grass is dormant in the winter so graze it as hard as snow cover allows..
leave some tall strips to hold snow, btw...they need to lay e to w...and only need to be bout 5 ft wide...ie tall grass.
likely your gonna need to supp some hay and/or ear corn 2.
sun even at 10 degrees F will beat off ( melt ) your E / S slopes off prretty good so you'll want to use the supps to bait em over to that in the winter ( get tracks and it melts more snow and ice and enables more winter grazing ).
good luck...seems 2 me like U better start with less than 200 head....say 50 decent cows and they'll Teach You how things Work.