I have a 3 year old chow/aussie shepard mix. He has been a real sweet dog until the last few months. He has become aggressive with other dogs on our walks. I am the alpha dog but don't understand this behavior. Any suggestions?
He likes smaller dogs but dogs his size or larger bring out aggression in him.

Thank you

Hi, Chriso.

What is your dog's posture like when he sees another dog? What is it like when other dogs come near? How do the other dogs react? What is their body posture? Did anything happen recently that may have caused your dog to start reacting this way?

Your dog could be aggressive or he could be reacting defensively by trying to scare the other dog away. I would suggest contacting an animal behaviorist (not a vet or a dog trainer) to help you work with this issue. They can help you to help your dog build up good associations when it comes to being around other dogs. Try contacting your local animal shelter (SPCA, Humane Society, etc.) to see if they have a behaviorist you can speak with. Phone consultations are usually free, but they'll more than likely need to see the dog to be able to fully assess the situation. In my area, it's roughly a $25 per session (1-hour) donation.

While there is no "cure" for aggression, with work, patience and commitment, you can help your dog keep this in check and even enjoy the thought of seeing another dog during walks!

Good advise Grace...
Right move is to consult someone who is expert in that manner...
So that your sure that the answer was right...
Just be very much responsible for a mean time...
To avoid your dog be in trouble...