A tumultuous year in US racing comes down to the wire at the Breeders' Cup at Santa Anita, where a spike in horse deaths has put the sport under scrutiny.

"I think you'd be naive not to acknowledge that people are watching very carefully and that's why we're paying so much attention to injury prevention," Breeders' Cup chief executive Craig Fravel said this week, acknowledging that 36 equine deaths this season at Santa Anita have made the picturesque California track a "focal point".

Investigations into the deaths have been launched not only by the California Horse Racing Board (CHRB) but also by state law enforcement agencies.

Animal welfare activists have demanded change. California Governor Gavin Newsom has weighed in and US lawmakers have again introduced legislation aimed at creating national oversight of a sport now governed in America by regional regulators.

In a letter sent Wednesday to Rick Baedeker, executive director of the CHRB, US Senator Dianne Feinstein called the two-day, $28 million Breeders' Cup slate a "critical test for the future of horseracing in California and in the United States.

"If horseracing cannot be conducted in a safe and humane manner that protects the life and safety of horses and jockeys, it may be time to reexamine the future of this sport in our state and in our country," the senator from California wrote.

After the first spike in horse deaths -- more than 20 in the first three months of racing this year -- Santa Anita paused racing to test the dirt track's surface and subsurface for problems after torrential winter rains.

Although no one cause has been pinpointed, the Stronach Group has instituted restrictions on allowed medications and beefed up veterinary scrutiny of horses at the track -- measures that are in force for the Breeders' Cup.

US racing was also shaken this year by the first disqualification of a Kentucky Derby winner -- Maximum Security -- for a race infraction in the 145-year history of the event.

Controversy lingered with a subsequent lawsuit and then the Preakness saw Bodexpress throw his rider coming out of the gate and run with the field past the finish line.

That Triple Crown turmoil paled in comparison to the outrage sparked by Santa Anita's safety record.

Santa Anita will host the Breeders Cup this week under the shadow of a spike in fatalities earlier this year
Santa Anita will host the Breeders Cup this week under the shadow of a spike in fatalities earlier this year GETTY IMAGES NORTH AMERICA / MARIO TAMA

Fravel, who will leave his Breeders' Cup post to join Stronach after the meeting, said the "amazing steps taken" at Santa Anita had led to a dramatic drop in injuries.

Certainly the controversy hasn't discouraged entrants from around the world -- more than 30 from Europe, two from Japan and one, in a Breeders' Cup first, from South Korea.

Irish trainer Aidan O'Brien seeks a record seventh victory in the $4 million Turf with Epsom Derby winner Anthony Van Dyck.

"We feel he has a very nice chance," O'Brien said. "We think he'll handle the track and the ground, the trip and the draw and everything else.

"He seems to be in good form," added O'Brien, who will be up against US trainer Chad Brown's early 9-5 favorite Bricks and Mortar in the 1 1/2-mile race.

'A lot on the line'

The event kicks off with five races for 2-year-olds on Friday.

Saturday's nine races are capped by the $6 million 1 1/4-mile Classic on Santa Anita's dirt track, with trainer Bob Baffert's McKinzie the early favorite.

South Korean invader Blue Chipper, trained by Kim Young-Kwan, will challenge in the Dirt Mile.

McKinzie can expect a strong challenge from Code of Honor and Vino Rosso while Elate, trained by Bill Mott, will try to become just the second mare, after Zenyatta in 2009, to win.

"I just want the horse to show up," Baffert said. "If he shows up and gets outrun, he gets outrun. But you know what? I want the horse to get beat (running) his style.

"There's a lot on the line," added Baffert.

He was thinking of the winner's circle and possible Horse of the Year honors, but at this year's Breeders' Cup there's even more at stake.