answered question
  NO! What ever you do, don't let him roll! Call the vet immediately and keep the horse on his feet and walking.  Rolling twists up their intestines and this could mean having a pricy surgery done to get them untangled!!!  NO!
answered question
  I like Quarter horses, but for a bad back, I would get a gaited horse, (Tenessee walker, rock mountain saddle horse, etc.) and drafts can be very comfortable!