Feeding the Horse


Related site sections:

Dietary Basis

Digestive System
































Gastric Ulcers

Gastric ulcers are a common problem:

Even foals aren't immune, particularly in the first couple of months of life.


The only definitive way to diagnose gastric ulcers is to have a vet perform a gastroscopy. This involves passing an endoscope with a small video camera at the end of it down into the stomach so that the lining of the stomach can be viewed. The pictures above show the level of detail that an endoscopy provides. Symptoms of gastric ulcers can be vague and vary in severity, but can include:

  • Low grade recurring colic
  • Intermittent abdominal pain
  • Unhappy while saddling and tightening girth
  • Chronic diarrhoea
  • Poor appetite
  • Poor body condition
  • Reluctance to train
  • Change in attitude


To understand what causes gastric ulcers we need to look a bit closer at the equine stomach. The lower part of the stomach is glandular, it is lined with thick, bumpy glands that produce digestive acids. This part of the stomach also has a thick layer of mucus and bicarbonate (a pH buffer) that protects the stomach wall from the digestive acids. The upper part of the stomach however is non-glandular. It does not produce digestive acids and is not as well protected.

Gastric ulcers can occur in either part of the stomach, less commonly in the lower glandular stomach. Here stomach ulcers are likely due to stress (environmental stress, travel, competition, strenuous exercise, illness) or the use of non-steroidal anti-inflammatories such as Bute.

60-80% of gastric ulcers occur in the upper part of the stomach when digestive acids from the lower stomach slosh upwards and burn the stomach lining. Why this happens fundamentally comes down to how the horse evolved and how we manage the horse today.


Horses evolved as trickle feeders, grazing, nibbling and picking for most of the day. This has two advantages:

  1. chewing produces saliva which contains bicarbonate which helps neutralise stomach acid
  2. the horse's upper stomach is rarely empty of fibrous matter which helps prevent any sloshing stomach acid hitting the stomach lining

By contrast, modern horse management often focuses on large grain/concentrate based rations and too little forage, which leaves the upper stomach empty of fibrous matter making it vulnerable to sloshing stomach acid. Add in exercise and it is easy to see how the lining of the upper stomach is damaged.


Make forage number 1!! Feed the horse what the horse has evolved to eat. Make forage the basis of the diet and then add grain/concentrate to make up any energy deficit. Recommended forage amounts per day:

So a 500kg racehorse in heavy work should be consuming at least 12.5kg of forage a day.


The good news is that there are effective treatments for gastric ulcers such as Omeprazole and Ranitidine. If you suspect gastric ulcers consult with your vet for diagnosis and a treatment plan.