ST. PAUL -- Every year, dairy producers are challenged with harvesting high-quality silage within a critical timeframe working around the weather, getting it to a storage structure and packing it adequately for good fermentation and preservation.
It's great when these challenges are met. There's nothing like feeding high-quality corn silage and/or haylage to keep feed costs in line and ensure excellent animal performance, health and milk production.
However, the next challenge is to maintain the silage in top condition through the months ahead. The consequences of not doing so are reduced forage quality and, thus, greater protein and energy supplement expenses. Also, deteriorated silage fed to the dairy herd can lead to health and production problems.
Air exposure
Air is the primary factor that can destroy silage. A poor seal of a bag, bunker or pile lets yeast, mold and aerobic bacteria grow during storage. Mold indicates deterioration, dry matter loss, less nutritional value and possibly mycotoxins. Moldy feed and mycotoxins have been associated with lower feed intake, reduced digestibility and health disorders in dairy animals.
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Silage storage units need to be monitored for holes, and patched. Damage by rodents is mainly waste and spoilage from holes chewed in bags or silage plastic. Weed control and fencing limits rodent populations around storage areas.
Once the silo is opened, the exposed face must be managed to limit the time silage is exposed to oxygen. Oxygen can penetrate several yards into a loosely packed silage mass, but dense forage limits the rate of oxygen infiltration. Good management during feed-out includes matching the face size to the daily removal rate and maintaining a clean, vertical face to stay ahead of aerobic spoilage.
Don't try to stretch silage inventory by feeding spoiled, moldy or heated silage to dairy animals. Feed bunks should be kept clean of decaying feed. The quality of the total mixed ration should not be compromised by incorporating spoiled silage; poor-quality silage in the total mixed ration creates a poor-quality total mixed ration.
Feeding spoiled silage even at only 5 percent of total ration dry matter will reduce intake. Nutrient digestibility and rumen health are compromised. Spoiled silage can partially or totally destroy the forage mat in the rumen. Cows then are more susceptible to metabolic disorders, displaced abomasums, hoof problems, as well as reduced milk production. There also are the added dollars spent replacing lost energy and protein in the ration to compensate for the poorer quality. In addition, feeding spoiled silage to dry cows and young heifers can negatively affect their fertility and reproductive efficiency.
Maintaining the high-quality silage you've already worked hard to put in storage can be a challenge. But with good management, time and effort preserving that high quality will minimize spoilage and give better animal performance and health.
Editor's Note: Broadwater is a dairy educator with the University of Minnesota Extension Service in St. Paul.
