CNN  — 

Medina Spirit is set to undergo a postmortem to determine the cause of the Kentucky Derby-winning horse’s sudden death at Santa Anita racetrack in Southern California, according to the California Horse Racing Board (CHRB).

The three-year-old colt collapsed near the finish line just as he was completing a workout on Monday and died immediately, the CHRB told CNN.

“Following the completion of a routine morning workout, Medina Spirit collapsed on the track at Santa Anita Park and died suddenly of a probable cardiac event according to the on site veterinary team who attended to him,” Santa Anita Park said in a statement.

Medina Spirit’s Hall of Fame trainer Bob Baffert said the horse died of a “heart attack”, however the CHRB will not determine cause of death until the necropsy and toxicology tests – to be conducted at the University of California, Davis – have been completed.

President of the American Association of Equine Practitioners Dr. Scott Hay told CNN that the “exact” cause of death is only typically determined in around half of such cases.

“Typically, sudden deaths are caused either by a cardiac issue, some sort of internal hemorrhage, more rarely a spinal issue of some sort,” Dr. Hay told New Day’s John Berman.

“It’s an extremely rare occasion. They’ve kept statistics in California specifically for these types of occurrences and I think the statistics I’ve seen are about 1 in 160,000 training starts and about 1 in 9,000 race starts.

“The autopsies will determine what the exact cause is in probably about 50% of the cases, and the other 50% there may still be some questions once the autopsy is done.”

Medina Spirit crosses the finish line to win the 147th running of the Kentucky Derby.

Kentucky controversy

Medina Spirit was involved in one of the sport’s biggest controversies in the US earlier this year: after crossing the line first in this year’s Kentucky Derby, the horse failed a post-race drug test.

Trainer Baffert was subsequently banned from fielding any horses at the Churchill Downs racetrack for two years following the confirmation of the test for a legal drug – betamethasone – whose presence is banned on race day.

Baffert later provided a lengthy statement claiming an ointment used to treat dermatitis may have caused the positive test.

Dr. Hay said that he doesn’t see “any correlation whatsoever” between the horse’s positive test for betamethasone following the Kentucky Derby and his death on Monday.

“I have never seen that on a postmortem examination being a cause of death,” Dr. Hay added.

Santa Anita racetrack has an unwanted record of equine fatalities, which prompted an investigation in 2019.

According to this year’s CHRB annual report regarding their Equine Postmortem Program, California recorded the lowest number of total catastrophic injuries since 1990 during 2020-21 – a 50% reduction from the previous two years and the lowest since their records began.

‘Tremendous spirit’

A statement from Baffert paid tribute to the champion colt, who raced four more times after the Derby – including two victories in California and a second placed finish at the prestigious Breeders’ Cup Classic in early November. He won half of his career 10 starts.

“My entire barn is devastated by this news,” Baffert’s statement read.

“Medina Spirit was a great champion, a member of our family who was loved by all, and we are deeply mourning his loss. I will always cherish the proud and personal memories of Medina Spirit and his tremendous spirit.”

CNN’s Nick Watt contributed to this report.