aggresssion with big dogs

Hi there

It sounds like your dog is trying to assert dominance over the other dogs. He may be getting along with the smaller ones as he doesn’t think they are a challenge to his authority, but may view the bigger ones as a threat to his position, as well as his pack. Both you and your husband will need to re-establish yourself as the alpha dogs of the pack, so that Shilo doesn’t feel the need to protect either of you from what he perceives as a threat.
There are a few things that you can incorporate into your daily routine to re-establish yourself as the alpha dog. These include insisting that you walk ahead of him through doorways and when walking on the leash, and feeding him after you have finished your own meal. You must ignore him if he comes up to you for attention, as he has to learn that attention from you is earned and not just given out whenever he wants it. Before you pat him or play with him, give him a command, such as 'sit-stay' so that he will see that your attention is a reward for good behavior. This will act as an incentive for the future. If you are playing a game with him, make sure it is you that chooses the toy and when you decide that you have had enough, take the toy away with you so that he realizes that it is you that controls playtime. When you first come home, you should greet the rest of the household first before saying hello to him, which will help him realize his place in the hierarchy. All these things can be incorporated relatively easily into your normal daily routine, although it will require some patience and perseverance from you. He may struggle initially as he sees himself as the alpha dog and therefore being in the submissive position to you, who he sees as a subordinate, is distressing. Soon, though, he will settle into his new place in the hierarchy and should become a more relaxed dog, as he has been relieved of the stressful role of protector.

It is also a good idea to set aside some time each day for a bit of obedience training, which will not only improve his obedience levels but also the relationship between you.
If he starts barking at other dogs or misbehaving at home, you must take him by the collar and lead him away to a 'time-out zone'. Don't speak to him or make eye contact when taking him away, so that he is getting absolutely no attention from anyone at all. This place should be quiet and free of distractions, away from other people and dogs so that he can be left completely alone. Leave him there until he calms down and then make him obey a command, such as 'sit-stay', before releasing him from the 'time-out zone'. If he misbehaves again, do exactly the same. He will soon learn that that is not the way to get your attention, in fact it will lead to complete isolation instead, which is not what he wants.

When you see big dogs approaching, you will need to catch him in that instance before he ‘switches off’ and becomes so focused on the dog that he can't hear anything else. Distract him by giving him a command, such as ‘sit-stay’ and then rewarding him when he obeys. You may need to use the ‘Alarm-No-Command’ method to get his attention. Make him hold the stay for a few minutes, by which he should have completely forgotten about the dog and be entirely focused on you instead.

I hope this helps and all the best with the training!