What causes diarrhea in horses and what are the symptoms?

Why do horses experience diarrhea?

In foals, causes of diarrhea may be secondary to non-infectious foal heat diarrhea or dietary issues. In adults and adolescent horses, a bacterial infection (Clostridium difficile, Clostridium perfringens, Salmonella, etc.), viral infection, parasitic infection, or cryptosporidium can be responsible. Obtaining fecal samples for either cultures or PCR (DNA) testing can be utilized to identify the specific cause.

In a general categorization, bacterial toxins cause a secretory diarrhea while viruses can result in a malabsorptive diarrhea. Malabsorptive diarrhea is the inability of the intestinal tract to reabsorb water and nutrients, and secretory diarrhea results in the hypersecretion of both water and electrolytes into the intestinal tract. In severe infections, bacteria and viruses can result in both secretory and malabsorptive diarrhea.

In many cases of adult diarrhea, the horse recovers before the cause is known. Within a horse’s GI tract, a healthy microflora is an essential part of the normal digestive processes. If the normal balance of bacteria is upset by a sudden change in diet, stress, or antibiotic treatment, digestion is upset and diarrhea may follow.

Which horses are most prone to diarrhea?

Unfortunately, diarrhea is common in adolescents as well as adult horses. However, horses that have recently changed diets or been exposed to stress are more prone to diarrhea.

What are common symptoms of diarrhea?

In most cases, it is obvious when a horse has diarrhea, but often the difficulty is in diagnosing the cause.

How do you treat diarrhea in horses?

Symptomatic treatment includes removing any obvious cause or exacerbating problems such as green grass, rich feed and antibiotic treatment. If the diarrhea is severe or symptoms persist, then treatment is necessary.

Treatment for diarrhea is directed towards supportive care (fluid therapy, nutrition) and targeted treatment for the specific infection as determined by clinical and diagnostic testing. Intestinal adsorbents, antidiarrheals, and electrolytes may be administered as needed.