I don't know where I'd save $75 in feed. I don't spend money on either cows or heifers other than a mineral-lyx barrel and a $6 salt block. I have found the mineral is important to calving and overall health. Consumption is very moderate, I'm sure it makes more money than it costs. 

And my hay is what it is. I don't keep two different classes of hay. As long as it is about 10% protein it seems to work.  Keep some legumes in a hay field mix, harvest it on time and it's good.

In weather as we are having tonight, -10F or lower, I want those girls' rumens full of hay for warmth when they go into the woods, out of the wind, for the night. I think about how much heat is given off when a hay bale burns.