For your cattle (cows, calves, bulls), hay forms the basis of the daily forage ration: it provides the fibre essential for rumination and proper rumen function. Straw, less nutritious, is mainly used as comfortable, absorbent bedding in the barn. Barley, rolled barley and corn add the energy needed for production requirements (growth, lactation, fattening): rolled barley is especially recommended for animals that digest whole grain less easily, thanks to its crushed grain being easier to assimilate.
