Cortisol Variations to Estimate the Physiological Stress Response in Horses at a Traditional Equestrian Event

SIMPLE SUMMARY: The centuries-old patronal festivals in Menorca (Spain) represent an alternative to the common use of horses. During festivals, horses are exposed to potential sources of transient stress. This study aimed to evaluate the variations in salivary cortisol concentrations to estimate the physiological stress response in horses at the Menorca patronal festivals. For this purpose, the salivary cortisol variations before, during, and after the celebrations were assessed using an enzyme immunoassay. All the samples collected during festivals were significantly higher than the control group samples (p < 0.05). Within twenty-four hours after the end of the celebrations, cortisol concentrations returned to baseline levels and did not differ significantly from the control group (p > 0.05). Overall, the study found that the horses’ participation in the festivals resulted in a transitory and measurable stress response. ABSTRACT: In many countries, horses remain involved in traditional equestrian events such as those celebrated in Menorca (Balearic Islands, Spain) every year since at least the 14th century. The present study aimed to evaluate the variations in salivary cortisol concentrations to estimate the physiological stress response in horses at the Menorca patronal festivals. Two different editions (years 2016 and 2018) of the festivals in honor of the Virgin of Grace in Maó (Menorca, Spain) were studied. Nineteen and seventeen Pure Breed Menorca stallions were included in the study, respectively. The stallions were aged between seven and twelve years. During celebrations, samples were collected before the start of the festivals between 8–9 a.m. and during the festivals at 8–9 p.m. On the second day of celebrations, the samples were collected at 8–9 a.m. and 3–4 p.m. Finally, on the day after the festivals, one sample was collected at 8–9 p.m. Additionally, a control group was sampled at 8–9 a.m., 3–4 p.m., and 8–9 p.m. Salivary cortisol concentrations were assessed by using a commercial enzyme immunoassay kit specially validated to quantify salivary cortisol in horses. Salivary cortisol concentrations did not show significant differences between sampling hours in the control group (p > 0.05). All the samples collected during festivals were significantly higher than samples of the control group (p < 0.05). Within the twenty-four hours after the end of the celebrations, cortisol concentrations returned to baseline levels and did not differ significantly from the control group (p > 0.05). Hence, the present study describes that the participation of the horses in these particular acts generate an acute and transitory stress response. Overall, the current work provides a reasonable basis for future research on the stress physiology and well-being of horses participating in traditional celebrations or similar events.