My mare is all shed out now except for her legs. I can't keep up with the hair. I brush and brush and curry and curry and it's still there. The winter fur won't stop coming out. And now she has this white flaky...stuff in the long hair on her lower legs. It looks exactly like dandruff. Someone at the barn suggested it could be something fungal. Or is it really just dandruff due to dirt and such that is caught in the longer hair? Opinions?