It's been awhile but five of the nine times my dogs have been attacked were by pits. I decided the last time that if it ever happened again I would end it. I'm not a violent person and I always look for any way to avoid conflict. I carry a pocket knife but for strictly utilitarian purposes. That said, if another dog ever gets a hold of mine again I'll aim for the heart and the jugular until I see arterial blood spray. 

I'm sure I'll have feelings of remorse but that will always be followed by reminding myself that the other dog was trying to kill mine. Also, mine are always on a leash and have only ever been attacked by dogs who weren't or even by dogs who were deliberately turned loos to attack mine while out on a walk.