Officials with the English Jockey Club have denied recent claims and reports that the drug Erythropoietin (EPO) is used by many in racing in that nation to enhance performance in horses. Use of the drug is said to increase the level of red blood cells in the body, allowing for greater oxygen intake. A press officer for the Jockey Club said the horses already have an "excess amount of red blood cells" making the organization "skeptical" of claims of enhancement, Sporting Life reports.

"When one takes into account the detrimental effect on a horse's health that repeated use of EPO would have, which could result in death or require serious veterinary treatment, the level of clamor doesn't quite tally with what would be the side effects on the equine population if it was being used to the degree with which some people are suggesting," said John Maxse.

The response from the Jockey Club came after a report in the Mail On Sunday that many horsemen in the country are using EPO to gain an advantage.

Trainer Charlie Mann said in the report that he was not "competing on a level playing field" due to use of the drug.

"You see good horses being blown away by animals that finish like runaway trains. It is not natural," Mann said. "If a trainer is convicted of using EPO, then he should be locked up for ten years for taking money illegally and killing horses. That's what we are talking about here, because EPO is so dangerous that horses are self-destructing on it."