By Rory Carroll

LOS ANGELES (Reuters) -The safety of race horses is paramount, Breeders' Cup officials said on Wednesday, a day after the death of a three-year-old colt who was scheduled to compete at the World Championships at Santa Anita Park this weekend.

Practical Move, who was the second choice for Saturday's $1 million Dirt Mile, suffered what race officials said was suspected to be a cardiac event when he collapsed and died after returning from a gallop.

Later on Wednesday, the owners of three-year-old Geaux Rocket Ride announced that he was euthanized after being seriously injured while training for the Breeders' Cup Classic at the track on Saturday.

The colt is the 72nd race horse to die at a California track this year alone and comes after 12 horses perished at Churchill Downs, the site of the Kentucky Derby, in May.

"For the Breeders' Cup, safety comes above all," Breeders' Cup CEO Drew Fleming said during a safety briefing panel.

"This year has been a tough one for the sport and reminds us why the efforts of everyone on this stage are of paramount importance to the future of racing."

This year marks the first time the Breeders' Cup will fall under the full jurisdiction of the Horseracing Integrity and Safety Authority (HISA) and its nationwide anti-doping program, which took effect in late May.

"There is no doubt that we have a lot of work ahead of us to ensure racing is safe for our equine athletes," HISA CEO Lisa Lazarus said.

"But for the first time ever we have national regulations and uniform standards in place to help us change the game forever and for the better."

HISA's Horseracing Integrity and Welfare Unit (HIWU) in July began identifying potential contenders for Breeders' Cup races and has collected 226 samples as of this week.

HIWU executive director Ben Mosier said the Breeders' Cup represents the group's most "high profile" assignment to date and said the agency will have six investigators on the ground through the championships, which run on Friday and Saturday.

Dionne Benson, chief veterinary officer for 1/ST Racing, said the track is equipped with best-in-class diagnostic capabilities including PET and MRI scanners for horses and a surgical suite for orthopedic surgeries. Safety measures for jockeys have also been beefed up.

"HISA has ushered in a new era for racing and given us the opportunity to move forward together as a sport despite the challenges we continue to face," Fleming said.

(Reporting by Rory Carroll in Los AngelesEditing by Toby Davis and Michael Perry)