Guide to Horse Ulcers: Symptoms, Treatment, and More

Symptoms of Horse Ulcers

Horse ulcers can have many faces and oftentimes go unnoticed for a long while. It is not uncommon that horses live their whole life without having the proper diagnosis or treatment. It is estimated that over half of sport and recreational horses, which are used under the saddle, suffer from horse ulcers. Off course the severity of symptoms varies from one individual to another and thus most mild cases of horse ulcers go unnoticed. The main symptoms of gastric ulcers in horses include:

Unwanted Weight Loss

Weight loss is one of the first and most common signs of ulcers in horses. It is not specific enough though and is often misinterpreted as underfeeding or overtraining of performance horses. Weight loss due to equine gastric ulcer syndrome is quite specific as it affects mainly the muscle weight. It means that horses with ulcers will present a poor muscle physique but might collect fat tissue around their lower belly. The typical image of a horse with stomach ulcers presents as such: visible ribs, sunk back, thin neck, angular hind and round lower belly. Weight loss can happen even if a horse is put on a Weight Gain Feed.

Not Finishing the Meal

Stomach ulceration is oftentimes a cause of inflammation and discomfort in the digestive tract and it causes horses a severe gastric pain. Horses that experience discomfort or pain might refuse to eat altogether or might have a tendency to leave unfinished meals. It can be observed that horses with gastric ulcers become picky about their food and eat small portions of feed at once and leave the rest for later or not finish it at all.

Diarrhoea, Constipation and Indigestion

Gastric ulcers in horses do not only affect the stomach, but rather the whole digestive tract. They disrupt the microflora (the good bacteria that naturally inhabit the gut). Why is it so? Ulcers make the gut environment unfavourable to microflora by disrupting the pH (causing it to become too acidic). Inflammation and pain itself is also bad to the natural microbiome. Pain, as mentioned earlier is oftentimes a cause of irregular or insufficient feeding that affects the bacteria and microorganisms that live in your horses gut and help with digestion. The decreased number of microorganisms in the gut makes the digestion a lot less efficient. A result of this process is poor formation of stool, problems with defecation and undigested pieces of food visible in horse poop.


Colic is more common in horses with gastric ulcers than in the normal population. Colic is a result of imbalances of microflora in the gut (as mentioned earlier). Digestive processed are disturbed and the passage of food through the gut is often slowed down. It results in excessive fermentation of feed in the gut and production of gas and further a life threatening colic. Colic in horses with gastric ulcers occurs most typically in the early spring (when horses diet becomes more abundant in fresh grass and when they undergo hormonal changes too.)

Dull Coat, Mane and Tail

Poor quality coating is an effect of two things. Firstly, as mentioned earlier, horses with gastric ulcers often become picky eaters and leave unfinished meals. If horses in such state are left untreated, they are likely to develop vitamin and mineral deficiencies. Secondly, ulcers affect the quality of feed digestion in the gut. A horse with untreated ulcers uses the feed a lot less efficiently and often even if a feed is rich in nutrients, your horses gut doesn’t absorb them and they end up being defecated. The second process also leads to deficiencies and malnourishment in time which is most likely going to affect your horses coat, mane and tail. The first visible changes might be too subtle for anyone to take action. These might include decrease in volume of the mane and tail, dry and brittle coat, dull coat with no shine. If your horse struggles with this problem, please review The Best Supplements for a Shiny Horse Coat (UK-2021) on our page.

Weak Hooves

Hooves that break easily, chip off and dry out are often a sign of ongoing problem with ulcers. Just like in case of a dull coat, weak hooves are a result of poor and inefficient absorption of vitamins and minerals in the gut. If you are looking at improving your horses hoof condition check out our complete guide to The Best Hoof Care Products (UK-2021)

Increased Irritability

Stomach ulcers are a painful condition. Horses that show signs of irritability and poor manners, such as biting (often when the girth is tightened), kicking, head shaking, bucking and other behaviours that arrive from stress and pain, in most cases suffer from ulcers. Most horses are not aggressive or uncooperative in their nature, but many equestrians fail to accept it and investigate the actual problem, blaming it on the horses character.

Increased Apathy and Laziness

Apathy, laziness and sleepiness can be a result of malnourishment due to the ulcers. It can be due to anorexia (when the body weight is too low) or due to lack of crucial vitamins, minerals and elements in the diet, or their poor absorption in the gut.

Back Pain and Bucking Under the Saddle

A huge percentage of horses with ulcers, experience some sort of back pain. It can vary from very mild to severe. Such horses often present discomfort under the saddle, by bucking, having trouble with riding straight lines, swishing the tail, taking irregular steps and presenting lameness, refusing to ride round and low, or laying back their ears. Off course a perfectly fitted saddle by a professional saddle fitter, saddle half pads or veterinary back injections with steroids are a temporary solution, but do not fix the actual problem. Some horses experience such severe pain that they avoid being brushed, cleaned or petted on their back, and will bend when pressure is applied by hands. This is a sign your horse needs an immediate vet care.

What do Ulcer Symptoms Depend on?

