Casey's Shadow (1978)

"An unknown horse trainer in Louisiana becomes the part owner of a colt sired by a famous quarter horse. He raises him with the help of his child Casey's pony, as the mare dies after the colt's birth. He recognizes talent in the colt. His son Casey runs the horse and hurts his legs. He recovers and places in the Ruidoso futurity. He breaks down after the race, which he wins. The vet recommends putting him down, but the father is trying to make up with his children who did not want him to run the horse in the race as he was hurt during the trials. He leg is surgically repaired and he takes the horse home. We don't know what happened to the horse."