FAQ Horse Care Other

Gastric Ulcers in Horses 101 (Behavior, Riding, Treatment)

horse ulcers
Written by Pam Levy

Get Well As Your Horse Gets Better: Living with Ulcers

My pony, Stella, is prone to ulcers. We have treated her for gastric ulcers three times in the five years she’s been with us. Ulcers are extremely painful for horses, and until you see the results of an ulcer for yourself, it may be difficult for you to understand how important it is to avoid their development at all costs.

A few years ago, I had barely even heard of the idea of gastric ulcers in horses. If you’d have asked me back then how often ulcers occurred in horses I likely would have answered “I’ve never seen a horse with ulcers.” I had no idea how prevalent they are — the statistics are staggering.

In a nutshell, gastric ulcers in horses are typically caused by chances to feed or routine, lack of turnout, travel, or NSAID medications. Though difficult to notice, at times, common symptoms include decreased appetite, teeth grinding, behavioral resistance, weight loss, and poor body condition. Luckily, there are ways to prevent and treat gastric ulcers.

How often do gastric ulcers occur in horses?

According to UC Davis Veterinary Medicine Center for Equine Health:

Gastric ulcers are common in horses. Their prevalence has been estimated to be from 50% to 90% depending on populations surveyed and type of athletic activity horses are engaged in.

The number seems to be highest in race horses in training (90%), and a little lower in endurance horses and show horses (70% and 60% respectively).

Overall, about one in three horses has ulcers. One in three. To me, this is a horrible statistic, especially since I’ve witnessed the devastating effects of gastric ulcers first hand.

horse with gastric ulcers

My horse Stella (Source: Pam Levy)

What causes gastric ulcers in horses?

  • Typical feeding routines:
    • Horses are designed to eat small meals very frequently, and to be grazing or foraging almost constantly. Many, if not most, horse owners prefer to feed horses two or three times a day, leaving their stomachs empty for hours at a time.
    • This works against the very design of the horse’s stomach, which produces acid twenty-four hours a day. With nothing in the stomach to buffer that acid, gastric ulcers can easily occur.
  • Stall confinement:
    • It is imperative to a horse’s physical and emotional well-being that they are allowed frequent turnout, constant grazing and foraging, and access to other horses.
    • Being confined to a stall for more than a few hours at a time means that these requirements are not being fulfilled and the risk of ulcers increases.
  • Transport stress:
    • It is obvious to any horse person that trailering is one of the most unnatural situations in which we put our horses. Being confined to a small space with limited ability to move is enough to cause stress even in humans.
    • In horses, it has been found that gastric ulcers can occur in as little as a few hours when being transported.
  • NSAIDs:
    • The use of anti-inflammatory drugs like Bute block the production of the chemical in the stomach that decreases acid production. This increases the likelihood of gastric ulcers.
  • Changes in routine:
    • This is true especially of changes in herd structure (i.e. losing a pasture buddy, introduction of a new horse to the herd, change in herd hierarchy, etc), but also includes things like moving to a new stable, going to a horse show, or even an increase in training intensity. All of these things cause stress for a horse, leading to an increased production of stomach acid.
white horse in field

Stella (Source: Pam Levy)

How can you tell if your horse has an ulcer?

Sometimes the signs are obvious. Other times, unless you know your horse very well, you might miss them altogether. Oftentimes the severe pain of ulcers can cause horses to behave in extreme ways, leading owners and trainers to think the horse is being “naughty,” and is in need of re-training or, even worse, punishment.

Any time your horse shows uncharacteristic “naughty” behaviour, first look into whether there could be a pain issue. 

When Stella’s having a ulcer occurrence, we normally see the following symptoms:

  • increased irritability or crankiness with both humans and her herd-mates
  • not wanting to be touched, groomed, have blankets changed, or be fussed with in any way
  • increased spookiness
  • being on “high alert” all the time
  • soft or even runny stools
  • her coat becomes dull, especially on her neck and chest area
  • increased rolling, often followed by rearing (The only time this mare ever rears for any reason, either under saddle or on her own, is when she has an ulcer. It is a tell-tale sign for her.)
  • when touched in the girth area, especially on her left side, she will try to bite you. (Again, for her, this is a tell-tale sign. This is the only time this sweet pony would ever offer to bite.)

Other symptoms of ulcers can include poor appetite, grinding of the teeth, resistance to training, weight loss, reluctance to finish their grain, and poor body condition.

It is interesting to note that none of these last symptoms have ever been seen in Stella. This could be partly due to the fact that she does not eat grain, but it just goes to show that the typical picture of the “skinny” ulcer horse is not always an accurate one. Stella has never lost weight during any of her three battles with ulcers.

The only definitive way to positively diagnose gastric ulcers is through gastric endoscopy (commonly referred to as “scoping”).

Because most vets do not have access to the equipment required for scoping, and due to the stress caused by having to travel hours to the nearest facility (which, in itself, could cause an ulcer or worsen the current condition), some vets will forego this option.

If relatively certain through examination that ulcers are the culprit, they may begin treatment for ulcers without scoping. This is what we have done with Stella all three times — and each time, the symptoms disappeared with treatment, confirming our suspicions.

How can we treat ulcers in horses?

If you suspect an ulcer, call your vet immediately. Contrary to popular opinion, there is no “natural” treatment for ulcers. This is a very painful and potentially dangerous situation, and it must be addressed by a veterinarian as quickly and effectively as possible.

This is not the time for trial-and-error or a wait-and-see approach.

