Sloth bear immobilization with a ketamine-xylazine combination: reversal with yohimbine.

Five captive sloth bears (Melursus ursinus) were immobilized with a combination of ketamine (5.80 to 9.75 mg/kg of body weight) and xylazine (1.40 to 2.44 mg/kg), given IM. The youngest bear was immobilized twice, 62 days apart; all other bears were immobilized only once. Induction times were 4 to 25 minutes. After completion of various intended procedures, yohimbine (0.125 mg/kg) was administered IV. Arousal times were 2 to 20 minutes and bears were standing in 17 to 51 minutes. Compared with reported recovery times of 2 to 3 hours for bears immobilized with ketamine-xylazine combinations but not given an antagonist, results of the present study indicated that yohimbine reduces anesthesia recovery times in sloth bears immobilized with ketamine-xylazine combination.