Colonic Ulcers in the Dressage Horse

Recent research developments are shifting some of the focus from gastric ulceration to hindgut ulceration

While gastric ulcers have been a popular topic of discussion, it might be time to start thinking a little differently as recent research developments are shifting some of the focus from gastric ulceration to hindgut ulceration, and what’s more, it’s surprisingly prevalent. 

It has been well accepted that performance horses are at a greater risk of gastric ulceration than their more sedentary counterparts. (Credit: o_sa)

For dressage riders, any change in a horse’s temperament or performance will almost always be noticed. However, the explanation of why this has happened may be less obvious. With a little lateral thinking and knowledge, we can learn to spot the signs of colonic ulceration and understand why this can be so important for the health and performance of our horses. 

Ulceration Beyond the Stomach

Horses have evolved over millions of years to survive on a fiber-rich diet accompanied by a low-stress lifestyle. However, this low-stress lifestyle is in stark contrast to that of today’s elite athlete, who is at significant risk of gastrointestinal disease, including ulceration. 

It has been well accepted that performance horses are at a greater risk of gastric ulceration than their more sedentary counterparts, and much research has been directed at the causes, management and treatment for gastric ulceration. However, comparatively little has been afforded to digestive disorders beyond the stomach. Since the introduction of gastroscopy 30 years ago, visualizing the presence and assessing the severity of gastric ulcers has become an easy and somewhat routine procedure. Our ability to see ulcers in the stomach of the horse makes the issue a reality for us. 

But what if, due to the location of the problem, we can’t see those issues? Does that mean they don’t exist? In 2005, Franklin Pellegrini, DVM, demonstrated in extensive cadaver studies that colonic ulcers are highly prevalent in competition horses and can also often be found concurrently with gastric ulceration. 

More recently, work being undertaken by Derek Knottenbelt, OBE, BVM&S, at the University of Glasgow vet school in Scotland, is helping to shift even greater attention toward intestinal disease, its prevalence and significance. In 2015, Knottenbelt reported that even apparently asymptomatic horses have significant evidence of large-bowel disease.

Recognizing Colonic Ulcers 

When it comes to medical conditions of the horse’s hindgut, diagnostic techniques available to veterinarians are limited. At this point, no endoscope can visualize the hindgut. Therefore, our veterinarians are left with interpreting blood and biopsy results and evaluating ultrasound images, clinical signs and symptoms in order to reach a diagnosis. Furthermore, symptoms of digestive disorders can often match those of other conditions, compounding an already difficult task. 

As riders, we can utilize what we feel under saddle to help recognize the signs of a health condition in the horse, especially a GI-tract issue. What we feel may relate to some degree of discomfort emanating from the abdomen and flanks. This might manifest as struggling to extend and collect, reluctance to accept the leg aids, frequent tail swishes, finding it difficult to flex over the back, engage the hindquarters or bend through the body (particularly to the right) or a general drop in performance and willingness to work. From the ground we might see negative changes in temperament, sensitivity to blanketing, girthing or brushing, loss of condition and weight or diarrhea. Sadly, many of these performance related red flags are often misinterpreted as bad behavior, particularly when clinical signs are vague. 

The GI tract is more than just the stomach, and any assessment should be comprehensive enough to investigate both gastric and hindgut disturbances. Early differential diagnosis is important for many reasons.

Gastric and colonic ulceration require different treatments so it is crucial to know where the issue originates. Management and dietary practices that mirror the horse’s natural behavior will help to potentiate any treatment plan and form the basis for future prevention. Limiting starch and sugar and providing smaller, more frequent meals can all help, as will increasing turnout to help limit stress. Specific nutritional support directed to the structure and function of the digestive tract may be useful.

When our horses are telling us something is not right, we need to stop and think. Apply a little empathy, consider the digestive system—not just the stomach, but the hindgut as well—and, perhaps most importantly, trust your instincts. Peak performance can only be achieved in the happy, healthy horse, both inside and out.

Emma Hardy, PhD, has been European Manager for Freedom Health LLC since joining the company in 2009. She earned a bachelor of science in equine sports science at the University of Lincoln in England and was later accepted into a research internship program with Kentucky Equine Research, USA. Upon returning to the United Kingdom, she undertook her doctor of philosophy also at Lincoln. She lives on the North Devon coast with her husband and two sons.






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