Do You Think I Am Living Well? A Four-Season Hair Cortisol Analysis on Leisure Horses in Different Housing and Management Conditions

The satisfaction of leisure horses’ behavioral needs has begun to be considered a priority, linked to the awareness that horses kept in single boxes may be deprived of social contact and the possibility to perform natural behaviors. Several factors may influence horses’ quality of life also in the paddock, and there are very few data on the effects of those variables on leisure horses’ chronic stress, measurable in terms of activation of the hypothalamic–pituitary–adrenocortical axis. Therefore, managerial choices faced by owners and stables managers are only based on experience, common sense, and anecdotal beliefs. This study assessed and compared the chronic stress levels in leisure horses hosted in structures in the same geographic and climatic area with different daily routines to verify which management strategy could be the one that better contributes to achieving the welfare of horses. Forty-seven horses were divided into three groups homogeneous in terms of sex and age: Mixed management group (n = 12), Paddock group (n = 19), and Natural management group (n = 16). The hair cortisol concentration, a reliable marker of long-term stress, was analyzed in all the horses the same day at four time points of the year. In addition to management strategies, the influences of other variables (sex, age, coat color, and season) were evaluated. Independently from the management strategies, significantly higher hair cortisol values were detected in the autumn and summer, as well as in individuals older than 15 years. No significant differences were highlighted between the sexes or the coat colors. The comparison of the different management strategies showed that, in the summer, autumn, and winter, the hair cortisol levels were significantly lower in the Mixed management group horses than the Paddock group, highlighting that those subjects had better homeostasis. The Natural management group horses’ hair cortisol levels were intermediate between the other two groups of horses in all the seasons. Spending the night in the stables would seem to positively impact the well-being of the horses. These findings, if confirmed by further studies, may be helpful in enhancing horse welfare and assisting in managerial choice decision-making. Simple Summary The satisfaction of behavioral needs in leisure horses has begun to be considered a priority. There is growing awareness that horses kept in single boxes may be deprived of social contact and the possibility to perform natural behaviors. However, many practical factors may influence horses’ quality of life also in the paddock. In the literature, few studies have compared the effects of different variables related to paddock housing on leisure horses’ welfare. Therefore, managerial choices faced by owners, stables managers, and breeders cannot be based on concrete facts that are scientifically supported but only rely on experience, common sense, and anecdotal beliefs. This study aimed to assess and compare the chronic stress level in three groups of leisure horses, homogeneous in terms of sex and age, hosted in paddocks in structures in the same geographic area with a different daily routine, in order to verify which could be the one that best contributes to achieve the welfare of horses. The hair cortisol concentration, a reliable marker of chronic stress, was analyzed in 47 horses; samples were collected the same day for all the subjects four times during a year, once for each season. The results highlighted that the highest hair cortisol values were detected in the autumn and summer independently from the management strategies and were also significantly higher in individuals older than 15 years. The hair cortisol concentration was not influenced by horses’ sex or coat color. The comparison of the different management strategies showed that in the summer, autumn, and winter, the hair cortisol levels were significantly lower in horses who spent the night in the stables, indicating that those subjects had the best homeostasis. These findings, if confirmed by further studies, may be useful to enhance horse welfare and assist in management choice decision-making.