CHEMICAL IMMOBILIZATION OF MOOSE AT THE MOOSE RESEARCH CENTER, ALASKA (1968-1981)

Abstract

Data from chemical immobilization of Alaskan moose (Alces alces) from 1968 through 1981 at the Moose Research Center was compiled and assessed. Immobilizing drugs tested during that period were succinylcholine chloride, CI 744, xylazine hydrochloride and etorphine hydrochloride. Other adjunct and reversing drugs were discussed. From 1968 to 1975 succinyl choline chloride was the routine drug used for immobilization at the Moose Research Center with 1258 moose darted and 908 immobilized. Mean induction time was 8.5 minutes and mean time immobilized was 25.7 minutes. Hyaluronidase added to succinylcholine chloride decreased induction time by 33% with no increase in mortality. Mortality rate for succinylcholine chloride was 5.5% of moose immobilized, however only 72.2% of moose darted  were immobilized. Etorphine hydrochloride became the routine immobilizing drug in 1975 and is used routinely. To date 138 moose and 98 calves and yearlings have been immobilized. Mean induction time for etorphine was 11.4 minutes, and time immobilized was dependent upon time of antagonist injection. The mortality rate using etorphine on adults was 8.7%, but nearly all moose darted went down but many required supplemental doses. The mortality rates were inflated because these figures include data from early experimental work with the drugs. Familiarization with the drugs and the conditions for their use has decreased mortality significantly. Etorphine with xylazine is the drug combination presently preferred, but it is far from the ideal drug as presently available. The conclusion is that the ideal drug or drug combination to immobilize moose has not been found.