Expeller Soybean Meal and Corn By-products Versus Solvent Soybean Meal for Lactating Dairy Cows Fed Alfalfa Silage as Sole Forage

Production responses obtained with supplemental protein from expeller soybean meal or corn by-products, relative to solvent soybean meal, were determined in three replicated 4 x 4 Latin square trials. Dietary forage (54 to 58% of DM) was solely alfalfa silage containing 30 to 55% DM and 21% CP (DM basis). Main concentrate ingredient was either ground shelled or high moisture corn; diets were fed as total mixed rations. In Trials 1 and 2, supplements were: control (0 CP), .6x (60% of the supplemental CP of the l x treatment) solvent soybean meal, .6x expeller soybean meal, and l x solvent soybean meal. In Trial 1 (DM intake = 24.4 kgld), supplement had no effect on production but increased weight gain; expeller soybean meal increased production of milk and lactose relative to either amount of solvent meal. In Trial 2 (DM intake = 20.0 kgld), supplement increased production of milk and milk components; milk production on .6x expeller soybean meal was greater than .6x solvent soybean meal. In Trial 3 (DM intake = 22.4 kgld), distillers dried grains plus corn gluten meal replaced .6x solvent soybean meal; supplement increased production of milk, 3.5% FCM, protein, and fat with no dif-