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

Abstract

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 alpha 2-adrenergic antagonists (2005-2006), and characterized the factors that affected chemical immobilization of male deer with a targeted dose of telazol (2.20mg/kg), ketamine (1.76mg/kg), and xylazine (0.44mg/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 (4mg/kg) treatment (n=16), and a yohimbine (0.11mg/kg) treatment (n=15). Recovery times $({\bar {x}}\pm {\rm SE)}$ were longer (P=0.0013) for control (150.6±21.7min) and yohimbine (74.5±13. 1min), compared with tolazoline (12.5±12.3min). 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. Copyright © The Wildlife Society, 2012.