Ulcers in Horses!


A Comprehensive Guide to Causes, Signs, Treatments, and Feeding Routines for the Ulcers in Horses


Depending on what study you read, you will find that anywhere from 50-90% of horses have gastric ulcers (the kind in the stomach). The research varies because some only look at racehorses, some look at show horses, some look at pleasure or backyard horses. At any rate, ulcers in horses can happen regardless of the horse’s job or age.


Table of contents:


Anatomy of the horse’s stomach and the relationship to ulcers.

What is Equine Gastric Ulcer Syndrome? (EGUS)

How do ulcers in horses happen?

How ulcers in the horse are diagnosed.

Signs of ulcers in horses

Risk factors for ulcers in horses

Science about ulcer formation in feral and domesticated horses

The best treatment for ulcers in horses – omeprazole paste versus powder

Other types of ulcer medications

What, and how, to feed a horse with ulcers

Go shopping!


Anatomy of the horse’s stomach and the relationship to ulcers.


  • The horse’s stomach has distinct areas. The upper region, closest to your horse’s back, is the squamous region. The esophagus is “connected” to this region by the cardiac sphincter.


  • This squamous region is designed similarly to the esophagus. The cells don’t produce any products that protect the area from digestive acids.


  • The lower portion of the horse’s stomach is the glandular mucosa. Here, digestive acids work their magic on your horse’s meals, preparing the food for its trip into the intestines. The glandular region also produces mucus and bicarbonates. These are buffering agents and help protect the lower portion of the stomach. The stomach’s digestive acid production runs all day and all night!


  • Ulcers can develop as the glandular mucosa’s acid contacts the stomach’s unprotected upper portion. This is the most widely understood way for ulcers to develop. However, they are not limited to the upper part of the stomach.


horse with head poking out of his stall window

Stall-kept horses are sometimes more stressed than field-kept horses.


What is Equine Gastric Ulcer Syndrome? (EGUS)


  • Equine Gastric Ulcer Syndrome is a more extensive blanket term for ulcers in the esophagus, stomach, and the duodenum, the first part of the intestines.


  • Ulcers and diseases occurring in the stomach’s upper part are Equine Squamous Gastric Disease (ESGD). You might see this as Equine Squamous Gastric Ulcer Syndrom (ESGUS). These are graded on a scale of zero to four. Zero is the absence of ulcers, and four is severe ulcers.


  • Ulcers and diseases in the lower portion of the stomach classify as Equine Glandular Gastric Disease (EGGD). You might see this as Equine Glandular Gastric Ulcer Syndrome (EGGUS). There is no grading system for these lesions, and some can be difficult to detect in this area.


  • Thanks, acronyms, for making this SO CLEAR.



How do ulcers in horses happen?


  • Gastric ulcers in the horse’s stomach happen because the horse is always producing stomach acid! All the dang time! Because horses need to eat all the dang time. Most horses don’t have this type of lifestyle, even with six feedings a day or more. For part of the day, your horse’s stomach fills with acid – without food. Hence, the acid gets frisky and does other things that it shouldn’t – like create ulcers.


This is ulcer formation at its simplest, but there’s a bit more to it than that.


  • Let’s look at the upper, squamous region of the stomach involved in Equine Squamous Gastric Ulcer Syndrom (ESGUS). This “naked” area can develop ulcers from the splashing of acids if there’s no food in the stomach.


  • Horses with extreme training routines, like racehorses, will also physically push the stomach around during exercise.


  • Diverting for a moment into human ulcer formation, it’s safe to assume that bacteria cause ulcers in horses as they do in humans. But there’s no evidence of this.


  • In horses, there is a possible parasitic or bacteria component for ESGUS. It’s not a direct line from the bug to the ulcer. In one study in Italy, donkeys were scoped for ulcers, in which about half of them had ESGUS. All had bot fly larvae in the stomach. Do the larvae contribute? It’s unknown.



  • Looking at Equine Glandular Gastric Ulcer Syndrome (EGGUS), the causes are less understood. It is suspected that bute and other NSAID’s alter the stomach’s lining in the glandular mucosa, creating opportunities for lesions. The role of NSAIDs can’t be confirmed or denied. The makings of an excellent spy novel, it seems.


How ulcers in the horse are diagnosed.


  • The only conclusive way to diagnose gastric ulcers is with endoscopy. A camera is placed into your horse’s stomach to take an actual peek around during this standing procedure! Your vet feeds a camera via a long tube into your horse’s nose, esophagus, and then into the stomach to take a look around.


  • Your horse needs sedation for this, and his stomach should be empty. Don’t feed your horse for 12-24 hours before endoscopy. Also, take away water a few hours before. Your vet will give you the details before the appointment.


  • If there are food and water in the stomach, the camera will not get a clear picture of what is going on! Yes, your horse will be miffed at you for skipping meals. But, you will hopefully have a much clearer diagnosis and plan!


  • Because endoscopy is not feasible for all budgets and situations, many vets and owners try the most likely treatments and then monitor for a positive change in the horse. Your horse might need several courses of medications and lifestyle changes.


Signs of ulcers in horses


  • So here’s the thing about gastric ulcers. Their signs are VAGUE at best and often non-existent. Thanks, horses, for not being able to send us an email or text about what’s wrong.


An overall “blah” attitude and feeling.


  • Does your horse seem just a bit off, or down, or under the weather? The malaise ould be hundreds of things, including ulcers.


A change of attitude.


  • Most horses have predictable vital signs, habits, and personalities. A change in any of these indicates that something is amiss. Again, this attitude can have a multitude of causes.


Decreased performance.


  • I’m beginning to sound like a broken record. Ditto for reduced performance and all of the following issues!


