Hair cortisol assessment of equine assisted therapy horses: Assessing long-term welfare and influencing management factors

Abstract

This study aimed to evaluate the long-term welfare of horses involved in Equine Assisted Therapy (EAT) using hair cortisol concentration (HCC) as an indicator of chronic stress. A total of 102 horses from 21 stables across the Czech Republic were included, with 69 horses participating in EAT (experimental group) and 35 horses participating in recreational riding (control group). Hair samples were taken from the mane and analyzed for HCC, reflecting stress levels over a six-week period. Statistical analyses were performed to compare cortisol levels between groups and to assess the influence of biological and management factors on HCC. The results showed no significant difference in HCC between the EAT horses (mean: 17.06 pg/mg, SD: 3.528) and the recreational horses (mean: 17.33 pg/mg, SD: 2.816) (p = 0.85), indicating that EAT does not inherently increase chronic stress levels when horses are managed appropriately. Among the factors analyzed, sex significantly influenced cortisol levels, with mares having lower HCC (mean: 15.776 pg/mg) compared to geldings (mean: 18.248 pg/mg) (p = 0.003). Other factors, such as age and type of housing, did not significantly affect HCC. In EAT horses, the type of therapeutic work performed was an important determinant of cortisol levels. Horses involved in less physically demanding activities, such as equine-facilitated learning and social care, had significantly lower HCC than those involved in more intensive therapies, such as equine-facilitated physiotherapy and occupational therapy (p < 0.001). Time spent with a client was also significant. The number of clients per day has not significantly impacted HCC. In addition, management practices such as the frequency and distribution of rest periods were important. More frequent rest days throughout the year were associated with lower cortisol levels, with a moderate negative correlation (r = -0.492, p = 0.003). Factors such as breed, client weight, and the number of clients per day did not significantly impact cortisol levels This study highlights that EAT, when conducted under appropriate management conditions, does not compromise the welfare of horses when compared to recreational use. The results emphasize the importance of tailoring therapeutic activities to individual horses and ensuring consistent downtime to support their welfare. Further research is needed to explore additional factors influencing welfare and establish evidence-based guidelines for managing EAT horses. These findings provide valuable insights into the long-term welfare of horses used in therapeutic environments and contribute to optimizing EAT practices.