Aflatoxin in Corn, Corn Silage and Distillers Grains
As in past drought years, dairy producers need to be extra cautious in suspecting aflatoxin when buying and feeding corn, corn silage, and corn dried distillers grains.
Aflatoxin is a toxic compound produced by the aspergillus species of mold. It is commonly found in feeds grown under warm and drought conditions, which stress the plant. Most of Southwestern Missouri had these conditions this year. A good discussion of aflatoxin is available in this University of Arkansas guidesheet: http://www.uaex.edu/Other_Areas/publications/PDF/FSA-4018.pdf.
Due to the toxic nature of aflatoxin, the FDA limits the level of aflatoxin in milk to 0.5 ppb (parts per billion). The FDA has established regulatory action levels for corn used in interstate shipment based upon its intended use. The levels are as follows:
- Less than 20 ppb; Dairy, immature animals, humans
Less than 100 ppb; Breeding beef cattle and swine, mature poultry
- Less than 200 ppb; Finishing swine of greater than 100 lbs.
Less than 300 ppb. Finishing beef cattle
The most likely animal symptoms of livestock affected by aflatoxin would be poor growth and performance. Research data suggests levels significantly higher for the respective livestock are required to cause impaired immunity and lesions on the liver. At 20 ppb no observable effects on milk yield would be expected.
Producers either buying grain, silage, distillers grains or that suspect grain produced on their farm contains aflatoxin are advised to take a representative sample and check it for aflatoxin. Samples should be taken from 10 different locations within a grain bin. Remember, one ppb is like one golf ball in the entire University of Missouri football stadium.
A simple screening test used by elevators is to test the grain for florescence; a greenish-yellow fluorescence of cracked or ground grain can suggest the presence of the aspergillus mold and possible aflatoxin contamination.
The University of Missouri Veterinary Diagnostic Lab can test a corn sample for aflatoxin. The cost is $42.25 and complete information may be found at: http://vmdl.missouri.edu/tests_toxicology.html. Other contact information for the labe is as follows:
Vet. Med. Diagnostic. Lab, PO Box 6023, Columbia, MO 65211. Phone 573-882-6811 or fax 573-882-1411.
If a producer or grain handler has a concern about a questionable feedstuff, please call the Missouri Department of Agriculture, Plant Industries Division, Bureau of Feed and Seed. Phone 573-751-4310.