Training issues.


Poor coat.


Weight loss.


Low-grade colic.


Sensitivity to the girth for grooming and tacking.


Teeth grinding.


Picky appetite.


Reluctance to drink or trouble finishing meals.


  • Notice that many of these signs are also signs of bad saddle fit, sore muscles, old age, back pain, lameness, dental issues, parasite infections, hindgut digestive issues, and more. You and your vet need to do lots of exploring and excluding other possible problems.



slow feeder for horse feeds and hay pellets

YES! There are slow feeders for pellets and grains, too!


Risk factors for ulcers in horses


  • Ah, by now, it feels like a horse merely existing will lead to ulcers. There are definite risk factors that are lifestyle-related. This allows us to make some changes to your horse’s day as part of a prevention and treatment plan.


  • Your horse’s feed. Highly concentrated meals instead of forage play a role in ulcer development. A larger volume of feeds and grains fed at once, instead of throughout the day, is also a factor.


  • How you feed – meals or slow feeders? Slow feeders for bagged feeds, grains, and fortified feeds are available! Horses that are chewing small amounts of food over entire days are less likely to create ulcers. It’s also helpful to feed concentrated grains and feed after there is forage in the belly. Hay before grain!


  • How stressed is your horse? Shows, travel, intense training, solitude from a herd, and life in a stall all create stress. Some horses have vices, are herd-bound, and are stressed by who-knows-what.

Movement is vital for overall health


  • What is your horse’s exercise routine? Hard training, like eventing or racing, is more stressful than trail riding.


  • How much natural movement and play does your horse get? Is his life mostly in a stall, or does he have the freedom to run, play, graze, and socialize? Restricted movement is challenging for many horses, mentally and physically.


Science about ulcer formation in feral and domesticated horses


  • There have been a few studies about ulcers in feral horse populations. One study in the UK found that about a third of feral horses had ESGD, and about a third had EGGD. The same research found about 60% of domesticated horses had ESGD, and 70% had EGGD.



  • The feral horses were transported during this study, which might account for some of their ulcer development.


The best treatment for ulcers in horses – omeprazole paste versus powder


  • The best treatment is one that works for your horse. Will these vary on a case-by-case basis? Absolutely.


But here are some common ulcer treatments for you and your vet to consider.


  • Omeprazole – this is the gold standard for ulcer treatment in horses. This drug goes into your horse’s bloodstream in the small intestine, then works to turn off the acid-producing pumps in your horse’s stomach.


  • You may recognize the names Gastrogard® and Ulcergard®. Both are omeprazole pastes. Both contain the same ingredients – 370 mg of omeprazole in 1 gram of product.


  • They are labeled differently – Ulcergard® is marked to prevent gastric ulcers, and Gastrogard® is for the treatment. The dosages are also different. Gastrogard® is prescription only, Ulcergard® is available over the counter.


  • You can also find omeprazole powders, but the jury is out on their effectiveness. For omeprazole to work, it must find its way to the small intestine to be absorbed. Powders are going to be destroyed by the stomach’s acids. Pastes are protected.


  • This study found that even coated omeprazole did not enter the bloodstream as much as paste omeprazole did.


  • This article, written by a veterinarian, stresses that compounded omeprazole is not FDA approved, doesn’t have quality control, and may degrade over time in the jar.


tube of omeprazole for gastric ulcers

Daily ulcer medications – AKA liquid gold!


Other types of ulcer medications


  • Pectin-lecithin and sucralfate increase mucus concentrations. Do they work for gastric ulcers? Maybe? There is a supplement called EGUSIN that has actual science attached to it – it was shown to possibly help horses with existing ulcers. EGUSIN does have pectin-lecithin.


  • H2 blockers. These medications are anti-histamines. Histamines can stimulate a horse’s stomach to produce more acid.


  • Supplements. The jury is out on these, too. They may or may not help your horse.


  • Antacids. Should your ulcer-prone horse eat TUMS? Talk to your vet about it.


  • It’s wonderful and great if you and your vet have found an ulcer treatment that works for your horse. Make the necessary lifestyle changes to prevent this from happening again!


three small hole hay nets in a hay loft

Hay nets help keep your horse’s belly full of hay – which can help with ulcers.


What, and how, to feed a horse with ulcers


  • Diet, exercise, and turnout seem to be the significant lifestyle factors for ulcer development and recovery.


  • Ulcer-prone horses benefit from low starch and low sugar diets, much like the metabolically challenged horses dealing with Cushing’s and Insulin Resistance. For simplicity’s sake, look for low non-structural carbohydrate (NSC) values.


  • Finding a low starch and low sugar diet starts with forage. You might need to switch hay variety. Alternatively, soaking hay will reduce the amount of sugars in the stems. Steaming hay is better suited for reducing dust and not as efficient as soaking hay.


  • There are benefits to adding alfalfa into your horse’s diet, as well. Alfalfa is high in calcium, which acts to buffer stomach acids. The higher calcium amount will disrupt the rest of your horse’s diet and needs balancing.


  • Then look at your horse’s concentrates, fortified feeds, or “grains.” It’s challenging to find low NSC values. Aim for finding a feed lower than 10%.


  • You have the option of using a low NSC ration balancer and adding other feeds like beet pulp for calories instead of a fortified feed.


  • Your horse’s meals also need slow and steady delivery. Use slow feeders, both for hay and processed foods. Feed your horse’s “grains” several times a day, after there’s plenty of forage in your horse’s belly.


  • I can’t suggest an equine nutritionist enough. They are affordable, can work remotely, and will create the perfect feeding plan for your horse. Equine nutritionists remove all of the guesswork from your horse’s diet.


Quick video about feeding the horse with ulcers!


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