A 24th horse has died at Santa Anita since December 26, the first since March 31.

Commander Coil broke down Friday during training hours just before 10am on the one-mile main track.

After sustaining a shoulder injury while galloping the 3-year-old gelding had to be euthanized.

'Equine shoulder injuries are rare, especially for a horse that is galloping as opposed to breezing or racing,' track owner The Stronach Group said in a statement. 'A comprehensive evaluation will be completed to understand what might have caused this uncommon injury.'

The horse had not yet made its racing debut. He was trained by Marcelo Polanco and owned by Jose Romero.

The Stronach Group are the owners of Santa Anita Park that was the site of 24 horse deaths over a span of three months

Santa Anita - where 2003 movie Seabiscuit was filmed - had gone six weeks without a horse fatality.

The previous fatality occurred March 31 when 5-year-old Arms Runner fell during a turf race where he collided with another horse.

Arms Runner's death occurred two days after they reopened the track. In an effort to figure out what was going on they closed indefinitely March 5 following the 21st horse death.

Since various reforms involving race-day medication and safety were instituted on March 15, The Stronach Group says there have been over 80,000 gallops during training with no fatalities.

During the period, a 22nd horse was euthanized March 14 at the park 20 miles northeast of Los Angeles. It led to limiting jockey use of whips.

Early March at the San Simeon Stakes, 4-year-old filly Let's Light the Way passed away after an injury.

Commander Coil was owned by Jose Romero (pictured) and had not yet made its racing debut

Also Friday, a 3-year-old filly named Congrats Gal collapsed just past the finish line of the Miss Preakness Stakes at Pimlico in Baltimore, a track also owned by The Stronach Group.

It was the 83-degree heat day before the track was due to host the second leg of the Triple Crown.

The Florida-bred was running her sixth career race. She came in last in the eighth race on the card and fell to the dirt about 100 yards past the finish line.

The death marred one of the two biggest days of the year at aging Pimlico, where a sizable crowd gathered for Black-Eyed Susan Day.

No cause of death was immediately announced.

A necropsy will be performed on both horses.

It's been a difficult year for horse racing - and 149-year-old Pimlico, which has deteriorated to the point where the Stronach Group has advocated moving the Preakness to nearby Laurel Park.