Tiletamine and zolazepam for immobilization of wild lions and leopards.

A 1:1 mixture of tiletamine and zolazepam was used for the immobilization of lions on 26 occasions and of leopards on 22 occasions. There was a significant (P less than 0.001) positive linear relationship between duration of anesthesia and dosage for all animals in which the duration was recorded (n = 36). This response could be divided into 4 separate regressions according to species and sex; lions being more susceptible to the drug than leopards and males more so than females. When dosage was expressed in terms of metabolic weight, the duration of anesthesia depended on the sex of the animal rather than the species, males being anesthetized 15 minutes longer than females for a given dosage. The threshold dosage was higher in leopards than in lions. The amount of time that could be spent working on the animal immobilized by the drug, compared with the total time committed to its induction, anesthesia, and recovery was 35 to 55%, a proportion that is similar to that associated with the use of other irreversible intramuscular anesthetics.