Iowa Livestock Feeders Need To Watch Nitrate, Aflatoxin Levels

Two potential problems to keep an eye on this fall are nitrates in cornstalks and aflatoxin in corn grain.

Published on: Oct 9, 2012

Livestock, especially finishing cattle and feedlot cattle, will be the end user of much of the aflatoxin-infected corn. Caution and management are crucial to ensure that negative results do not occur from feeding this feed.

Test and monitor aflatoxin levels of corn to be fed to livestock

It is recommended that stored corn that has the aspergillus flavus mold present needs to be dried down to less than 14% moisture content to limit mold growth. Also, cool the grain down after drying and use aeration to control grain temperature. Mold inhibitors may also be applied to corn to reduce mold growth.

ISU recommends testing and monitoring aflatoxin levels of corn to be fed to livestock. Testing corn coproducts such as distillers grain is also recommended. If corn has more than 10 parts per billion, most processors such as ethanol plants will reject that load of corn because in the fermentation process the aflatoxin concentrates by a factor of three in the distillers grain. For example, if corn has 10 ppb of aflatoxin, it ends up 30 ppb in distillers grain.

Blending aflatoxin-bearing corn with clean corn at time of feeding can be a good practice to reduce aflatoxin levels in the animals' diet. But remember, if corn has aflatoxin it can't be fed to dairy cattle, notes Loy. Corn that contains aflatoxin can be safely fed to hogs up to 100 parts per billion. It can be fed to feedlot beef cattle up to 300 parts per billion. "Talk to your veterinarian and nutritionist," he advises. "There is a level you don't want to feed to bred cows or reproducing cattle, but for feedlot and finishing cattle, they can use the corn as long as the aflatoxin level isn't too high."

For more information go online and read the ISU Extension publication "Aflatoxins in Corn", PM-1800 Revised August 2012.