Risk factors associated with gastric disease prevalence in extensively kept horses in Iceland evaluated four times in a calendar year.
Authors: Luthersson Nanna, Harris Patricia A, Parkin Tim, Þorgrímsdóttir Úndína Ýr, Bennet Euan D
Journal: Equine veterinary journal
Summary
# Editorial Summary Gastric ulceration remains pervasive in extensively grazed horses, yet whether seasonal pasture changes drive disease prevalence has remained unclear. Luthersson and colleagues conducted gastroscopic examinations on 80 Icelandic horses across four farms at quarterly intervals throughout a calendar year, documenting squamous gastric disease (ESGD) in 48–72% of animals and glandular disease (EGGD) in 33–45%, with prevalences remarkably consistent across seasons. Notably, reduced grass availability without supplementary forage increased odds of significant ESGD tenfold (OR 10.55), whilst horses in Iceland's southern regions showed over ten times greater risk than northern counterparts (OR 10.11); higher body condition scores (≥7/9) also conferred substantially elevated risk (OR 4.44). For EGGD, age emerged as a critical factor—horses older than 14 years were nearly three times more likely to develop significant glandular disease than younger animals—as did dental abnormalities and the concurrent presence of ESGD. These findings challenge the seasonal hypothesis, instead implicating management-related factors and individual characteristics in gastric disease pathogenesis, suggesting that farriers, veterinarians and nutritionists should prioritise gap-free forage provision and dental assessment, particularly for older, heavier-condition horses maintained on marginal pasture.
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Practical Takeaways
- •Even extensively grazed horses on forage-only diets show moderate-to-high ESGD prevalence year-round; supplementary forage during low grass availability significantly reduces risk and should be standard practice
- •Regional differences and body condition management matter: Southern Icelandic locations and overweight horses (BCS ≥7/9) are at substantially higher risk, suggesting monitoring and dietary management should be tailored to location and individual horse condition
- •Dental abnormalities and advanced age are important EGGD risk factors; routine dental care and gastroscopic screening in older horses (>14 years) with dental issues may help identify and manage disease earlier
Key Findings
- •ESGD prevalence ranged from 48-72% across four seasonal timepoints, while EGGD prevalence ranged from 33-45%, in extensively grazed Icelandic horses
- •Reduced grass availability without supplementary forage provision increased ESGD risk 10.55-fold compared to low grass with forage provided
- •Geographic region (South vs. North Iceland) showed 10.11-fold increased ESGD risk, and higher body condition score (≥7/9) increased risk 4.44-fold
- •Presence of ESGD increased EGGD risk 3.38-fold, while age >14 years and dental abnormalities (score >0/2) were significant EGGD risk factors with odds ratios of 2.93 and 2.30 respectively