Reversal by Tolazoline Hydrochloride of Xylazine Hydrochloride-Ketamine Hydrochloride Immobilizations in Free-Ranging Desert Mule Deer

Abstract

We captured 10 free-ranging desert mule deer (Odocoileus hemionus crooki) (five males and five females) by net-gun from a helicopter and immobilized them with xylazine hydrochloride (HCl) (100 mg) and ketamine HCl (300 to 400 mg) injected intramuscularly. Arousal and ambulation times were 13.9 ± 4.2 and 14.3 ± 4.2 min in eight deer injected intravenously with tolazoline HCl (3.0 mg/kg). We observed a curvilinear relationship (R = 0.50, P \u3c 0.01) between rectal temperature and time after induction of anesthesia. Mean peak temperature (41.4 C) occurred at 23.7 ± 3.2 min postinduction and was greater (P \u3c 0.01) than the mean temperature measured initially (40.8 C). Heart and respiratory rates (108 beats/min and 75 breaths/min) were elevated prior to immobilization. Mean heart rate increased (P \u3c 0.05) from 90 ± 9 beats/min in anesthetized deer to 120 ± 13 beats/min after tolazoline HCl injection. A 20% capture-related mortality rate suggests this combination of physical and chemical capture has serious limitations. Captive deer permitted to recover from xylazine HCl–ketamine HCl immobilization without a reversal agent were able to walk in 290 ± 79 min