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Diagnosis: gastric ulcer in a horse?

Tanja Dietz


10 Min. Lesezeit

Many roads lead to gastric ulcers in horses. If you look at the percentages, currently in the 60%–90% range, you can assume that hardly any horse can avoid such a diagnosis during its lifetime.

There are no specific symptoms that clearly point to gastric ulcers, along with many factors which, when combined, may encourage and ultimately cause ulcers. This doesn’t make it easy for animal owners, who must balance prevention against their horses’ daily routine.

Feeding can be a thorny issue for horses with stomach problems. Order your free  Equine 74 Gastric feed sample here.

In this blog article we’ll describe, explain and provide comprehensive information on the following questions:

What are gastric ulcers in horses?

The usual term for this is EGUS, which is short for equine gastric ulcer syndrome. Basically, gastric ulcers develop where lesions occur, caused by injuries to the mucous membrane of the stomach.

A distinction is made between three different forms of injury:

  • inflammation
  • erosion
  • and ulcers.

EGUS, meanwhile, is "only" the generic term for this problem. Depending on the occurrence, ESGUS (equine squamous gastric ulcer syndrome) and EGGUS (equine glandular gastric ulcer syndrome) may be present. This distinction is important due to different approaches during later treatment.


What are the symptoms of gastric ulcers in horses?

Since there are no specific symptoms that would clearly signal gastric ulcers and stomach inflammation, it is absolutely essential that the horse’s caretaker pay close attention to the animal's behaviour, feed intake and physical signs.

These signs include reduced appetite, weight loss, a resulting drop in performance and a dull coat. They also include behavioural changes. Horses and ponies love routine in their daily activity. An important part of this daily routine is a greeting when you enter the yard.


If a horse does not appear for this ritual and instead remains visibly distant, this is an indication that something may be wrong with this horse. Behaviour may also change in such a way that normally tame and obedient horses suddenly become sullen or aggressive. It is also quite possible that such behavioural changes in individual horses only become visible during work, and are not immediately noticeable during the first morning check.

In the context of animal observation, the following symptoms are considered to be indications of a more advanced course of the disease:

Important: The symptoms mentioned here may also stem from other health issues. It is therefore essential to observe and examine the animal carefully, without prematurely concluding the presence of gastric ulcers, and to treat the animal accordingly. False diagnoses, with unnecessary treatments and stress for the animal, should be avoided at all costs.

How can I prevent the occurrence of gastric ulcers in my horse?

There are many factors in the causes of gastritis and gastric ulcers. Similar to symptoms, there is no single cause, but rather a combination of several factors that facilitate an occurrence and make it difficult to set priorities for effective prevention – whereby feeding management, which too often includes periods of excessive length between feeding, should certainly not be underestimated. In addition to availability, rations also play a decisive role: too much concentrated feed may lead to metabolic disorders.

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The leading cause, as well as a catalyst for other animal health problems, is stress.

Avoiding stress for the horse is an important aspect of prevention – and not only because stress is seen as one of several causes of gastric ulcers and inflammation in horses.

Stress is now a very far-reaching term, but it can basically be described as a disturbance factor in the desired physical equilibrium of the horse. In practice, stress leads to reduced blood circulation in the mucous membranes and increased production of gastric acid.

However, the course for these internal processes is set externally. This includes, for example, a horse "moving away” from his friends – but the opposite can also apply when horses who cannot stand each other are kept in the same area.

Even feed distribution can also lead to stress. Animals love fixed routines and feel good when feeding time rolls around. If feeding is delayed, it can cause stress – in the worst case, competition may develop amongst the horses and no one wants aggression in the herd.

And let’s not forget one of the greatest stress factors for horses: Clinic stays. 

Clinic stays, with unfamiliar environments and strange smells, on top of whatever is causing it to feel bad.  At this point, the person who accompanies the animals also play an important role.

As a trusted person with a calm and level-headed manner, they can relieve the animals of some stress or directly prevent it. Well, we can set aside hospital stress for now: after all, overnight stays in veterinary clinics should not account for a large part of everyday life. But transports, e.g. to events and competitions, can also develop into stressors for horses.

The same is true for training, which brings us back to today’s topic: gastritis and gastric ulcers.

Forced gaits reduce digestion activity and blood supply, while at the same time gastric juices reach the glandless part of the horse's stomach. This can be prevented through regular breaks between training sessions. Providing your horse a balanced diet is an important part of avoiding gastric ulcers. This brings us to feeding and rations.

How should feeding and rations be determined for a horse with gastric ulcers?

Here, too, the principle applies that the desired goal should be a balanced diet. A continuous supply of feed and – very important – hay must be ensured to avoid metabolic disorders.

This aspect of feeding is particularly important when the ration consists of concentrated feed and roughage. A healthy 500 kg healthy horse with average activity often serves as an orientation in the calculation and composition of the correct ration, i.e., he neither simply stands his whole life in the stable nor must he work excessively hard. For such a horse, a hay quantity of 2% of its body weight is recommended. With our model horse, this comes to 10 kg.

Since the life of a horse in human care is very different from that of a horse in the wild, you should at least make sure that there is enough food available during the night so that the horse can eat continuously.

