The last race (1979)

Twelve-year-old son of a divorced parents live in a skyscraper, but the drab of urban living is somewhat improved by the proximity of hippodrome and horse farm. Boy's favorite is a former champion named Evergreen, a stud whom the administration decides to sell to the slaughterhouse. After an unsuccessful attempt to change their mind, children steal the horse and disappear. After realizing what this horse mean to them, they give it as a present to the boy's class.