Gastric ulcers in horses


The training of a horse is important - owners or trainers observe the animal very closely. However, horses often suffer the consequences of illness due to stress (e.g. due to demands, training sessions, transport, etc.) without the symptoms being correctly interpreted: If one notices that the horse grinds its teeth, eats poorly or choosily, suffers from "discharge" and mouth odour, gastric ulcers (ulcerations, technically "Equine Gastric Ulcer Syndrome" EGUS) may be the cause. This malady often goes undetected: Studies show that up to 90 % of thoroughbred racehorses, 60 to 80 % of trotting horses, 60 % of show horses and 37 % of leisure horses are affected by gastric ulcers. Half of the suckling foals are also affected. Univ. Prof. Dr. Heidrun Gehlen (Dipl. ECEIM, specialist veterinarian for horses) confirms: "Stomach ulcers in horses are widespread. However, they often go unrecognised because they can appear clinically unspecific or the symptom picture is not interpreted correctly." This is particularly dangerous because many animals often fall ill silently. Dr Ulrike Binding, equine veterinarian from Leichlingen, confirms: "Many animals don't even show that they suffer from stomach ulcers."

Acid in the horse's stomach

The horse's stomach is quite small and in it - unlike in humans - gastric acid is already produced around the clock from the second day of life. This originally made sense because the horse, as a steppe animal, was designed to pluck fodder and ingest steppe grass rich in raw fibre all day long. This was to be permanently chewed and salivated in, providing bicarbonate as a buffer from the saliva. The acid-buffering saliva is only produced during chewing or suckling. Two thirds of the stomach wall is covered with glands, one third consists of more sensitive, gland-free mucosa. Especially in suckling foals, the stomach mucosa is still very thin. The balance between sufficient acid production, so that digestion can proceed undisturbed, and at the same time sufficiently functioning endogenous protective mechanisms and sufficient consumption of the acid through regular food intake is therefore decisive for a healthy stomach. Very young up to old horses can suffer from stomach irritations up to stomach ulcers in case of an imbalance, most frequently in the gland-free part: in 55 to 80 % of horses depending on the type of use, in foals up to 88 % (newborns) and 50 % (weanlings) depending on age.

Multiple symptoms of disease

All horses can develop gastric ulcers; however, the symptoms are often non-specific and the symptom picture is varied. A mere assessment of the severity of individual symptoms does not yet allow an assessment of the severity of the possible disease.

Foals may show the following symptoms: Recurrent colic or frequent supine lying, aborted drinking, strong salivation and teeth grinding. Diarrhoea and fever occur, through to a shaggy, lacklustre coat, an overall poor developmental state and changes in the blood count.

Adult horses often show the following symptoms: they are reluctant to eat, eat poorly or fussy, or stop eating altogether and then lie down. Recurrent colic, teeth grinding, "flehmen" and yawning as well as "belching" and mouth odour also occur. Weight loss, reduced performance and an overall poor general condition are the result. Depressive behaviour, restlessness and even aggression can also occur.


Diagnosis: Correctly identifying stomach ulcers

If stomach ulcers are suspected, only the veterinarian can make a definitive diagnosis with the help of gastroscopy, as there are no reliable laboratory tests or biochemical markers available yet. This is done with the help of a flexible endoscope camera, which is pushed into the inside of the stomach and makes the effects (from severity 0= intact mucosa to severity 4 = widespread lesions with deep gastric ulcers) immediately visible via video. Prof. Dr. Gehlen recommends that in any case, after a gastroscopy and subsequent concrete findings, targeted treatment should be given depending on the localisation and severity, and the choice of medication, with single preparations or combinations, as well as the length of therapy should be adapted accordingly. If a gastroscopy is not possible, a so-called diagnostic therapy usually helps: If the symptoms improve after the use of appropriate medication, ulcers are likely to be the cause.

