Physiological responses of farmed red deer to management practices and their modulation by long-acting neuroleptics

Abstract

SUMMARYTwelve red deer (Cervus elaphus) hinds from a research facility in Eastern Scotland were randomly divided into two groups between June and September to study the physiological response to three management practices, given sequentially, which were expected to cause increasing levels of stress (herding; herding and handling; and herding, handling and a veterinary procedure). One group of animals received a long-acting neuroleptic (LAN; perphenazine enanthate and zuclopenthixol acetate) on three occasions at 4-week intervals. Automatic blood sampling equipment (ABSE) was used to obtain blood samples remotely before, during and after the application of each of the stressors. The plasma concentrations of cortisol, creatine phosphokinase (CPK), aspartate aminotransferase (AST), total protein (TP), 3,5,3'-triiodothyronine (T3), thyroxine (T4) and testosterone (T) were measured and heart rates recorded. The ABSE provided a useful means of collecting blood samples without the superimposition of stress factors associated with conventional sampling. Increases in plasma concentrations of cortisol (P<0·01), CPK (P<0·01) and AST (P<0·05) were observed in all animals in response to all three management practices. There were smaller increases in plasma cortisol concentration (P<0·05) in those animals treated with LAN. The results suggested a degree of habituation of the hinds to some procedures common to all treatments, in agreement with previous analysis of the behavioual response of these animals. Peaks of heart rate were recorded over the 30-min period stressors were applied. Higher heart rates and T3 and T4 concentrations were observed in LAN-treated animals. Heart rates returned to baseline more rapidly in the LAN-treated animals. Higher plasma concentrations of testosterone were recorded in the first week of the study (P<0·001). Physiological and behavioural evidence supports the view that LANs are effective long-term tranquillizers in red deer.