I have posted on this previously, but wish to add to this thread. Most people have no idea what dogs are capable of. I presently own and train an American Bulldog for personal protection. I understand people's concern with this issue. However, the issue is how to defend against "loose" dogs that may attack you. This is a serious issue. More effort should be brought to bear on the powers to be to ENFORCE the leash laws that exist. It distresses me to see that right now, in my state, they are AGAIN trying to pass a BS law listing dogs as dangerous weapons. This law would target specific breeds and make it possible for communities, cities, and townships to outlaw the ownership of certain breeds. This is due to Gross misunderstanding of dogs in general. lets pick on Pit Bulls. They are naturally a target. People have been attacked by dogs labled as "Pit bulls". Even though TRUE pits are completely not people aggressive and are actually a rather small dog. There is NO way to enforce such a law. Also, it is ridiculous. For example, I have a pit bull living next door. It is a great dog and totally non people aggressive. Two doors down is a "mutt" that is incredibly vicious and would attack anyone if it could get out of it's fence. Labs are kown to be lovable family pets. Yet I personally know of very vicious labs. There is no way to enforce such legislation. However, you can enforce the existing leash laws and punish owners who ignore them. My dog never leaves the house, even to go to the fenced back yard, with out being on a leash with a 3.8mm spike collar. He is completely in my control as all good training systems emphasize obedience over attack training. I know of one trainer who temperment tests his dogs at a young age BEFORE protection training them. If they fail they are euthanized. That is how seriously they take this issue. In addition, if you do the statistical research on the number of dog attacks compared to the number of dogs owned as contrasted to violent attacks perpertrated by humans... we should be outlawing humans. Much of the problem is perception and propaganda. I have a right to talk about this because my daughter has been attacked five times. It is personal with me. She loves my AB and dogs in general despite her negative experiences.
If you want a loving companion and are concerned about self defense but don't have the time, money, inclination or whatever to learn to defend yourself physically or with weapons, a good dog is a wonderful option. Walking with a dog is a good deterrent in itself. If you do own a dog and walk it on a leash, do not let strangers approach your dog to pet it. Most dogs are fear biters unless trained and many people emit pheromones that agitate even the most passive of dogs.
As a lifelong martial artist, protection dog owner and trainer, let me say this:
There is no tried and true general method for defending yourself. As stated above different things have worked for different people in different situations and it is also dependent upon the dog. If you are attacked..please prosecute the neglegent owner to the full extent of the law. Your martial skills however, will probably provide little if any assistance. They are much faster than you are. Their reflexes are actually faster than cats reflexes. You will need some type of weapon, your belt, a stick anything. Wrap a coat or shirt or something around your arm and put it between you and the animal. That is...if you have time to do so. You cannot outrun the animal. If the animal is determined, you may be in the fight of your life. After you have prosecuted the owner, insist that the dog is euthanized. There already exist specific laws regarding this in most states.
I am going to try and post a photo here of a protection trained American bulldog. This is just to show how capable a dog is of protecting you and that it is a good option for self protection. It is also completely legal and requires no special permits as do guns.
This is Panda, two years old. Her self confidence has been built up to the point that she fears no weapon or opponent. My AB is not yet two years old, weighs 106 lbs and is still growing. This is just one of many excellent breeds for personal protection, and my favorite. Panda is slightly smaller.