XYLAZINE AND A XYLAZINE FENTANYL CITRATE/AZAPERONE COMBINATION IN FARMED DEER .2. VELVET ANTLER REMOVAL AND REVERSAL COMBINATIONS/

Three studies were undertaken on farmed red and red x wapiti deer to e valuate xylazine and a xylazine/fentanyl citrate/azaperone combination for velvet antler removal. In the first experiment, 30 1-2 year-old r ed 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 azaperon e per mi. Physiological, behavioural and analgesic responses and rever sal times after yohimbine or yohimbine and naloxone were monitored. Th ere were no differences in heart rate, respiration rate, sedative or a nalgesic properties detected between xylazine or the xylazine/fentanyl citrate/azaperone combination. All deer became recumbent, but those g iven the xylazine/fentanyl citrate/azaperone combination became recumb ent 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 experim ent evaluated the reversal of the xylazine/fentanyl citrate/azaperone combination with either yohimbine or yohimbine and naloxone in 43 3-ye ar-old red deer stags after velvet antler removal. There were no diffe rences in arousal pattern or time to standing between reversal treatme nts. Sixteen 1-year-old red and 25% red x wapiti stags were used in th e third experiment to evaluate clinically the analgesic properties of xylazine and xylazine/fentanyl citrate/azaperone combination during ve lvet removal without the application of a local anaesthetic agent. Wit hdrawal responses were observed in most deer after the xylazine/fentan yl 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 th e surgical procedure of velvet antler removal. These studies, have sho wn that the knock-down effect of the xylazine/fentanyl citrate/azapero ne combination was more rapid than that of xylazine alone, but that ot her physiological, behavioural and analgesic responses at doses used a nd evaluated by the methods used were similar. Reversal of both the xy lazine and xylazine/fentanyl citrate/azaperone combination was similar when using either yohimbine alone for xylazine and the xylazine/fenta nyl citrate/azaperone combination or yohimbine and naloxone for the xy lazine/fentanyl citrate/azaperone combination. The evaluation of surgi cal analgesia for antler removal suggested that both xylazine alone an d the xylazine/fentanyl citrate/azaperone combination provided insuffi cient analgesia and that local anaesthetic should be used in all cases .