Safe, effective, and reversible immobilization protocols are essential for the management of free-ranging red wolves (Canis rufus). Combinations using an alpha2-adrenoceptor agonist and
ketamine have been shown to be effective for immobilization but are not reversible and can produce severe
hypertension and prolonged or rough recoveries. To minimize
hypertension and provide reversibility, 24 red wolves were immobilized using three
medetomidine-
butorphanol (MB) combinations without the use of
ketamine in the initial injection. All wolves were administered
medetomidine (0.04 mg/kg i.m.) and
butorphanol (0.4 mg/kg i.m.). Seven wolves received no other immobilization agents (MB wolves), nine received
diazepam (0.2 mg/kg i.v.) at the time they were instrumented (MBD wolves), and eight received
ketamine (1 mg/kg i.v.) 30 min after instrumentation (MBK30 wolves). Physiologic parameters were monitored during immobilization. The heart rate was similar among the three groups for the first 30 min, and marked
bradycardia was noted in one wolf from each group.
Hypertension was observed initially in all three groups but was resolved within 10-30 min. The MBK30 wolves had significant elevations in heart rate and transient
hypertension after intravenous
ketamine administration. Most wolves had mild to moderate metabolic acidemia. Immobilizing drugs were antagonized in all wolves with
atipamezole (0.2 mg/kg i.m.) and
naloxone (0.02 mg/kg i.m.). The
medetomidine-
butorphanol-
diazepam wolves were also given
flumazenil (0.04 mg/kg i.v.). All wolves were standing within 12 min and were fully recovered within 17 min. Medetomamine-
butorphanol and MBD combinations provided effective and reversible immobilization of red wolves without the sustained
hypertension associated with the use of alpha2-adrenoceptor agonist-
ketamine combinations. Delaying the administration of
ketamine reduced its hypertensive effects.