ST. CLOUD, Minn. — Putting up silage is always a hectic time, pulling producers in a hundred directions at once. Nevertheless, ensiling forages in a timely and precise manner is pivotal. Forages contribute a significant percentage to a conventional total mixed ration and capturing the highest nutritional value available for your dairy herd is a huge asset to any producer. Conversely, naturally occurring molds, like fusarium, can not only lower forage quality but hurt the health of livestock when forage is incorrectly ensiled. This article will discuss crop production environments contributing to fusarium mold and general appearance of molds in feed.
Fusarium mold growth in harvested crops is more likely to occur under cool, wet conditions during growth, harvesting, and storage (experienced by some in central Minnesota this year). Storing forages at moisture levels beyond recommended ranges or in poor storage units also may increase mold-related problems during feeding. Visible mold does not mean mycotoxins are present, and no visible mold does not mean there are no mycotoxins. When feeding livestock, moldy feeds can decrease digestibility of the ration, reducing energy content by 5% for ruminants (leading to the observable decrease in milk production and weight gain).
When feeding out forages, take a moment before throwing them in the dairy’s mixing wagon. A sensory analysis (visual appearance and smell) can be used to superficially evaluate fermentation of the silage and determine next steps. Feeds with atypical colors such as blue or green can be indicative of problematic species of storage molds like fusarium and aspergillus. Fusarium molds can be visually observed when silage has reddish to white mold growth (ex: pink). Regarding smell, normal silage has minimal odor due to lactic acid. Silage that smells musty, of mildew, or rotten should not be fed.
These sensory observations can get you into the ballpark of when to talk to your nutritionist about moldy feed and send silage samples in for analysis at a lab. Next week’s article will discuss how to navigate mycotoxins from fusarium molds in feedstuffs. The information for the above article was from UMN Extension (https://z.umn.edu/UMNExtDroughtMoldDairy), NDSU Extension (https://z.umn.edu/NDSUCornSilageMold) and Penn State Extension (https://z.umn.edu/PennSTMoldMycotoxins). Residents of Stearns, Benton, and Morrison counties can direct questions to either my email (email@example.com) or call my desk phone at (320) 255-6169 x 3.
— Dana Adams, University of Minnesota Extension