.5 versus 48.1 ± 5.1 mmHg). Immobilization quality was greater with etorphine-azaperone than with etorphine alone (median scores: 4 versus 3; p < 0.0001).

      Conclusions and clinical relevance

      Both treatments provided satisfactory immobilization of blesbok; however, in addition to a deeper level of immobilization, etorphine–azaperone caused greater ventilatory impairment. Oxygen supplementation is recommended with both treatments.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Veterinary Anaesthesia and Analgesia
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Buss P.
        • Miller M.
        • Fuller A.
        • et al.
        Cardiovascular effects of etorphine, azaperone, and butorphanol combinations in chemically immobilized captive white rhinoceros (Ceratotherium Simum).
        J Zoo Wildl Med. 2016; 47: 834-843
        • Bowdle T.A.
        Adverse effects of opioid agonists and agonist-antagonists in anaesthesia.
        Drug Saf. 1998; 19: 173-189
        • Christie R.V.
        • Loomis A.L.
        The pressure of aqueous vapour in the alveolar air.
        J Physiol. 1932; 3: 35-48
        • Ding X.Z.
        • Long R.J.
        • Mi J.D.
        • Guo X.S.
        Measurement of methane and carbon dioxide emissions from ruminants based on the NDIR technique.
        Guang Pu Xue Yu Guang Pu Fen Xi. 2010; 30: 1503-1506
        • Grimm K.A.
        • Lamont L.A.
        • Tranquilli W.J.
        • et al.
        Veterinary Anesthesia and Analgesia: The Fifth Edition of Lumb and Jones.
        John Wiley & Sons, Inc., Ames, IA, USA2015: 1061
        • Guyenet P.
        Regulation of breathing and autonomic outflows by chemoreceptors.
        Comp Physiol. 2014; 4: 1511-1562
        • Haigh J.C.
        Opioids in zoological medicine.
        J Zoo Wildl Med. 1990; 21: 391-413
        • Haskins S.
        • Rezende M.
        The caprine oxyhemoglobin dissociation curve.
        Res Vet Sci. 2006; 80: 103-108
        • Heard D.J.
        • Kollias G.V.
        • Buss D.
        • et al.
        Comparative cardiovascular effects of intravenous etorphine and carfentanil in goats.
        J Zoo Wildl Med. 1990; 21: 166-170
        • Hedenstierna G.
        • Edmark L.
        Mechanisms of atelectasis in the perioperative period.
        Best Pract Res Clin Anaesthesiol. 2010; 24: 157-169
        • Izwan A.
        • Snelling E.P.
        • Seymour R.S.
        • et al.
        Ameliorating the adverse cardiorespiratory effects of chemical immobilization by inducing general anaesthesia in sheep and goats: implications for physiological studies of large wild mammals.
        J Comp Physiol Compar B. 2018; 188: 991-1003
        • Kim D.
        • McLeod K.R.
        • Klotz J.L.
        • et al.
        Evaluation of a rapid determination of fasting heat production and respiratory quotient in Holstein steers using the washed rumen technique1.
        J Anim Sci. 2013; 91: 4267-4276
        • Kock M.D.
        • Burroughs R.E.
        Chemical and physical restraint of wild animals.
        in: International Wildlife Veterinary Services (Africa). 2nd edn. 2012 (Greyton, South Africa)
        • Kuriyama T.
        • Wagner W.W.
        Collateral ventilation may protect against high-altitude pulmonary hypertension.
        J Appl Physiol. 1981; 51: 1251-1256
        • Lees P.
        • Serrano S.
        Effects of azaperone on cardiovascular and respiratory functions in the horse.
        Br J Pharmacol. 1976; 56: 263-269
        • Mentaberre G.
        • López-Olvera J.R.
        • Casas-Díaz E.
        • et al.
        Use of haloperidol and azaperone for stress control in roe deer (Capreolus capreolus) captured by means of drive-nets.
        Res Vet Sci. 2010; 88: 531-535
        • Meyer L.C.R.
        • Hetem R.S.
        • Fick L.G.
        • et al.
        Thermal, cardiorespiratory and cortisol responses of impala (Aepyceros melampus) to chemical immobilisation with 4 different drug combinations.
