He has always been a great pet to have in our house up until recently.

Did anything happen recently that could trigger the change? Have there been changes in your routine or your family’s routine? Changes to the dog’s routine? Did anything different happen recently? How is his physical health?

Before this, did he get along with your Shih Tzu? What was his daily routine like before the change and after the change?

Based on what you describe, it will probably be very helpful to get advice from a professional trainer. I worked with several of them when I first got my Shiba Inu, and the good ones were able to identify his aggression/reactivity triggers and help me desensitize him to those triggers.

She is aggressive whenever she meets a new dog,and will lunge at them.

Does she pull to meet the other dog or do you pull her to meet the other dog? What is her body language like when she sees other dogs? Is her tail up or down? Does she try to make herself look small or does she puff up her chest and stare?

With Shiba Sephy, what helped with him is to first create a lot of neutral experiences. We just ignore other dogs and walk on. I don’t stop to chat or anything, just keep moving at a normal pace. I also stay calm and make seeing other dogs into a non-event. Since nothing ever happens when we see other dogs, it just got to be old hat, and Sephy started to calm down.

Dog-to-dog desensitization exercises can also be helpful.

My Shiba Inu was reactive to dogs when he was young. There are many reasons why a dog may get ‘aggressive’ with another, and there are also many different definitions of what aggressive means.

Sephy gets along well with playful large dogs. He tends to overwhelm smaller dogs with his rough play-style, and this may cause a smaller dog to get fearful and resort to aggression. Therefore, I only choose large, playful dogs to be his playmates.

Some things that helped with Sephy-
1. Dog-to-dog desensitization exercises.
This was a good way to get him comfortable with dogs in a positive context. I teach him that we just ignore other dogs, and he gets rewarded for being calm and focusing on me.
http://shibashake.com/dog/dog-to-dog-aggression#desensitize

2. Creating neutral experiences.
Ignoring other dogs was also helpful for Sephy. In this case, he learns that when we are out on walks, nothing special happens when we meet dogs. Therefore, there is no reason to get excited or stressed when there are other dogs about. I describe more of this in the article above.

3. Control my own energy.
In the beginning, I was always fearful that Sephy might act out. As a result, whenever we see other dogs, I would get tense and stressed. Sephy very quickly picked up on this energy and became tense and stressed as well. This made him become even more reactive toward other dogs, which made me even more tense, and caused things to quickly spiral downward. Once I was able to stay calm, things improved with Sephy as well.

As for alpha rolls, they did not work well on Sephy. Here is more on my experiences with alpha-rolls-
http://shibashake.hubpages.com/_srec/hub/Cesar-Milan-Dog-Training-the-Dog-Whisperer#mod_1470395

With dog-to-dog aggression, getting help from a good professional trainer can be very helpful. A trainer can read the dog’s body language, and identify what is triggering the dog’s behavior. I visited with several trainers when I got Sephy and many of them were helpful.

Note however, that the dog training area is not regulated much, if at all. Pretty much anybody can claim to be a trainer. I found that it was also very important to do a lot of my own research and read all that I can about Sephy’s issues. In this way, I could tweak things to suit Sephy’s temperament, and more importantly, identify the good trainers from the bad ones. I also visited a lot of breed specific forums and learned much from veteran Shiba owners.

Here are a couple of articles that may be interesting-
http://thedoginc.com/how-dogs-learn-how-dogs-think
http://shibashake.com/dog/the-dominant-dog-dealing-with-dominance-in-dogs

Thank-you
John

Here are some of my experiences with off-leash neighborhood dogs-
http://shibashake.com/dog/off-leash-neighborhood-dogs/comment-page-1#comment-16740

My Shiba Inu was also reactive to other dogs when he was young. Doing dog-to-dog desensitization exercises with him was helpful. I was able to slowly train him to focus on me, and to use other behaviors to deal with his stress, other than aggression.
http://shibashake.com/dog/dog-to-dog-aggression#desensitize

I also did people desensitization exercises with my Shiba and taught him how to meet people.
http://shibashake.hubpages.com/hub/Dog-Anxiety-Fearful-Dog#mod_15989160

If the dog has a bite history, it is usually best to get help from a professional trainer. In such cases, timing and reading the dog’s body language become very important, which is something that a good trainer can really help with.

I observed a similar behavior with my Shiba Inu when he was young. In his case, there were several contributing factors-
1. Shiba Sephy is very sensitive to my energy. If I am feeling angry, frustrated, fearful, or worried, he picks up on that and becomes stressed himself. This often causes him to get even more reactive to other dogs.

2. When already in an excited state, putting undue tension on the leash can also cause Sephy to get more stressed and reactive. Pulling a dog directly back or other types of restraint, can sometimes cause an automatic lunge forward reaction. When I lead my dog away, I first go to the side and turn him around (in am arc), rather than pulling directly backward.

3. When Sephy was young, I took him to the dog park pretty often to play with other dogs. However, the environment in the dog park was very unstructured, and rather than learning how to socialize properly, Sephy’s behavior actually got worse. He would get over-excited, copy bad behaviors from other dogs, and redirect his excited energy onto me when I tried to calm him down.

I learned that Sephy does much better in smaller and highly supervised play groups. Instead of going to the dog park, I would invite my neighbor’s friendly dog over for a play session. I supervised them, and had many play breaks to prevent over-excitement. Play breaks are also a great way to train our dog to listen to us when in an excited state.

Here is more on Sephy’s dog park experiences.

Here are a list of techniques for recall training.
http://aspcabehavior.org/articles/84/Teaching-Your-Dog-to-Come-When-Called-.aspx