Santa Anita management sent a text to trainers Tuesday morning advising them that workouts would be canceled because of the air quality. "The AQI is at 159 this morning. We are going to cancel workouts and only allow gallopers and joggers," the text said. In conjunction with Dr. Rick Arthur, the Equine Medical Director at UC Davis, where he is assigned full time to the California Horse Racing Board, the Stronach Group has a policy that any air quality index about 150 could be unhealthy for horses, and that exercise...