We (my husband, and 3 children) just brought home a male german shepherd puppy two weeks ago who is now 10 weeks old. We have a 5 year old female cockapoo to whom the new pup is showing aggression by pawing at her and nipping at her ears, etc. So far, I have let them go at it a bit as my 5 yr old has stood her ground and growled when he got too aggressive. However today he seemed more aggressive to the point where I could see she did not want to 'play' anymore. I separated them and then later today he did the same thing to her again resulting in her leaving our property which she never ever does.
I suggested to my husband that we get a muzzle for the pup to be put on whenever he becomes overly aggressive. My husband disagrees. We have had several german shepherds before but this is our first experience socializing a german shepherd pup with an existing house pet. I took our previous german shepherd for obedience training and learned about the whole alpha male, top dog theory. Any suggestions from those with more experience would be most grateful.

It sounds like the puppy is playing and not being aggressive?

We have had this discussion before here. It basically boils down to that the puppy is playing and needs to learn that biting hurts.

Best way is you bite the pup when pup starts biting the other dog.

Puppy socialization classes are a great experience for you pups, and can be a great out let for younger dogs to become properly socialized. He will learn when to back off and when it's okay to play. You can try preoccupying him yourself with some extra toys, a little more exercise, when he gets a little rough, distract him with something appropriate to chew and play with.

Does the 5 year old ever play back with him?

It sounds like the puppy is playing and not being aggressive?

That's what I thought up until yesterday but when my 5yr old cockapoo left the property because she had just had enough of this 'playing' I became concerned. He is jumping on her back to take her down and then biting her ears. I don't think he is playing anymore - instead I think he is trying to be top dog/alpha male and needs to be put in his place of order. I'm afraid if I don't do that early enough he might continue this aggressive behaviour with her. I think socialization with other dogs should start soon with him. My cockapoo is well socialized and can stand her ground with other dogs. Right now he is the same size as she but he is only 10 weeks old. He will be a big and powerful dog soon and I worry he will hurt her. My goal is to find them snuggled up together taking a nap or to have

We have had this discussion before here. It basically boils down to that the puppy is playing and needs to learn that biting hurts.

Best way is you bite the pup when pup starts biting the other dog.

I don't want to bite the pup. I need to show him that that behaviour is intolerable and that I will protect my other dog against him. Should I hold his muzzle, tap him on the nose, or command him?

Puppy socialization classes are a great experience for you pups, and can be a great out let for younger dogs to become properly socialized. He will learn when to back off and when it's okay to play. You can try preoccupying him your self with some extra toys, a little more exercise, when he gets a little rough, distract him with something appropriate to chew and play with.

Does the 5 year old ever play back with him?

That's what I thought up until yesterday but when my 5yr old cockapoo left the property because she had just had enough of this 'playing' I became concerned. He is jumping on her back to take her down and then biting her ears. I don't think he is playing anymore - instead I think he is trying to be top dog/alpha male and needs to be put in his place of order. I'm afraid if I don't do that early enough he might continue this aggressive behaviour with her. I think socialization with other dogs should start soon with him. My cockapoo is well socialized and can stand her ground with other dogs. Right now he is the same size as she but he is only 10 weeks old. He will be a big and powerful dog soon and I worry he will hurt her. My goal is to find them snuggled up together taking a nap or to have him be somewhat protective of her. I'm also feeding them at the same time (separate food and bowls of course) to try and show him that he is her equal but hurting her is not acceptable. Am I on the right track or should I become more dominating with him? My past experience with training a German Shepherd was such that I really had to assert myself as Alpha and top dog through obedience classes but this is my first experience bringing a new puppy into the territory with an existing house dog.

Well you do need him to know that YOU are the pack leader. When it comes to feeding you can try eating yourself first, than the cocapoo and than the shepherd. You can start with obedience classes now too. That's a great way for you to establish alpha. When he starts getting aggressive, basically take him off her, make him sit and wait. Kind of like a time out.

Socializing him now is going to be crucial as he dog aggression is a terrible thing and needs to be nipped in the bud asap. They may never be curled up together, and he may never be able to be left alone with the coca poo, but if it truly is aggression, you will learn the triggers, and if addressed by professionals in either behavior modification or through obedience classes, they should be able to live harmoniously together in one home.