This past year, horse racing regulators worldwide have turned their attention to a seemingly innocuous substance: cobalt. Every horse needs this important element to survive, but some horsemen believe that supplementing the substance will help their horses gain a competitive advantage on the race track.

At the 2015 University of Kentucky (UK) Equine Showcase, held Jan. 23 in Lexington, Kentucky, Cynthia Gaskill, DVM, PhD, Dip. ABVT, reviewed cobalt, its use in racehorses, and recent research on the topic. Gaskill is a veterinary toxicologist at the UK Veterinary Diagnostic Laboratory (UKVDL), also in Lexington.

Cobalt is a trace mineral found in B vitamins that horses require in tiny amounts for correct functioning of their physiology. As a result, all horses will have trace amounts of the substance in their systems.

Gaskill explained that doctors used cobalt to treat anemia (essentially by increasing the blood’s oxygen-carrying capacity) in humans for decades. However, it was associated with a variety of adverse effects, including gastrointestinal, neurologic, cardiovascular, and thyroid problems. As a result, doctors have largely ceased using it. Some athletes, however, continue using it as a doping agent, she said.

Until recently, she added, researchers had not evaluated cobalt supplementation’s beneficial or adverse effects in horses. Since racing regulators’ interest in the element has increased, however, the amount of research into it has, as well.

In 2014, Gaskill said, Heather Knych, DVM, PhD, of the University of California, Davis, and colleagues carried out a study evaluating how cobalt distributes and w