Dealing with Chronic Diarrhea in Horses

Chronic diarrhea can be very frustrating for horse owners and veterinarians to treat. An equine nutritionist offers advice for handling these challenging cases.

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thin chestnut horse grazing in field
Chronic diarrhea can cause a horse to lose weight if not handled quickly. |

Q: My horse has chronic diarrhea, and my veterinarian and I have found a formula that has been relatively successful in controlling it. However, he is still not digesting his hay well. Do you have any recommendations to better my gelding’s digestive system?

A:  It sounds like you have been dealing with this issue for a while and have your veterinarian involved, which is what my first recommendation would have been. Diarrhea is a sign of an intestinal disorder that causes fluid manure. If the large intestine isn’t working properly, its ability to absorb water is compromised, causing this excess water to be released in the manure. Your veterinarian has likely eliminated any serious problems as the cause, and unfortunately it is often difficult to determine the cause of chronic low-grade diarrhea.

You might want to try adding a supplement that contains prebiotics because these supplements are designed to support the health of the hindgut and promote production of beneficial bacteria in that region. Common prebiotics include psyllium and yeast products.

You should also evaluate the diet with an equine nutritionist and make any necessary adjustments. Feeds high in nonstructural carbohydrates or easily digested sugars are not recommended for these horses and should be eliminated if possible. Introducing some different fiber sources might also help. Unmolassed beet pulp shreds can be beneficial because they contain structural carbohydrates, which are digested in different parts of the intestines. This can help eliminate diarrhea in some cases. Soaking the beet pulp in water can help with your horse’s hydration status as well.

You could also consider adding a chopped forage product to increase the variety of nonstructural carbohydrates. Working with a qualified equine nutritionist can ensure the diet meets all your gelding’s nutritional requirements. Horses with diarrhea are sometimes lacking in nutrients. A malfunctioning hindgut can indicate some nutrients are not being absorbed.

Cases of chronic diarrhea can be frustrating because there is no single definitive diagnosis. Much of the treatment for chronic diarrhea is “trial and error,” since no single treatment or product works for every horse, and sometimes treatments stop working well. Products like prebiotics and probiotics fall into the category that I often call “it can’t hurt and might help,” so they are always worth a shot.

Good luck with trying to find the cause of your horse’s diarrhea and in treating it. Keep your veterinarian involved, especially if you notice changes in the appearance of your horse’s feces, and have an equine nutritionist evaluate your diet for nutrient content. As always, be sure to provide fresh water at all times since horses can become dehydrated easily when water is not being absorbed properly in the hindgut.


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Written by:

Janice L. Holland, PhD, is an Associate Professor and Director of Equine Studies at Wilson College in Chambersburg, Pennsylvania. A graduate of both Penn State and Virginia Tech, her equine interests include nutrition and behavior, as well as amateur photography. When not involved in horse activities she enjoys spending time outdoors enjoying nature.

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