Horse Side Vet Guide ®

Equine Health Resource

Manure has Blood in It, or Bleeding from Anus

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

Blood in a horse’s manure can be a sign of many conditions. Bright red blood or blood clots often originate in the rectum or anus, and are most likely caused by a bleeding tumor or mass within the anal canal, rectum or lower colon.

Rectal tears caused by veterinary rectal palpation or other traumatic injury can also cause this type of bleeding. Horses could have blood in their manure after colic surgery if the intestine is surgically opened and there has been some bleeding into the intestine.

Manure containing dark red (almost black) blood generally means that the blood originates upstream in the intestine. Horses with clotting problems can bleed into their intestine, and this appears as dark or light red blood in the manure.


If you see blood in your horse’s manure or coming out from their anus, assess the horse’s general health using the Whole Horse Exam (WHE), and contact your vet with your findings and concerns.


Your vet rules out conditions that could cause this sign. That usually starts with a general physical exam to assess body-wide health. In some cases, we look for trace amounts of blood in the manure using special sensitive tests to identify blood components.

Author: Doug Thal DVM Dipl. ABVP


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