Equine gastric ulcers are extremely common, especially in performance horses. But ulcers can also occur in the horse’s hindgut and have negative consequences for digestive health.

Hindgut ulcers are also known as colonic ulcers. Veterinarians often refer to the condition as right dorsal colitis (RDC) since most hindgut ulcers occur in this region of the large intestine.

Hindgut ulcers are less common than gastric ulcers, but have been reported to affect 44 – 63% of horses. [4] It is also possible for a horse to have both gastric and hindgut ulcers at the same time.

Horses affected by hindgut ulcers may experience decreased performance, weight loss, reduced appetite, diarrhea, recurrent colic or a rough coat.

Colonic ulcers can be caused by stress, hind gut acidosis, use of non-steroidal anti-inflammatory drugs (NSAIDs), parasites and other disturbances to the gut microbiome. Dietary management plays a key role in preventing hindgut ulcers from recurring and in supporting the healing of the intestinal lining.

Equine Hindgut Ulcers | Mad Barn Canada

The Importance of the Horse’s Hindgut

To understand the impact hindgut ulcers can have on the horse, it’s important to start with the basic anatomy and physiology (or function) of the hindgut. The hindgut is composed of the cecum, large colon, and small colon. In horses, the large colon is quite large, and can be subdivided into several regions- left ventral colon, right ventral colon, right dorsal colon, and left dorsal colon.

Horses evolved to have such large, specialized hindguts because they are herbivores that digest their food via fermentation in the hindgut. Therefore, when the function of the hindgut is impaired, it can have wide-ranging impacts on the health and well-being of your horse.

When feed moves through the horse’s digestive system, the stomach and small intestine produce enzymes that start to break down the feed. Simple sugars and amino acids are mostly absorbed in the small intestine.

But fibre makes up a huge portion of the horse’s diet and it does not get digested in the small intestine. Horses cannot break down fibre without the help of microbes in the hindgut.

Bacteria, yeast and other microorganisms digest fibre through a process known as fibre fermentation. This process provides the horse with energy, volatile fatty acids, vitamins, minerals, and amino acids necessary for good health.

These nutrients are then assimilated through the intestinal wall for utilization in the horse’s body. A healthy intestinal wall provides a protective barrier that allows nutrients to be absorbed, but doesn’t allow toxins and microbes to enter the bloodstream.

If this barrier becomes damaged by ulcers or compromised by leaky gut syndrome, harmful substances can cross into the bloodstream and can lead to infection and disease.

Gut disturbances have been linked to a wide range of equine health concerns, including insulin resistance and equine metabolic syndrome, laminitis, and colic. [1] [2] [3]

When hindgut health is compromised, a horse may also have trouble absorbing important nutrients. This can result in poor coat and hoof condition, reduced immune function, and a change in behaviour.

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Equine Hindgut Ulcers

Hindgut ulcers in horses occur when there is erosion