Horse Side Vet Guide ®

Equine Health Resource

Manure is Watery, Diarrhea (in Adult)

Code Red - Call Your Vet Immediately, Even Outside Business Hours

Code Orange - Call Your Vet at Their First Available Office Hours

Code Red - Call Your Vet Immediately, Even Outside Business Hours

  • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp>101F/38.3C), or heart rate greater than 48 BPM.
  • If diarrhea is profuse and watery and persists for more than 2 movements.

Code Orange - Call Your Vet at Their First Available Office Hours

  • If the horse's appetite and attitude are normal and you see nothing else wrong.
  • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.
  • If manure is more soft (cowpie) than outright liquid diarrhea.

Water uptake in the equine gut takes place primarily in the large colon. If this function is lost for any reason, it results in diarrhea. Horses that are stressed by management or diet changes may have short-term diarrhea or soft stool. A single pile of soft or watery manure (“cow pie”) followed by normal feces may be considered normal, especially for an anxious horse. However, multiple watery movements should always prompt a call to your vet.

Adult horses with severe diarrhea can become rapidly dehydrated and go into shock. The greatest concern with adult horse diarrhea is that the horse has infectious colitis, a condition caused mostly by bacterial organisms like Salmonella. Bacterial colitis can be fatal if not treated rapidly and correctly. Delayed treatment also results in a higher incidence of potentially fatal complications, like laminitis.

Less frequently, adult horses can have chronic diarrhea. The causes and diagnostics for longer term diarrhea are somewhat different. In chronic diarrhea, horses must adjust their water and electrolyte intake and excretion in order to maintain hydration in the face of excessive water loss from the colon.


First, be sure to wear gloves and observe quarantine protocol, as some conditions causing sudden diarrhea are contagious to other horses. Assess your horse’s general health using the Whole Horse Exam (WHE), paying particular attention to heart rate, gum color, and capillary refill time. Assess the feet for digital pulse and heat.

A horse with abnormal vital signs and diarrhea is a veterinary emergency, whereas one with normal findings is usually at less risk. Test the horse’s appetite. A horse with severe colitis will usually not want to eat and will seem depressed.

If you see more than one pipe-stream of diarrhea, you should contact your vet immediately. In contrast, you can monitor a horse with soft “cow pie” manure for a while without immediate veterinary assistance. It may be just a case of temporary loose stool. Continue to offer the horse fresh water and hay and watch attitude and appetite carefully.


Your vet can usually tell through examination and early diagnostics whether this will be a condition that requires more aggressive diagnosis and treatment. In some cases, these horses must be hospitalized in order to receive adequate treatment.

Helpful Terms & Topics in HSVGWritten, Reviewed or Shared by Experts in Equine Health

Author: Doug Thal DVM Dipl. ABVP


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