Bleeding from the Rectum

Editor's Note: This excerpt is from Understanding Equine First Aid by Michael Ball, DVM. The book is available from

Blood coming from the rectum can represent an extremely serious veterinary medical emergency. If a relatively healthy horse is observed to be bleeding from the rectum, the most likely cause is some type of trauma. I have seen this result from malicious insertion of an object into the horses rectum and from a stallion raping another horse.

These situations need to be evaluated as soon as possible due to the potential for tearing of the rectum deep enough to allow fecal contamination of the abdominal cavity. Should this occur, the prognosis is grave. If there is a tear and the abdomen has not yet been contaminated, immediate attention is required to evaluate the injury and perform reparative measures.

If the bleeding is a result of thermometer insertion or breaking inside the rectum, it is not usually deep enough in the rectum to cause abdominal contamination, but still should be carefully monitored or evaluated due to the potential for perirectal (around the rectum) abscess formation. A thermometer should be well-lubricated and never forced into the rectum.

In addition, rectal bleeding can be observed occasionally in horses which are very sick and suffering from a blood coagulation abnormality called DIC; these horses usually have evidence of hemorrhage from multiple sites and have a grave prognosis.

About the Author

Michael Ball, DVM

Michael A. Ball, DVM, completed an internship in medicine and surgery and an internship in anesthesia at the University of Georgia in 1994, a residency in internal medicine, and graduate work in pharmacology at Cornell University in 1997, and was on staff at Cornell before starting Early Winter Equine Medicine & Surgery located in Ithaca, N.Y. He is also an FEI veterinarian and works internationally with the United States Equestrian Team.

Ball authored Understanding The Equine Eye, Understanding Basic Horse Care, and Understanding Equine First Aid, published by Eclipse Press and available at or by calling 800/582-5604.

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