Top tips for preventing equine ulcers

Feeding a species-appropriate diet and taking steps to reduce your horse’s stress can lower his chance of developing a gastric ulcer.

Have you ever heard the phrase “You’re giving me an ulcer”? Basically, it means “you’re stressing me out!” Though we joke about it, research shows that stress really does lead to ulcers in horses.1 In fact, gut disease is an epidemic issue among horses, and studies confirm that between 80–90% of performance horses have gastric ulcers.2,3 Let’s take a closer look at what equine ulcers are and what steps you can take to prevent them.

Know the symptoms

Horses with ulcers can be asymptomatic or may show clinical signs depending on the severity. Symptoms can include:

  • hard keepers
  • dull coat
  • low energy
  • diarrhea or dry manure
  • gut pain (e.g. grumpy faces when the girth is being tightened)

Ulcers are also associated with other gastrointestinal issues, mainly colic. A study of 111 horses published by the Journal of the America Veterinary Association showed that 91 of the 111 horses had gastric ulcers and of those 91 horses, 83% of them were confirmed to have recurrent colic.4

So what can we do to protect our horses, reduce their stress, heal their guts, and prevent this heartbreaking disease from affecting them?

Understanding the causes of gastric ulcers in horses

1. Physical and mental stress

Stress has been scientifically proven to be a major contributor to ulcers in horses. Researchers have identified tangible connections between ulcers and common stressors such as lack of turnout, lack of social interaction, sudden changes in routine or housing, horses that are handled by a number of different caregivers and/or riders, horses who go for long periods without eating (more than six hours) and those who have diets that do not resemble natural forage.5,6

2. Muted social interaction

Regular turnout reduces the risk of ulcers, especially turnout with other horses.6 What this shows is that it’s not just the act of eating that reduces the risk of gut disease; it’s also the social interaction. Animals that cannot express themselves socially through movement, mutual grooming, and grazing with others have higher stress levels.

3. Regular use of non-steroidal anti-Inflammatory drugs (NSAIDs) 

The regular use of NSAID drugs such as phenylbutazone (otherwise known as Bute) and meloxicam has been indicated as a risk factor for gastric ulcers.7,8 NSAIDs destroy the protective mucosal lining of the digestive tract, which is where all the healthy bacteria live. The microbiome is a major part of the mammalian immune system, so damage to it can cause immunological chaos. Gut damage can cause inflammation all over the body – in the joints, ligaments, skin, hooves, and almost anywhere else, depending on the individual predisposition of the horse. NSAIDs are not meant for long-term use.

There are better ways to reduce inflammation in your horse’s body. Drugs are not the only solution to inflammatory reduction and there are non-invasive, preventative measures that you can use to help your horse stay ulcer and inflammation-free. Furthermore, prevention is much more powerful than damage control.

4. Grain and soy in the diet

Starchy grain feeds and extruded feeds are high in hydrolysable carbohydrate, which is quickly digested into sugar. Horses are highly sensitive to excess dietary sugar. Given excessive access to grain concentrates is associated with a number of common equine diseases including:9,10

  • ulcers
  • gastric pH and microbiome imbalance of the cecum and the colon
  • insulin resistance
  • obesity
  • laminitis
  • chronic founder
  • development of orthopedic disease
  • Cushing’s disease

Avoid industrial, starch-heavy feeds in your horse’s diet. There are a number of alternatives that can help improve and maintain your horse’s energy and body condition.

Soy is another no-no when it comes to equine nutrition. Typically, soy is heavily sprayed with Round-Up (glyphosate), a poisonous pesticide that, when inhaled or ingested, is known to cause ulcers. It’s also indicated in gut disease, neurological diseases and cancer in humans.11

Prevention tactics

Preserving the health of your horse’s gut is important for preventing colic and ulcers, as well as other common equine diseases. So now that we understand how lack of movement, unnatural feeding methods, and stress are detrimental, how do we prevent disaster? The answer is simple – by creating a life for your horses that aligns with how their bodies and minds evolved over millions of years.

Mental and emotional equine stress reduction 

Turnout (forage, friends and dirt!)

Turnout has multiple benefits for horses. It increases low-impact movement, promoting healthy gut motility and blood circulation. This increases nutrition and oxygen to the cells and creates a healthy vascular environment throughout the entire body, including the gut.

Grazing time gives horses access to fresh forage (if pastures are properly managed), increasing access to important omega-3 fatty acids. Omegas-3s are important inflammatory modulators, meaning they help control inflammation in the body. They are indicated as important dietary nutrients for preventing gut disease (IBS), insulin resistance, and reducing the risk of equine metabolic disease and osteoarthritis.12 Horses need access to pasture forage or other whole foods in order to get enough omega 3s.

Freedom is a major factor in stress reduction because it allows horses to behave naturally. The first thing many horses do when they’re turned out is roll, since it’s hard for them to do this comfortably in confined quarters. Being able to roll, run and interact however they wish promotes relaxation and reduces stress.

Last but not least, turnout gives your horse access to dirt! Thousands of microbes that are necessary for a healthy gut microbiome live in the soil. Microbes in the digestive tract are the mechanism for fermentation of plant material that allows the horse to absorb important nutrients from those plants. Without them, your horse may develop nutritional deficiencies, even if you are feeding the best of everything.

