Stomach Ulcers in Icelandic Horses - More Common Than Expected

Stomach ulcers in Icelandic horses have traditionally been linked to stress and changes in care during training. However, new research reveals that many horses already have stomach ulcers when brought in from outdoor grazing. The study examined 71 horses from 10 farms across Iceland, with surprising results.

Horses Enter Training with Ulcers

“It was shocking to see how common stomach ulcers were when the horses came in from pasture,” said the researcher. Over 71% of the horses had ulcers in the upper part of their stomachs during the initial examination. After eight weeks of care, this number dropped to 25%.

What Causes Stomach Ulcers?

Research suggests that autumnal changes in grass quality, less chewing, and reduced saliva production can lead to increased stomach acidity and ulcers. Weather conditions, herd size, and social hierarchy also play a role. Stress from injuries or pain is another contributing factor, especially for ulcers in the lower stomach.

How Can You Help?

Feeding Regularly: Feed horses at least 3–4 times daily. Avoid long fasting periods, ideally no more than 4–5 hours during the day.

Hay Before Training: Provide a small amount of hay before exercise to prevent acid splash in the stomach, which can cause irritation.

Monitor Behavior: Horses with stomach ulcers may be sensitive to touch, especially when saddled. They may also appear lethargic and avoid social interaction.

New Study Underway

To better understand why ulcers are so common, a follow-up study is monitoring 80 horses that graze outdoors year-round. The study includes collecting grass samples, tracking weather conditions, and performing quarterly gastroscopies.