Tail hair falling out

Almost every year for the past three years we have had atleast one of our show calves have their tail hair twist up, and fall out slowly.
Does anybody know what is causing this, or what to do to fix it? Please Help!

I had a fungus in my show heifers for a few years that only affected the tail switch.  The hair would fall out, mostly on one side of the switch (strange).  Betadine scrubs for a few days usually cleared it right up.

I just bought a few steers from a guy.  The steers had lost their tail hair, the vast majority of them, and he said it was from mites.  I don't know if that is total fact, but you might want to check into it.  Our hair is slowly coming back in, but they are young and have a whole year to grow some back.

Pout some Cydectin down the tail to kill the tail mites before they kill the tail.

Thanks guys!