ARCADIA, Calif. (AP) — The Breeders’ Cup and Santa Anita came within 220 yards of staging a safe weekend of championship racing.

It all came down to the $6 million Classic in front of nearly 70,000 fans and a prime-time television audience. The 11-horse field thundered out of the final turn, with favorite McKinzie in the lead and Vino Rosso bearing down on him.

Behind them along the rail, Mongolian Groom suddenly faltered. Jockey Abel Cedillo jerked on the reins to ease the 4-year-old gelding, who hopped on three legs. His injured left hind leg dangled distressingly.

Vino Rosso charged past McKinzie to claim victory, triggering cheers and a celebration by his human connections. Up the track, a screen was set up to shield Mongolian Groom and an equine ambulance drove to his rescue.

But there was nothing to be done after the gelding sustained what Cup officials described as “a serious fracture” of his leg. Given the extent of the injury, four veterinarians recommended that he be euthanized.

Mongolian Groom became the 37th horse to die at Santa Anita since last December, and the seventh since the fall meet began Sept. 27.

It was a final blow in a strife-filled season for a sport struggling to protect the lives of horses and jockeys amid a steady drumbeat of public criticism by everyone from Democratic Gov. Gavin Newsom to animal rights activists demanding an end to horse racing in California.

The deaths had prompted track owner The Stronach Group to change rules involving medication and training. The Breeders’ Cup beefed up its own pre-race exams and observations of runners.

But no one can eliminate the unpredictability of sports or injury.

“You just don’t know when it is going to happen,” two-time Triple Crown-winning trainer Bob Baffert said. “We try to keep them as safe as we can.”

A day after the Breeders’ Cup ended its record 10th running at Santa Anita, all was quiet at the track.

All nine races went off without incident Sunday on closing day of the fall meet. A horse in the last race was pulled up but was uninjured.

Racing moves to Del Mar starting Friday through Dec. 1 at the seaside track north of San Diego.

Santa Anita opens its winter-spring meet on Dec. 26.

By then, more changes could be in place. The Stronach Group has said it’s looking into the feasibility of replacing Santa Anita’s main dirt track with a synthetic surface, something tried before in California and cast aside.

Craig Fravel has now left his post as CEO of the Breeders’ Cup to join The Stronach Group, where he’ll be in charge of executing and enforcing effective procedures and integrity standards for horses and riders.

The California Thoroughbred Trainers organization has agreed to help raise money for the purchase of an equine MRI (to scan horses while standing) for the equine imaging center on the Santa Anita backstretch. A Nov. 15 deadline is looming to contract for the equipment so it would be installed before the winter-spring meet opens.

The imaging center already has nuclear scan technology and will add an equine PET scan, with The Stronach Group kicking in $500,000 for it and another $200,000 coming from a private foundation dedicated to research on equine health issues.

People for the Ethical Treatment of Animals is demanding all racing nationwide be suspended until specific measures are put in place, including the installation of CT scan equipment at all tracks.

“Any reluctance to do so will lead to more deaths and the self-destruction of horse racing,” PETA senior vice president Kathy Guillermo said.

Political action committee Animal Wellness Action is urging Congress to pass the Horseracing Integrity Act, which seeks to establish a national, uniform standard for medication in the industry. It would also create an independent organization managed by the U.S. Anti-Doping Agency to oversee medication rules, testing and enforcement.

The Breeders’ Cup, The Jockey Club and The Stronach Group are supporting the bill through the Coalition for Horse Racing Integrity.

Churchill Downs, home of the Kentucky Derby, isn’t part of that group and instead wants to create a new coalition that would advocate with state regulators for fair and uniform regulation in the 38 racing jurisdictions nationwide.

“If they don’t step up in support of the bill, then we’ll see more groups take up the issue and the debate will shift away from eliminating doping in horse racing to eliminating horse racing itself,” said Marty Irby, executive director of Animal Wellness Action.

The California Horse Racing Board plans to release in December the results of its investigation into the deaths at Santa Anita. The Los Angeles District Attorney’s office has yet to indicate when its probe will conclude.

As with the other fatalities, Mongolian Groom will undergo a required necropsy at UC Davis.

The gelding whose owner and trainer are Mongolian had been a surprising success story after being bought for $12,000 as a 2-year-old in training in 2018.

Besides winning the Grade 1 Awesome Again at Santa Anita in September to earn a berth in the Classic, Mongolian Groom had a second and two thirds in other graded stakes to go with career earnings of $579,141.

A day before the Classic, trainer Enebish Ganbat wouldn’t lay out his vision for the race.

“Mongolian people do not predict the race before the race,” he said. “It’s bad luck.”