What is a "pig" in horse racing?

Question

I heard someone say "the Belmont is won on a pig" recently, and was wondering if "pig" is a racing term for an unlikely champion or something. Just curious!

Answer 1

IS A HORSE THAT WINS, BUT SHOULD HAVE BEEN BEATEN, OR NEXT TIME OUT AGAINST BETTER HORSES WILL GET BEAT.  I DON'T THING RAGS TO RICHES IS A PIG..I THINK THE GUY MUST HAVE LOST A LOT OF MONEY ON CURLIN.