Richard S. Adams Penn State Emeritus, Professor of Dairy Science
814-863-3917

Liquid whey is a by-product or waste product that is available at moderate costs in cheese-making areas. Whey may be tanked to animals on a continuous basis. Generally large breed cows will consume about 90 lb of liquid whey daily. If grain feeding is not reduced, forage dry matter intake may drop somewhat. While drinking water should be available to cattle on liquid whey at all times, they will drink less water than usual since whey often contains 93 to 95% water. Intakes of 150-200 lb of liquid whey are not uncommon when rations using whey are properly balanced.

Whey usually contains about 13% crude protein on a dry matter basis. Its protein content may range from 9 to 15% or so, depending upon the types of cheese made, the casein content of the milk supply and the efficiency of the plant. It is not a protein-rich feed as some test reports or promotional materials suggest. On a dry matter basis the protein and energy content of whey is similar to oats, but it is appreciably higher in calcium and phosphorus.

Sometimes whey is made available at no cost to farmers except for a delivery charge. A gallon of whey weighs approximately 8.45 lb. This means that a gallon of liquid whey may provide .42 lb of dry matter if it contains 5% dry matter (8.45 x .05 = .42). To determine if it is a good buy at any particular cost, calculate how much is being paid for 85-90 lb of dry matter and compare it with the price for a cwt of dry shelled corn, oats, barley, or a 12 to 13% dairy feed.

Liquid whey also may be used in the feeding of replacement heifers and calves over 3 weeks of age. Milkfat test often is at optimum levels when whey is fed to milk cows. It may alleviate milkfat test depression from certain causes. This characteristic probably stems from its lactose or milk sugar content and its effect on metabolism.

Recommendations and cautions on the use of liquid whey are given in a Penn State Dairy Science Extension fact sheet, DSE-82-38. This is available from county Cooperative Extension offices. Whey should be kept before the animals constantly to avoid acidosis and possible deaths from an overload by hungry animals. For best results get professional help to balance rations containing whey.

Source: Richard S. Adams