white foam while eating

Question
Seiko is a Golden retriever and as he eats he foams at the mouth and it drips all over the damn place. He also gets this while he runs on his walks. Is there a reason for this? He eats quite fast like its his last meal. Could it be saliva overproduction or?

Answer
The rapid eating is enough of a problem that my puppy raising manual has 2 different methods of slowing it down.  You can spread the chow out on a cookie sheet or something.  Or you can put some large rocks in the dish.  The cookie sheet might catch some of the slobber too.  

Some of them do drool excessively.  There isn't an answer to that in my manual.  

Is Seiko a watch dog?