In Oklahoma, if there is a wild animal harassing your animals, i.e coyote, bobcat, etc, you can shoot it. Just have to call the game warden. Additionally, animal control doesn't exist in the country.
I've killed venomous snakes before. Generally to protect pets. While I know to run the other way, dogs tend to be stupid and go "Thing in my yard! yapyapyapyapyap!". There's no one to call to remove the snakes and I'm certainly not brave enough to go and relocate it, either. If the snake is out in the pasture/woods/large ponds, I leave it alone. The house/small pond is a no go area for venomous snakes.