Erythropoietin (rhEPO) Potentially Fatal in Horses

One of the key factors in enabling horses to perform at their maximum is the ability to get oxygen to tissues via red blood cells. Trainers and horse owners have used a number of approaches to accomplish this, but one of those procedures can have fatal consequences, according to a report by C. Schwarzwald, DVM, Dipl., ACVIM, graduate student in the department of veterinary clinical sciences at The Ohio State University.

Schwarzwald told his listeners at the 50th annual American Association of Equine Practitioners (AAEP) Convention in Denver, Colo., Dec. 4-8, 2004, that some owners and trainers administer recombinant human erythropoietin (rhEPO) to horses in an effort to increase red cell mass, which would increase the amount of oxygen carried to muscles and decrease fatigue. When the compound was administered three times a week to test horses, he said, it did indeed increase the red cell mass, "suggesting the potential of this compound to improve the athletic capacity."

Then, Schwarzwald dropped this bombshell: "Adverse effects of administration of rhEPO to horses are potentially fatal." He said that administration of the compound is associated with severe anemia that can cause death.

In one stable of 115 horses, Schwarzwald said, 14 were administered rhEPO. Anemia was detected in eight of the 14 after being treated, and five of those eight died.

His conclusion: "rhEPO should not be administered to horses because of the high incidence of red cell aplasia (poor development) and death associated with its use in the horse."

About the Author

Les Sellnow

Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at or by calling 800/582-5604.

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