Feeding Ulcer-Prone Horses: Diet & EGUS Management

Gastric ulcers are common in horses, particularly those in regular work, travelling, competing or spending significant time stabled. While ulcers usually require veterinary diagnosis and treatment, feeding and management play an important role in reducing risk and helping to prevent recurrence.

For an ulcer-prone horse, the goal is not simply to find an “ulcer feed”. Instead, the whole feeding program should be designed around the way the equine digestive system naturally functions: frequent forage intake, plenty of chewing, limited periods with an empty stomach and controlled amounts of starch.

What is EGUS?

Equine Gastric Ulcer Syndrome (EGUS) is an umbrella term for disease involving ulceration or erosion within the horse's stomach and, in some cases, nearby structures. Importantly, EGUS is not one single disease. The two main forms are:

Equine Squamous Gastric Disease (ESGD) affects the upper, non-glandular or squamous region of the stomach. This area has relatively little protection against gastric acid. Acidic stomach contents can come into contact with the squamous lining, particularly during exercise or when the stomach is relatively empty.

Equine Glandular Gastric Disease (EGGD) affects the lower glandular portion of the stomach. This region normally has protective mechanisms including mucus and bicarbonate. Glandular disease appears to involve disruption of these protective mechanisms, and its causes are less clearly understood than those of ESGD.

This distinction matters because feeding practices are particularly important in reducing the risk of squamous disease, while glandular disease may have a more complicated relationship with factors such as stress, exercise and individual susceptibility.

Why does feeding matter?

Unlike humans, horses continually produce gastric acid. Their digestive system evolved around spending much of the day grazing and consuming relatively small amounts of fibrous material.

Chewing forage stimulates saliva production, and saliva helps buffer acidity. Fibre also helps create a physical mat within the stomach that can reduce the movement or “splashing” of acidic contents into the vulnerable upper portion of the stomach.

Problems can arise when horses are managed very differently from this natural feeding pattern. Risk factors for EGUS include high-concentrate diets, restricted forage, intermittent feeding, intense exercise, transport, confinement and other forms of environmental stress.

Make forage the foundation of the diet

Forage should be the starting point when designing a diet for an ulcer-prone horse.

Where appropriate, horses should have access to pasture, hay or other suitable forage for as much of the day as possible. Long periods without forage should be avoided. Research has associated lower forage intake and fewer meals with an increased prevalence of gastric ulceration.

As a general guide, at least around 1.5% of bodyweight per day as forage dry matter is commonly recommended as a minimum for long-term digestive health, although many horses will appropriately consume closer to 2% or more depending on their condition and requirements.

For a 500 kg horse, 1.5% of bodyweight represents approximately 7.5 kg of forage dry matter, meaning the actual weight of hay fed may need to be higher because hay contains some moisture.

Slow-feed hay nets can be useful for horses that consume hay rapidly, provided they allow the horse to maintain sufficient overall forage intake.

Consider including lucerne

Lucerne can be particularly useful in feeding ulcer-prone horses.

Lucerne is naturally relatively high in calcium and protein, which gives it a greater acid-buffering capacity than many grass hays. Veterinary guidance recognises lucerne hay as a useful component of dietary management for gastric ulcers.

This does not necessarily mean the entire forage ration needs to consist of lucerne. Providing some lucerne hay or chaff alongside a suitable grass hay can be a practical approach.

A small amount of lucerne or other fibrous feed before exercise may also help ensure the stomach is not completely empty during work. Exercise increases abdominal pressure and can push acidic stomach contents upward towards the squamous portion of the stomach.

Keep starch intake under control

Large grain meals are one of the most important dietary considerations for ulcer-prone horses.

Higher intakes of sugars and starch have been associated with an increased risk of EGUS, particularly when concentrates are fed in large individual meals.

It is generally recommended that horses should receive no more than approximately 1 gram of starch per kilogram of bodyweight per meal and no more than 2 grams per kilogram per day.

For a 500 kg horse, this means keeping starch below approximately 500 g in any individual meal.

It is important to remember that this refers to starch content, not simply the weight of the feed.

Rather than relying heavily on cereal grains such as corn, barley or wheat to provide energy, many ulcer-prone horses are better suited to feeds that derive more of their calories from digestible fibre and fat.

Depending on the individual horse, suitable ingredients may include:

• beet pulp

• soy hulls

• lupins

• quality forage and forage-based feeds

• stabilised oils or high-fat feeds

• low-starch commercial horse feeds

• low-intake vitamin and mineral balancers where additional calories are not required.

If a horse needs a substantial quantity of concentrate feed to maintain weight or support performance, dividing it into several smaller meals is preferable to feeding one or two very large meals.

Avoid leaving the stomach empty

Meal timing is just as important as the feed itself.

Long periods without eating mean less saliva is entering the stomach and there is less fibrous material available to help buffer and physically contain the acidic contents.

This makes overnight management particularly important. A horse that receives its last hay at 6 pm and has finished it by 9 pm may potentially spend much of the night without forage.

Providing sufficient forage, using slow feeders where appropriate and spreading forage allocations across the day and night can help reduce these prolonged fasting periods.

Don't forget water, turnout and stress

Feeding cannot be separated from management.

Fresh water should always be readily available except when temporarily withheld under veterinary direction. Turnout, opportunities to forage and appropriate social contact may also benefit horses that become stressed by prolonged confinement.

Transport, competition, changes of environment and increased training intensity can all coincide with increased ulcer risk. 

Particular attention should also be paid to feeding routines during these periods rather than allowing travel or competition schedules to result in long periods without forage.

What about ulcer supplements?

There are many supplements marketed for gastric health containing ingredients such as pectin, lecithin, calcium, magnesium, sea buckthorn, aloe vera or various buffering compounds.

Some may have value as part of an overall management program, but they should not be considered substitutes for adequate forage, appropriate concentrate feeding or veterinary treatment.

Feeding management supports treatment — it doesn't replace it

Possible signs of gastric ulcers can include reduced appetite, poor condition, mild recurrent colic, behavioural or attitude changes and reduced performance. However, these signs are nonspecific and can occur with many different conditions.

Gastroscopy remains the definitive method of diagnosing gastric ulcers, and identifying whether a horse has ESGD, EGGD or both can influence treatment.

Medication such as omeprazole is commonly used under veterinary direction, but simply treating the existing ulcer without addressing the horse's underlying feeding and management may leave the factors that contributed to the problem unchanged.

For the ulcer-prone horse, think forage first, frequent feeding and controlled starch. Provide plenty of opportunities to chew, minimise unnecessarily long periods without food, consider incorporating lucerne, choose fibre- and fat-based energy sources where suitable, and divide concentrates into small meals.

There may be no single feed that guarantees an ulcer-free horse, but a well-designed feeding and management program can create a stomach environment considerably better suited to the horse's natural digestive physiology — and form an important part of reducing the risk of EGUS returning.

This article provides general educational information only. Horses with suspected or previously diagnosed gastric ulcers should be assessed by a veterinarian, and feeding programs should be tailored to the individual horse's workload, body condition and health requirements.