Experimental comparison of ketamine with a combination of ketamine, butorphanol and medetomidine for general anaesthesia of the Eurasian badger (Meles meles L.).

The refinement of anaesthetic regimes is central to improving the welfare of captured wildlife. The Eurasian badger (Meles meles) has been the subject of an intensive long-term ecological and epidemiological study at Woodchester Park, Gloucestershire, England. During routine trapping operations (June 21st, 2000-January 23rd, 2001) an experimental trial was conducted on 89 badgers to compare the physiological effects of anaesthesia using ketamine hydrochloride alone, and in conjunction with medetomidine hydrochloride and butorphanol tartrate. The mixture induced a significantly longer period of anaesthesia, and either substantially reduced or eliminated the adverse effects associated with ketamine anaesthesia (e.g., excessive salivation, bouts of sneezing, rough recoveries, and muscle rigidity). In a sub-sample of badgers given the mixture, anaesthesia was reversed using atipamezole hydrochloride. Under ketamine anaesthesia, heart rates were initially significantly higher and respiration rates were consistently higher, than in badgers given the mixture. In all badgers heart rates declined and respiration rates increased during anaesthesia, but the rate of change was greatest in animals given only ketamine. Overall, the mixture provided a more balanced anaesthesia characterised by muscle relaxation and complete unconsciousness.