Physiological responses of fishers to immobilization with ketamine, ketamine-xylazine, or Telazol®

We immobilized wild-caught fishers (Martes pennanti) to evaluate health and identify and treat pre-existing injuries or diseases prior to their reintroduction into Pennsylvania. We determined the safely and effectiveness of ketamine (KET), ketamine and xylazine (KET-XYL), and Telazol(R) (TEL) with anesthesia intervals (induction time, down time, alert time, and recovery time) and physiological parameters (rectal temperature and respiration rate monitored at 4-min intervals). We sufficiently immobilized 90 of 106 fishers (85%) for examination with 100 mg KET (n=47), 100 mg KET and 10 mg XYL (n=14), or 30 mg TEL (n=29). Differences occurred among drugs for down time (P=0.007), alert time (P=0.006), and recovery time (P less than or equal to 0.001). Differences in mean body temperatures occurred among drug groups at 8 minutes (P=0.009) and 20 minutes post-injection (P=0.020). Differences in mean respiration rates occurred among drug groups at 4 minutes (P=0.013), 8 minutes (P less than or equal to 0.001), 12 minutes (P less than or equal to 0.001), and 16 minutes (P less than or equal to 0.001), but not at 20 minutes (P=0.193). Ketamine immobilization of fishers was most appropriate for brief examinations (recovery time (x) over bar+/-SD: 61.6+/-26.44 min), a valuable characteristic for field examinations. Ketamine-xylazine immobilization provided relatively short recoveries (128.9+/-56.67 min) and is considered a safe immobilant in a variety of situations. Long recoveries (238.6+/-89.25 min) may restrict Telazol to use in captivity or prior to extended transport. However, all 3 immobilants were safe and effective to facilitate physical examinations of fishers.