Robertino Diodoro Suspended, Fined For Oaklawn TCO2 Violation - Horse Racing News | Paulick Report

Robertino Diodoro Suspended, Fined For Oaklawn TCO2 Violation

Robertino Diodoro

Robertino Diodoro, leading trainer at the recently concluded Oaklawn meet, will serve a 15-day suspension at the outset of the 2023-'24 season at the Hot Springs, Ark., track as a result of a total carbon dioxide (TCO2) finding above the permitted limit.

The violation, issued by the Arkansas Racing Commission and posted on the Association of Racing Commissioners International website on Monday, said Diodoro-trained Aristocracy, sixth-place finisher in the $200,000 Bath House Row Stakes on April 22, had a TCO2 reading of 42.3 millimoles per liter, well above the permitted limit of 37 mmol/L. According to the ruling, the 3-year-old Tapit colt owned by Gordon Christoff was disqualified from purse money.

The violation is considered a Penalty B infraction under ARCI guidelines. The suspension is for 30 days, with 15 days stayed provided Diodoro has no Class A or Class B medication violations within 365 days of the May 15 ruling. The 15-day ban, reciprocal in all states, runs from Dec. 8-Dec. 22, 2023, at the start of the next Oaklawn meet. He was also fined $1,000.

Diodoro waived his rights to a hearing and will not appeal.

Purposely increasing the TCO2 levels in a horse is believed to prevent lactic acid buildup, which leads to muscle fatigue. The practice is commonly called “milk shaking” and can involve the use of baking soda and a liquid delivered via nasogastric tube. Read more about TCO2 levels here.

Diodoro said Aristocracy was not milkshaked.

“Who the heck is milk shaking a horse in 2023?” he said. “That'd be like you sitting in a bar, drunk and falling off your stool, and someone telling you, 'Hey, Ray, there's a check stop just down the road. You better not drive.' Then you have a couple more drinks and get in your vehicle and think you're going to make it through.”

TCO2 testing for most races is random at Oaklawn, though Diodoro said every horse entered in a stakes race is tested.

Still, the trainer had no explanation for how the horse's TCO2 was so elevated.

“I do not know,” he said. “The only thing I can say, and I don't want to go into detail, our feed program has been the same for 10 years and we've never had a problem. This was a new horse in the barn.”

Prior to the Bath House Row Stakes, Aristocracy was campaigned by his breeders, Gary and Mary West, and trained by Brad Cox. He ran ninth in his previous start, the March 4 John Battaglia Memorial Stakes at Turfway Park, before joining the Diodoro barn for a new owner.

Diodoro led all trainers during the 2022-'23 Oaklawn meet, with 61 wins from 266 starts. In January, he became the 37th North American trainer to reach the 3,000-win milestone. He currently has 3,077 wins from 14,770 career starts. He began training in 1995.

According to, this  is Diodoro's first medication violation since 2020. He said there are no other pending cases involving TCO2 levels for his stable.

The Oaklawn meet ended May 6.

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