Use of long-acting neuroleptics to reduce the stress response to management practices in red deer

Abstract

Three groups of six adult red deer hinds were used to determine whether long-acting neuroleptic (LAN) tranquillisers were able to modify the behavioural and physiological responses of the deer to a range of routine management stressors: such drugs may eventually prove useful in capture procedures for wild animals. While the stressors increased moving activity and decreased inactive lying and inter-animal distances, these changes were reduced in LAN-treated animals. Blood samples, collected remotely using automatic equipment, showed that following application of the stressors there was a distinct rise in plasma cortisol concentrations which returned to pre-treatment levels more rapidly in LAN-treated animals. However, there was no effect of LAN treatment on plasma concentrations of creatine phosphokinase (CPK), aspartate aminotransferase (AST), total protein or testosterone. Overall, LAN-treated animals had higher concentrations of plasma thyroxine. Heart rate increased in response to the stressors and while the LAN-treated deer showed a greater increase, as with plasma cortisol concentrations, heart rate returned to baseline more rapidly in these animals. We conclude that LANs may have a role to play in wild deer capture and habituation to farming conditions through a reduction in fear and anxiety, but that further work is required to determine an optimal strategy.