Immobilization of free-ranging African lions (Panthera leo) with a combination of xylazine hydrochloride and ketamine hydrochloride.

The combination of 55 mg/ml xylazine hydrochloride and 200 mg/ml ketamine hydrochloride was effective for immobilizing African lions in Tanzania. Nineteen adult females were given between 55 and 110 mg xylazine hydrochloride in the first dart. Initial doses of 110 mg xylazine hydrochloride and 450 mg ketamine hydrochloride equivalent to >0.9 mg/kg xylazine hydrochloride were most effective in achieving rapid immobilization. Lower doses of xylazine hydrochloride required supplementation with ketamine hydrochloride. These doses could be delivered easily in 3-ml darts. The use of lightweight darts and a blowgun was found to be useful as a supplement to longer range dart projector systems since many animals could be approached at short range.