Eight blue wildebeast (Connochaetes taurinus) were immobilized using a combination of either 0.006 mg/kg etorphine and 0.25 mg/kg xylazine or 0.055 mg/kg fentanil, 0.2 mg/kg azaparone, and 0.2 mg/kg xylazine, delivered IM using a remote injection system. Animals (n=8) were immobilized twice in a random cross-over design. Induction and recovery times, heart rate, respiratory rate, rectal temperature, oxygen saturation, end-tidal CO2 (ETCO2), anesthetic depth, indirect blood pressure, and arterial blood gases were recorded. Wildebeast were not intubated and no supplementary oxygen was administered. Fifty minutes after induction, anesthesia was antagonized with naltrexone and atipamezole. Mean oxygen saturation was consistent with hypoxia in both the fentanil group and the etorphine group. In both groups, but most pronounced in the fentanil-azaparone-xylazine group, there was a gradual improvement in arterial oxygenation followed an initial depression. In both groups arterial pH decreased and partial pressure of carbon dioxide increased during anesthesia. These findings were consistent with respiratory acidosis and decreased ventilation. Values for respiratory rate, temperature, oxygen saturation, ETCO2, blood gases, and blood pressure were similar for both groups at all time periods. In conclusion, both 0.006 mg/kg etorphine with 0.25 mg/kg xylazine and 0.055 mg/kg fentanil with 0.2 mg/kg azaparone and 0.2 mg/kg xylazine provide reliable, light anesthesia in wildebeast. Ventilatory performance was compromised with both protocols and oxygen should be administered.
The authors thank Karin Magnusson for excellent technical assistance.