Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge.
Authors: Peeters M, Sulon J, Beckers J-F, Ledoux D, Vandenheede M
Journal: Equine veterinary journal
Summary
# Editorial Summary Cortisol measurement forms a cornerstone of equine stress assessment, yet the traditional serum sampling method presents practical challenges: it is invasive, potentially stressful in itself, and measures both bound and free cortisol fractions—only the latter being biologically active. Peeters and colleagues investigated whether salivary cortisol could serve as a more welfare-friendly alternative by comparing serum and salivary cortisol responses to ACTH (adrenocorticotropic hormone) challenge in horses, a protocol that stimulates cortisol release and allows direct assessment of the hypothalamic-pituitary-adrenal axis. Their findings revealed that salivary cortisol concentrations correlated reliably with serum free cortisol levels, suggesting that saliva sampling captures the physiologically relevant cortisol fraction without the stress and invasiveness of venepuncture. For practitioners—particularly those involved in stress assessment, training load management, or post-operative monitoring—this offers a non-invasive means of evaluating HPA axis function and stress status in individual horses, with particular value in situations where repeated sampling is necessary or where minimising handling stress is clinically important.
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Practical Takeaways
- •Salivary cortisol may provide a more accurate and horse-friendly alternative to serum cortisol testing for stress assessment in equine practice
- •Non-invasive saliva sampling reduces procedural stress that can confound cortisol results, improving measurement reliability
- •Consider salivary cortisol testing when repeated or routine stress monitoring is needed to minimize animal welfare impact
Key Findings
- •Salivary cortisol measurement represents the biologically active free cortisol fraction, unlike serum cortisol which includes both free and bound forms
- •Salivary cortisol collection is a non-invasive, welfare-friendly sampling method compared to the stressful blood serum sampling procedure
- •Study compares cortisol concentrations between blood serum and saliva using ACTH challenge in horses