By Blake Jackson
As producers open silo structures after harvest, they may encounter mold growth, mycotoxins, or unusually warm silage. Corn silage completes its initial fermentation in about 30 days, at which point producers can begin assessing fermentation success and nutrient quality.
Over the next several months, pH levels and starch digestibility may continue to shift as silage acids break down parts of the starch structure.
Value of a Forage Analysis
Conducting a forage analysis is essential for balancing livestock rations, reducing purchased feed expenses, and avoiding animal health problems. Beyond measuring nutrient levels like protein, starch, and fiber, modern laboratory analyses now include fermentation profiles, mold and mycotoxin screenings, and energy index calculations.
Annual forage testing also allows producers to compare their silage quality with industry benchmarks and understand how seasonal growing conditions affect nutrient variations.
Assessing Fermentation Quality
The purpose of fermentation is to preserve forage as a stable, nutritious feed. Once oxygen is removed, microorganisms convert sugars into fermentation end products that lower pH and inhibit harmful microbes. High-quality silage has a clean, mildly acidic smell.
Lactic acid, produced by lactic acid bacteria, is the primary fermentation acid and should reach 3-6% of dry matter in corn silage, with a final pH between 3.7 and 4.0. Acetic acid, typically 1-3%, is also beneficial for its antifungal properties.
Other compounds propionic acid, ethanol, 1,2-propanediol, and butyric acid may appear in test results and can indicate desirable or undesirable fermentations depending on concentration.
Molds, Mycotoxins, and Prevention
Common mycotoxins in corn silage include aflatoxins, deoxynivalenol, zearalenone, and fumonisins. Prevention begins with choosing disease-resistant hybrids, reducing insect damage, and practicing good crop rotation. Proper harvest moisture, tight packing, immediate sealing, and, when appropriate, inoculant use also help limit mold growth.
Shrink Management
Shrink dry matter loss during harvest, storage, or feeding reduces profitability. Losses above 15-20% warrant management changes. Shrink can be minimized by harvesting at proper moisture, rapid filling and sealing, adequate packing, reducing oxygen exposure, and maintaining strong fermentation.
Photo Credit: gettyimages-fotokostic
Categories: Pennsylvania, Crops, Corn