When faced w/ this situation, it may well be that you will not be charged w/ anything regarding the dog, however, you may still be charged w/ discharging a firearm within a city(if that is your locality). This was the answer given to me about a situation I was in, in Wyoming.
"The right of the citizens to bear arms in the defense of themselves and of the state shall not be denied." Wyoming Constitution Article 1, Sec24
"Better to be tried by 12 than carried by 6"