Changes in Saliva Analytes Correlate with Horses' Behavioural Reactions to An Acute Stressor: A Pilot Study.
Authors: Contreras-Aguilar María D, Henry Séverine, Coste Caroline, Tecles Fernando, Escribano Damián, Cerón Jose J, Hausberger Martine
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Salivary Markers as Behavioural Stress Indicators in Horses Understanding how individual horses respond to acute stressors remains clinically important for handlers and veterinarians, yet physiological and behavioural measures don't always align clearly. Contreras-Aguilar and colleagues measured six salivary analytes—including cortisol, salivary alpha-amylase, and several enzymatic markers—in nine riding horses exposed to an umbrella-opening test, with samples collected at baseline, pre-stress, during stress, and at 30 and 60 minutes post-stress, whilst simultaneously recording behavioural responses. Butyrylcholinesterase (BChE) emerged as the strongest correlate of behavioural emotionality, laterality bias, and alarm signals, whereas salivary alpha-amylase declined in horses exhibiting calmer responses, with both markers showing peak changes at stress exposure and recovery within 30 minutes. For practitioners managing stressed horses—particularly in performance, handling, or veterinary contexts—these findings suggest that salivary enzyme panels, especially BChE measurement, could provide objective physiological validation of stress-related behaviour, potentially bridging the interpretive gap between what we observe and what is biochemically occurring, though larger studies will be needed to establish clinical utility and individual variation thresholds.
Read the full abstract on PubMed
Practical Takeaways
- •Salivary BChE and sAA levels may offer non-invasive, objective markers to assess individual horses' stress responses and emotional states during handling or training situations
- •Measuring these salivary biomarkers could help identify horses with heightened stress reactivity earlier and allow targeted management or training modifications
- •Pairing behavioural observation with simple saliva sampling may bridge the gap between visible reactions and underlying physiological stress, improving welfare assessment on farms and in competitive settings
Key Findings
- •Butyrylcholinesterase (BChE) was the most reliable salivary marker, correlating with emotionality index, laterality, and alarm signals during acute stress
- •Salivary alpha-amylase (sAA) decreased when horses expressed quieter behaviours, suggesting inverse relationship with calm responses
- •BChE increased at time of acute stressor (umbrella test) and decreased 30 minutes post-stress in riding horses (n=9)
- •Multiple salivary analytes (sAA, lipase, TEA, BChE) showed significant temporal changes across five sampling points from basal to 60 minutes post-stress