A longtime exercise rider and the horse he was riding both died after a training accident early Saturday morning at Churchill Downs racetrack in Louisville.

Odanis Acuna was “breezing,” or gently working out, 2-year-old colt New York Harbor just before 6 a.m., when the horse broke down about a sixteeth of a mile from the finish line. The horse broke either one or several bones in his leg and Acuna sustained fatal injuries to the head and neck during the fall, trainer Kenny McPeek told racing magazine Blood Horse.

On-site emergency workers arrived quickly to treat the rider, Churchill Downs said in a news release, but they “believe he died instantly.” Acuna was 42.

“He was a good man — a very good man,” McPeek told Blood Horse. “It’s not an easy day. Just a really bad day. Our heart was swallowed.”

Churchill Downs halted training after the accident. The track held a moment of silence before the afternoon’s first race at 1 o’clock.

Acuna was a native of Cuba who had worked for McPeek for close to a decade. Churchill Downs officials said he was focused on saving money to bring his wife and three sons, including twin boys, from Cuba to Kentucky. He was in the process of purchasing a home and completing immigration paperwork for the move.

“He was just a wonderful, wonderful person,” Sherry Stanley, executive director of the Backside Learning Center at the racetrack, said in the release.

Acuna also worked a side job selling feed to send money home to his family, McPeek told Blood Horse.

“When he started with me he had little or nothing and he got himself pretty well set up and had been saving money,” McPeek said. “He bought himself a car and was getting ready to buy a house. He was hard at it all day, every day. We worked together a long time and he traveled with us wherever we went. He rode a lot of my best horses for years and was a guy who could handle just about any horse you put him on. He was just a good guy and loved what he was doing. I am just sickened by this tragedy.”

The horse, New York Harbor, was an unraced colt. He was euthanized shortly after the accident. Broken bones in horses' legs are often very difficult to heal. More than 300 racehorses have died either training or during a race in 2018, according to Horseracingwrongs.com.

It has been “several decades” since an exercise rider died at Churchill Downs, the track said in the news release. McPeek said he has never had a rider sustain serious injuries.

“As long as I’ve been at it,” he said to Blood Horse, “I’ve had a rider hurt an arm or a leg — never anything major. We’re just all really sad and trying to work through it.”

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