Changes in Salivary Cortisol Concentration in Horses during Different Types of Exercise

Abstract

This study aimed to estimate the change of stress level in horses based on cortisol concentration levels in their saliva. A total of 61 horses were divided into the following three groups: i) tourist riding experience (TR, n = 23); ii) resting group (RR, n = 14); and iii) horse-riding education (ER, n = 24). The saliva samples of TR and ER groups were taken using plain cotton Salivettes four times a day: at 07:00 (basal), 11:00 (Exercise 1, after 1-hour exercise in the morning), 14:00 (Exercise 2, after 1-hour exercise in the afternoon), and 16:00 (Exercise 3, after 1-hour exercise in the afternoon). The saliva samples of RR were measured at the same time. The samples were analyzed using the SAS program general linear model procedure. In a percentage relative to the base value, cortisol levels in Exercise 3 were confirmed to decrease in all groups as compared to the basal value percentage in the following sequence: ER>TR>RR. The highest peak was confirmed in Exercise 2 (approximately 131%) of RR group and the lowest peak appeared in Exercise 3 (approximately 52%) of ER group. Therefore, resting without any particular exercise can also increase the stress level of horses. Thus, it is better to exercise, as exercise can reduce the stress level, even in cases when riders are clumsy or lack appropriate horse-riding experience. The results of the present study are useful to equestrian center owners and educational riding instructors in that they provide a meaningful insight into a better horse management.

Bone Marrow Aspiration Does Not Induce a Measurable Pain Response Compared to Sham Procedure

“…While there is an abundance of literature evaluating serum cortisol levels in horses, salivary cortisol may be a better measure of pain response as it measures the unbound metabolically active portion, as opposed to serum cortisol, which measures both bound and unbound fraction ( 7 ). The salivary cortisol concentrations in our horses were not different due to treatment or over time and cortisol concentrations in both groups (1.4 and 1.7 ng/ml after BMA and SHAM procedures) were below the known resting salivary cortisol concentrations of 2 ng/ml ( 7 , 10 , 13 ). This indicates there was minimal stress or pain response in either group.…”

“…Saliva was collected using a commercially available salivary collection swab (Salivette,® Sarstedt, Germany) that was placed in the buccal space for 1 min as previously described ( 7 , 13 ). Collection swabs were stored at room temperature for 2 h prior to being centrifuged at 1000 g for 2 min and the resulting saliva frozen at −80°C for 30–60 days prior to analysis.…”

Action Mechanisms and Pathophysiological Characteristics of Cortisol in Horses

“…CORT is frequently used to assess stress levels induced by exercise [70,71]. Different studies have been carried out in relation to stress in horses such as the load stress in tow [61], participation in equestrian dressage competition [72][73][74], competition of resistance [75] jumping [76], tourist driving and education [77]. It has been shown that moderate exercise in horse increases CORT by up to 29% compared to baseline levels through the stress response.…”

Salivary cortisol concentrations changes in horses during daily routine

“…Thus, we can state that the values of cortisol in horse saliva are highest in the morning and continually decline over the course of the day and are lowest in the evening/night. Kang and Lee (2016) observed changes in salivary cortisol concentrations in tourist-riding horses, resting group and education horse-riding group of horses. They found out that basal concentrations of cortisol in horse saliva in resting group were 1.113 ng/mL which is in the middle of our measured values.…”