Removing access to soil may even decrease a horse’s ability to handle stress. A 2019 study revealed that a soil-derived bacteria called Mycobacterium vaccae produces a novel polyunsaturated fatty acid that reduces immunological and nervous system inflammation and anxiety/fear-related defensive behavioral responses.13 This fat was also recognized for reducing symptoms of inflammatory bowel disease in humans. This is only one bacteria of possibly thousands found in soil that could have positive outcomes for your horse. If you take away their access to dirt, you take away their ability to develop and maintain their gut flora, their immune system, and even their mental well-being.


If you have a good connection with your horse, he’ll view you as part of his social network. Healthy human/horse interactions not only reduce the horse’s stress levels, but ours as well. A good connection can also help you assess your horse’s stress load. If you have a horse with recurring health or behavioral problems, it’s important to assess his overall stress levels. This is often best done with the help of a professional equine behaviorist. Getting back to the basics of ground work, calming exercises, and connected riding is important for assessing his mental and physical stress levels.

Dietary support for ulcer prevention

Species-appropriate diet

A diet with high-quality hay as the base is fundamental for gut health in horses. If you’re using processed feed, turf it and go with high-fiber whole foods, species-appropriate fat and protein sources, and food-based vitamins and minerals. Keep alfalfa to a minimum (make sure it’s organic) and find high quality (no spray) timothy and/or orchard grass hay. Be sure it has been analyzed so you know the quality and nutrient profile.

Feeding with frequency

Horses need to eat at least every six hours to avoid ulcer risk. If your horse consumes his hay very quickly, use a slow feeder or a hay net to slow him down and simulate grazing more accurately. Turn him out or hand graze them on well-managed pasture as much as you can.

Omega 3 fatty acids

Omega 3 fatty acids are essential in reducing inflammation in all tissues of the body, especially the gut, joints, ligaments, and nervous system. However, they are lacking in most equine diets. Horses have the ability to create their own omega 3s when the microbiome is functioning correctly, but with so much gut damage occurring, it’s hard to say how well this mechanism is functioning. Flax, chia, camelina and ahiflower are all environmentally sustainable, equine-appropriate sources of Omega 3s that can be given in small amounts with great gut-protective benefits.


All stable-kept horses should be on good quality probiotics. If they aren’t able to access grass and dirt, they need to get their probiotics from somewhere else. Remember, not all probiotics are equal. Make sure you use several (over 10) strains at a time and offer a high quality prebiotic as well (not sugar-based or cellulose-based). Equine-specific probiotics have additional health benefits for horses including:

  • proven tolerance to gastric acid, bile, and digestive enzymes pepsin and pancreatin
  • proven adherence to equine intestinal epithelial cells (important as this allows colonization and proliferation)
  • proven ability to produce bacteriocins to inhibit pathogens including E. coli, Salmonella enterica, Listeria monocytogenes, Clostridium perfringens, among others
  • proven ability to positively impact the immune system (cell mediated and humoral immunity)


Not only do good quality herbs contain vitamins and minerals, they are also fantastic prebiotics. Choosing the right herbs for your horse may require help from an equine herbalist or nutritionist, but some gut-restorative herbs you can start with are aloe vera, marshmallow root, peppermint, and chamomile.


If you suspect ulcers in your horse, L-glutamine is a must. It’s well recognized for repairing the gut mucosal lining where the good bacteria live. If you’re giving probiotics, L-glutamine should also be included to ensure the bacteria have a home. Ulcers happen when there is a destruction of the mucosal lining and L-glutamine can help to repair it without the side effects of drugs. L-glutamine is found naturally in foods like cabbage, carrots, and Brussels sprouts.

If you’re struggling with your horse’s gut health, a better understanding of equine ulcers is the first step in prevention!


1Veterinary Medicine (Auckland, New Zealand): Equine glandular gastric disease: prevalence, impact and management strategies (2019)

2Equine Sports Medicine and Surgery – Equine Gastric Ulcer: A Review – Nanna Luthersson, Jenifer A. Nadeau (2013)

3Journal of Equine Veterinary Science – Results of a large-scale necroscopic study of equine colonic ulcers – Pellegrini (2005)

4Journal of the American Veterinary Assopciation: Gastric Ulceration in Horses: 91 cases (1987-1990)

5European College of Equine Internal Medicine Consensus Statement: Equine Gastric Ulcer Syndrome in Adult Horses (2015)

6Journal of Veterinary Internal Medicine: Management factors and clinical implications of glandular and squamous gastric disease in horses (2019)

7Canadian Veterinary Journal: Prevalence of and risk factors for equine glandular and squamous gastric disease in polo horses (2018)

8Journal of Internal Veterinary Medicine: Effects of Meloxicam and Phenylbutazone on equine gastric mucosal permeability (2012)

9Journal of Equine Veterinary Science: Effect of feed processing method on daily gain and gastric ulcer development in weanling horses (2011)

10Middle Tennessee State University: Carbohydrate metabolism and metabolic disease in horses (2009)

11Glyphosate: Pathways to modern diseases 3. Manganese, neurological disease and associated pathologies. (2015)

12Colorado State University Department of Animal Science: Omega 3 fatty acid supplementation in horses (2014)

13John Hopkins University: Identification and characterization of a novel anti-inflammatory lipid isolated from Mycobacterium vaccae, a soil-derived bacterium with immunoregulatory and stress resilience properties (2019)

14The Professional Animal Scientist: Markers of inflammation in arthritic horses fed omega 3 fatty acids (2009)