I recently just got a 7 week old puppy and brought him home. We decided it was a good idea to get our 2 year old Great Dane a playmate, but one we could train ourselves. Well we didn't expect it to go so horribly. We understand that the puppy is a little too much for the Great Dane, and he's taking it considerably well. He's never bitten him, and the only time he gets angry is when the puppy is near his bone or his food. But we could tell that our Great Dane's mood was not as great as usual.

But the worst part is that our Great Dane use to get along with ALL dogs. Male, females. But since we've brought the puppy home he's been attacking and hurting every male dog he's not familiar with! He's been well socialized all of his life, and he's even grown up with four male dogs, so we really don't understand what's going on. This has been happening for a week, and we're not sure if it's ever going to stop. If anyone could give some advice i'd be grateful.