ARS | Publication request: Impact of Alfalfa Hay Neutral Detergent Fiber Concentration and Digestibility on Holstein Dairy Cow Performance: Ii. Diet Digestibility

Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract
Publication Acceptance Date: March 15, 2005
Publication Date: June 24, 2005
Citation: Raeth-Knight, M.L., Linn, J.G., Jung, H.G., Mertens, D.R., Peterson, P.R. 2005. Impact of alfalfa hay neutral detergent fiber concentration and digestibility on Holstein dairy cow performance: III. Diet digestibility [abstract]. Journal of Dairy Science. 88(Supplement 1):250.

Technical Abstract: Multiparous Holstein cows were fed 1 of 4 treatment diets containing alfalfa hay varying in neutral detergent fiber concentration (NDF) and 48-h in vitro NDF digestibility (IVNDFD). In study 1, 60 early lactation cows were randomly assigned to treatments containing approximately 15% alfalfa hay (DM basis). Diet composition was detailed in Part I (lactation performance). In study 2, 20 late lactation cows were randomly assigned to treatments containing 95.8% alfalfa hay and 4.2% molasses (DM basis). Apparent total tract DM and fiber digestibility were measured using the acid insoluble ash technique. In study 1, alfalfa hay NDF and IVNDFD did not result in any difference in apparent total tract DM digestibility (DMD) or NDF digestibility (NDFD). However, within low NDF hays there was a trend for lower IVNDFD to increase DMD; and within the high NDFD hays, high NDF hay increased DMD. In study 2, cows fed hay with higher IVNDFD had increased DMD within low NDF hays and decreased DMD within high NDF hays. Alfalfa hay IVNDFD did not impact apparent total tract NDFD in high NDF hays. However, in low NDF hays, higher hay IVNDFD increased apparent total tract NDFD. Alfalfa hay NDF and IVNDFD did not affect diet in vivo DMD or NDFD when included at 15% of the diet DM. Alfalfa hays included at 96% of the diet dry matter resulted in an interaction between hay NDF and IVNDFD for in vivo digestibility.