Shih Tzu aggression

Question
Hey,
I have a 10 month old female shih tzu. She has a really nice nature and everything. But some dogs she doesn't like and she will start growling, snapping, yapping and sort of batting them (like our cat does to her).
    We really don't know how to control her as she never listens once she's being aggression. Any suggestions?
    As she is usually off the lead when she is on her walk there is no way we can pull her back if she is already with the dog.
    We have noticed that its usually puppies and dogs that want to play or show too much interest that she goes for.

Thanks.

Answer
First thing is to not allow her to be in that situation. Once a dog is in reactive mode, they really aren't able to listen. Many small dogs put on an impressive display to show other dogs that they are "big". It's not actual aggression and is mostly a bluff. Still, if she does it with the wrong dog, that dog could call her bluff and a real, dangerous, fight would occur. She could be hurt. Also, if she is running up to puppies and displaying, can you imagine how scary that could be? At certain times in their development (critical periods) she could do permanent emotional damage to that pup - making it fearful or aggressive towards small fuzzy dogs. You don't want to be responsible for that.
When you are in areas where you are likely to meet other dogs, she needs to be on lead, since you know she has this habit. You can even use a long line (not a retractible or flexi - even a long piece of cotton clothesline with a snap securely attached will work) so she can range a bit and check things out. But you will be able to get her back to you before she has a chance to charge in. If she sees the dog before you do and gets excited, quickly go the opposite direction until you are far enough away for her to be able to look at the dog and take treats - and pay some attention to you. Look for a good, positive manners class in your area, where she can see other dogs in a more controlled situation. Look for a clicker trainer, and look for a class which is not over crowded. A great game to play with her is "Look At That" from Leslie McDevitt's book "Control Unleashed" which would be an excellent book to read. The instant she looks at another dog, click and treat her. Continue to click every time she glances at the dog - immediately - before she has a chance to stare or get worked up. Soon another dog will be a predictor of a wonderful, interactive game with you, and she'll be focusing on you instead of the other dog. But in this situation, prevention is the name of the game. Knowing that she will charge at other dogs, you simply can't, responsibly, allow her the chance to behave badly and dangerously! Every time she gets to do that, she rewards herself, the habit gets stronger, and it becomes harder to fix. Good luck! Sandy Case MEd, CPDT