I have reviewed the answers and reasoning behind it. I think people have missed the obvious.
You are the proud winner of a goat.
By giving up your goat you can pick another door knowing you will get another goat or a boat. GO FOR IT! It doesn't matter if there are 1000 goats and one boat. You already have the worst prize so screw the probabilities and go for the Boat.
Just my two cents
Ken Wardwell