Reversible Chemical Restraint of Fishers with Medetomidine-Ketamine and Atipamezole

Abstract

We chemically restrained wild-caught fishers (Martes pennanti) as part of a captive management protocol designed to facilitate veterinary evaluation, treatment of injuries, and conditioning on a high caloric diet prior to their reintroduction in Pennsylvania. We evaluated medetomidine-ketamine (MED-KET) and atipamezole (ATI) for reversible restraint of fishers (n = 10) by monitoring anesthesia intervals and physiologic response. We administered MED-KET to fishers at 0.4 mg MED combined with 20.0 mg KET to males, and 0.2 mg MED combined with 10.0 mg KET to females. Atipamezole at 2.0 mg to males and 1.0 mg to females or physiologic saline was administered to fishers approximately 20 min post-MED-KET injection, Atipamezole reversed the anesthetic effects of MED-KET, reducing mean down time, alert time, and recovery time, Physiologic response to MED-KET and ATI was generally unremarkable. However, we observed bradycardia in females restrained with MED-KET, and a hypotensive response in both sexes upon administration of ATI. Medetomidine-ketamine would be useful for field or clinical restraint of fishers because induction was rapid, recovery was calm, and there were no adverse physiologic responses. Medetomidine-ketamine may enable invasive procedures such as tooth removal or surgery. Atipamezole enhanced practical field application of MEDKET because it effectively and safely reversed MED-KET restraint of fishers.