Body condition and dosage effects on ketamine–xylazine immobilization of female white‐tailed deer

Abstract Ketamine and xylazine are an effective chemical combination for white‐tailed deer (Odocoileus virginianus) immobilization, but the effects of body condition on ketamine–xylazine efficacy have not been examined. We assessed the influence of ketamine dosage, xylazine dosage, body condition, age class, and injection site on successful adult female deer chemical immobilization. From January to March 2009–2011, we captured 87 deer (age ≥1.5 yr) in Clover traps and immobilized them using ketamine–xylazine ratios of 400 mg (n = 58) or 300 mg (n = 29) of ketamine to 100 mg of xylazine. Mean deer body mass was 67.8 kg (SD = 12.3, range = 43.0–93.0). We considered immobilization successful if deer induction was achieved ≤15 minutes from first ketamine–xylazine injection. Seventy‐five percent of injected deer (81% with 400:100 mg ketamine:xylazine; 62% with 300:100 mg ketamine:xylazine) achieved successful induction. We recorded deer heart rate, respiration rate and rectal temperature at 0 minutes, 10 minutes, and 20 minutes post‐induction. Comparison of 7 generalized linear models indicated that the probability of successful induction increased by about 6.7% with every 1.0 mg/kg increase in ketamine dosage and by about 0.7% with every 1‐unit decrease in body‐condition index. The remaining parameters did not influence the success of deer induction. Deer heart rate, respiration rate, and rectal temperature decreased over time post‐induction, with >95% within reported ranges for ketamine–xylazine immobilization. We suggest that deer weighing ≤93.0 kg be injected with 5.8 mg/kg ketamine and 1.6 mg/kg xylazine to produce satisfactory induction when using similar capture methods during winter. © 2012 The Wildlife Society.