Moldy Corn Alert

January 30, 2010 06:00 PM

Record rainfall and poor drying conditions this past fall resulted in high corn moistures—and a higher potential for moldy feed grains in your bins and potentially in the feedbunk. Before feeding livestock, be on the lookout and take precautions to avoid animal health problems that may come from mold in corn and silage.

"Both molds and the myco-toxins produced by molds can cause health problems in livestock,” says University of Minnesota Extension livestock specialist Jim Linn. At heightened risk for mycotoxin problems are young animals, breeding animals and lactating dairy cows, with swine and poultry species even more susceptible than ruminants.

Mycotoxins in large doses can cause acute health, reproduction and production problems. However, the most likely scenario with feeding of moldy and/or mycotoxin-containing feeds is a higher incidence of general chronic health problems, poor reproduction and overall poor animal growth or milk production.

How should you handle mold challenges in livestock feed? Linn suggests these three steps when assessing risks of feeding moldy corn or silage:
■ Visually inspect feeds for molds. Not all molds produce mycotoxins, but "chances are good mycotoxins are present when molds are,” he says.
■ Test grains, grain byproducts and corn silage for mycotoxins since they are not visible. A variety of mycotoxins are produced by molds, so testing grains is the only way to determine if molds or fungi will be dangerous to animals. Ask your veterinarian, animal nutritionist or Extension specialist how to test feeds and interpret results.
■ Assess options if molds and myco-toxins are present in feed. The best solution is not to use contaminated feed, but this isn't always possible. "The rumen can partially degrade mycotoxins, so dilution of the contaminated feed with clean, high-quality feed is a way of using some contaminated feed,” Linn says.

The exact dilution rate or amount that can be fed will depend on the type and amount of toxin present and the animal receiving the ration, he adds.

Also be careful feeding distillers' grains that come from moldy corn.

"Distillers' grains could contain mycotoxins if the original grain contained them,” says Galen Erickson, animal scientist at the University of Nebraska. "Because the starch is removed from the grain, which is two-thirds of the kernel, mycotoxins are concentrated by two or three times. This may or may not be an issue, and ethanol plants have to be diligent.”

You can e-mail Kim Watson-Potts at

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