Peptic ulcers are factor diseases

Stomach ulcers rarely have just one trigger; rather, many factors are involved. Gastric ulcers often occur in the glandular part when the ratio of the stomach's own protective mechanisms and acid buffers does not function properly. In the sensitive, non-glandular part, (unnecessary) stress and the use of medication are often the cause. (Incorrect) feeding, illnesses as well as operations or (excessive) training also play their part.

Cause feeding errors

In nature, horses eat very slowly and up to 18 hours a day of roughage-rich food, so that the stomach is almost never empty. The following feeding errors can lead to over-acidification of the stomach and promote ulceration: too much concentrated feed, too little roughage, too long feeding breaks, snares due to feed envy and restlessness in the stable and poor feed quality. Roughage remains in the stomach for a short time between one and five hours, in contrast to grain and ready-made feed. Leaving grain or ready-made feed in the stomach for a longer time can lead to fermentation, which promotes stomach ulcers.

If there is too much grain in the feed, the starch is not completely digested in the small intestine. Some residual starch then enters the large intestine and shifts the balance of microorganisms, leading to acidosis, as do feed deprivation and periods of starvation.

Stress makes horses sick

In principle, horses can cope well with acute stress because, as flight animals, they urgently need stress as a survival mechanism in the wild. It becomes dangerous for the stomach with other types of stress, because just as with humans, it is also said with horses: too much stress makes you sick. A horse has basic needs that want to be satisfied: Light, air, food, exercise and good social contacts. If there is a disbalance here, the result can be unruly behaviour such as barking or restlessness/hecticness. Stress in horses is difficult to measure, but it has been shown that certain situations can promote the formation of stomach ulcers.

Pressure to perform, social stress (e.g. when being stabled or weaned), stress on the horse's sensitive nervous system, unloved neighbours in the stall, fights over rank or pain can also cause stress, as can badly fitting saddles and snaffles.

Training can also be causative

There is a direct connection between (excessive) training and the occurrence of stomach ulcers. The more intensive the training, the higher the probability of gastric ulcers. The trotting and galloping alone increases the pressure in the abdomen and allows the acidic gastric juice to come into prolonged contact with the stomach wall.

Acute stress: Diseases, pain and operations

Horses with existing diseases have an increased risk of developing stomach ulcers. Surgery under general anaesthesia and the administration of certain drugs (e.g. phenylbutazone) can also promote the occurrence of gastric ulcers. Last but not least, colic, illness and surgery as well as pain mean acute stress. About 80 % of colics presented to clinics, for example, suffer from peptic ulcers.

Remedy of choice: Omeprazole

EGUS can be treated well. There are two approaches: The administration of a drug to release gastric acid and an adjunctive administration of feed supplements.

The drug of choice is omeprazole, a proton pump blocker that is very effective in reducing the release of gastric acid into the stomach. This stops the cause and healing can begin. Omeprazole is approved in a special paste formulation for the horse that can be easily administered once a day into the animal's mouth by the owner himself. Only omeprazole has been proven to be sufficiently effective and safe for use in horses, so that the horse can continue to be worked with during therapy.

As a dietary supplement, for example, one with a patented pectin-lecithin-glycerol complex is available. This has three effects: it counteracts hyperacidity and stabilises the natural acid balance, inhibits the reflux of bile acids and the protective mucous membrane layer of the stomach is strengthened.

Once stomach ulcers have developed, they take several weeks to heal completely. In times of unavoidable strain and stress, prophylactic administration of omeprazole is therefore advisable.

Preventing stomach ulcers

Stomach ulcers can be prevented. Sensible prevention through adapted feeding, stress reduction and adequate training as well as support of stomach health are important measures to keep horses healthy. The best feeding cannot prevent stomach ulcers if the environment is not right. Prof. Dr. Gehlen also emphasises: "Management in feeding and husbandry is the most important prophylaxis. Stress factors should be avoided if possible. If stress is unavoidable, the administration of omeprazole can be helpful for prevention." The focus is on good feed quality, adapted feed rations as well as measures for the horses' sensitive psyche.