Effects of breed, management and personality on cortisol reactivity in sport horses.
Authors: Sauer Fay J, Hermann Marco, Ramseyer Alessandra, Burger Dominik, Riemer Stefanie, Gerber Vinzenz
Journal: PloS one
Summary
# Editorial Summary: Cortisol Reactivity and Management in Sport Horses Understanding how management practices influence the physiological stress response in sport horses remains critical to optimizing both performance and welfare. Researchers in Switzerland used ACTH stimulation testing on 149 sport horses (94 elite, 55 amateur) across multiple disciplines, measuring salivary cortisol at 60 and 90 minutes post-injection whilst simultaneously collecting detailed information on breed, husbandry, demographics and personality via owner questionnaires. Breed emerged as a significant factor, with Thoroughbreds and Warmbloods demonstrating greater adrenal reactivity than Franches-Montagnes horses, whilst three management variables proved particularly influential: horses with multiple riders showed blunted cortisol responses compared to those handled by a single person, increased time at pasture correlated with lower post-stimulatory cortisol, and group-housed horses paradoxically displayed higher cortisol values than those kept singly. Notably, personality traits had no measurable effect on cortisol reactivity, and elite competition status or discipline type did not significantly alter the adrenal response, suggesting that environmental and management modifications—particularly maximising turnout time and potentially limiting handler variability—may offer greater welfare gains than alterations to training intensity or competitive level. These findings provide evidence-based justification for prioritising stable, consistent management and extensive pasture access as foundational welfare considerations across all levels of sport horse operation.
Read the full abstract on PubMed
Practical Takeaways
- •Husbandry management factors (outdoor time, number of handlers, housing type) have measurable effects on stress physiology and may be more influential than competition level or discipline—review your barn's management practices with this in mind
- •Increased outdoor time is associated with lower adrenal reactivity; prioritize turnout as a welfare and stress-management tool regardless of competition demands
- •Multiple, familiar handlers may reduce stress reactivity compared to single-handler situations; consider structured ridden work by different competent riders as a normalizing exposure
Key Findings
- •Breed significantly affected cortisol response at 60 minutes post-ACTH, with Thoroughbreds and Warmbloods showing increased adrenal response compared to Franches-Montagnes horses
- •Horses with multiple riders had less pronounced cortisol reactivity than horses with a single rider
- •Horses spending more time outside showed decreased cortisol response compared to stabled horses
- •Group housing was associated with higher post-stimulatory cortisol values than single housing, contrary to expected welfare benefits
- •Personality traits showed no significant association with cortisol responsiveness, and elite vs. amateur status and equestrian discipline did not affect cortisol response