What are the white things in race horses ears?

Answer 1

There are a couple of things it could be, first and most likely it is white ear plugs that you are seeing. racehorse trainers will put ear plugs in to deaden the noise of the crowds and to help keep dirt and mud out of a horses ears. Secondly it could be a type of growth called Aural plaques. Aural plaques (Also called Aural papilloma) is typically a benign condition that causes warty / crusty white growths to form on the insides of a horses ears. Aural Plaques are thought to be caused by a wart like virus that may be spread by flies.