Effects of Grain Source and Enzyme Additive on Site and Extent of Nutrient Digestion in Dairy Cows

¹ Livestock Sciences Section, Research Center, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada T1J 4B1

Four lactating, cannulated Holstein cows were used in a 4 x 4 Latin square design to investigate the effects of grain source and fibrolytic enzyme supplementation on ruminal fermentation, nutrient digestion in the rumen and in the intestine, and milk production. A 2 x 2 factorial arrangement was used; two grains (barley and hull-less barley) were combined with and without enzyme. The enzyme supplement (Pro-Mote®; Biovance Technologies Inc., Omaha, NE) contained primarily cellulase and xylanase activities and was applied daily to the total mixed diet. Dry matter intake was not affected by diet, but starch intake was greatest when hull-less barley was fed. Starch from hull-less barley was more digestible in the rumen and in the total tract than was starch from barley, but opposite results occurred for fiber digestion, indicating that hull-less barley depressed fiber digestion. As a result, cows fed the hull-less barley diets tended to produce more milk with a higher milk lactose content than did cows fed the barley diets. Enzyme supplementation had minimal effects on ruminal digestion but increased nutrient digestibility in the total tract and the proportion of microbial N in nonammonia N. Consequently, cows fed diets supplemented with enzyme had a higher milk protein content and tended to produce more 4% fat-corrected milk than did control cows. These results indicate that the use of hull-less barley rather than barley increased the digestible energy intake of dairy cows, resulting in higher milk production. The use of a fibrolytic enzyme mixture enhanced feed digestibility and milk production.

Key Words: grain source • enzymes • digestibility • milk production

Submitted on May 7, 1998
Accepted on September 14, 1998

This article has been cited by other articles:

				E. A. Elwakeel, E. C. Titgemeyer, B. J. Johnson, C. K. Armendariz, and J. E. Shirley Fibrolytic Enzymes to Increase the Nutritive Value of Dairy Feedstuffs J Dairy Sci, November 1, 2007; 90(11): 5226 - 5236. [Abstract] [Full Text] [PDF]

				K. F. Knowlton, M. S. Taylor, S. R. Hill, C. Cobb, and K. F. Wilson Manure Nutrient Excretion by Lactating Cows Fed Exogenous Phytase and Cellulase J Dairy Sci, September 1, 2007; 90(9): 4356 - 4360. [Abstract] [Full Text] [PDF]

				I. R. Ipharraguerre and J. H. Clark Impacts of the Source and Amount of Crude Protein on the Intestinal Supply of Nitrogen Fractions and Performance of Dairy Cows J Dairy Sci, May 1, 2005; 88(e_suppl_1): E22 - E37. [Abstract] [Full Text] [PDF]

				J. D. Sutton, R. H. Phipps, D. E. Beever, D. J. Humphries, G. F. Hartnell, J. L. Vicini, and D. L. Hard Effect of Method of Application of a Fibrolytic Enzyme Product on Digestive Processes and Milk Production in Holstein-Friesian Cows J Dairy Sci, February 1, 2003; 86(2): 546 - 556. [Abstract] [Full Text] [PDF]

				J. L. Vicini, H. G. Bateman, M. K. Bhat, J. H. Clark, R. A. Erdman, R. H. Phipps, M. E. Van Amburgh, G. F. Hartnell, R. L. Hintz, and D. L. Hard Effect of Feeding Supplemental Fibrolytic Enzymes or Soluble Sugars with Malic Acid on Milk Production J Dairy Sci, February 1, 2003; 86(2): 576 - 585. [Abstract] [Full Text] [PDF]

				K. A. Beauchemin, D. Colombatto, D. P. Morgavi, and W. Z. Yang Use of Exogenous Fibrolytic Enzymes to Improve Feed Utilization by Ruminants J Anim Sci, February 1, 2003; 81(14_suppl_2): E37 - 47. [Abstract] [Full Text] [PDF]

				N. R. St-Pierre Reassessment of Biases in Predicted Nitrogen Flows to the Duodenum by NRC 2001 J Dairy Sci, January 1, 2003; 86(1): 344 - 350. [Abstract] [Full Text] [PDF]

				K. F. Knowlton, J. M. McKinney, and C. Cobb Effect of a Direct-Fed Fibrolytic Enzyme Formulation on Nutrient Intake, Partitioning, and Excretion in Early and Late Lactation Holstein Cows J Dairy Sci, December 1, 2002; 85(12): 3328 - 3335. [Abstract] [Full Text] [PDF]

				G. R. Bowman, K. A. Beauchemin, and J. A. Shelford The Proportion of the Diet to which Fibrolytic Enzymes are Added Affects Nutrient Digestion by Lactating Dairy Cows J Dairy Sci, December 1, 2002; 85(12): 3420 - 3429. [Abstract] [Full Text] [PDF]