Non-Invasive Monitoring of the Adrenocortical Response in Red Deer

Abstract

To facilitate easy and non-invasive assessment of the stress experienced by red deer (Cervus elaphus), we tested whether adrenocortical function can be monitored by measuring fecal corticoid metabolites. We measured concentrations of a group of cortisol metabolites (3α,11-oxo CM) in the feces of 6 captive red deer hinds before and after an adrenocorticotropic hormone (ACTH) challenge or a control saline injection by enzyme immunoassay (EIA). Results revealed that analysis of fecal cortisol metabolites enabled monitoring of adrenocortical activity. Administration of ACTH resulted in a 6.5 to 20-fold increase in fecal cortisol metabolite levels after approximately 18 hr. Following a planned disturbance, fecal cortisol metabolite concentrations increased 3 to 10-fold in 4 out of 6 individuals. Concentrations of 3α,11-oxo CM were not significantly different in feces collected within approximately 6 hr from defecation as compared to feces sampled immediately after defecation. Thus, fecal corticoid metabolite analysis could be used to evaluate disturbances in farmed red deer, even if immediate sample collection after defecation may not be possible. It also may evaluate stress responses in wild red deer, provided information on the time since defecation is available.