Around 25 trainers have lost horses at Santa Anita this season, which some are attributing to heavy rainfall on the dirt track and excessive use of medications.
On Saturday, hall of fame trainer Jerry Hollendorfer was banned from the track after a fourth horse from his stable died.
Jerry Hollendorfer has been banned from Santa Anita racetrack
A statement from The Stronach Group, which owns the track in Arcadia, said he was “no longer welcome to stable, race or train his horses at any of our facilities”.
A four-year-old gelding trained by Mr Hollendorfer was euthanised after getting injured while exercising on the training track this weekend.
The death was the 30th overall since the racing season began on Boxing Day.
Officials at Santa Anita and the California Horse Racing Board have initiated several measures to address horse and rider safety.
Mr Hollendorfer could not immediately be reached for comment.
However, he told the Daily Racing Form: “I’m training over 100 horses right now. Santa Anita didn’t want me stay on the grounds. My opinion was that was a premature thing to do. I thought it was extreme. Now I have to step away for a while.”
Mr Hollendorfer has 7,617 winners from 33,519 starters and purse earnings of $199,737,768 (£156,755,199) over a 40-year career, according to Equibase.com.
The Stronach Group said in a statement on Saturday that Mr Hollendorfer’s recent record “has become increasingly challenging and does not match the level of safety and accountability we demand.”
The California Horse Racing Board (CHRB) is investigating the deaths.
Stefan Friedman, spokesman for The Stronach Group, said there were other issues to consider.
He told CNN: “It’s not just the surface they’re running on. There are medication issues.”
