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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Dairy Forage Research » Research » Research Project #444522

Research Project: Utility of Mechanical Processing to Decouple Alfalfa Yield from Digestibility

Location: Dairy Forage Research

Project Number: 5090-31000-027-025-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2023
End Date: Jul 31, 2027

As much as 50% of the fiber in alfalfa silage passes through the dairy cow’s digestive tract and is not utilized for milk production. The overall objective of this research is to improve the utilization of alfalfa by dairy cattle through an “extreme” mechanical processing method that could significantly improve alfalfa fiber digestibility and lactation performance. The specific objective will be to evaluate the utility of mechanical processing to mitigate the impact of alfalfa maturity on animal performance.

A feeding study will be conducted to determine the effect of mechanical processing on lactation performance of high producing dairy cows. The effect of how mechanical processing of alfalfa harvested at two different maturities (bud stage and mid-flower) affects intake, milk production, nutrient digestibility, and feed conversion efficiency of lactating dairy cows will be evaluated. Experimental design will be a randomized complete block design with 15 cows/treatment diet. Cows will be fed a common covariate diet for 2 weeks followed by an 8-week experimental period evaluating mechanical processing of forages. Milk yield will be recorded daily during the sampling period. Milk samples will be analyzed for fat, protein, lactose, and milk urea nitrogen. Standing, laying, eating, and ruminating behaviors will be visually assessed and recorded during the study. Fecal grab samples will be collected over a 4-day period to determine nutrient digestibility of the diets.