Nutrition Manage corn mold

December 3, 2009 06:00 PM
Jim Linn

With the economic depression in dairy and all of the livestock industry, a large crop of high-quality forages and grains was needed. For most of the Upper Midwest and the Corn Belt, forage crops were good, but the corn crop is creating a challenge.

Record rainfall and poor drying conditions resulted in corn moistures in the high 30s and even low 40s at the end of October. This has created many harvest challenges, but also a high risk for mold and mycotoxin development in corn.

With corn grain composing 20% to 30% of the ration dry matter and corn-based byproducts potentially adding another 10% or more, feeding moldy and low-quality corn can have a significant impact on animal health and milk production.

The molds or fungi of greatest concern this year are Fusarium, Penicillium and the ear rot mold of Diplodia. All except Diplodia are capable of producing mycotoxins.

As you assess the risks, consider taking these three steps:

1. Visually inspect feeds for molds. Fusarium will appear pink/red to white. Penicillium will be blue/green to gray. Diplodia is white and between kernels. These molds in themselves can affect the health of cattle in an inconspicuous way through lowered immunity, poor health and diarrhea or possibly hemorrhagic bowel syndrome.

While molds do not always produce mycotoxins, chances are good mycotoxins are present when molds are.

A wet growing season spurred an outbreak of Diplodia in Midwest corn fields and grain.
2. Test grains, grain byproducts and corn silage for mycotoxins since they are not visible. Common mycotoxins produced by molds are deoxynivalenol (DON), T-2 and zearalenone by Fusarium and ochratoxin and patulin by Penicillium.

Mycotoxin symptoms in dairy cows include reduced feed intake, rumen upsets and altered fermentation of feeds, suppressed immunity, increased metabolic and general health problems at calving and poor reproduction.

3. Assess options if molds and mycotoxins are present in feed. The best solution is not to feed the 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 feeding some contaminated feed. 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. Feed diets that are balanced for minerals, vitamins, fiber, energy and protein. Acidic diets may exacerbate the effects of mycotoxins.

Finally, consider adding a mycotoxin binder product to the diet. The efficacy of most of the products that are available have not been tested by the FDA, however.

Bonus content:

American Dairy Science Association
Click on S-PAC. For $5, you will have access to 75 articles on mycotoxins, 117 article on "mold and corn” and 27 articles on "mold and soybeans.”

Molds and mycotoxins show up in corn

2009-2010 Dairy Cattle Feeding Issues with High-Moisture Corn, Snaplage and Dry Shelled Corn

Late harvest resources from the University of Minnesota Extension

More from the Unviersity of Minnesota Northwest Research and Outreach Center

2009 Harvest Consideration Resources

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