Submitted to: Minnesota Forage Update
Publication Type: Popular Publication
Publication Acceptance Date: May 8, 1995
Publication Date: N/A
Technical Abstract: Bacterial inoculants are the most common additives used for making alfalfa silage in the U.S. Inoculants contain lactic acid bacteria and supplement the natural lactic acid bacteria on the crop to guarantee a fast and efficient fermentation in the silo. When the inoculant bacteria dominate the silage fermentation, they change the products formed during ensiling, increasing the proportion of lactic acid and reducing the loss of dry matter by approximately 2 percentage units. Inoculants have been shown to improve animal performance: increasing feed intake, liveweight gain, milk production and feed efficiency. To get the most benefit from inoculants, a number of factors must be considered: what to purchase, the method of application and the conditions under which an inoculant will be most effective. Purchase products that are formulated for use on alfalfa or haylage supply at least 90 billion viable lactic acid bacteria per ton of wet alfalfa and are applied as a liquid. Both liquid and dry inoculants are best applied at the forage harvester to help distribute the inoculant uniformly. Inoculants applied as liquids should be diluted with unchlorinated water if possible because chlorine residuals may kill lactic acid bacteria. Finally, inoculants are not always successful because alfalfa may have high natural populations of lactic acid bacteria that overwhelm those supplied by the inoculant. Graphs have been developed to allow farmers to determine when the natural population is high on alfalfa, making inoculant use unprofitable. These graphs require the farmer to know the average air temperature during wilting, the wilting time in days and the moisture content of the alfalfa at chopping. Using the graphs, farmers can restrict inoculant use to the most profitable conditions.