What are the allowable levels for vomitoxin in feed for various animal species?

This answer is developed from an excellent document prepared by Dwight Aakre and others with NDSU Extension Service at North Dakota State University. For more information, see

The U.S. Food and Drug Administration (FDA) has established vomitoxin (DON) advisory levels to provide safe food and feed. Unlike aflatoxin in corn, DON is not a known carcinogen. Human food products are restricted to a 1-parts per million (ppm) level established by the FDA. This level is considered safe for human consumption. The food industry often sets standards that are more restrictive. DON causes feed refusal and poor weight gain in some livestock if fed above the advisory levels. FDA advisory levels are as follows:

Intended use Grain and by-products Vomitoxin levels Notes
Human consumption Finished wheat products, such as flour, bran and germ 1 ppm The FDA does not set an advisory level for raw grain intended for milling.
Swine Grain and by-products 5 ppm Providing that these ingredients do not exceed 20 percent of the diet
Chickens Grain and by-products 10 ppm Providing that these ingredients do not exceed 50 percent of the diet
Feedlot cattle Grain and by-products 10 ppm Ruminating beef and feedlot cattle older than four months, providing that these ingredients do not exceed 50 percent of the diet
Dairy cattle Grain and by-products 10 ppm Providing that these ingredients do not exceed 50 percent of the diet
Other animals Grain and by-products 5 ppm Providing that these ingredients do not exceed 40 percent of the diet

Additional information is available from Ohio State University at

Vomitoxin research on humans is prohibited for legal and moral reasons, but we do know the effects of vomitoxin on animals with similar body systems to humans (such as pigs and primates). Low levels of vomitoxin (0.05 to 0.1 mg per kg body weight) can cause vomiting in pigs. This would be similar to exposing a 175-pound person to 0.0003 ounces of vomitoxin (a VERY small amount!). In humans, scabby grain has been associated with food poisoning symptoms (nausea, abdominal pain, dizziness and fever) 30 minutes after consumption. Long-term and continuous exposure to even lower levels of vomitoxin might cause dangerous reduction in appetite, weight loss, damage to the gastro-intestinal tract and impair the immune system.

— Answer by Bill Wiebold

Is wheat straw from plants infected with Fusarium fungi toxic to animals?

This answer is based on a document prepared by Ohio State University. For more information, see

Yes. Straw from scabby fields does contain vomitoxin and other mycotoxins. Results from studies done at the University of Illinois (with laboratory tests done at North Dakota State University) confirmed that vomitoxin levels might exceed 2 ppm in wheat straw, even in fields treated with fungicide. As a result, the same caution exercised when handling and feeding scabby grain should be exercised when dealing with moldy straw. Get the straw tested before using it for silage or bedding. The risk of contamination is much lower when straw is used for bedding; however, you should still avoid straw with very high levels of vomitoxin because it is impossible to tell how much the animals will munch on the straw. Little information is available on hay, but wheat hay is much more likely to be consumed by animals than straw.

— Answer by Bill Wiebold


Hay is flooded and contaminated with dirt and other stuff. Will this contamination affect the animals?

Perhaps. Most often animals will refuse forage covered with soil or other contaminants. The greatest threat will be when livestock are forced to eat forage they would otherwise refuse.

— Answer by Craig Roberts and Rob Kallenbach

Will moldy hay affect animals? Is there something to decrease impact?

It can, but it is unusual. Often animals will refuse moldy hay if there are other sources of feed. Be most careful feeding moldy hay to horses because it can cause colic. Diluting the diet with other non-moldy feedstuffs can lessen the impact.

— Answer by Craig Roberts and Rob Kallenbach


How do you handle a lagoon or pit that is full when there is no dry ground where it can be spread or crops that use the nutrients?

The full answer to this question depends on the size of operation and the type of permit.

Most operations in Missouri are “no-discharge” operations, which means they are not allowed to discharge effluent without incurring a potential notice of violation. For these operations, you are choosing between the lessor of two evils under these conditions. If your manure storage is about to overflow, it is better to land-apply manure under poor conditions then have a storage spill directly to a creek or other body of water.

Missouri Department of Natural Resources (MDNR) has a publication to help producers minimize damage from emergency land application under wet weather conditions (

If you are applying under emergency conditions, be sure to apply at low rates onto land that has cover (e.g. pasture and hay ground). Maintain separation distances between application area and sensitive features (see publication for guidance). Apply on areas with low slope that are not prone to flooding. Rigorously monitor the area during land application to ensure that no manure is running off the field. Keeping records to document extreme weather affecting your farm and your application practices is highly recommended.

If manure from an overflow of your storage or from land application on wet ground leaves your property or reaches a stream or other body of water, you are required to report the spill to your regional MDNR office.

— Answer by John Lory