I found this topic interesting and thought I would bring it back to the top. I was surprised of the many people who suggested Crested Wheatgrass.
If you go into western South Dakota, Montana, and other places west and ask a rancher what his favorite grass is, he will likely say Crested Wheatgrass. However I would not call it my favorite. In the past 50 years or so a lot of Crested has been planted here on wore out farmland. It makes good spring and early summer grazing but is not all that productive after a few years. I have always believed it is best in places where conditions are harsh, where moisture is limited and where fertility is lower, but it is an introduced grass that needs a good supply of nitrogen. Some vareities of crested are bunch grasses so fields tend to get humpy and rough. Crested Wheatgrass has a tendency to move into and invade native grass pastures, that can be either a good or a bad thing.
I prefer Intermediate Wheatgrass, although it does also have it's drawbacks and limitations. We do not really have adequate moisture or fertile enough soil for it to continue to do well. Fertilizer helps but unless we also get moisture it does not always pay out.
Smooth Brome has been used too, but it is losing it's popularity, it does best where there is more rainfall than we have here, and it is also a heavy user of nitrogen, it produces good a few years then get sod bound. Years back our conservationist recomended to seed 1/2 pound of brome per acre on our rolling hills and erodable soil, this proved to be a mistake as the brome just took over. It is terrible bad about invading fields and native pasture where is crowds out more desireable grasses.
What about Orchard Grass? We can not grow it here, except under irrigation, but would it do well in Minnesota?
It is my belief that cool season grasses make more growth farther north than they do here. Where the soil warms up later there is more hours of sunlight when grasses start their growth.