could very well be ring worm. They have a cream to treat it, but I have heard that once they get out in the pasture, and get some sunlight it will clear up. Never had first hand experience with it tho. Just wash your hand if you touch the animal, people can get it too.
It probably IS ringworm. there have been more cases than usual this year in my area, attributed to a dreary winter. if it is you can treat it or it will go away by itself. however once you have it you have it.