The first year we planted brassicas at camp, deer didn't know what they were, so didn't bother with them. 2nd year, deer started hitting them. 3rd year - the mix was DER, PTT, Pasja forage brassica, and Groundhog radishes. Deer were hammering that plot. It seemed deer were eating all of the tops from all varieties. Turnip bulbs were eaten first ( when the tops were eaten/frozen down ) and the radish bulbs were the last thing to be eaten.
Deer use varies in all areas it seems. Our camp is in mountains with no ag nearby - only woods. It was an old farmstead, so fields were there & we rehabilitated them for plots. Once acorns are gone, those winter brassica plots get lots of attention. Anywhere from late Sept. through March, deer will be in the brassicas, winter wheat, & winter rye.
This fall - little rain has our brassica plot way behind last year's growth levels. Deer are eating the tops already, but at only 6" to 7" tall, it's gonna take rain & moderate temps. to get 'em going.