fRI Research Grizzly Bear Program (fRI)

We captured six free-ranging adult (6–15 years) male brown bears in western Alberta, Canada (52.865360–54.368277 N, 117.865738–119.017687 E) in May 2014–2015 by barrel (culvert) trap [32]. We applied a randomized, double-blinded study in which three bears were allocated to the MTZ group and three to the DTZ group. We prepared MZT by adding 12 mg of M (20 mg/ml; Chiron Compounding Pharmacy Inc., Guelph, Ontario, Canada) and 0.9 ml of sterile water for injection (Hospira 10 ml per vial, Montreal, Quebec, Canada) per vial of TZ (Telazol^®, 286 mg tiletamine + 286 mg zolazepam; Fort Dodge Laboratories, Inc., Fort Dodge, Iowa, U.S.A.). DZT was prepared in 2014 by adding 5.7 mg of D (3 mg/ml; Chiron Compounding Pharmacy Inc.) and 0.2 ml of sterile water for injection per vial of Telazol^®. In 2015, we used 6 mg of a higher concentration of D (5 mg/ml), plus 0.9 ml of sterile water for injection, per vial of Telazol^®. All formulations resulted in 2.5 ml of drug solution per vial with concentrations of 234 mg/ml for MTZ and 231 mg/ml for DTZ, and ratios of 1:48 for M:TZ and 1:95 for D:TZ.

We used a remote drug delivery system (Dan-Inject^®) to administer a combination of 50μg/kg estimated body weight of M, or 25μg/kg of D, and 2.45 mg/kg of TZ intramuscularly. Darts used in the study consisted of 3 ml syringes with 2.0x40mm barbed needles (Dan-Inject^®). When necessary, we administered ketamine at 2 mg/kg (200 mg/ml; Chiron Compounding Pharmacy Inc.) intramuscularly by syringe and needle to extend the duration of anesthesia.

We recorded the induction time for each bear. Capillary refill time, respiratory rate, heart rate, and rectal temperature of anesthetized bears were obtained immediately after induction and every 15 min throughout anesthesia. Respiratory rate was monitored by observation of thoracic movements. We recorded pulse rate and hemoglobin oxygen saturation (SpO₂; %) with a pulse oximeter (Nellcor NPB-40, Nellcor, Pleasanton, California, U.S.A). Rectal temperature was measured with a digital thermometer (Adtemp V Fast Read Pen Type Digital Thermometer, American Diagnostic Corporation, New York, U.S.A).

We collected one venous blood sample (4 ml) from the femoral vein of each bear to measure cortisol concentrations (nmol/L; Immulite 1000; Siemens Medical Solutions Diagnostics, California, U.S.A). We also collected two anaerobic arterial blood samples (3ml each) from the femoral artery of each bear in pre-heparinized syringes 30 and 60 min after the bear was darted. We used the same equipment and measured the same parameters as previously described. Blood gas values and pH were corrected to the rectal temperature. Although oxygen was available, we did not administer it to any of the bears captured in Alberta, Canada.

We extracted a premolar tooth for age estimation by counting cementum annuli [33]. We administered 0.1 mg/kg of meloxicam (Metacam^®, 5mg/ml solution for injection; Boehringer Ingelheim Vetmedica Inc., Missouri, U.S.A) subcutaneously to provide analgesia. We weighed all bears with an electronic load-cell scale.

After completion of measurements and sampling, we administered 5 mg of atipamezole (20 mg/ml; Chiron Compounding Pharmacy Inc.) per mg of M or 10 mg of atipamezole per mg of D intramuscularly for anesthetic reversal. Bears were left to recover from anesthesia undisturbed at the site of capture. We recorded the handling time, and the time interval from atipamezole administration until the bear showed the first signs of recovery (recovery time, in min).

Brown bear captures were authorized under the permitting authority of the Alberta Department of Environment and Sustainable Resource Development (provincial jurisdiction lands), Alberta Tourism and Parks (provincial parks and protected areas jurisdiction lands), and Parks Canada (federal jurisdiction lands). Captures were approved by the University of Saskatchewan’s Committee on Animal Care and Supply (Animal Use Protocol # 20010016) and were in accordance with guidelines provided by the American Society of Mammalogists’ Animal Care and Use Committee [3] and the Canadian Council on Animal Care for the safe handling of wildlife [34].