Horses' lifestyles changed when humans domesticated them. In their natural environment, gastric ulcers were almost unknown: horses spent most of their time looking for food and frequently eating small amounts of stems, dried tufts of grass and twigs.
Modern management and use of horses look very different and greatly increase ulcer risk. Horses are kept in stables with limited space and rationed forage. In sport, frequent competition travel adds stress, while increased energy needs are met with large concentrate rations. Leisure horses are fed similarly. Unfortunately, all these factors contribute to the disease, making equine ulcers a global problem. As many as 70-90% of the world's horse population are affected.
As an owner, you can play an important role in your horse's welfare by understanding ulcer causes and symptoms. Learning to recognise gastric ulcers through behaviour and prevent them effectively allows you to make a real difference to your horse's health and comfort.
What causes gastric ulcers in horses?
The causes vary, but ulcers generally develop in the same way.
Gastric ulceration occurs when the natural balance between stomach acid and the stomach lining is disturbed. The horse's stomach produces acid around the clock to digest food arriving continuously. When food does not arrive, excess acid and its increasing concentration damage the stomach walls and lining. Causes include stress, irregular feeding, increased physical exertion and long-term use of non-steroidal anti-inflammatory drugs. Ulcer risk rises the further a horse's lifestyle departs from its natural pattern.
Many studies show a correlation between gastric ulcers, stress and inappropriate feeding. Stress reduces blood flow in mucous membranes and increases acid production, causing more acid to reach the stomach walls. Stress can have many causes, including frequent transport, prolonged stabling, competing or moving yards. Knowing the causes makes it easier to determine whether your horse is at increased risk.
How can you tell if your horse has ulcers?
The problem is not just how common ulcers are, but how difficult they are to diagnose. Symptoms are often ambiguous and hidden by the animal. Several behaviours occurring together may indicate gastric ulcers:
loss of appetite behavioural problems, bucking deteriorating physical condition, a dull coat tenderness around the abdomen and flanks stereotypies - crib-biting, teeth grindingRepeated colic episodes that do not respond to standard antispasmodic medication should also cause concern.
How do you treat ulcers in horses?
Whenever you suspect your horse has gastric ulcers, consult a vet, who will perform a gastroscopy.
Diagnosing gastric ulcers in horses
Equine gastroscopy can be performed at the stable, but requires careful preparation. The horse must fast for 16 hours before examination, staying in a box bedded with shavings or peat, or wearing a muzzle. Water access must also be restricted for the final 4 hours. The procedure takes place under light sedation. The gastroscope passes through the nasal cavity into the stomach; after inflating the stomach with air, the lining is assessed.
Gastroscopy allows the vet to identify the type of gastric ulcer syndrome. There are two forms: ESGUS in the non-glandular region (Equine Squamous Gastric Ulcer Syndrome) and EGGUS in the glandular region (Equine Glandular Gastric Ulcer Syndrome). This distinction matters because treatments differ.
Imaging the stomach walls also allows the vet to rule out botfly larvae, which can cause symptoms similar to gastric ulcers.
Treating gastric ulcers in horses
Factors affecting gastric ulcers include acid secretion, acid concentration and the presence of a buffering substance, amylase, in equine saliva. The most common therapy involves medicines containing ranitidine and cimetidine, chemicals that inhibit stomach acid production. Omeprazol, with the same effect, is also often mentioned in ulcer treatment. Equestrian forums frequently discuss the human ulcer medicine Ranigast as a substitute for equine gastric ulcer products. Remember, however, to leave medical ulcer treatment to your vet, who will examine your horse, prescribe appropriate medicines and explain an effective treatment plan. Appropriate treatment often depends on disease severity and the location of ulcers in the stomach.
How should you feed a horse with ulcers?
Ideally, feed your horse small amounts frequently. Stable routines naturally require owners to follow the yard's rules, but aim for at least 3 meals daily. Even for large horses, a single concentrate meal should not exceed 2kg.
Limit starch in the diet of a horse with ulcers. Despite their popularity, oats are not a good option because their starch content exceeds 50%, considerably lowering digestive pH. Feed for horses with ulcers that contains no oats makes tackling the condition much easier. As well as being low in starch, the feed should suit your horse's workload and condition.
Adding chaff to concentrates is also beneficial. Where possible, give around 200g of chaff before riding or competing. This does not burden the digestive system but creates a mat buffering acid splashing against the stomach walls during movement. However, the type of chaff matters for a horse with ulcers. Check for hard stem pieces that could mechanically damage the weakened stomach lining. For ulcer prevention, the best option is alfalfa chaff, which buffers stomach acid thanks to its high calcium concentration.
Always provide enough forage. Adequate forage is crucial for horses with gastric ulcers. Affected horses should have constant access to hay. Hang a small-holed haynet in the stable so your horse can eat small amounts of fibre whenever desired. Horses produce stomach acid 24h a day, so do not allow acid to enter an empty stomach. Using a haynet and dividing the daily concentrate ration into at least three smaller meals can already significantly influence ulcer severity.
Gastric ulcers in horses - prevention and supplements
Preventing ulcers becomes easier the more your horse's daily life meets its natural needs. Reduce stress through sufficient exercise and opportunities to satisfy the strong behavioural need to chew.
It is also important to include appropriate supplements and productsin the diet. These help ease discomfort caused by gastric ulceration, speed up drug treatment and make it easier to prevent ulcers in your horse in future. When choosing a product, check that the supplement contains suitable ingredients for horses with ulcers. Added calcium and magnesium buffer stomach acids, while magnesium also has a calming effect. Slippery elm relieves pain and increases mucus production by the stomach lining, as does threonine. This essential amino acid is found in large amounts in soya products such as soya bean meal. Laminaria hyperborea, a species of seaweed, provides extra protection for the non-glandular stomach region. Probiotics and prebiotics in the form of yeast cultures and oligosaccharides also provide components for effectively restoring beneficial digestive bacteria in horses with ulcers or digestive problems.
Reducing starch and overall feed quantities can significantly lower energy supplied to horses in training. You can safely compensate by adding oil to your horse's daily diet, preferably one rich in omega fatty acids.
