Head Off Post-Flooding's 'Toxic' Silage

Take precautionary harvest measures to minimize flood pollution of silage corn.

Published on: Sep 21, 2011

Recent flooding of cropland will haunt Northeast farmers long after the fields are dry enough to harvest. Here's some crucial advice recently offered collectively by Greg Roth, Jud Heinrichs, Craig Altemose, Virginia Ishler and Marvin Hall of Penn State's Departments of Crop and Soil Sciences and Dairy and Animal Science.

Decreased milk production and performance is likely when flood damaged crops are fed. That's why flooded corn may be better harvested as grain rather than silage due to concerns over silage feed quality and higher risk of contamination by soil, mycotoxins plus manure, sewage treatment plant effluent and other chemicals.

MUDDED MESS: Flooded fields like this one near Burlington, Vt., pose serious harvest decisions. Photo by Alison Kosakowski
MUDDED MESS: Flooded fields like this one near Burlington, Vt., pose serious harvest decisions. Photo by Alison Kosakowski

Proper fermentation is almost always an issue with flood-damaged silage crops. A good fermentation will kill many but not necessarily all fungal and bacterial pathogens. If you must use flooded corn for silage, consider these protective measures:

Take steps to promote good fermentation, such as heavy inoculation and extra packing in the silos.

Target the least affected fields for silage and harvest above the silt line to avoid soil contamination.

Segregate any corn chopped for silage so that it can be evaluated before feeding. Ensiling it separately in bags will be easier to cope with than blending it with high-quality silage in a bunker or upright silo.

CAKED CORN: Corn caked like this with flood water mud may be best harvested for grain, not silage, due to risks of pathogens that could be dangerous to cow health. Photo by Alison Kosakowski
CAKED CORN: Corn caked like this with flood water mud may be best harvested for grain, not silage, due to risks of pathogens that could be dangerous to cow health. Photo by Alison Kosakowski

Consider using higher rates of silage inoculants and possibly a buffered proprionic acid for silage stored in an ag bag. Keep in mind that one must be applied during chopping, the other at the ag bag. An inoculant with L. buchneri may help by increasing the (fermenting) acetic acid that inhibits mold formation.

Forage test before feeding, paying particular attention to dry matter percent, starch, ash, mycotoxins and fermentation profile. That may require a wet chemistry analysis.

Silage and even high-moisture corn from these fields should be evaluated at feed-out. Animal health should be closely monitored.

What about hay and pasture crops?

Soil and organic matter on forage crops can also lead to fermentation issues, increased ash, decreased digestibility, and animal health problems, especially for horses.

Avoid pasturing or harvesting silt-laden forage crops if at all possible. It might be best to mow the previously flooded pastures and wait for them to regrow before grazing.

Mowed forage that has been lying in the field for more than one week should simply be chopped and blown back onto the field, particularly if it's showing signs of molding.

Roots in soil flooded for two to three weeks may die from suffocation. Diseases such as rhizoctonia or phytophthora can increase in wet soils and lead to thinned stands next year.

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