Salivary Cortisol, Equine Characteristics, and Management Factors Associated With Strongyle-Type Egg Shedding of Ohio Horses.
Authors: Keating Danielle L, Lehman Jeffrey S, Burk Steffanie V
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Reducing unnecessary anthelmintic use whilst managing the growing threat of resistance requires a better understanding of which horses are genuinely at risk of significant strongyle burdens. Researchers in Ohio collected faecal and saliva samples from 200 horses, administered management questionnaires to barn staff, and analysed the samples using modified Stoll faecal egg counts and salivary cortisol ELISA to identify factors associated with egg shedding levels (using 50 EPG as the threshold). Three variables emerged as statistically significant: older horses and those with higher salivary cortisol concentrations showed higher odds of shedding fewer than 50 EPG, whilst pasture mowing at least weekly also reduced the odds of elevated egg counts. The cortisol finding warrants careful interpretation—whilst immunocompromised horses might theoretically shed more eggs, the inverse relationship here suggests baseline stress physiology does not straightforwardly predict parasite burden, and practitioners should not assume elevated cortisol alone indicates increased worm risk. Conversely, the management data offer more actionable guidance: regular pasture maintenance alongside age-appropriate monitoring protocols could help identify which horses genuinely require treatment, thereby supporting responsible anthelmintic stewardship.
Read the full abstract on PubMed
Practical Takeaways
- •Implement frequent pasture mowing (at least weekly) as a practical parasite management strategy to reduce fecal egg counts in horses
- •Age-related differences in parasitic egg shedding suggest younger horses may require more intensive parasite monitoring and management protocols
- •Salivary cortisol measurement may be a useful non-invasive biomarker for identifying horses at risk for higher parasitic egg shedding, potentially enabling more targeted anthelmintic administration and reducing anthelmintic resistance
Key Findings
- •Older horses had significantly higher adjusted odds of having fecal egg counts below 50 EPG compared to younger horses
- •Pasture mowing frequency of at least once per week increased adjusted odds of low egg shedding (<50 EPG)
- •Horses with salivary cortisol concentrations in the highest tertile (>0.0712 µg/dL) had increased adjusted odds of having <50 EPG, contrary to the hypothesized immunocompromise association
- •Final logistic regression model identified horse age, salivary cortisol concentration, and pasture mowing frequency as significant factors associated with strongyle egg shedding levels