I have never shot an animal in SD of another human but did kill two neighbors pitbulls in my yard in defense of my small dog.
However, another neighbor was coming out of his house with his g-daughter in his arms and was met by a dog at the end of his porch digging in the trash. He tried to run the dog off. Dog snarled at him and he went in, grabbed a pistol and shot the dog. He then took the dog down, dumped it in the yard of where it lived, knocked on the door and told the guy what happened. The dog owner called the sheriff and when it was all done, my neighbor had to pay just under $2000.
Judge asked neighbor "was dog attacking a human or any animal owned by him". He answered "no".
Ironically , the two pits I shot were from the same house as where the dog my neighbor shot was from. Animal control went to that residence and found several unlicensed dogs running lose, dog houses , water/food bowls all over but couldn't cite the resident as he told animal control the dogs didn't belong to him.
...animal control rounded up all the dogs.