Comparison of xylazine-ketamine and dexmedetomidine-ketamine anesthesia in captive Formosan serows (Capricornis swinhoei)

The Formosan serow (Capricornis swinhoei) is a rare endemic species found in Taiwan. Few studies, including studies on anesthetic protocols, have been conducted on this species. This study evaluates the anesthetic effectiveness of intramuscular xylazine-ketamine and dexmedetomidine-ketamine on captive Formosan serows. Fifty-seven anesthetic events were performed on 22 adults using a combination of xylazine (2.6 ± 0.5 mg/kg) and ketamine (3.7 ± 1.0 mg/kg). Forty-eight anesthetic events were performed on 29 adults using a combination of dexmedetomidine (33.9 ± 4.3 μg/kg) and ketamine (3.4 ± 0.4 mg/kg). Xylazine-ketamine anesthesia was antagonized with tolazoline (3.3 ± 0.8 mg/kg). Dexmedetomidine-ketamine anesthesia was antagonized with atipamezole (272.8 ± 78.2 μg/kg). Both drug combinations showed smooth anesthetic and recovery processes without statistical differences in respiratory rate, heart rate, rectal temperature and hemoglobin oxygen saturation. Dexmedetomidine-ketamine reversed by atipamezole showed a significantly shorter recovery time (1.8 ± 2.3 min) than xylazine-ketamine reversed by tolazoline (4.5 ± 1.7 min) (P0.05). Both anesthetic protocols indicated safe and reliable immobilization whereas atipamezole provided better reversal.