The symptoms highly depend on the severity of the gastric ulcers from a clinical perfective. A five step scale 0-4 is used in assessment of ulcers, during a gastroscopy. On that scale 0 means no ulcers in the gastroscopic image and 4 is a severe illness which affects a high precentage of the stomach lining. Or speaking easier, the higher the number on the scale, the more clinically severe the disease is and thus your horse will present with more symptoms.

Symptoms might also depend on your horses lifestyle and personality. Symptoms might be more noticeable in horses that are being ridden under the saddle and are put to work. Ulcers give more discomfort on empty stomach (when stomach acid directly irritates the stomach lining) so are commonly noticed in horses that have infrequent feeding times. Often horses that are more delicate or expressive show the symptoms a lot quicker or inadequately to the clinical assessment. This is often the case with warmblood horses used in sport.


Horse ulcers are rarely a cause of death. Their symptoms and outcomes can be though and thus it is very important to address the issue and speak to your vet. Many horses die yearly of an ulcer related colic. Ulcers can also significantly decrease the performance of sport horses.

How to Diagnose Horse Ulcers?

Horse ulcers can be diagnosed by a vet through an endoscopy. Endoscopy is a harmless procedure of inserting a camera through an oesophagus to the stomach and the first part of the duodenum (small intestine). This allows the vet to carefully inspect the mucus lining of the stomach and asses the changes on the surface. Endoscopy is quick and easy but requires a horse to be on an empty stomach. Vets will most often suggest to put your horse off food (including hay) for at least eight hours prior to the procedure. Many vets can perform endoscopy with a portable equimpent at your own stable, but some may require you to bring your horse to the clinic. Depending on the vet and the place of the procedure, the cost should not exceed 300 GBP. Due to costs, some people ‘diagnose’ their horses by observing the symptoms and introduce the treatment (proton pump inhibitors), without performing endoscopy at all. Speak to your vet to get the best possible option of diagnosis and treatment for yourself and your horse.

How to Treat Horse Ulcers?

The treatment depends on the severity of the ulcers (assessed based on the gastroscopic image). In most cases though, the treatment can be divided into four stages.

Stage 1

The first stage focuses on dealing with the severe ulcer pain and discomfort and is the most intensive stage in the whole treatment. A horse is given a proton pump inhibitor (such as omeprazole, polprazole etc.), prior to every meal, typically three times a day. Ideally the medication should be given half an hour before the actual meal, but many horse keepers, out of convinience give the medication together with the meal . Proton pump inhibitors decrease the production of the stomach acid. As a result, the pH of digestive liquids becomes more alkaline. Together with the medication it is suggested to put your horse on a veterinary gastric feed dedicated to horses which suffer from ulcers. These feeds are alkaline, rich in oils, fibres and are slowly digested, making sure your horses stomach isn’t left empty and more prompt to irritation. Good feeds contain probiotics, which role is mainly to restore the natural microflora balance in the gut and aid in healthy digestion. For more information on feeding recommendations see the section: How to Prevent Horse Ulcers. In stage one it is suggested to avoid riding the horse or putting it though any forms of work. Many horse owners decide to give their horses a time off work, but let them go out on the paddocks or pastures daily. Depending on the severity of the ulceration, the first stage lasts is carried on for about two weeks.

Stage 2

In this stage of treatment the dosage of the proton pump inhibitors is decreased to one less meal a day. So, if in stage 1 the horse was given omeprazole three times a day, in stage two omeprazole is given twice a day. The horse continues to be feed with the right feed. A light exercise can be reintroduces e.g. lunging. This stage typically lasts another two weeks.

Stage 3

Proton pump inhibitor is given only once a day. Horse is reintroduced to normal work regime but remains to be feed with the specialist feed. Muscle mass is slowly rebuit by introducing high calorie – low energy feed such as beet pulp, rice bran and oils (linseed, rice, soy etc.). This stage takes two to four weeks.

Ongoing treatment

It has to be understood that treated ulcers do not guarantee a horse will stay healthy forever. In fact, if the factors that caused the ulcers in the first place will not be eliminated, the horse will most likely develop the ulcers again. It is therefor important to make a few permanent changes regarding feeding, training, competing and general horse care. For more information on how to prevent ulcers check the section: How to Prevent Horse Ulcers Long Term.

What Causes Ulcers in Horses?

Ulcers are a result of overproduction of hydrochloric acid in the stomach which irritates the walls of the digestive tract. Ulcers develop in the irritated places where the protective stomach lining is destroyed and erosions appear. Gastric acid production moreover decreases the pH of the intestinal tract, making the whole environment more acidic. This causes a group of symptoms also referred to as gastric ulcer syndrome, or equine gastric ulcer syndrome. To see the possible symptoms please go to the section of this article “Symptoms of Horse Ulcers” where we have touched upon this topic in detail.

