How long is the horse’s small intestine? Earn your Horse Health Badge at Mane-U! 1. How long is the horse’s small intestine? 3 – 4 feet 10 – 12 feet 60 – 70 gallons 50 – 70 feet Loading… Share this:ShareFacebookTwitterPinterestLinkedIn Related Related posts: Love horses? Build your horse IQ, earn and share free badges T/F Horses can eat pumpkin? How much water does a horse drink daily? White line disease affects what part of the horse?