If you have animal control in your area, call them. Unfortunately, where I live I am the only animal control there is. The population here is so sparse that we know each other's animals and we all keep ours up. If one shows up that we don't own, it's usually a stray. If it's friendly and I can catch it I do. Sometimes they are hunting dogs that have gotten loose and I call the owner on the tag to let them know. If the dog is unfriendly, well I put it out of it's misery and mine. It's harsh but sometimes prevention is part of farm life.