JUst recently noticed that our weanling gelding has a lot of dandruff flakes on tail and in the mane. Looked at teh rest of the coat (long already) and it seems clear. He is rubbing a lot on the tail area. Have been told could be lice? If so, what do I use to treat it. Its getting cold here in Kansas so bathing I think is out of the question. He has been combed regularly and well taken care of so don't know how he would have gotten lice?