Comparing the effects of tranquilisation with long-acting neuroleptics on blue wildebeest (Connochaetes taurinus) behaviour and physiology

[摘要] ENGLISH ABSTRACT: In South Africa, large numbers of game animals are translocated annually. These animals are subjected to a great amount of stress and the use of long-acting neuroleptics (LANs) has become a common practice to minimize animal stress. Long-acting neuroleptics suppress behavioural responses without affecting spinal and other reflexes, and can be administered in such a manner that a single dose results in a therapeutically effective tissue concentration for anywhere between three to seven days.The mammalian stress response consists of a variety of physiological responses, and the study aimed to quantify a number of these responses in blue wildebeest (Connochaetes taurinus). This was done in order to compare the effects of a commonly used LAN, Acuphase® (zuclopenthixol acetate in vegetable oil), with a newly developed LAN, Acunil® (zuclopenthixol acetate in a low-release polymer), in minimizing the stress response of blue wildebeest in captivity. A human biotelemetry belt, Equivital™ EQ02, was modified to fit this species, and the results from a validation study indicated that the belt accurately measured heart and respiration rate, respectively, in blue wildebeest. The belt also measured motion accurately, and this made the monitoring of conscious animals prior to and after being treated with a LAN, possible. A faecal glucocorticoid metabolite (FGM) assay was also validated for use in blue wildebeest.Three sets of trials were performed in which animals received one of three treatments; Acuphase®, Acunil® or a placebo in order to evaluate the effect of each. Animals were monitored for 12 hours before and 12 hours after treatment. The results showed that although both Acuphase® and Acunil® resulted in a decrease in vigilant behaviour and an increase in resting behaviour, similar results were observed when animals received a placebo. Animals treated with Acunil®, however, exhibited a decrease in explorative behaviour as well as an increase in the time they spent eating. Heart rate was unaffected by any of the three treatments, and this lack of effect by either of the LANs may potentially be due to reflex tachycardia in response to hypotension. Respiration rate was lowered by both LANs, specifically during certain behaviours, with this effect being absent in placebo-treated animals. In addition, the motion of the animals indicated that LAN-treated animals had a lowered flight response to a person entering the enclosure.Endocrine parameters measured in the blood and faeces of the animals before and after treatment revealed a minimal effect. Neither the acute nor the chronic stress response appeared to be significantly reduced by treatment with Acuphase® or Acunil®. In addition, immune function (as quantified by white blood cell count and neutrophil response) revealed that the chronic stress of captivity lowered the immune response of the animals. This decrease in immunocompetence, however, could not be ascribed to any of the LAN treatments.In conclusion, the most pronounced effects observed with the administration of both LANs included a decrease in respiration rate, and responsiveness of the animals. Long term studies on the effect of LAN administration on immune function and endocrine responses may yield more conclusive results regarding the stress responses of wild animals in captivity.

[发布机构] Stellenbosch University