The relevance of this recommendation becomes apparent on closer examination of the equine stomach and its physiology, as well as the lifestyle of horses living in the wild. 

Here you get information about Equine 74 Gastric and why it's so special. 


Horses produce gastric acid continuously, independently of food intake.

This, a potential problem for domesticated animals and their feeding intervals, was originally an excellent concept in nature. As grazing animals, they stand virtually up to their hooves in feed. They have unlimited access to it, and the stomach is permanently ready for digestion. It's not the stomach alone, however.

The saliva of a horse contains bicarbonate, which acts as a buffer to gastric protecting the stomach from damage. Regular intake and good salivation of feed before swallowing ensures a balancing buffer.

Something to keep in mind: on the one hand, it is important that the animals salivate their feed thoroughly, which is much easier when it is rich in fibre. On the other hand, coarse fibrous straw or heavily woody hay can also cause gastric ulcers.

The consistency of the feed in the stomach plays an important role as well. Here it should mix with gastric acid. If not, the feed remains "on its own", while the gastric acid may attack the stomach wall. Naturally, it goes without saying that the feed should always be of high quality.

For example, the feed must not be used if something should go wrong during the silage fermentation process. This can happen very quickly: a small hole in the protective foil is sufficient to allow oxygen to enter, stopping the anaerobic processes and causing the feed to spoil.

How is a gastric ulcer diagnosed?

Even with prevention, the figures mentioned at the beginning suggest that there is still a lot of room for improvement. A gastroscopy is often the only way to find out for certain whether a horse suffers from gastric ulcers.

The examination involves an endoscope being inserted into the horse's stomach to check the lining for gastric ulcers or lesions. The stomach must of course be empty in order for the examination to go smoothly, so forget for a moment the recommendations for prevention discussed above.

For horses, such an examination means no eating 12-24 hours before the procedure and no drinking 2-3 hours before. These are the basics.

While at first glance a gastroscopy appears to be the best path to a diagnosis, another challenge lurks here.

Gastric ulcers come and go, sometimes very quickly. If the gastroscopy turns up no abnormalities, that doesn’t mean everything is in perfect order.

Gastric ulcers may have been present a few days before the examination and have since disappeared – or they may occur two days after this "satisfactory" examination.

This is exactly why it is so important to observe the horses closely for any of the symptoms mentioned above. One should also know the individual characteristics of one’s healthy animals, in order to spot behaviour changes that may arise. A further challenge lies in the simplified presentation of gastric ulcers in all stages. Rats have been used for research in this area because their stomachs are similar to those of horses.

For those who may feel somewhat overwhelmed by the information in this article, the American Association of Equine Practitioners (AAEP) offers a 5-point plan for the prevention of gastric ulcers. This plan is part of a white paper which is freely accessible and easy to find via Google. The author is veterinarian Beth Davis of Kansas State University.

Can I actively ride a horse again that has suffered from stomach ulcers?

If your horse has been diagnosed with stomach ulcers, you should first ask your vet if it is OK to ride during this time. An acute stomach ulcer can make movement very unpleasant and painful for the horse, as it causes the stomach acid to slosh back and forth and reach the affected areas. A time-out is therefore usually needed for recovery.

You should start training the horse again slowly after you get his stomach problems and their causes under control. Exercise caution at first, because the horse should enjoy being ridden and not associate this with stomach pain. It is important to listen to your horse and to interpret the signals he gives you. If your horse prefers to go off-road or is much better at cantering than at trotting, he should be ridden accordingly to keep motivation high.

The 5 most important points for preventing stomach inflammation and gastric ulcers in horses!

  1. Allow your animals access to grass or hay.
  2. Horses are grazing animals with the ability to eat roughage continuously.
  3. Try to design the stables in such a way that one horse can see the other horses with which it likes to spend time outside.
  4. The second sentence is quite interesting: the American Association of Equine Practitioners (AAEP) recommends toys.
  5. For example, one can give a horses a ball with which they can amuse themselves in their stables.


At the beginning of this article we described the many paths that lead to gastric ulcers. Although the recommendations of measures to prevent gastric ulcers from occurring in the first place are clear and therefore provide a good orientation, these must also be easy to incorporate into the daily routine – and it is not always possible to avoid stress. In later parts we will examine individual aspects more closely and discuss how stomachs that evolved for life in the wild can be reconciled in horses under human care.

Sources used in this article:

Equine gastric ulcer syndrome: The continuing conundrum (EQUINE VETERINARY JOURNAL Equine vet. J. (2009) 41 (1) 00-00 doi:

Keeping Horses Healthy: Update on Equine Gastric Ulcers (Beth Davis, DVM, PhD, DACVIM Kansas State University Manhattan, Kansas)

If, after reading the 5 points above, you would like more information from the American Association of Equine Practitioners (AAEP), please visit www.myHorseMatters.com

“Magengeschwüre beim Pferd erkennen und verhindern” (Detecting and preventing gastric ulcers in horses) by Dr. Meyer (IWEST) in the magazine Endurance Insight, May/June 2010 issue.

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