Heavy clouds are seen over the San Gabriel Mountains at Santa Anita Park in Arcadia, Calif., Thursday, March 7, 2019. (Photo: AP)

Santa Anita will impose new rules to scrutinize horses training on its racetrack and add a director of equine welfare following the deaths of 21 horses since Dec. 26.

The main dirt track and turf courses were in a third day of examination Saturday in an effort to uncover what may have led to the series of catastrophic breakdowns. The racetrack remains closed indefinitely for racing.

The inner training track, which has not had any breakdowns, was open for horses to jog and gallop only for the second straight day.

It was supposed to be a huge day of racing Saturday at the historic track. But the San Felipe Stakes for 3-year-old Kentucky Derby hopefuls and the Santa Anita Handicap for older horses were scuttled when the track was closed on Tuesday.

Tim Ritvo, chief operating officer of The Stronach Group, said the new safety and welfare measures will take effect when racing resumes in the coming weeks.

The new rules announced by Santa Anita’s owner TSG include requiring trainers to apply to hold timed workouts for their horses at least 24 hours in advance. Officials believe that will give track veterinarians time to identify potential at-risk horses through their past performances, workout date and physical inspection.

TSG says it has hired extra vets to observe all horses entering and exiting the dirt and turf course during morning training hours.

The morning training schedule will change, too.

The first 15 minutes of training after the dirt track opens, and each time its surface is renovated, will be reserved for horses completing official timed workouts. Officials say it will reduce the number of horses on the track at the same time and create a safer environment.

TSG plans to hire an accredited vet as the new director of equine welfare. That person will lead a rapid response team for injuries and conduct transparent investigations into the injury while communicating the findings to the racing and general public.

Santa Anita will require veterinary records of a horse to follow that animal through any ownership or trainer change. A similar rule is in effect at Florida’s Gulfstream Park, which is also owned by TSG.

“This has worked very well at Gulfstream Park,” Ritvo said. “There was some pushback from the trainers at first, but this is the best thing for the horse.”

Ritvo said TSG will invest in any new technology or equipment that will help discover pre-existing injuries in horses.

Santa Anita is expected to retain the services of Mick Peterson of the University of Kentucky and veteran track superintendent Dennis Moore, who are reviewing the dirt and turf courses.

“We’re looking forward to returning to normal,” Ritvo said, “but it will be a new normal.”