Reversible immobilization of free-ranging red deer (Cervus elaphus) with xylazine-tiletamine-zolazepam and atipamezole.

Forty-eight free-ranging red deer (Cervus elaphus) were immobilized with xylazine (X) and tiletamine-zolazepam (TZ) by dart injection during winter 2008 in Norway. A follow-up study in five animals during winter 2010 included arterial blood samples analyzed with a portable clinical analyzer in the field. Thirty-five of 48 animals were effectively immobilized and 13 required a second dart. Mean ± SD doses were 2.89 ± 0.45 mg X/kg and 2.89 ± 0.45 mg TZ/kg in calves and 2.97 ± 0.66 mg X/kg and 1.91 ± 0.43 mg TZ/kg in adults. Mean induction times for calves and adults were 8.5 ± 5 min and 11.6 ± 5.5 min, respectively. The main physiologic side effect during immobilization was hypoxemia (pulse oximetry, SpO2<85%). All five animals evaluated with arterial blood gas samples were hypoxemic (PaO2<10 kPa). Xylazine was antagonized with 0.43 ± 0.19 mg/kg and 0.27 ± 0.05 mg/kg of atipamezole in calves and adults, respectively. Time to standing/walking in calves and adults was 12 ± 7 min and 12 ± 11 min, respectively. Two capture mortalities occurred.