title: Immobilization of Wyoming bears using carfentanil and xylazine.
abstract: Seven grizzly (Ursus arctos; four male, three female) and three black (Ursus americanus; two male, one female) bears caught in culvert traps or leg snares were immobilized in northwestern Wyoming with carfentanil and xylazine at doses, respectively, of 0.011 ± 0.001 and 0.12 ± 0.01 mg/kg for grizzly bears and 0.014 ± 0.002 and 0.15 ± 0.04 mg/kg for black bears. These drugs were antagonized with 1 mg/kg naltrexone and 2 mg/kg tolazoline. Induction and recovery times, respectively, were 4.3 ± 0.5 and 7.1 ± 0.8 min for grizzly bears and 5.2 ± 0.4 and 9.1 ± 2.2 min for black bears. Inductions were smooth and uneventful. Recoveries were characterized initially by increased respiration followed by raising of the head, which quickly led to a full recovery, with the bears recognizing and avoiding humans and moving away, maneuvering around obstacles. All bears experienced respiratory depression, which did not significantly improve with supplemental oxygen on the basis of pulse oximetry (P=0.56). Rectal temperatures were normothermic. Carfentanil-xylazine immobilization of bears provided significant advantages over other drug regimens, including small drug volumes, predictable inductions, quick and complete recoveries, and lower costs. On the basis of these data, both grizzly and black bears can be immobilized effectively with 0.01 mg/kg carfentanil and 0.1 mg/kg xylazine.
authors.affiliation: Wyoming Game and Fish Department, 2362 Highway 34, Wheatland, Wyoming 82201, USA. tkreeg@gmail.com
authors.forename: Terry J
authors.initials: TJ
authors.lastname: Kreeger
authors.forename: Dan
authors.initials: D
authors.lastname: Bjornlie
authors.forename: Dan
authors.initials: D
authors.lastname: Thompson
authors.forename: Justin
authors.initials: J
authors.lastname: Clapp
authors.forename: Colby
authors.initials: C
authors.lastname: Clark
authors.forename: Cole
authors.initials: C
authors.lastname: Hansen
authors.forename: Matt
authors.initials: M
authors.lastname: Huizenga
authors.forename: Sam
authors.initials: S
authors.lastname: Lockwood
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000031:analogs & derivatives*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007103:Immobilization / Q000379:methods / Q000662:veterinary*; D008297:Male; D012119:Respiration / Q000187:drug effects; D001503:Ursidae / Q000502:physiology*; D014959:Wyoming; D014991:Xylazine / Q000008:administration & dosage*
chemical_list: D006993:Hypnotics and Sedatives; D014991:Xylazine; C017114:carfentanil; D005283:Fentanyl
keywords: Black bear; Ursus americanus; Ursus arctos; Wyoming; carfentanil; grizzly bear; immobilization; xylazine