I have a 2 year old registered black angus bull that is losing hair on his backbone, starting at his shoulders. A patch about 4 inches wide and 12 inches long. Another small patch at his tail head. This doesn't appear to be winter hair loss, because his skin is bare. Is this caused by lice, and if so how do I treat it. I also have 8 other animals that have no hair loss. Do I need a vet? Thank you for your help.