Medium and large-sized mustelids were live-captured and immobilized in winter field conditions in British Columbia. Inventory and population studies of wolverine (Gulo gulo), fisher (Martes pennanti) and badger (Taxidea taxus taxus) required placement of collar and abdominal cavity radio transmitters, measurement of morphometric data, collection of genetic samples and blood for disease surveys. A variety of traps were used for initial capture, including leg hold, metal barrel, log construction, and Havahart (Ekco Canada, Niagara Falls, ON, Canada) designs.
Immobilization agents used were zolazepam-tiletamine (Telazol, Fort Dodge, Fort Dodge, IA, USA) alone, and in combination with isoflurane (Aerrane, Ohmeda Caribe Inc., Guayama, Puerto Rico, USA) or halothane (Fluothane, Ohmeda Caribe Inc., Guayama, Puerto Rico, USA) gases, and midazolam (Versed, Hoffman-La Roche Inc., Nutley, NJ, USA) with ketamine hydrochloride (Ketaset, Fort Dodge, Fort Dodge, IA, USA). Zolazepam-tiletamine was delivered by intramuscular injection to wolverine at doses ranging from 7–15 mg/kg; however, 10 mg/kg was considered most desirable.
Induction times were generally under 5 minutes; however, some animals required second injections, apparently due to incomplete first injections. Analgesia and anaesthesia depth was often inadequate for invasive procedures, such as extraction of premolars, unless the procedure was performed within the first 15 minutes of the immobilization. Arousal after 45–60 minutes was common in wolverines given only zolazepam-tiletamine. Isoflurane gas was used to extend the length and depth of anesthesia and improve analgesia for abdominal implant surgery in young and adult wolverines.
Fisher were given zolazepam-tiletamine by intramuscular injection at doses of 9–17 mg/kg. Rectal temperatures were decreased in most fisher immobilized in the field and extended recovery times of over 90 minutes were noted in a captive group given 12–17 mg/kg.
A limited number of badgers were given zolazepam-tiletamine by intramuscular injection at doses of 7–14 mg/kg for restraint or induction with anesthesia maintenance on halothane gas. Induction was generally under 2 minutes with routine recovery from the gas anesthesia. Inadequate results in some badgers resulted in a trial dose of midazolam at 0.2 mg/kg and ketamine hydrochloride at 6 mg/kg. The immobilization was considered superior to those previous and recovery was rapid; however, the combination requires further evaluation in this species.
In general, zolazepam-tiletamine was found to be a safe and effective combination in all three mustelid species for minor procedures in-field conditions; however, further trials are recommended with more vigorous monitoring.