Physiological validation of a non-invasive method for measuring adrenocortical activity in goats.

Summary Glucocorticoids can be determined as a parameter of the stress response in plasma samples, and since recently also in faecal samples. The measurement of faecal cortisol metabolites (FCM) avoids confounding effects due to the disturbance during fixation and blood collection. The aim of this study was to demonstrate that FCM can be measured to reliably and non-invasively monitor adrenocortical activity in goats. Therefore, following the morning milking, ACTH (0.5 mg) was injected into the lateral cervical muscles of 20 goats. All voided faecal samples of each individual were collected immediately before until 24 hours after injection. FCM were determined by 2 group specific 11-oxoaetiocholanolone enzyme immunoassays (EIAs). After approximately 9 hours concentrations of FCM started to increase. Peak values, which represented a ninefold increase above baseline, were reached about 13 (± 1.3) hours after ACTH administration. Afterwards, levels decreased again. However, even 24 hours after the injection, levels had not returned to baseline in all animals. The present study demonstrates that measurement of FCM by EIAs can be used to monitor adrenocortical activity in goats. This non-invasive method is a valuable tool to evaluate potentially aversive situations. It can be used in different research fields, such as ethology, livestock production, husbandry and animal welfare. Schlusselworter: Ziegen, Stress, Tierschutz, Kortisolmetaboliten im Kot.