Dandruff in horses mane!! HELP ME

I noticed that my horses mane has been getting shorter and shorter He has been rubbing it off on the tree's/hay bale ring.... I checked his mane and he has TONS and TONS of white flaky junk at the very base of his mane.....

* how can I get rid of this?
* What's it called?

The picture isn't a close up, so I can't be sure. If you can get a better pic that will help. If it is dandruff you will most likely need to heal from the inside out. Flaxseed and rice bran oil in the feed will give omegas and fats necessary for good skin condition, just remember they both add calories, esp. The oil, so be careful not to overfeed. If it is mites or rot or fungus I can't tell, but they all need different treatment. Is your round bale keeper for horses or cattle? The cattle ones are rough on manes!
Posted via Mobile Device