It’s difficult to go anywhere online (and probably off) where people are talking about horses without having something come up about hind gut ulcers, symptoms and treatments. There are even commercial supplements out there from companies who should know better. There is no such thing as “hindgut ulcer syndrome” that is a correlate of gastric ulcer syndrome, and certainly no cause that a supplement would correctly treat.

It is not unusual today to hear people claiming 60%-65% of horses have hind gut ulcers. However, if you read medicine, surgery and pathology textbooks or other published literature there is no mention of this widespread “hindgut ulcer disease”. It isn’t even mentioned in the horse health articles for owners on AAEP.org.

When ulceration (an open sore or erosion in the lining of the intestine) occurs it is inevitably linked to tapeworm (or bots in the stomach) attachment sites, migration and emergence of small or large Strongyle larvae, or exposure of the lining to NSAIDs (usually phenylbutazone, or some caustic substance like arsenic).

Severe inflammation secondary to pathogenic bacteria or extreme acidosis caused by grain overload or massive doses of pure fructan can also cause this, but the entire lining of the organ is compromised and such horses are obviously very ill with fever, colic, diarrhea, sepsis and laminitis. Another potential but relatively rare cause of inflammation and erosion is autoimmune bowel disease.

You may read that this “breakthrough finding” of widespread colonic ulceration was made during a University autopsy study. In fact, it was a cursory inspection of the digestive tracts in a slaughterhouse by the owner of a supplement company. Any abnormality of the lining, regardless of size, depth, appearance, etc., was called an ulcer.

No history was available on the horses, including phenylbutazone use, but it is well known that large doses are routinely used in slaughter horses in hopes of making them sound enough to bring better than kill price. No deworming history. No diet history. All horses below a certain age were called “performance horses” regardless of breed and history. Presence of parasites was not recorded. No blood tests for drugs. No cultures for pathogenic bacteria. No pH/acidity testing. No microscopic sections (helpful because cell types give clues as to cause). No pathologist.

Disturbances of the hind gut/large intestine definitely exist but the correct treatment is to find the cause and correct it.

Intricately woven into this story of hind gut ulcers is the idea of colonic acidosis. As above, feeding very large amounts of grain or pure fructan can cause a cecal acidosis severe enough to damage the intestinal lining but it is also true you can feed as much as 6 lbs of whole barley, whose starch is poorly digested and passes into the large intestine, with no change in pH or digestive upset. As a general rule, pH has to get below 6 to cause damage to the intestinal lining as detected by increased bacterial products circulating in the blood. However, feeding as much as 13 lbs. of sweet feed does not decrease pH below 6.

All horses with overload of rapidly fermentable, lactate yielding carbohydrate in their hind gut have at the very least obvious “cow plop” diarrhea and are off feed.

Despite all this, even horses predominantly or entirely on hay diets are being diagnosed with hind gut ulcers based on vague and totally nonspecific symptoms such as “not liking their flanks touched” or dragging their toes. They are being treated with the goal of neutralizing acidity in their hind gut. Some are even given medications to stop acid secretion in the stomach despite the fact there are no acid secreting cells in the hind gut. One extremely pricey supplement contains only low doses of ingredients that would be digested and absorbed before they reached the hind gut.

Disturbances of the hind gut/large intestine definitely exist but the correct treatment is to find the cause and correct it. “Hind gut ulcers” is not a real disease.

 

All articles are for informational purposes only. Opinions expressed are not necessarily endorsed by Horse Network. Contact your local veterinarian if you have any questions regarding the health of your animals.


About the Author

Eleanor Kellon is the Staff Veterinary Specialist for Uckele Health and Nutrition. Dr. Kellon also offers private nutritional consultations and online courses through Equine Nutritional Solutions. Find out more at www.drkellon.com.