The board of directors of the Breeders' Cup horse race Thursday decided to keep the event at Santa Anita Park, the embattled track in Arcadia, California, where 30 thoroughbred horses died either racing or training during the six-month racing meet that ended Sunday. A venue shift would have potentially cost Santa Anita and Arcadia a projected $100 million in economic benefits generated by events at the 300-acre property, which has faced activist calls for its closing and been eyed for redevelopment.