A man took his Rottweiler to the vet and said to him,

"My dog’s cross-eyed. Is there anything you can do for it?"

"Well" said the vet "let's have a look at him"

So he picks the dog up by the ears and has a good look at its eyes.

"Well," says the vet "I'm going to have to put him down."

"Just because he's cross-eyed?" say's the man.

"No, because he's heavy." says the vet.