Veteran Vet McCrosky Banned 24 Years for Doping Violations

Illinois veterinarian fined $300,000 for trafficking, possession, and use of banned substances

Published on Feb. 11, 2026

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Dr. Donald McCrosky, a licensed veterinarian in Illinois for over 50 years, has been banned for 24 years and fined $300,000 by a Horseracing Integrity and Welfare Unit (HIWU) arbitrator for a series of nine anti-doping rule violations, including trafficking banned substances, possession of banned substances, tampering, and using a banned substance.

Why it matters

This case highlights the ongoing efforts by horse racing regulators to crack down on doping and maintain the integrity of the sport. McCrosky's lengthy ban and hefty fine send a strong message that such egregious violations will not be tolerated, protecting the welfare of racehorses and restoring public trust in the industry.

The details

In April 2025, HIWU investigators searched McCrosky's minivan at Fairmount Park and found several banned substances, including Testosterone Cypionate/DHEA, Thyro-L, Ammonium Sulfate, P-Bloc, and OsPhos. McCrosky claimed he used these for off-track, non-covered horses, but was warned not to take them back. During an interview, McCrosky admitted to administering Testosterone to a horse he treated, Tigger Attack, owned by his wife. He also sent HIWU a handwritten note claiming he had performed a castration on another horse, Childersattack, to explain a positive Testosterone test, but HIWU later determined the horse had been fully gelded in 2020. Furthermore, McCrosky was found to have sold two syringes containing banned Testosterone and Glaucine to trainer Isidoro Castro in a parking lot.

  • On April 22, 2025, HIWU investigators searched McCrosky's minivan and found the banned substances.
  • In October 2024, McCrosky's horse Tigger Attack tested positive for Testosterone, which he admitted to administering.
  • In October 2024, McCrosky's horse Childersattack tested positive for Testosterone, and he claimed to have performed a castration, which HIWU later determined was false.
  • In August 2025, HIWU investigators found two syringes containing banned substances that McCrosky had sold to trainer Isidoro Castro one month prior.

The players

Dr. Donald McCrosky

A 50-year licensed veterinarian in Illinois who was banned for 24 years and fined $300,000 for a series of anti-doping rule violations.

Tigger Attack

A horse owned by McCrosky's wife that tested positive for Testosterone, which McCrosky admitted to administering.

Childersattack

Another horse owned by McCrosky's wife that tested positive for Testosterone, which McCrosky falsely claimed was due to a castration procedure.

Isidoro Castro

A trainer who purchased two syringes containing banned substances from McCrosky in a parking lot.

Hugh Fraser

The HIWU arbitrator who issued the final decision banning McCrosky for 24 years and fining him $300,000.

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What they’re saying

“The actions of Dr. McCrosky were not due to innocent misinterpretation of the rules or a misunderstanding of his obligations. In committing these nine Anti-Doping Rule Violations, Dr. McCrosky acted with intent, and with a flagrant disregard for the ADMC Program Rules and for their overarching objectives of horse welfare and the integrity of the Thoroughbred racing industry.”

— Hugh Fraser, HIWU Arbitrator (thoroughbreddailynews.com)

What’s next

The judge in the case will decide on Tuesday whether or not to allow Walker Reed Quinn out on bail.

The takeaway

This case highlights the ongoing battle against doping in horse racing, with regulators taking strong action to protect the integrity of the sport and the welfare of the animals. The lengthy ban and hefty fine imposed on Dr. McCrosky serve as a warning to others who may be tempted to engage in such egregious violations.