A growl is a warning. Considering that you do not ever WANT a dog to bite, I would simply use a soft muzzle on him at the vet. You can train that at home and have him learn to accept it.
The LAST place you want to train it (for the first time especially) is at the Vet where he is anticipating less than ideal things happening to begin with.
Prevention is most of the cure. Muzzle him at the vet. You don't want a bite history.
Meanwhile continue your work at home. YOU touching him all over is a lot different than a stranger touching him. He may never accept strangers touching him in even the best of circumstances.
That is OK. I don't know why strangers want to pet a strange dog. If they want to pet a dog they should get their own dog to pet.
The LAST place you want to train it (for the first time especially) is at the Vet where he is anticipating less than ideal things happening to begin with.
Prevention is most of the cure. Muzzle him at the vet. You don't want a bite history.
Meanwhile continue your work at home. YOU touching him all over is a lot different than a stranger touching him. He may never accept strangers touching him in even the best of circumstances.
That is OK. I don't know why strangers want to pet a strange dog. If they want to pet a dog they should get their own dog to pet.