MiG farming

Cattle can and will graze thru up to 3 inches of snow to eat stockpiled forages. You will look kinda funny to the neighbors moving wire or polytape in the snow, but it can save you from feeding hay a few more days of the year.
Beyond 3 inches of persistant snowcover, we throw in the towel and feed hay.

Gideon,
I'm in the snow belt area of Western NY, and agree with UpNorth. Jan/Feb I'm under x feet of snow, so hay's the only option that I have. But prior to that, when there's only a few inches or the wind's blown the snow off the frozen pastures, the cows will try to forage.