Immobilisation of impala (Aepyceros melampus) with a ketamine hydrochloride/medetomidine hydrochloride combination, and reversal with atipamezole hydrochloride.

M Bush,W Lance,L.G Phillips,J.P Raath

doi:10.4102/jsava.v75i1.442

Abstract

A combination of medetomidine hydrochloride (medetomidine) and ketamine hydrochloride (ketamine) was evaluated in 16 boma-confined and 19 free-ranging impalas (Aepyceros melampus) to develop a non-opiate immobilisation protocol. In free-ranging impala a dose of 220 +/- 34 microg/kg medetomidine and 4.4 +/- 0.7 mg/kg ketamine combined with 7500 IU of hyaluronidase induced recumbency within 4.5 +/- 1.5 min, with good muscle relaxation, a stable heart rate and blood pH. PaCO2 was maintained within acceptable ranges. The animals were hypoxic with reduced oxygen saturation and low PaO2 in the presence of an elevated respiration rate, therefore methods for respiratory support are indicated. The depth of sedation was adequate for minor manipulations but additional anaesthesia is indicated for painful manipulations. Immobilisation was reversed by 467 +/- 108 microg/kg atipamezole hydrochloride (atipamezole) intramuscularly, but re-sedation was observed several hours later, possibly due to a low atipamezole:medetomidine ratio of 2:1. Therefore, this immobilisation and reversal protocol would subject impalas to possible predation or conspecific aggression following reversal if they were released into the wild. If the protocol is used on free-ranging impala, an atipamezole:medetomidine ratio of 5:1 should probably be used to prevent re-sedation.

Highlights

The impala is a sentinel species for disease monitoring in South Africa and it is important in game ranching
The purpose of this study was to investigate a combination of medetomidine and ketamine with hyaluronidase as a non-narcotic drug combination for the rapid and safe immobilisation of free-ranging impala, and reversal by a specific "2 antagonist, atipamezole hydrochloride [Antisedan®, (5.0 mg/m ) Orion Corp., Orion-Farmos, Espoo, Finland)
Impala appear to tolerate moderate to high doses of ketamine i.m. with no obvious adverse effect

Summary

Introduction

The impala is a sentinel species for disease monitoring in South Africa (especially foot-and-mouth disease) and it is important in game ranching. In a captive setting the sleek and agile impala is an attractive addition to an African hoofstock collection, but its excitable character presents management challenges. The impala is a moderately sized antelope lending itself to physical restraint once confined, but physical restraint induces physiological and behavioural alterations indicative of stress and can induce a mortality rate of 10–40 % . 10,11,12 The induced stress of physical restraint is detriaConservation and Research Center, Smithsonian’s National Zoological Park, Front Royal, Virginia 22630, USA. E-mail: mbush@crc.si.edu cSchool of Veterinary Medicine, University of California, Davis, California 95616, USA.

Objectives

Methods

Conclusion