Jeff, they don't have to rip your arm off. They're trained to break the bones in it, rendering it usless. If you need them to be more lethal, you can train them to make killing bites on command. There's simply no need for the additional size, and you're giving up a lot by going with a fighting dog who isn't bred to take minute and complex orders from his owner. How many of the dogs you mention can earn their schutzhund titles? How many can do a bark and hold or stop short after a fifty yard dash against a target and NOT attack?
If you really want more size, a quality working line Rott is an option, though they're getting difficult to find due to a lot of insane breeding by boneheads trying to make, you guessed it, FIGHTING DOGS out of them for back yard dog fights and because assorted boneheads keep trying to make them bigger. The fighting dogs you mention, used as a service dog, are an open invitation to a law suit or criminal charges. You will never see one in a professional capacity, even as a modern military dog. Cortez and his boys would use enormous mastiff breeds like the Presa Canarios as a tool of terror. They were simply unleashed on the villages to kill anything that moved. Men, women, children, livestock. I'm not saying they're no good as pets for prepared owners, but to use one for real life protection work is a very very dangerous notion. They should never be allowed to taste manflesh, or very bad things can happen.
but a smaller dog would not likely survive such an encounter, because of its smaller mas
Absolute hogwash. Unless the human has a knife or firearm and gets lucky, the dog will have his hind end. Thousands upon thousands of criminals have thought as you do, that they were strong enough to beat up a "little" malinois or GSD bitch. WRONG. The bites aren't like play bites, they're like getting shot, with over 200 ft. lbs. of force in each bite plus the damage of the teeth. You're stunned, your bones break, and your instinct to flee the jaws takes over. They don't walk up and try to bite you, they fly at you faster than human reflexes can respond, slamming into you in whatever manner they've been trained.
What's the 300 lb. goblin going to do if after five seconds HIS HANDS AND FOREARMS ARE USELESS AND BLEEDING PULP? And believe me it can happen even faster than that. Each time he tries to strike out, his hand is intercepted by the razors long before doing any damage to the dog.
Hold out your left arm, then smack your wrist with your right hand, open palm, as hard as you can five times in quick order. Then imagine that happening with ten times the amount of force you just applied, PLUS an array of cutting and bone breaking teeth. That will give you some idea. These dogs can break you down like lawn furniture. They understand joints and can leap high enough to disable any of them--including the back of your neck. Indeed in ringsport they routinely jump barriers higher than a man's head.
We were thinking of fencing the backyard and then found out that we would have to have a fence taller the eight feet, because she could get over one of those.
