TICA, I don't even use a brush on my horses this time of year, except for their faces.
http://www.llbean.com/llb/shop/71553?productId=1189940&subrnd=0&qs=3016887_pmd_google_pla
If you buy a dog furminator for large breeds, they aren't that much shorter (in width) than a Furminator for horses but they are a few dollars cheaper.
I rake the horses down, then take the shop vac to them. I used to use drag the upright Kirby down from the house but "borrowing" the shop vac from Mr. TWH's workshop was a lot more appealing and the shop vac has a longer hose. Just do NOT vacuum the family jewels and some horses don't like their faces vaccuumed.
Two of mine love their faces vacuumed, the other two are trying to get my cell phone to call for help, so I leave them alone - lol lol
The vacuum does a great job of pulling up excess dander, more than hair. That in turn helps stop the rainrot until it warms up to where you can give him a nice shampoo bath

nthego:
I "borrowed" the shop vac three years ago - the work shop is only 50 feet away but the vac has never been back to visit - lol lol lol