A man takes his Rottweiler to the vet

A man takes his Rottweiler to the vet. ‘My dog’s cross-eyed, is there anything you can do for him?’ ‘Okay,’ says the vet. ‘Let’s have a look at him.’ So he picks up the dog examines his eyes and checks his teeth. Finally he says, ‘I’m going to have to put him down.’ ‘What? Because he’s cross-eyed?’ asks the man. ‘No,’ replies the vet. ‘Because he’s really, really heavy.’