A total of 276 attempts was made to immobilize white-tailed deer (Odocoileus virginianus) using succinylcholine chloride (SC). SC was injected in powder form by dart in 256 deer (mostly free-ranging) and in solution in 20 deer (all captive). Details of dose levels, age, sex, bodyweight, whether immobilized, time interval injection to immobilization and survival rates were recorded. For the SC solution injected animals, packed cell volumes (PCV) were recorded prior to and at several intervals after injection. Among those deer injected with powdered SC, a 64.1 percent capture rate was obtained (63.6 percent for adults, 65.5 percent for fawns). Fatalities were recorded in 8.6 percent of attempts with adults and in 13.8 percent of attempts with fawns. The non-lethal, successful, dose range for adults was 0.078 to 0.265 mg/ kg. The lethal dose range for adults was 0.141 to 0.298 mg/kg; the lethal dose range for fawns was 0.176 to 0.229 mgj kg. Reaction times varied from less than one minute to 23 minutes (mean =6.19 +0.31 S.E.). For SC injected as a solution, mean knockdown time was 9.35 minutes (Range = 4 to 13 minutes). Time from knockdown to recovery average 37.5 minutes (Range = 19 to 86 minutes). All injections ranging from 3.8 to 6 mg SC in solution successfully induced immobilization. PCV's tended to drop after injection of SC.
