Elliott Gould was the original voice of the horse. After a poor test screening of the film, the horse's half of the script was rewritten by Andy Breckman in an effort to make the film funnier. John Candy was hired to re-record the horse's voice; he ignored the new script and improvised the dialogue instead.
Virginia Madsen claimed to have made this movie for two reasons: one, so that her sister's children could see the film; secondly, for the money. She admits the movie was an embarrassment, but she was not ashamed to take the role, since she needed the money at the time.