CHAPTER 776 JUSTIFIABLE USE OF FORCE has zero to do with anything in this thread. It never mentions police dogs or any other animal, it is centered on humans and humans alone.
The other link though which does talk about police dogs operates on the premise that a person knows that a police dog is a police dog. We dont have any information as to the actual circumstances that led up to the dogfight and the shooting of the family pet. There is no mention of whether the police dog was leashed or not. They do mention in the article several times that the homeowners dog was unleashed which is untrue. The dog had an electronic leash on that shocked the dog if he dared to cross the property line.