Xylazine and a xylazine/fentanyl citrate/azaperone combination in farmed deer II: Velvet antler removal and reversal combinations

Abstract

Three studies were undertaken on farmed red andred x wapiti deer to evaluate xylazine and a xylazine/fentanyl citrate/azaperone combination for velvet antler removal. In the first experiment, 30 1–2 year-old red and 25% red x wapiti deer whose velvet was to be removed were given either 5% xylazine alone at 0.5 mg/kg body weight intramuscularly or the same dose rate of a commercially available mixture of 5% xylazine with the addition of 0.4 mg of fentanyl citrate and 3.2 mg of azaperone per ml. Physiological, behavioural and analgesic responses and reversal times after yohimbine or yohimb'lne and naloxone were monitored. There were no differences in heart rate, respiration rate, sedative or analgesic properties detected between xylazine or the xylazine/fentanyl citratelazaperone combination. All deer became recumbent, but those given the xylazine/fentanyl citrateiazaperone combination became recumbent more rapidly than those given xylazine alone (9.4 and 12.5 minutes, respectively, p<0.05). The arousal pattern and timing of reversal of xylazine and xylazine/fentanyl citrate/azaperone using yohimbine and yohimbine and naloxone, respectively, were similar.

The second experiment evaluated the reversal of the xylazine/fentanyl citrate/azaperone combination with either yohimbine or yohimbine and naloxone in 43 3-year-old red deer stags after velvet antler removal. There were no differences in arousal pattern or time to standing between reversal treatments.

Sixteen 1-year-old red and 25% red x wapiti stags were used in the third experiment to evaluate clinically the analgesic properties of xylazine and xylazine/fentanyl citrate/azaperone combination during velvet removal without the application of a local anaesthetic agent. Withdrawal responses were observed in most deer after the xylazine/fentanyl citrate/azaperone combination at dosages containing 0.5, 0.7 and 0.75 mg of xylazine/kg and after xylazine alone at 0.7 mg/kg, indicating that insufficient analgesia was provided by the systemic agent for the surgical procedure of velvet antler removal.

These studies have shown that the knock-down effect of the xylazine/fentanyl citrate/azaperone combination was more rapid than that of xylazine alone, but that other physiological, behavioural and analgesic responses at doses used and evaluated by the methods used were similar. Reversal of both the xylazine and xylazine/fentanyl citrate/azaperone combination was similar when using either yohimbine alone for xylazine and the xylazine/fentanyl citrate/azaperone combination or yohimbine and naloxone for the xylazine/fentanyl citrate/azaperone combination pr ovidedin of sufficient analgesia for andthat local anaesthe tic both xylazine alone and the xylazine/fentanyl citrate/azaperone combination provided insufficient analgesia and that local anaesthetic should be used in all cases.