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

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.

Determination of the minimum infusion rate of alfaxalone during its co-administration with fentanyl at three different doses by constant rate infusion intravenously in goats

“…Compared with the reported dose of 3 mg kg −1 when alfaxalone is used alone for induction (Dzikiti et al. ), fentanyl markedly reduces the alfaxalone dose for induction of anaesthesia, even at the lowest fentanyl dose 0.005 mg kg −1 used in the present study. This observation is in agreement with what has been previously reported for other inductions agents in various species such as propofol in humans (Bansal et al.…”

“…As already stated earlier, premedication with drugs such as midazolam might ameliorate the excitatory effects associated with fentanyl in goats (Dzikiti et al. , ).…”

“…Midazolam has been reported to be an effective sedative when administered intramuscularly prior induction of anaesthesia with alfaxalone (Dzikiti et al. ) or propofol (Dzikiti et al. ) in goats.…”

“…The general anaesthetic induction dose and MIR of alfaxalone for maintenance of general anaesthesia in unpremedicated goats have recently been reported as 3 mg kg −1 and 9.6 mg kg −1 hour −1 , respectively (Dzikiti et al. ; Ndawana et al. ).…”

Evaluation of the use of midazolam as a co‐induction agent with ketamine for anaesthesia in sedated ponies undergoing field castration

“…Midazolam has been shown to act synergistically with other induction agents [20] and is reported to reduce the induction dose of propofol in both dogs and cats [21,22]. Reduced respiratory rates associated with midazolam have been previously reported in horses and rabbits [8,25] along with increased post-induction apnoea in horses and goats [26,27], although these are not consistent observations [26,28]. Nishimura et al [23] demonstrated that midazolam has no intrinsic analgesic properties but when co-administered with dexmedetomidine it enhanced analgesia in rats [24].…”