Here are the main factors that are often the cause of horse ulcers:

  • Irregular Feeding :the lining of an empty stomach is at a higher risk of being damaged by the stomach acid compared to a full stomach, with a more alkaline environment
  • Stress: stress is one of the main factors in development of horse ulcers. Stress (both mental and physical) lead to overproduction of acid in the stomach.
  • Poor Diet: diet which is highly acidic (for example oats) can lead to gastric ulcers. Likewise a diet abundant is a slowly released energy, i.e. diet abundant in omega-3, omega-6 fatty acids, plenty of insoluble fibres and molasses free has got protective properties.
  • Breed: warmblood horses are more than three times more prone to developing horse ulcers in their lifetime than all the other horse breeds
  • Non steroidal anti inflammatory drugs: medication that is commonly given to horses when performing veterinary and dentist care. These medications are scientifically proven to increase the risk of stomach ulcers, due to the stomach mucus layer loosing its protective function.

How to Prevent Horse Ulcers Long-Term

Proper Feeding

A few changes to your horses diet can make a big difference. There are plenty of complete feeds dedicated to horses that suffer from ulcers, but those can also be safely given as a method of ulcer prevention. A diet should consist of the following: high fibre elements, low acidity, essential amino acids and omega-3 and -6 oils and should be high in calories for horses that struggle to put on or maintain weight.

  • Low acidity food protects the mucus lining. In fact, high acidity feed should be avoided altogether, no matter if your horse has ever suffered from ulcers. Oats which are commonly given to horses as the basic feed, are an example of an acidic food. Alternatives include corn, barley or black oats.
  • High fibre feed is crucial for effective and healthy digestion and stool formation. High fibre foods take longer to digest and as we have mentioned earlier, food in the digestive tract has protective properties. Moreover, fibre acts as a fuel for the good microbiome of the gut. Alfa alfa hay should be added to every meal.
  • Essential amino acids allow your horse to built and retain muscle mass.
  • Omega oils help in maintaining a healthy weight and improve the general condition of horses coat, mane, tail and hooves.
  • Beet pulp or rice bran is a great feed that provides volume to the meals without giving an excess energy. Given a few times a week, it helps with weight gain and maintenance.
  • Mash should be added to your horses diet at least twice a week. Linseed present in the mash, releases mucus like substances that have healing properties in the digestive tract. They aid the recovery of stomach lining and give an extra protective layer.
  • Horses which are prone to ulcers should be on a molasses-free diet (read: sugar free). Sugary foods including sugary treats and most fruits should be avoided. Be aware that many horse feed producers add molasses to their complete feeds to make them more taste-appealing to the horses. Find a feed or treats with a molasses-free label or one which is dedicated to horses with ulcers.
  • Your horses diet should also be constant. Once you find a feed that your horse functions well on, stick with it and do not experiment too much. One of the biggest mistakes many people do is make too many changes too frequently and this results in misbalances in horses gut and might lead to ulcers.

Regular Feeding

Regular and frequent feeding is just as important as what you feed your horse. Your horse should be grazing on something at all times. This means that horses prone to ulcers and digestive issues should be given a free access to hay at all times, even during the turnout. It is also important to provide your horse access to hay when traveling in. a trailer or a horse van. When it comes to the meals, horses such be fed at least three times a day, but many suggest to up this number to four or five.

Feeding Pre-Training

Many people have heard to never feed the horse prior or during the training as this could potentially result in a colic or girth stress. This is a myth though as horses are designed to function and run with a full stomach. Allowing your horse to eat a light meal prior to your training will precept your horse from discomfort, pain and potentially ulcer formation. Alfa alfa hay is the best feed your horse can get before the training.


Probiotics are a common additive in feeds dedicated to horses with ulcers. They regulate the digestion, making the poop healthy and your horse happy. Probiotics are not necessary in the long term but are a great help during the moments of the highest stress (such as changes in the feeding, introducing to green grass, competitions, transport, changes of the livery yard etc.).


It is not necessary to give your horse multiple supplements in the long term but can improve your horses condition if depleted of a specific vitamin. I always recommend running a blood test for horses that are in ulcer recovery and supplementing only the vitamins that the horse really lacks. It saves money and you can be sure your horse is getting exactly what it needs. However, I do recommend all year round magnesium supplementation (or supplementation with calming supplements) for horses that are easily excitable, young and hot. Magnesium helps horses to remain calm, and less stress means less chance of developing stomach ulcers.

Proton Pump Inhibitors

Proton pump inhibitors can be given to a horse as a protective measure. They are useful in the times of increased stress related to veterinary procedures, competitions, moving the yard etc. It is recommended to give one sachet of omeprazole daily, before the feeding, during the time on the increased stress.

Review Your Training

Make sure your horse is not overtrained and has enough recovery and chill time. Remember that ground work or lunging are equally important as riding and are also a great form of exercise. Some experts even suggest that the best and most healthy type of exercise is the non-induced one. It means that letting your horse run around paddocks or pastures freely can be of a great benefit to its mental and physical health.


Horse physiotherapy, massage or magnetic therapy can help relieve the muscle tension. It prevents the buildup of stress and thus makes your horse less likely to develop gastric ulcers.


Some horses have a problem with expressing their emotions and with overall communication. They tend to stress a lot and can not cope with their own mental state. It is really worth giving behaviourist a try. A behaviourist can teach your horse to be a calm and collected and help you build a stronger and more meaningful bond with your horse.