You got snow already!
A rancher friend of mine calls those "range cubes," which I never understood because they are NOT cubes... Technically, they're cylinders, LOL!
As far as what to feed your cow... We keep ours on pasture with a creek, and during the late fall, winter, and early spring provide free choice good quality hay. We also give them 14% protein grain while they're being milked (twice a day), and free choice mineral/salt mix.
IMHO, whole corn is not a good choice for cows. A grain mix for cattle from your feed store would be a better choice. It has about twice as much protein and is easier for them to chew. In our area, it's very close in price to corn.
We never let the calves nurse our cows. We prefer to milk the cow out twice a day and bottle feed the calf. May sound like a lot of needless work, but we do it for three main reasons. One, because calves can cut the cow's teats with their teeth, which makes milking very little fun until it heals. Two, because the calf will be people friendly when he grows up if you bottle feed him. And three, because the cow will be more manageable if she isn't worrying about the welfare of her calf.
Just my two cents worth! Feel free to let it come in one ear and out the other, I don't mind!