What to do when your horse has the runs…

Hey there, time traveller!
This article was published 18/12/2019 (2093 days ago), so information in it may no longer be current.

Horses can get diarrhea, just like all other creatures, and we see cases of it year-round.
Horses are particularly sensitive to diarrhea as it can quickly dehydrate them and result in systemic illness and in some cases death.

Diarrhea is any form of loose manure. In its severe variety, it has been described as ‘hosepipe’ as it can become pure liquid and shoot straight out. Signs of diarrhea are weight loss, loose or watery manure, depression, feces wetting the tail, straining to defecate and a poor hair coat. Diarrhea occurs when there is inflammation of the intestinal tract. The most common location is the large colon, which in horses is a significant component of the intestinal system compared to other animals.

When there is inflammation or infection of the colon, there is decreased absorption capacity and ability and the colon wall will begin ‘leaking’ body fluids back into the colon which contributes to dehydration of the body overall. With all this fluid from inflammation and leaking fluids, the result is diarrhea — watery feces.

There are many causes of diarrhea in horses. Some of the common ones ,such as bacterial infection, include salmonella, clostridium and lawsonia species. Viruses can also cause diarrhea and we have seen an increase in coronavirus diarrhea in horses. Parasites such as worms are a historical cause of diarrhea and we still see them today.

Horses need to be checked for parasites at least once yearly to monitor for worm burden and appropriate deworming can be done when needed to avoid this problem.

Of particular concern in Manitoba is anaplasmosis which can cause fever, diarrhea, weight loss and limb edema. This bug is a frequent contributor to diarrhea cases in our province but is usually responsive to antibiotics when caught early in the disease.

Immune-mediated issues of the colon and small intestine are also a concern, as in humans and other animals. Toxins and over eating of highly concentrated sugars are also causes in horses.

Some of the issues associated with diarrhea include stomach ulcers and in some cases, unfortunately, laminitis. Horses that develop laminitis (inflammation of the feet) can have difficulty recovering from the episode and in some cases can pass away from the irreversible pain.

Prevention and early recognition with treatment are key to stopping diarrhea from becoming a major issue for your horse. If your horse develops diarrhea or loose manure, contact your equine vet for advice about how to approach it before it becomes a major issue.

Chris Bell is an equine veterinarian and surgical specialist who operates Elders Equine Veterinary Service, with clinics in Cartier and Winnipeg. See www.eldersequineclinic.com.