Correct levels of copper, as well as other minerals, will also prevent Johne's disease and Brucellosis. Also, worms can't live in an animal that has the right amount of copper. A few years ago we had some pretty shaggy looking goats (reddish brown curled hair instead of glossy black on their sides) and offered them a nibble of copper sulfate for the first time. In two weeks their coats were all shiny and they have stayed that way most of the time since. Copper is a must!