We treated each of Stella’s three ulcer outbreaks with GastroGard, which is a brand name for the proton pump inhibitor omeprazole. There are other recognized treatments such as ranitidine and cimetidine, which are histamine type-2 receptor antagonists, and some people claim to have found relief for their horses with sucralfate (although studies have not conclusively shown that sucralfate is particularly useful in healing gastric ulcers in horses).

No matter which treatment you choose, please be sure to follow your vet’s instructions to the letter, especially when it comes to length of treatment, and weaning off the medication. Coming off omeprazole takes a long time, and painful rebound effects will be your horse’s punishment for your not having followed the correct weaning protocol.

Prevention is the Best Medicine

Having dealt with the devastating effects of gastric ulcers, I am a firm believer in doing everything humanly possible to prevent them from happening in the first place. For Stella, this meant first, changing everything about her current lifestyle, and second, putting some protocols in place to keep the ulcers at bay.


Click to stock up on Ulcergard to help prevent ulcers

Because one of the most common causes of ulcers is a faulty feeding routine, our first change involved Stella’s hay routine. From the day she was diagnosed, we have followed one simple but non-negotiable rule: free choice hay 24/7. Luckily for us, Stella’s not one to gorge herself on hay.

We noticed that she didn’t really eat any more hay once she had constant access to it than she did before. But having it available at all times takes away the stress of wondering where her next meal is coming from, along with providing a fairly constant buffer from stomach acids.

(As an interesting aside, even our horses who do are not ulcer prone found great benefits, both physically and mentally, in having ad-lib hay).

The next change we made for Stella was to move her out of the busy training/lesson barn where I was boarding her, to a friend’s breeding farm, where the horses lived out as a herd in lovely big fields with access to cozy shelters. Stella began to thrive in this environment, so when we bought our own farm and built our own barn and paddocks, we made sure to keep to the same set-up.

All of our horses have constant access to the paddocks, and can always make a choice between being indoors or out.

I also made a big change to Stella’s training routine. We now keep our work as stress-free and low-key as possible. This means fewer trips off the property to shows and clinics, shorter training sessions and more days off. This year, instead of heading off to shows or trailering out for lessons, I’ll be exploring the world of online dressage competitions, and video-lessons with my coach.

Frequently Asked Questions

Chief Rookie Aside: We’ve added a few FAQs to continue your education about gastric ulcers. 

How do you treat gastric ulcers in horses?

The only approved FDA medication for ulcer treatments or prevention is omeprazole. There are two omeprazole products in the United States—UlcerGard and GastroGard. Omeprazole works to destroy the acid pumps in the stomach and should be administered once a day. It is broken down by stomach acid, and must be protected to be effective.

Manufacturers formulate omeprazole into a buffered paste or coated granule; simply purchasing powered omeprazole from a compounding pharmacy will not be effective in treating ulcers.

Another method to treat ulcers is adding sulcralfate, a medication that coats the stomach. This works in conjunction with omeprazole, but increases treatment cost. Including alfalfa hay in the diet can be helpful for horses with ulcers, as alfalfa hay is high in calcium which acts as a buffer in the stomach. Increasing the number of feedings per day and minimizing the amount of grain fed can also help combat ulcers.

What are the symptoms of gastric ulcers in horses?

Most horses with ulcers do not exhibit outward symptoms; instead, symptoms are more subtle: decreased appetite, a poor hair coat, weight loss, poor performance, behavioral issues or changes in attitude, and low-grade colic.

The only way to know for sure if your horse has ulcers is for your vet to perform a gastroscopy. To do this, your vet will sedate your horse and put a tiny camera up the nostril, down the esophagus, and into the stomach.

It will be easy to see if the horse has ulcers using this procedure. Treating ulcers is expensive—a gastroscopy is a worthwhile procedure to consider before medication.

How long does it take for a horse to recover from ulcers?

Most horses affected with ulcers have a good prognosis. With proper treatment, ulcers can heal in approximately four weeks. It is important to consider the root cause of the ulcers and address it to prevent recurrence.

What do you feed a horse with stomach ulcers?

If your horse has ulcers, you should re-evaluate not only the type of feed you are providing, but also feeding times. Horses are grazing animals; their digestive systems are designed to process forage in small quantities throughout the day. A twice-daily diet of hay and grain was created by humans, based on convenience. Ideally, a horse would be fed four times a day at approximately 6 hour intervals.

Alfalfa hay is beneficial for horses with ulcers, as it has a higher calcium content than grass hay. Calcium has a buffering effect on stomach acid. Grain can also contribute to ulcers; while it may be needed for to maintain body condition, feeding smaller quantities of grain can be helpful.

Do ulcers in horses go away?

Ulcers are caused by a combination of stress and environment; they are very common in both performance and racehorses. Even trailering or training can be stress-inducing enough to cause ulcers. If the root cause is determined and the ulcers treated, they can heal, but it is important to address the cause and work to manage it as best you can.

For example, if you have a show horse that is fed twice a day, try to spread out the same amount of feed over 3 meals per day. If you only feed grass hay, add in some alfalfa hay. If you will be trailering to a horse show, consider using a preventative dose of UlcerGard or GastroGard during that high-stress times.

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About the author


Pam Levy

Pam Levy is an equestrian blogger and the creator of The Horse and Human Wellness Project, a blog that chronicles her quest to create a stronger connection with her horses. Pam has been riding since she was seven, and in love with horses for as long as she can remember. These days, she’s living her dream on the small farm she owns with her husband in rural Nova Scotia, on Canada’s east coast. Their herd includes three horses (Sunny, Stella and Q) and two cats (Jack and Arthur).