Wild Beauty.

A soldier returns home from World War I with a beautiful black horse that he saved on the battlefield, and names Thunderhoof. He enters the horse in a local race, hoping to earn enough money to save the family ranch of the girl he loves. However, the crooks intent on taking the ranch manage to capture a notorious wild horse and enter it in the same race, believing that it can beat Thunderhoof and thereby ensure that they're able to take the ranch.