The rainy period the past month or so has created an environment where molds/funguses may be developing on standing corn in the field. The concern with molds is their ability to produce mycotoxins that impact animal performance negatively. We can have mold but not mycotoxins and also situations where mold growth is not apparent but significant levels of mycotoxins are produced. Work with your dairy nutritionists and agronomists to closely evaluate both corn silage and corn for grain for mycotoxin levels.
Here is one important take away from the article.
Will drying, heating, freezing, or applying chemicals reduce mycotoxins in grain?
No. Mycotoxins are extremely stable and heating, freezing, roasting, or treating with chemicals cannot reliably reduce mycotoxin levels within kernels. In some cases, you can reduce the overall mycotoxin concentration in the grain by removing broken grain (fines), foreign materials, and lightweight moldy kernels. You can greatly reduce the further accumulation of mycotoxins in harvested grain by properly drying corn to less than 15 percent moisture. Dry grain to 13 percent for long-term storage. Moisture greater than 18 percent elevates the risk of DON, zearalenone, and fumonisins. Warm conditions will accelerate the rates of spoilage and mycotoxin accumulation. There is no evidence that mycotoxin levels will increase in grain stored at an appropriately low moisture (Figure 8). It’s important to point out that while high-temperature drying will stop mold growth and mycotoxin production, it will not reduce the level of mycotoxins already present. Quick drying is preferred over low-heat drying. Be wary of low-temperature, in-bin dryers for moldy corn, and be sure to meet proper ventilation requirements for dry corn storage.
Following is a paper that was developed in 2009 when we had serious issues with ears rots.
Will ensiling or organic acid addition kill field molds in storage or detoxify the mycotoxins?
No. Ensiling or addition of organic acids do not kill the mold spores or detoxify the mycotoxins per se. Ensiling corn or adding organic acids to corn at the proper rate (low pH) creates an environment not suitable for mold growth. If oxygen becomes present (oxygen rich) and pH rises then the mold spores will reacquire an environment for growth and mycotoxin production. If mycotoxins were present in the field at harvest they will remain present in storage at similar concentrations.
Here are a couple of additional articles that where developed in 2009 that may be useful as well.
Please see link for a list of labs that can offer qualitative and quantitative analysis for mycotoxins.