With proper care and nutrition they can live well into their 30's. Purina Feed did a search back in 2003 for older horses to be on the feed bag. The horse that won was 36 years old. They just got an email not to long ago saying that the horse had just turned 40years old. In 2006 we lost our 30 year old to severe colic. I am currently riding a 27 year old 1/2 arab 1/2 quarter horse. Most people cant believe he is as old as he is. But when it comes down to it, it is proper care (regular dental care), good nutrition, they will be in the back yard for a long time.