My Brother Talks to Horses (1947)

Living with his family in Baltimore, 9-year-old Lewie Penrose claims that he can converse with horses--and also pick the winners of upcoming races. When it appears as though Lewie is telling the truth, he attracts the interest of gambler Rich Roeder who needs a "sure thing" in the upcoming Preakness. Meanwhile, Lewie's older brother John carries on a romance with the lovely Martha.