Optimal Moisture Key for Safe Silage Storage
Recent frost across North Dakota has damaged many acres of corn. According to North Dakota State University (NDSU) Extension forage crops production specialist James Rogers, the impact of frost on corn depends on temperature, duration, and plant maturity. Farmers can still chop frost-damaged corn for silage, but only if the moisture level is correct for proper fermentation.
“Proper moisture content at the time of ensiling is key to achieving adequate fermentation of the silage and preservation,” said Rogers. Although frosted plants quickly lose their green color, their internal moisture may remain high. Harvesting too early, especially at the milk stage, can result in silage that is too wet, leading to nutrient loss and sour feed.
“A caution with frost-damaged corn at the milk stage is the potential for mold development in the ears,” said Rogers. “Not all corn molds are harmful to livestock, but some can produce mycotoxins that can be.”
The ideal whole-plant moisture content is 62%–68% for most storage methods. Corn can ensile at up to 75% in a bunker or trench silo and 60%–70% in a bag silo. At the milk stage, moisture averages 80% and must dry before chopping, even though this reduces dry matter yield. Corn at the dough stage averages 75% moisture and may need a few days to reach the safe range. Corn in mid- to late-dent stage should be harvested as soon as possible.
Rogers also cautions about mold growth and potential mycotoxins in the ears. Farmers should test samples at the NDSU Veterinary Diagnostic Laboratory and note that nitrate levels, though higher in frosted corn, are lowered during proper ensiling.
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