Effect of feeding macerated alfalfa silage on nutrient digestibility and milk yield in lactating dairy cows

• Published in: Journal of dairy science Vol. 82; no. 11; pp. 2472 - 2485
• Main Authors: Broderick, G.A, Koegel, R.G, Mauries, M.J.C, Schneeberger, E, Kraus, T.J
• Format: Journal Article
• Language: English
• Published: Savoy, IL Am Dairy Sci Assoc 01.11.1999; American Dairy Science Association
• Subjects: alfalfa silage; amino acids; ammonia; Animal Nutritional Physiological Phenomena; Animal productions; Animals; Biological and medical sciences; Cattle - physiology; chemical composition; cutting date; cutting frequency; dairy cows; diet; Dietary Fiber - metabolism; Dietary Proteins - administration & dosage; Dietary Proteins - analysis; digestibility; digestibility markers; Digestion; dry matter; Eating; Feed and pet food industries; feed conversion; feed intake; Female; Fish Products; Food Handling; Food industries; forage conditioning; Fundamental and applied biological sciences. Psychology; Glycine max; Lactation; liveweight gain; macerating; maturity stage; Medicago sativa - chemistry; milk; milk fat percentage; milk fat yield; milk protein percentage; milk protein yield; milk yield; Rumen - metabolism; rumen fluids; Silage; solids not fat; Terrestrial animal productions; urea; Vertebrates; volatile fatty acids; Weight Gain; Zea mays; United States; North America; America; Performance evaluation; Organic matter; Lactation; Animal feeding; Ruminant animal; Dairy cattle; Ox; Silage; Milk fat; Lucerne; Maceration; Ungulata; Net energy analysis; Digestibility; Farming animal; Nutritive value; Fodder; Cow; Milk production; Vertebrata; Mammalia; Diet; Artiodactyla; Crude protein; Soybean meal
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(99)75499-8

Five feeding studies were conducted with 141 lactating Holstein cows comparing macerated and control alfalfa silage harvested at two cuttings in each of 2 yr. Overall, silage made from macerated alfalfa contained more ash (suggesting improved soil contamination); greater fiber and lower nonprotein nitrogen (NPN) content suggested greater fermentation in the silo. In a digestion study, two diets were fed containing [dry matter (DM) basis] 72% of either control or macerated second-cutting alfalfa. Apparent digestibility of neutral detergent fiber and acid detergent fiber (ADF) was increased by maceration, and similar changes in digestibility were observed with Yb or indigestible ADF as marker; indigestible ADF was used as a marker in later studies. Lactation trials were conducted with first- and second-cutting alfalfa from each year. In each study, diets were formulated from alfalfa silage plus concentrate based on processed high moisture ear corn; mean compositions were (DM basis): negative control (61% control alfalfa silage), macerated (61% macerated alfalfa silage), and positive control (50% control alfalfa silage). All diets contained 2% crude protein from either roasted soybeans or low-solubles fish meal; soybean meal was added to make the positive control isonitrogenous (but not equal in ruminal undegraded protein). Milk yield was greater on macerated than negative control in two of four trials but not different in the other two trials. Yields of milk and milk components were not different between macerated and positive control in one of four trials. Versus the negative control, milk fat synthesis was depressed on macerated alfalfa in one trial. Overall performance on macerated versus negative control indicated greater apparent digestibility of organic matter (OM), greater yield of milk, protein, and solids not fat, but lower milk fat content. Yields of milk and milk components were greater overall on positive control versus macerated. Estimation of net energy for lactation (NE(L)) from maintenance, milk yield, and body weight gain indicated that control and macerated alfalfa silage contained, respectively, 1.36 and 1.42 Mcal of NE(L), of OM, an increase of about 5% due to maceration of alfalfa in these trials.