Wet fall creates ideal mycotoxin environment

Ontario’s record rainfall this autumn was a damper during harvest, and now, the negative effects are lingering.

A joint feed analysis of the 2017 grain harvest, led by animal health company Alltech Canada, shows wet conditions created an ideal environment for the development of mycotoxins in feed.

Alexandra Weaver, mycotoxin management technical specialist with Alltech, says mycotoxins are produced by certain species of molds, which grow particularly well in damp conditions.

In higher amounts, mycotoxins can affect feed intake, reproduction, milk production and gut health.

Weaver says rainfall is the key to their development. Rain prior to flowering causes the release of spores from molds. During flowering, rain helps the fungus to establish on a grain. And rain right after flowering helps the fungus spread to other grains.  

Conditions were right

Ontario experienced all these conditions. Significant mycotoxin development took place in isolated pockets throughout Canada, but mainly in Ontario where high levels of rainfall were widespread.

In the feed analysis, mycotoxins were found in corn, haylage and corn silage. The latter was the biggest problem, she says, because the whole plant is harvested, rather than just cobs, fungus and bacteria from the soil accompany the plant into storage and proliferate.

And that’s certainly the case this year. Of the 432 feed test samples, almost 88 per cent of corn silage samples had more than one part per million of the mycotoxin deoxynivalenol, commonly known as DON and also known as vomitoxin. Over half the samples had two parts per million or even more. 

DON levels vary by region

The highest levels of contamination in corn silage samples were in Norfolk County. Other counties with significantly higher levels than average were Haldimand, Middlesex, Ottawa, Simcoe, Niagara and Renfrew.

Weaver urges producers to be diligent in determining the problem in their own feed.

“There’s a level of concern,” Weaver says. “Mycotoxins seldom exist in isolation. Producers should definitely check their feed and watch for signs of mycotoxins affecting their livestock.” 


Managing mycotoxins is a multi-faceted effort, she says. Healthy plants have a better chance of surviving mycotoxins, so plant early, use fertilizer and protect crops from insects, weeds and plant disease. Know your humidity level before and during harvest, and be aware of how you treat contaminated grains whether you are exposing them to other grains.

Weaver suggests producers eliminate all feed that has visible signs of mold. Proper storage is important for forages, especially packing and storing to reduce exposure to moisture and further mycotoxin development. The same goes for grain, along with proper drying.

“Eliminate opportunities to mould to grow,” Weaver says.

Other companies involved in the 2017 feed analysis were Masterfeeds and Stratford Agri-Analysis.

More information on mycotoxins can be found at knowmycotoxins.com.

Bottom line

Mycotoxin contamination is rampant in Ontario. Check your feed and watch your livestock for signs of mycotoxin poisoning as it can affect their feed intake, reproduction, milk production and gut health.

Article by: Owen Roberts