Effects of Increasing Levels of Grain Supplementation on Rumen Environment and Lactation Performance of Dairy Cows Grazing Grass-Legume Pasture

¹ Escola de Veterinária UFMG, Brazil and Department of Dairy Science, University of Wisconsin, Madison 53706
² Department of Dairy Science, University of Wisconsin, Madison 53706

The impact of supplemental energy on nutrient utilization, fiber digestion, rumen fermentation, and lactation performance was evaluated in dairy cows grazing pastures composed of brome, orchardgrass, red clover, and alfalfa. Three amounts [0, 5, and 10 kg dry matter (DM)/d] of ground dry shelled corn-based concentrate were supplemented to nine rumen cannulated Holstein cows in a 3 x 3 Latin square replicated three times. Cows were on average 84 ± 13 d in milk and producing 41.6 ± 5.9 kg of milk/d at the beginning of the study. An increase in amounts of concentrate in the diets was associated with an increase in milk production, solids-corrected milk, and concentrations of milk protein and SNF. Milk fat percentage and milk urea nitrogen concentration decreased linearly with supplementation. Milk production and protein percentage were 21.8, 26.8, and 30.4 kg/d, and 2.85, 2.95, and 3.05% for the increasing levels of concentrate, respectively. Intake and digestibility of DM and organic matter (OM) increased as grain supplementation increased. Ruminal pH and total volatile fatty acid concentration (VFA) were not affected by supplementation or the amount of concentrate. Ruminal ammonia concentration was reduced by supplementation, presumably due to a decrease in N intake and greater use of ammonia-N for rumen microbial protein synthesis. Rumen fermentation varied throughout the day, with lower mean pH and higher VFA concentrations at night. Supplementation increased total OM intake, decreased forage OM intake, and increased the proportion of OM that was digested in the intestines. Total DM intake by grazing dairy cows can be increased using ground dry shelled corn-based concentrate without causing negative effects on forage digestion.

Key Words: dairy • starch • rumen • grazing

Submitted on February 24, 2000
Accepted on June 6, 2000

This article has been cited by other articles:

				Q. Zebeli, J. Dijkstra, M. Tafaj, H. Steingass, B. N. Ametaj, and W. Drochner Modeling the Adequacy of Dietary Fiber in Dairy Cows Based on the Responses of Ruminal pH and Milk Fat Production to Composition of the Diet J Dairy Sci, May 1, 2008; 91(5): 2046 - 2066. [Abstract] [Full Text] [PDF]

				C. M. Mikolayunas, D. L. Thomas, K. A. Albrecht, D. K. Combs, Y. M. Berger, and S. R. Eckerman Effects of Supplementation and Stage of Lactation on Performance of Grazing Dairy Ewes J Dairy Sci, April 1, 2008; 91(4): 1477 - 1485. [Abstract] [Full Text] [PDF]

				G. B. Penner, K. A. Beauchemin, and T. Mutsvangwa An evaluation of the accuracy and precision of a stand-alone submersible continuous ruminal pH measurement system. J Dairy Sci, June 1, 2006; 89(6): 2132 - 2140. [Abstract] [Full Text] [PDF]

				S. L. Boken, C. R. Staples, L. E. Sollenberger, T. C. Jenkins, and W. W. Thatcher Effect of Grazing and Fat Supplementation on Production and Reproduction of Holstein Cows J Dairy Sci, December 1, 2005; 88(12): 4258 - 4272. [Abstract] [Full Text] [PDF]

				C. V. D. M. Ribeiro, S. K. R. Karnati, and M. L. Eastridge Biohydrogenation of Fatty Acids and Digestibility of Fresh Alfalfa or Alfalfa Hay Plus Sucrose in Continuous Culture J Dairy Sci, November 1, 2005; 88(11): 4007 - 4017. [Abstract] [Full Text] [PDF]

				C. M. Graf, M. Kreuzer, and F. Dohme Effects of Supplemental Hay and Corn Silage Versus Full-Time Grazing on Ruminal pH and Chewing Activity of Dairy Cows J Dairy Sci, February 1, 2005; 88(2): 711 - 725. [Abstract] [Full Text] [PDF]

				A. N. Hristov, S. Ahvenjarvi, T. A. McAllister, and P. Huhtanen Composition and digestive tract retention time of ruminal particles with functional specific gravity greater or less than 1.02 J Anim Sci, October 1, 2003; 81(10): 2639 - 2648. [Abstract] [Full Text] [PDF]

				J. J. Loor, W. H. Hoover, T. K. Miller-Webster, J. H. Herbein, and C. E. Polan Biohydrogenation of unsaturated fatty acids in continuous culture fermenters during digestion of orchardgrass or red clover with three levels of ground corn supplementation J Anim Sci, June 1, 2003; 81(6): 1611 - 1627. [Abstract] [Full Text] [PDF]

				J. H. Fike, C. R. Staples, L. E. Sollenberger, B. Macoon, and J. E. Moore Pasture Forages, Supplementation Rate, and Stocking Rate Effects on Dairy Cow Performance J Dairy Sci, April 1, 2003; 86(4): 1268 - 1281. [Abstract] [Full Text] [PDF]

				F. Bargo, G. A. Varga, L. D. Muller, and E. S. Kolver Pasture Intake and Substitution Rate Effects on Nutrient Digestion and Nitrogen Metabolism during Continuous Culture Fermentation J Dairy Sci, April 1, 2003; 86(4): 1330 - 1340. [Abstract] [Full Text] [PDF]

				J. Kennedy, P. Dillon, L. Delaby, P. Faverdin, G. Stakelum, and M. Rath Effect of Genetic Merit and Concentrate Supplementation on Grass Intake and Milk Production with Holstein Friesian Dairy Cows J Dairy Sci, February 1, 2003; 86(2): 610 - 621. [Abstract] [Full Text] [PDF]

				F. Bargo, L. D. Muller, E. S. Kolver, and J. E. Delahoy Invited Review: Production and Digestion of Supplemented Dairy Cows on Pasture J Dairy Sci, January 1, 2003; 86(1): 1 - 42. [Abstract] [Full Text] [PDF]

				F. Bargo, L. D. Muller, J. E. Delahoy, and T. W. Cassidy Performance of High Producing Dairy Cows with Three Different Feeding Systems Combining Pasture and Total Mixed Rations J Dairy Sci, November 1, 2002; 85(11): 2948 - 2963. [Abstract] [Full Text] [PDF]

				F. Bargo, L. D. Muller, J. E. Delahoy, and T. W. Cassidy Milk Response to Concentrate Supplementation of High Producing Dairy Cows Grazing at Two Pasture Allowances J Dairy Sci, July 1, 2002; 85(7): 1777 - 1792. [Abstract] [Full Text] [PDF]