Although the corn crop looks great in many parts of the U.S., areas with drought stress, such as Kansas, are starting to see evidence of aflatoxin in the corn crop. “We’ve been going through quite a bit of drought stress over the last two months in many areas,” said Kansas State Research and Extension swine specialist Joel DeRouchey. “It’s not in all corn coming in but fairly wide spread from the reports that we have been getting.”

Aflatoxin is produced by the ear-rotting fungus Aspergillus flavus. “It is favored by hot, humid and droughty conditions during the grain fill period,” said Doug Jardine, Kansas plant pathology leader.

What that’s likely to mean for the ethanol industry is reduced levels of distillers grains in swine rations, DeRouchey told EPM. DDGS inclusion rates have varied widely in the past two years and may change again with the new corn crop. “Really it’s been kind of roller coaster,” he said.

The 2009 corn crop had high levels of vomitoxin, meaning swine producers cut back on use of DDGS. “Especially in the eastern Corn Belt, many producers could not feed any distillers grains because their corn was already at a level that was of a high concern,” he said.

Then, in 2010, the corn crop was very high quality with low levels of mycotoxins. As a result, swine producers bumped up their inclusion rates thanks to the economics and quality of the product. Finishing pigs were receiving about 40 to 50 percent DDGS and gestating sows 40 to 60 percent. “The levels have been as high as they probably ever been using distillers grains in swine,” he said.

Now, with a new corn crop, that may change in areas where aflatoxin is a problem. The ethanol production process concentrates mycotoxins the DDGS  by about a factor of three. “If we start incorporating new crop corn, whether that’s in the corn source itself, or back through distillers, we have to be watching very close,” he said.

“Keep in mind that aflatoxin is a carcinogen, and that levels build up in the body over time,” said K-State swine specialist Mike Tokach. “So, when feeding corn that contains aflatoxin, there may be reduced feed intake in the short term, but it’s the long term where the biggest negative impact can occur.”

Corn fed to young pigs must contain less than 20 parts per billion aflatoxin, while breeding animals are limited to 100 ppb and finishing pigs less than 200 ppb, according to Food and Drug Administration regulations. Corn with aflatoxin levels of more than 200 ppb must be blended with other corn to lower the contamination levels. FDA regulations also state that blended corn can only be used onsite and cannot be sold.

DeRouchey and Tokach also outlined several points for corn and swine producers to keep in mind.

* Aflatoxin contaminated fields should be harvested quickly. The toxin levels continue to increase due to mold growth.

* Moldy corn should be cleaned, if possible, before storage. Removing damaged kernels can lower toxin levels by about 50 percent.

* To limit further growth of the fungus and toxin production, corn should be stored at less than 15 percent moisture. Levels of 13 percent or less is ideal.

* The system should be cleaned after handling contaminated corn.

* Adding 0.5 propionic acid in storage limits further fungal growth.

* Grain bin temperatures should be monitored because hot spots will increase fungal growth and toxin production.

* High- and low-level aflatoxin bins should be segregated.