Given that cows can eat only a certain amount per day, forage alone cannot supply the required amount of energy and protein. Generally, the purpose of adding concentrates to the ration of dairy cattle is to provide a concentrated source of energy or protein to supplement the forage and meet the animal requirements. Thus, concentrates are important feeds that allow for formulating diets that will maximize milk production. In general, the maximum amount of concentrates a cow can receive per day should not exceed 12 to 14 kg. Corn gluten feed , another by-product of starch production, contains less protein and more fiber.
Wheat bran is a good source of phosphorus and functions as a laxative.
Intact oilseeds can be used as high energy feeds, but they usually contain anti-nutritional substances. They need to be handled properly to avoid the risk of bacterial infections. However, those nutrients may be very dilute when the whey is not dried. For example, milk fever in early lactation is due to an imbalance in calcium metabolism, and phosphorus is essential for high herd fertility. Deficiencies may result in large economic losses.