        J S Afr Vet Assoc. 2008; 79: 121-129
        • Meyer L.C.R.
        • Hetem R.S.
        • Mitchell D.
        • Fuller A.
        Hypoxia following etorphine administration in goats (Capra hircus) results more from pulmonary hypertension than from hypoventilation.
        BMC Vet Res. 2015; 11: 18
        • Neary J.
        • Garry F.
        • Raabis S.
        Age-related changes in arterial blood-gas variables in Holstein calves at moderate altitude.
        Open Access Anim Physiol. 2014; 6: 13-20
        • Nyman G.
        • Funkquist B.
        • Kvart C.
        • et al.
        Atelectasis causes gas exchange impairment in the anaesthetised horse.
        Eq Vet J. 1990; 22: 317-324
        • Pang D.
        • Boysen S.
        Lactate in Veterinary Critical Care: Pathophysiology and Management.
        J Am Anim Hosp Assoc. 2007; 43: 270-279
        • Radcliffe R.W.
        • Ferrell S.T.
        • Childs S.E.
        Butorphanol and azaperone as a safe alternative for repeated chemical restraint in captive white rhinoceros (Ceratotherium simum).
        J Zoo Wildl Med. 2012; 31: 196-200
        • Ramadoss J.
        • Stewart R.H.
        • Cudd T.A.
        Acute renal response to rapid onset respiratory acidosis.
        Can J Physiol Pharmacol. 2011; 89: 227-231
        • Riviere J.E.
        • Papich M.G.
        Veterinary Pharmacology & Therapeutics.
        9th edn. Wiley-Blackwell, Iowa, USA2009
        • Roquebert J.
        • Delgoulet C.
        Cardiovascular effects of etorphine in rats.
        J Auton Pharmacol. 1988; 8: 39-43
        • Sarkar M.
        • Niranjan N.
        • Banyal P.
        Mechanisms of hypoxemia.
        Lung India. 2017; 34: 47-60
        • Schultz H.D.
        • Li Y.L.
        • Ding Y.
        Arterial chemoreceptors and sympathetic nerve activity: implications for hypertension and heart failure.
        Hypertens. 2007; 50: 6-13
        • Semjonov A.
        • Adrianov V.
        • Raath J.P.
        • et al.
        Evaluation of butorphanol–azaperone–medetomidine (BAM) in captive blesbok immobilization (Damaliscus pygargus phillipsi).
        Vet Anaesth Analg. 2018; 45: 496-501
        • Shakespeare A.
        Aspiration lung disorders in bovines: A case report and review.
        J S Afr Vet Ass. 2012; 83: 1-7
        • Still J.
        • Raath J.P.
        • Matzner L.
        Respiratory and circulatory parameters of African elephants (Loxodonta africana) anaesthetised with etorphine and azaperone.
        J S Afr Vet Assoc. 1996; 67: 123-127
        • Swan G.E.
        Drugs used for the immobilization, capture, and translocation of wild animals.
        in: McKenzie A.A. The Capture and Care Manual. The South African Veterinary Foundation. 1993: 3-59 (Pretoria, South Africa)
        • Thatcher C.D.
        • Keith J.C.
        Pregnancy-induced hypertension: Development of a model in the pregnant sheep.
        Am J Obstet Gynecol. 1986; 155: 201-207
        • Walsh V.P.
        • Wilson P.R.
        Sedation and chemical restraint of deer.
        N Z Vet J. 2002; 50: 228-236
        • Wenger S.
        • Buss P.
        • Joubert J.
        • et al.
        Evaluation of butorphanol, medetomidine and midazolam as a reversible narcotic combination in free-ranging African lions (Panthera leo).
        Vet Anaest Analg. 2010; 37: 491-500
        • Zeiler G.E.
        • Meyer L.C.R.
        Chemical capture of impala (Aepyceros melampus): A review of factors contributing to morbidity and mortality.
        Vet Anaest Analg. 2017; 44: 991-1006
        • Zeiler G.E.
        • Meyer L.C.R.
        Comparison of thiafentanil-medetomidine to etorphine-medetomidine immobilisation of impalas (Aepyceros melampus).
        J S Afr Vet Assoc. 2017; 88: 1-8