Money from Home (1953)

Herman owes a lot of gambling debts. To pay them off, he promises the mob he'll fix a horse, so that it does not run. He intends to trick his animal-loving cousin Virgil, an apprentice veterinarian, into helping him. Of course, he doesn't tell Virgil what he is really up to. Mistaken identities are assumed, while along the way, Virgil meets a female vet and Herman falls for the owner of the horse.