I've tried to break two large fighting dogs apart two or three times in my life. I was bitten each time, once by my own dog. They have extreme tunnel vision during fights, focusing on their kill instinct to defend themselves. I personally would have stated my own safety was at risk on the complaint.
Unfortunately, we have many new felony animal abuse laws on the books today in NC. It is literally easier to walk out of jail after being found guilty of assaulting a police officer than to be found guilty of felony animal abuse. I still raise animals today, and always have. It's just very difficult for me to live in a new world where animals are considered to have "rights", and their life is on equal ground with mine and my family's.
I'd shoot until empty on ANY attacking animal, whether I was charged by police or not. Unlike animals, pet owners still are required to carry the burden of responsible ownership of their posessions. Animals and guns are just some of them. If a car driver swerves at a pedestrian, would the argument be the same? In most states, I think so.