The practice of “doping” racehorses with cobalt chloride not only fails to enhance their performance but also puts their health at risk, according to a review study from England.

Cobalt is an essential trace mineral that is important in the formation of the vitamin B12 complex and as an activator of enzymes involved in the oxygen-carrying function of red blood cells. Although it is a banned substance in many racing jurisdictions, some unscrupulous trainers administer cobalt chloride to horses either intravenously or orally in hopes of increasing the oxygen-carrying capacity of their blood and thus enhancing their performance.

University of Surrey researchers note, however, that studies have shown that the mineral can accumulate to toxic levels in the body organs and can cause other health problems. In particular, the researchers say, high blood levels of cobalt can have adverse effects on a horse’s cardiac and nervous systems.

In addition, the researchers note, cobalt supplementation may actually be deleterious to equine performance, potentially interfering with cardiac muscle function.

Reference: “Cobalt chloride doping in racehorses: Concerns over a potentially lethal practice,” Veterinary Journal, April 2015

This article first appeared in EQUUS issue #456, September 2015.