Corn silage in a number of rain-ravaged states is testing positive for levels of molds and mycotoxins, warns Brian Steinlicht, technical director at Dairyland Labs, Arcadia, WI.

"I probably answer 40-50 calls a day on this," said Steinlicht during a Nov. 18 University of Illinois webinar on wet corn. He had compiled data on corn grain and corn silage samples sent to Dairyland for testing and presented his findings via the Web.

"Out of 307 corn silage samples, 21% came back with some level of fusarium mold in them and 11% with some form of aspergillus mold," Steinlicht said. States he gathered data from include Indiana, Michigan, Pennsylvania, Ohio, Wisconsin, Illinois, Minnesota, Iowa and North and South Dakota. Samples sent in were suspected of having mold or mycotoxin problems, he added.

"A lot of what we first saw were cladosporium-infested and fusarium-infested samples. We had a period where there was a brief freeze and the number of viable molds that came in was lower, though still fusarium and cladosporium. Then we had a warm-up and the mucor molds began to bloom ... and, most recently, we saw a fair amount of penicillium molds. It seems like, as the season goes on, the type of mold is changing."

Mold on corn doesn't necessarily mean it also contains mycotoxins, experts warn. And corn showing no mold may not be mycotoxin-free. But Steinlicht said that mycotoxins are showing up in some levels in corn silage he's tested using thin-layer chromatography.

"It's a perfect storm – the weather conditions and not getting the corn out are good breeding grounds for molds." So far, of 62 samples tested for vomitoxin, 55% tested positive at some level. A total of 46% of 28 samples tested positive for zearalenone. Sixteen samples tested for T2 toxin showed no positive results. Only 9% of 23 samples tested positive for aflatoxin.

Signs of toxin problems in dairy cows include loose fecal discharges; reduced microbial digestion, dry matter intake and fertility; hormonal changes; and immune suppression to disease challenges, said Mike Hutjens, University of Illinois extension dairy specialist.

Besides analyzing feeds, producers may want to consider using mycotoxin binders, Hutjens suggested during the webinar. For aflatoxin problems, he recommended clay-based compounds such as bentonite, zeolite and calcium aluminosilicate at 50-225 grams/cow/day. For feed infected with T2, DON and zearalenone toxins, he advocated yeast cell-wall extracts – also called MOS or glucomannans – at 10 grams/cow/day. "You may need to double up or triple up" on amounts, he said.

And beware of possible mycotoxin concentrations in distillers grains, Hutjens said. He advised producers to ask for test results before buying distillers grains this year. For additional information, click here: Watch For Moldy Corn. The University of Illinois' update webinar on Wet Corn Strategies and Alternatives will be held Dec. 3. Dairyland Labs offers online corn silage and shelled corn data summaries of mycotoxin testings.