The effects of midazolam and butorphanol, administered alone or combined, on the dose and quality of anaesthetic induction with alfaxalone in goats.

T Brighton Dzikiti,Eva R Garcia,Gareth E Zeiler,Loveness N Dzikiti

doi:10.4102/jsava.v85i1.1047

T Brighton Dzikiti, Eva R Garcia + Show 2 more

Open Access

https://doi.org/10.4102/jsava.v85i1.1047

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Abstract

Goats are rarely anaesthetised; consequently, scant information is available on the efficacy of anaesthetic drugs in this species. Alfaxalone is a relatively new anaesthetic agent, of which the efficacy in goats has not yet been studied. In this study, the sedative and alfaxalone sparing effects of midazolam and butorphanol, administered alone or concomitantly, in goats were assessed. Eight clinically healthy goats, four does and four wethers, were enlisted in a randomised crossover manner to receive intramuscular sedative treatments consisting of saline 0.05 mL/kg, or midazolam 0.30 mg/kg, or butorphanol 0.10 mg/kg, or a combination of midazolam 0.30 mg/kg with butorphanol 0.10 mg/kg before intravenous induction of general anaesthesia with alfaxalone. Following induction, the goats were immediately intubated and the quality of anaesthesia and basic physiological cardiorespiratory and blood-gas parameters were assessed until the goats had recovered from anaesthesia. The degree of sedation, quality of induction and recovery were scored. When compared with saline (3.00 mg/kg), midazolam,administered alone or with butorphanol, caused a statistically significant increased level of sedation and a reduction in the amount of alfaxalone required for induction (2.00 mg/kg and 1.70 mg/kg, respectively). Butorphanol alone (2.30 mg/kg) did not cause significant changes in level of sedation or alfaxalone-induction dose. During induction and recovery, the goats were calm following all treatments, including the control group. Cardiorespiratory and blood-gas parameters were maintained within clinically acceptable limits. The present study showed that midazolam, administered alone or combined with butorphanol, produces a degree of sedation that significantly reduces the dose of alfaxalone required for induction of general anaesthesia in goats, without causing any major adverse cardiorespiratory effects.

Highlights

Administration of sedatives as premedication prior to general anaesthesia is a widely accepted concept in veterinary practice (Bednarski et al 2011; Dzikiti et al 2009)
The control dose of alfaxalone required for induction of general anaesthesia was 3.00 mg/kg (2.50 mg/kg – 3.00 mg/kg)
Alone or combined with butorphanol, significantly reduced the dose of alfaxalone required for induction of general anaesthesia without causing clinically significant adverse effects, whilst butorphanol premedication alone did not cause any alteration in alfaxalone dose compared with the control treatment

Summary

Introduction

Administration of sedatives as premedication prior to general anaesthesia is a widely accepted concept in veterinary practice (Bednarski et al 2011; Dzikiti et al 2009). Benefits of pre-anaesthetic sedation include reduced patient excitement during anaesthetic induction and fewer drug-related adverse effects, as lesser amounts of anaesthetic agents are required to induce and maintain general anaesthesia (Bednarski et al 2011). The commonly used sedatives before induction of general anaesthesia include: α2-adrenoceptor agonists such as xylazine; phenothiazines such as acepromazine; benzodiazepines such as diazepam and midazolam; and opioids such as butorphanol (Riebold 2007). Induction of general anaesthesia can be achieved by administration of ketamine, propofol or thiopentone (Dzikiti 2013; Prassinos et al 2005). Its efficacy as an induction agent in goats has not yet been reported

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