Understanding Gastric Ulcers in Off-The-Track Thoroughbreds

Understanding Gastric Ulcers in Off-The-Track Thoroughbreds 

Equine Gastric Ulcers are one of the most common health concerns affecting Off-The-Track Thoroughbreds (OTTBs). They are the result of progressive erosion of the lining with the distal oesophagus, stomach and proximal small intestine, caused by gastric acid. They are most often present on the upper lining of the stomach, and at the junction between the upper and lower regions. It can be a painful condition, and have various health implications.  

While ulcers can occur in any horse, Thoroughbreds are particularly susceptible due to the unique management, feeding and training practices associated with racing. In fact, studies have indicated as much as 85-95% of racehorses show some grade of ulceration, with many carrying these ulcers into retirement and retraining. Thus, understanding why ulcers develop, recognising the signs and knowing how to manage them can help support your OTTB’s health and performance. 

Why Are OTTBs More Prone to Gastric Ulcers? 

Unlike humans, horses produce stomach acid continuously, whether they are eating or not. In a natural environment, horses may spend up to 16 hours a day grazing, which provides a constant flow of forage and saliva to help buffer stomach acid. 

Racehorses however, often experience several factors that can increase ulcer risk, including: 

• High-grain, energy-dense diets 

• Periods without access to forage 

• Intensive exercise programs 

• Frequent travel 

• Changes in environment and routine 

• Stabling for extended periods 

• Racing and training stresses 

Even after retirement from racing, many OTTBs remain at increased risk, particularly during the retraining period when management, diet and workload are transitioning. 

Signs, Symptoms and Diagnosis 

The signs of gastric ulcers can vary significantly between horses. Some horses show obvious symptoms, while others continue working despite considerable discomfort. 

Common signs include: 

• Poor appetite or fussy eating 

• Weight loss or difficulty maintaining condition 

• Poor, dull or dry coat quality 

• Changes in behaviour or attitude, particularly more nervous or erratic temperaments 

• Girthiness 

• Development of behavioural stereotypies such as weaving, stall walking or wind sucking 

• Reduced performance 

• Reluctance to move forward under saddle 

• Mild recurrent colic 

• Poor recovery after exercise 

These signs can be an indication but are not necessarily exclusively caused by ulcers. They can be associated with many other health conditions, thus Veterinary advice for a diagnosis and/or prescription treatment is required. The only way to definitively diagnose gastric ulcers is through gastroscopy, which allows your veterinarian to examine the stomach lining and determine the location and severity of any ulceration.  

It is important to note that a prescription drug, such as a Ranitidine or Omeprazole, are the only registered treatments for ulceration. Over-the-counter options can be useful aids and incorporated into management programs, but are not registered “treatments”. Your veterinarian can develop an appropriate treatment plan and monitor your horse’s response throughout recovery. 

Management Strategies to Reduce Future Risk 

Once veterinary treatment has been completed, management and feeding practices play a critical role in reducing the likelihood of ulcers recurring. 

Prioritise Forage Intake: One of the most effective ways to support stomach health is to maximise forage consumption. Chewing forage stimulates saliva production, which helps buffer stomach acid, while also creating a fibrous mat within the stomach that protects the upper regions from acid splash. Where practical, horses should have access to forage for as much of the day as possible. This may be via ad lib pasture or hay access, or the use of slow feeders to extend consumption time of set roughage volumes. At a minimum, a horse should consume 1% of its body weight in roughage per day.  

Feed Before Exercise: Feeding a small amount of hay 20–30 minutes before exercise helps create a protective fibre layer in the stomach, reducing the amount of acid that can splash onto sensitive areas during exercise. This is particularly important for horses undertaking more intensive work which induces a higher splash rate. 

Maintain Consistent Routines: Horses generally thrive on routine, and especially for thoroughbreds, can significantly reduce environment stresses, a notable trigger of ulceration. Keeping feed time consistent, providing regular turnout and social interaction, and making dietary changes gradually, can all assist in both digestive and overall wellbeing

Identifying, treating and managing Gastric Ulcers can be overwhelming, with lost of information and messaging around the topic. Your Veterinarian or an Equine Nutritionist is your best avenue for trusted advice. Book a support call, or get in touch with our team via email if you are looking for assistance in managing equine gastric ulcers.