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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Environmentally Integrated Dairy Management Research » Research » Publications at this Location » Publication #369331

Research Project: Improving Nutrient Use Efficiency and Mitigating Nutrient and Pathogen Losses from Dairy Production Systems

Location: Environmentally Integrated Dairy Management Research

Title: ALL forages are not created equally (for ensiling)

item Coblentz, Wayne

Submitted to: Forage Focus
Publication Type: Popular Publication
Publication Acceptance Date: 12/13/2019
Publication Date: 12/26/2019
Citation: Coblentz, W.K. 2019. ALL forages are not created equally (for ensiling). Forage Focus. p. 4-5.

Interpretive Summary:

Technical Abstract: Preserving forages as silage is a common practice throughout the north-central US, but it is important to remember that all forages are not created equally for this purpose. Aside from the obvious differences, such as legumes vs. grasses, annuals vs. perennials, or long-stem (baled) vs. precision-chopped, there also are internal differences that can profoundly affect the way forages ensile. Of these, two of the most prominent characteristics are concentrations of water-soluble carbohydrates (WSC) or sugars, and buffering capacity (BC). During silage fermentation, WSC serve as the substrate for fermentation, in which they are converted by bacteria under anaerobic conditions to various fermentation products, of which acetic and lactic acids are the most common. Accumulation of these volatile fatty acids drives down the pH of the silage mass, and imparts some stability to the silage. In contrast, BC can be defined in most simple terms as the inherent resistance within any forage to a pH change, and is principally affected by concentrations of various organic acids or their anion salts. It is important to note that a large number of factors can affect concentrations of WSC, and these can include forage species, cultivar, stage of growth, time of day, climate, drought, frost events, N fertilization, rain damage (wilting), or poor/extended wilting conditions. Buffering capacity is often associated more closely with the leaf, rather than stem tissue. As a result, BC usually declines with any production or growth factor that reduces leaf-to-stem ratio. While the factors affecting WSC and BC in forages are complex, a basic understanding of these concepts can be helpful in managing good silage production.