Bye Bye By Beautiful was appreciated by veterinarians on the road after sliding past the pole half a mile away, according to Mike Wilman, spokesman for Santa Anita Park.
The veterinarian observed that "the branch suffered a right anterior lateral condylar fracture involving a medical sesamoid, and because of the severity of the injury, decided the human euthanasia of the horse," a statement in Santa Anita Park says.
2-year-old filly makes her second start for owners Greniow, Lawless or Lew , et al finished fourth in his first start on September 13 in Los Alamitos, according to a track statement.
On Friday, 6-year-old mare GQ Covergirl was euthanized after injuring her front two legs while running on a training track.  Santa Anita Park closed for evaluation in March after more than 20 horses died within three months.
There were many changes when it opened later that month: Coaches had to apply two days in advance before working out. horse; jockeys had to replace whips with softer "pillow cultures" and restrictions on steroids, anti-inflammatory drugs and drugs for race day were introduced.
The two deaths occur just a week before Santa Anita hosts the Breeders' Cup, a thoroughbred racing championship at the end of the year. This event is scheduled for November 1-2.