A horse has died after fracturing a shoulder while training, making colt Derby River the 27th horse death since Santa Anita opened its season in late December.
The Los Angeles Times reports the 2-year-old unraced horse was euthanized in the nearby city of Chino.
California Horse Racing Board spokesman Mike Marten said the euthanization was being treated as an on-track training death.
A necropsy is planned.
Last year's national average for fatal injuries was 1.68 horses per 1,000 starts. At Santa Anita, the rate was 2.04.