They have to be exposed to animals you wish them to guard from a young age. We didn't get goats until the past few years, so Bear had never seen a goat before. He was always a hyper and playful dog, definitely like daylight and dark to his brothers, who were all mellow and calm. He must have gotten excited when he saw the goats and played with the goat until it keeled over with a heart attack I guess? All water under the bridge now, but I like keeping a goat in with my dogs just in case. A lot of our neighbors have goats.