Don't know the nutritional content but here in Pa. Purple top turnips work good. The deer consume the big leafs and stems in the fall and the big turnips that are left growing half way out of the ground are then consumed later. They are still digging through 16 inches of snow to get to the turnips and the turnips are still there. I like this idea because they wont over browse them as they are growing. The leaves are bitter until frost hits them and sweetens them up. Then they are able to come back and find the big roots at a later date. Also there is absolutly no waste. The total plant and root is eventually consumed. They are fairly easy to plant and grow also.