Immobilization of white-tailed deer with telazol,ketamine, and xylazine,and evaluation of antagonists

Telazol–xylazine and ketamine–xylazine are versatile and safe drug combinations that are used frequently for chemical immobilization of cervids. Although neither combination consistently offers rapid induction and recovery, we hypothesized that a combination of Telazol, ketamine, and xylazine (TKX) would provide a safe and effective alternative for immobilization of white-tailed deer (Odocoileus virginianus). During a 2-stage study, we evaluated the effectiveness of yohimbine and tolazoline as alpha₂-adrenergic antagonists (2005–2006), and characterized the factors that affected chemical immobilization of male deer with a targeted dose of telazol (2.20 mg/kg), ketamine (1.76 mg/kg), and xylazine (0.44 mg/kg), using explosive-charged darts (2007–2010). During the first stage, we randomly assigned deer to antagonist treatments, including a control group that did not receive an antagonist (n = 8), a tolazoline (4 mg/kg) treatment (n = 16), and a yohimbine (0.11 mg/kg) treatment (n = 15). Recovery times were longer (P = 0.0013) for control (150.6 ± 21.7 min) and yohimbine (74.5 ± 13.1 min), compared with tolazoline (12.5 ± 12.3 min). Tolazoline resulted in faster and more complete recovery compared with the frequent incomplete antagonism and ataxia observed with yohimbine. During the second stage, 56 immobilization events (2007–2010) with TKX yielded a mean induction time of 7.8 minutes (SE = 0.44). Repeated-measures analyses indicated that induction and recovery were affected by body weight, with larger males taking longer to become recumbent (P = 0.08), but they recovered more rapidly (P = 0.003) following administration of tolazoline. Physiological parameters we measured under anesthesia were within normal ranges for white-tailed deer; however, initial temperature was higher (β = ?0.86) for younger males (P = 0.014). Final physiological parameters were closely related to initial measurements, with rectal temperature being the most preserved (β = 0.90); heart and respiration rate declined (β < 0.60) during anesthesia. Our results indicate that TKX may be useful for chemically immobilizing white-tailed deer, and we recommend tolazoline as an antagonist for xylazine. © 2012 The Wildlife Society.