When I was a teenager we moved out into the country with our 5 year old pointer. I got involved with the FFA and soon enough I had a small herd of goats. Well Duke (our pointer) loved the goats...in a bad way
. He never killed one, but he tried. With some training, he never did it again. I could actually have him inside the pen with me and he was fine. The whole "taste of blood" thing is absurd.
First, you should never leave your dogs to roam around the farm unattended...they WILL get into trouble. If you must leave them out, I suggest an electric fence....although it is not guaranteed to work, sometimes it can (a friend uses one with her GSD and it works great).
I was a young teenager when I 'trained' my GSP to leave the goats alone. Basically, I punished him for even looking at the goats. He soon learned to leave them alone. After a while, he was aloud to look...he would spend all day just watching the goats. And we never had a problem with him again.
Now that I know more about dog training, I would have gone a different route. Positive reinforcement. Reward your dog for leaving the goats alone (ignoring them). I am sure others will have some great techniques for you to try. My rottie has a MUCH higher pray drive than my GSP did....I would NEVER trust her alone with goats. Killing pray is a normal thing for dogs...it does not mean they will kill humans. Please do not get rid of your dog for that reason; he is simply being a dog...chasing his prey.
Oh, and I would not get into herding...unless you keep him inside during the day (which you should be doing anyways IMO). When dogs are left to 'herd' animals unattended, they often go overboard. They will herd the sheep/ goats until the poor things cant move anymore. Often, this is when the killing begins. A herd dogs natural instinct is to keep the goats moving; once they stop, the dogs bite the goats to get them moving again
...resulting in a lot of dead goats. Who knows, maybe your dog is already trying to herd the goats.