Project Number: 3655-31000-018-06
Project Type: Specific C/A

Start Date: Sep 08, 2003
End Date: Mar 15, 2006

Objective:
To determine if: 1) differences in NDF digestibility of alfalfa hay, with similar NDF concentration, affect feed intake, milk production, and/or milk composition of dairy cows fed mixed diets; 2) the impact of NDF digestibility on cow performance differs with level of NDF concentration; and 3) NDF digestibility interacts with level of alfalfa hay inclusion in mixed diets fed to dairy cows. Additional funds to be used for graduate assistant's salary to continue this work.

Approach:
Four alfalfa hays will be obtained from commercial sources that will contain two NDF concentrations each with high and low in vitro NDF digestibility. Lactation trials will be conducted with 21 cows per hay treatment, beginning shortly after calving and extending for 120 days. At the University of Minnesota, the alfalfa hays will contribute one-third of the forage fiber in the diet; at the USDFRC, the alfalfa hays will contribute two-thirds of the forage fiber in the diet. Feed intake, milk production, and in vivo digestibility of the major nutrients will be measured in each trial. Trials will be conducted with rumen-fistulated cows in order to measure rumen pH and volatile fatty acid concentrations at each location using rations similar to those for the lactating trials. Additional time is to conduct experiments designed to improve accuracy & repeatability of laboratory in vitro fiber digestibiltiy assays.

Project Team

Mertens, David James Linn - Professor, Dept Of Anim Science, Univ Of Minnesota 608-264-5228

Related National Programs

Food Animal Production (101)