Really depends on what condition they are in, what else they have to graze on and how cold/wet it is. I was always taught to think about feeding 40 pounds of hay per day for bred/lactating cows and about 20 pounds per day for calves. But I always try to figure on waht else they have to eat and the weather. And from the figures you showed, that works out to be about 43 pounds per day
For us, we run our cattle on grown up hay fields. There is not alot to graze, but we can move them to other fields also. We feed a little hay when it snows or gets wet and cold. And we dont feed alot of alfalfa at all, it is mostly timothy hay kick outs and they graze timothy fields, and we have had cows gain weight over the winter on just that. But the big thing for us is that we are under stocked for our summer irrigated pasture and I think our cows are way to fat, so this time of year I try to make them hunt for feed. I don't starve them, but I don't feel too sorry for them.
If you look at my post about my day part 1, the replacement heifers told me this morning they were out of grass, they had jumped the tape. So thats telling me I am being a little too tough and needed to give them more grass and feed them hay every other day to help the grass. Even though they are in really good shape, there was just not much to eat anymore.
I think your probably doing fine, as long as it works out right for your checkbook.