That way you can take quality into account as you store bales for winter feeding. Depending on the forage and the nutrient requirements of the cattle, you may need an energy or protein supplement or a balanced combination. One supplement doesn't fit all situations. This is why a forage test is critical. Compare cost of nutrients.
Many factors affect cost.
After deciding what nutrients the cattle need, feed the supplement that delivers those nutrients most economically. It's less expensive to purchase feed in bulk, but transportation and storage are a problem for many producers. Supplements in blocks, tubs, cubes or tanks are often more expensive, but save time and labor. Protein enhances forage intake. That's because the rumen microbes that digest forage have to have protein to do their work.