Sedative and cardiopulmonary effects of acepromazine, midazolam, butorphanol, acepromazine-butorphanol and midazolam-butorphanol on propofol anaesthesia in goats

Abstract

The sedative, propofol-sparing and cardiopulmonary effects of acepromazine, midazolam, butorphanol and combinations of butorphanol with acepromazine or midazolam in goats were evaluated. Six healthy Boer - Indigenous African crossbreed goats were by randomised cross-over designated to 6 groups: Group SAL that received saline, Group ACE that received acepromazine, Group MID that received midazolam, Group BUT that received butorphanol, Group ACEBUT that received acepromazine and butorphanol and Group MIDBUT that received midazolam and butorphanol as premedication agents intramuscularly on different occasions at least 3 weeks apart. The degree of sedation was assessed 20 minutes after administration of the premedication agents. Thirty minutes after premedication, the dose of propofol required for induction of anaesthesia adequate to allow placement of an endotracheal tube was determined. Cardiovascular, respiratory and arterial blood-gas parameters were assessed up to 30 minutes after induction of general anaesthesia. Acepromazine and midazolam produced significant sedation when administered alone, but premedication regimens incorporating butorphanol produced inconsistent results. The dose of propofol required for induction of anaesthesia was significantly reduced in goats that received midazolam alone, or midazolam combined with either acepromazine or butorphanol. The quality of induction of anaesthesia was good in all groups, including the control group. Cardiovascular, respiratory and blood-gas parameters were within normal limits in all groups and not significantly different between or within all groups. In conclusion: sedation with midazolam alone, or midazolam combined with either acepromazine or butorphanol significantly reduces the induction dose of propofol with minimal cardiopulmonary effects in goats.