Ugh! Horsehair on clothes!

Don't store your play clothes and your work clothes in the same closet. I have 6 degrees of clothing...kinda like "6 degrees of 'separation' "--
(1) Super dressy, like going to a wedding clothes,
(2) Very dressy, business and Christmas/Easter "at church" clothes
(3) Casual business
(4) Casual, go shopping, NO STAINS
(5) Schooling horses clothes
(6a) Mucking, gardening
(6b) REALLY DIRTY mucking, gardening and painting clothes
Just run them in the dryer, then put a wet washcloth in to dry and collect any hair that might turn up on your next washload.
Really, animal hair is the name of the game, so get used to it. =b

Wrap a loop of duct tape around your hand and pat it all over to get the hair off. Cheaper than a lint roller. I have a white horse, and have pretty much given up but the duct tape works pretty well...

Eventually the hair will build up enough to lend warmth to your riding clothes. Good luck in this endeavor.