My dogs are great on the trail (my property) and either stay in front or behind. They come when called and never run off. I especially like having them with me in the summer to warn me of snakes.
I hate people who let their dogs roam free. Its dangerous especially if they try to bite you or the horse. I told my neighbor last summer that if her dogs EVER came onto my property again to attack my horses that I would shoot them dead. She knows I wasn't jocking and I haven't seen the dogs since. (I'm assuming she penned them up because they still bark).