Abstract
Objective
To characterize and compare two intramuscular drug protocols using alfaxalone and
alfaxalone–medetomidine combination for the field immobilization of free-ranging koalas.
Study design
Blinded, randomized, comparative field study.
Animals
A total of 66 free-ranging koalas from the Mount Lofty Ranges, South Australia.
Methods
Koalas were randomly allocated into two groups. Group A animals were given alfaxalone
alone at 3.5 mg kg–1. Group AM animals were given alfaxalone 2 mg kg–1 and medetomidine 40 μg kg–1, reversed with atipamezole at 0.16 mg kg–1. Blinded operators recorded heart rate (HR), respiratory rate (fR), cloacal temperature, depth of sedation and times to: first effect, sedation suitable
for clinical interventions, first arousal and full recovery. Data were analysed using
independent t test, Mann–Whitney U test, chi-square analysis and log-rank test at 5% level of significance.
Results
Suitable immobilization for clinical examination and sample collection was achieved
in all animals. In groups A and AM, median time to working depth was 6.5 minutes (range:
3.4–15) and 8.1 minutes (range: 4.3–24) and time to complete recovery was 66 minutes
(range: 12–138) and 34 minutes (range: 4–84), respectively, following reversal. Time
to first effect was significantly shorter in group A (p = 0.013), whereas time to full arousal was significantly shorter in group AM (p = 0.007) probably due to the administration of atipamezole. Maximum HR was 117 ±
28 beats minute–1 in group A, which was a significant increase from baseline values (p < 0.0001), whereas group AM showed a significant tachypnoea of 67 ± 25 (normal fR 10–15; p < 0.0001).
Conclusions and clinical relevance
Both the protocols produced immobilization, enabling clinical examination and sample
collection; however, protocol AM was more suitable for field work due to shorter recovery
times.
Keywords
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References
- Surgical implantation of temperature-sensitive transmitters and data-loggers to record body temperature in koalas (Phascolarctos cinereus).Aust Vet J. 2016; 94: 42-47
- Koalas.in: Vogelnest L. Woods R. Medicine of Australian Mammals. CSIRO, Collingwood, Victoria2008: 227-327
- Evaluation of medetomidine-alfaxalone and medetomidine-ketamine in semi-free ranging Bennett's wallabies (Macropus rufogriseus).J Zoo Wildl Med. 2011; 42: 617-622
- Dissociative anaesthesia in free-ranging male koalas and selected marsupials in captivity.Aust Vet J. 1990; 67: 449-451
- Metabolism and heat balance in an arboreal marsupial, the koala (Phascolarctos cinereus).J Comp Physiol. 1979; 134: 293-301
- Confronting a tough issue: Fertility control and translocation for over-abundant Koalas on Kangaroo Island, South Australia.Ecol Manag Restor. 2005; 6: 172-181
- Combination of zolazepam and tiletamine as a sedative and anaesthetic for wombats.Aust Vet J. 1998; 76: 355-356
- Chlamydia pecorum prevalence in South Australian koala (Phascolarctos cinereus) populations: Identification and modelling of a population free from infection.Scientific Rep. 2019; 9: 1
- Prevalence and clinical significance of the Koala retrovirus in two South Australian koala (Phascolarctos cinereus) populations.J Med Microbiol. 2019; 68: 1072-1080
- Anaesthetic effects in the ferret of alfaxalone alone and in combination with medetomidine or tramadol: a pilot study.Lab Anim (Lond). 2014; 48: 313-320
- Schirmer tear tests and intraocular pressures in conscious and anesthetized koalas (Phascolarctus cinereus).Vet Ophthalmol. 2011; 14: 292-295
- Assessment of the effects of intramuscular administration of alfaxalone with and without medetomidine in Horsfield's tortoises (Agrionemys horsfieldii).Vet Anaesth Analg. 2013; 40: 68-75
- A steroid anesthetic prolongs inhibitory postsynaptic currents in cultured rat hippocampal neurons.J Neurosci. 1987; 7: 604-609
- Marsupials.in: West G. Heard D. Caulkett N. Zoo Animal and Wildlife Immobilization and Anesthesia. 2nd edn. Blackwell Publishing, IA, USA2014: 521-528
- Effects of medetomidine or midazolam alone or in combination on the metabolic and neurohormonal responses in healthy cats.Can J Vet Res. 2008; 72: 332-339
- Sedative and cardiorespiratory effects of medetomidine, medetomidine-butorphanol, and medetomidine-ketamine in dogs.J Am Vet Med Assoc. 2000; 216: 1578-1583
- Use of medetomidine for chemical restraint of captive gray wolves (Canis lupus).J Zoo Wildl Med. 1996; 27: 507-512
- Capture of koalas (Phascolarctos cinereus) by remote injection of tiletamine and zolazepam (Zoletil) and medetomidine.Wildl Res. 2003; 30: 255-258
- Use of quantitative real-time PCR to monitor the shedding and treatment of chlamydiae in the koala (Phascolarctos cinereus).Vet Microbiol. 2007; 120: 334-342
- The Koala: Natural History, Conservation and Management.2nd edn. University of New South Wales Press, Sydney1999
- Cardiorespiratory and anesthetic effects of clinical and supraclinical doses of alfaxalone in dogs.Vet Anaesth Analg. 2008; 35: 451-462
- The protocols for koala research using radio-collars: a review based on its application in a tall coastal forest in New South Wales and the implications for future research.Aust Mammal. 2006; 28: 187-200
- A review of thirty-three Queensland koala (Phascolarctos cinereus adustus) immobilization procedures.J Zoo Anim Med. 1981; 12: 121-123
- Sedation and anesthesia in marsupials.in: Fowler M.E. Miller R.E. Zoo & Wild Animal Medicine. 4th edn. WB Saunders Co., PA1999: 333-336
- DNA and chromosomal damage in medical workers exposed to anaesthetic gases assessed by the lymphocyte cytokinesis-block micronucleus (CBMN) assay. A critical review.Mutat Res. 2016; 770: 26-34
- Temporal variation in reproductive characteristics of an introduced and abundant island population of koalas.J Mammal. 2010; 91: 1160-1167
- The paradox of euthanizing koalas (Phascolarctos cinereus) to save populations from elimination.J Wildl Dis. 2015; 51: 833-842
- Cardiovascular and respiratory effects of tiletamine-zolazepam.Pharmacol Biochem Behav. 1993; 44: 1-8
- Phascolarctos cinereus. The IUCN Red List of Threatened Species.
- Cardiovascular effects of medetomidine, detomidine and xylazine in horses.J Vet Med Sci. 2000; 62: 1025-1032
Article Info
Publication History
Published online: February 27, 2020
Accepted:
October 8,
2019
Received:
June 7,
2019
Identification
Copyright
© 2020 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
