Mycotoxins in Your Feed- What you Need to Know and Steps to Reduce Your Risk Next Year


2018 is shaping up to be one of the worst years on record for vomitoxin levels in Ontario Corn. This is a huge concern for livestock farmers this fall.  This article will help to inform you on how to manage Vomitoxins moving forward.

First, vomitoxin infection in our corn crop is always a risk. However, with any disease the environment must be conducive to allow it to take hold. The requirements are having a host, which is your corn crop; the disease must be present, it is present every year; and you must also have the right environment, this is normally the variable that controls the severity of the infection.

The climate in South Western Ontario is very unique. Between the Great Lakes we tend to have higher humidity levels and warmer temperatures. This problem is very localized to our area as this issue is not often seen in the US or the rest of Canada outside of primarily Western Ontario. When these warm and wet conditions occur at tasseling through till silk browning, there is a large risk for ear mould infection. If you recall the weather from mid-July to mid-August, it was consistently wet for extended periods of time and crop canopies stayed wet longer than normal. The infection tends to occur when the silks of the corn are still green. The inoculum that is present in the environment will land on the silks and if there is the right temperature and moisture the infection can occur.  It is important to note that severe infection pressure tends to be fairly isolated to South Western Ontario in counties such as: Oxford, Perth, Huron, Middlesex, Lambton, Elgin, Chatam-Kent and Essex. More moderate infections can still be found outside of these hot spots.

At this point there are management strategies that you can take to reduce the impact of vomitoxins in your feed. It is important to be aware that vomitoxins can be present in corn silage, cob meal, high moisture corn and dry grain corn. It can also be in Dry Distillers Grain (DDG’s) and Wet Distillers grain.

For corn silage and cob meal that are already harvested, it is very important to test your feed and identify the vomitoxin level in your feed. Consult with your nutritionist to determine what amount of intake your livestock can have on a daily basis. There are toxin binders that can be added to rations to help tie up the toxins and make them less harmful to your livestock. Again, consult your nutritionist to determine if you need to be using a toxin binder.

For high moisture and dry grain corn – if you have yet to harvest your crop take extra care to have a clean sample coming off the combine or drier. Try to remove all broken cobs and any fines that may be in the sample. Higher wind speeds on your combine, closely adjusting the sieves and aggressive cleaning after the drier can all help reduce the toxin levels.

For any distillers grains, be sure when buying these products to know the vomitoxin levels. The toxins will accumulate in the distillers grain after fermentation and can be much higher coming out than what was present in the original grain.

If you end up with feed that does have high levels of vomitoxin, the risk of exposure to different livestock is important to know. Mono-gastric animals like pigs and chickens are more susceptible than ruminant animals, and reproducing livestock are more sensitive than feeder animals. Below is list for livestock groups in order from most affected to least affected.

Risk of exposure: Sows/ Gilts> Feeder Pigs> Chickens> Reproducing Cattle> Feeder Cattle

Looking Forward

What can I do next year to reduce vomitoxin levels in my feed? Below there are three management strategies that can be easily implemented in your operation to help reduce the risk of vomitoxins in your corn:

Improve Corn Stand Uniformity– When assessing corn fields this year it was apparent that plant stand variability made for some quality issues this fall. Late emerging and runt corn plants were common to find in corn fields. These plants tended to have smaller cobs and longer, tighter husk covers. When the tips of the ears stay tightly bound by the husk on these plants the cobs became severely infected by mould. When comparing the runt cobs to the average size cobs in the same row it was obvious that the mould was worse on the smaller cobs. Also where there were skips in the row, some of the plants that had more space in the row would throw second ears on the plant due to the extra space. These second ears rarely fill out and also cause a similar issue where the husk stays tight and may also have some tip back. These cobs often were mouldy and rotten and still make their way into the combine and contaminate the grain sample.  We strongly encourage growers to consider improving their plant stands moving forward to reduce plant to plant variability and mould risk. Below are some suggestions:

-Improve seed bed uniformity so that the planter can do a better job placing each seed

-Fine tune planter performance to do a more accurate job planting

-Plant deeper (2” deep minimum) to help improve germination and emergence timing

-Plant at a slower speed to allow planter to ride better and have less variation on seed drop


Fungicide Applications- Spraying fungicides on corn at Tassel can be an effective tool to help reduce vomitoxins. However, spraying a fungicide will never eliminate vomitoxins and growers must use the right fungicides and apply them at the correct timing. We have heard many producers complain that they sprayed a fungicide and still have vomitoxins in their feed. It is critical to use the right fungicides as not all fungicides will have activity on diseases like Gibberella that produces Vomitoxins. Growers need to use products such as Proline or Caramba if they wish to see some toxin reduction. If you used products such as Headline, Trivapro or Priaxor, they have no activity on reducing vomitoxins. Proline and Caramba also need to be applied when the silks are emerged and still green. Some early or late applications may miss this window. Please note that these can be effective tools to help reduce vomitoxin levels but will not eliminate them completely.

Fungicide Suggestions:

-Use products like Proline, Caramba

-Spray once Silks are emerged and before they turn brown and dry out

-Avoid using foliar disease-only products like Headline, Trivapro and Priaxor


Hybrid Selection- It is apparent that some Hybrids can be affected by Gibberella infections more than others and this can result in vomitoxin production. This tends to be more likely with certain phenotypes that can produce longer husk covers. There may be some hybrids in your area that are more prone to mold and vomitoxin susceptibility. But remember that 2018 has shown that different years can result in different hybrid responses.  Farmers should also aim to grow multiple hybrids on their farm to reduce the environmental risk of a hybrid having a bad year. We also suggest you pay close attention to flowering dates of your hybrids and try to spread out flowering timing so that there is less risk of all your corn tasseling at the same time. Talk to your trusted seed partner for recommendations for your operation.

Hybrid Management Suggestions:

-Identify hybrids that may be more prone to vomitoxin infections

-Identify hybrids that tend to be lower risk to vomitoxin infections

-Plant at least 3 different hybrids on your farm to spread out your environmental risks

-Select hybrids with different flowering dates to spread out your tasseling window


Going forward it is important to recognize that there is a risk every year of mould and vomitoxin infection. This year produced a perfect storm of events that have resulted in some high Vomitoxin levels. It does not necessarily mean that these levels will be common moving forward. To reduce your risk , use proactive measures as discussed here to reduce the impact of future disease infection in your operation.