Agrarian Marketing Corporation

Some argue that Kingda Ka (Six Flags Great Adventure – NJ) is the fastest, most vertical roller coaster in the US. Dairymen likely thought they were experiencing just that last year when mycotoxin levels in corn, wheat, and silage soared to record-breaking heights. And now, one hears a collective sigh of relief from the industry as lower, more sporadic, and more typical levels of DON, zearalenone and others are reported in late 2010. But like most roller coasters, that ‘first’ hill last year was not the last! Mycotoxins have historically shown seasonal rises and falls. Generally, growing and stored feedstuffs are most vulnerable when temperature changes are most extreme; therefore, spring and fall are the times mostly likely to produce mycotoxin spikes. Even under laboratory conditions, the greatest yields of mycotoxins are achieved when mold cultures are grown under variable temperatures rather than steady temperature incubations.

Go back to 2009 again. Many of the regions experiencing the highest level of toxin contamination in corn were also those which had wet conditions at normal planting time, delaying getting the seed into the ground, and, then, wet fall with delays in harvest, sometimes to the point where first snows had fallen. From the more normal 250-1000 ppb DON, corn tests showed new harvest corn reaching as high as 90,000 ppb! And reports on silage from various locations also showed higher-than-average DON levels. And consider that ’09 crop issues left specific toxigenic mold spores in the fields that are subsequently replanted in corn. Yes! When we put the same crop into the same field year after year, we are promoting the rise of adapted mold strains; if they are also toxin producers, each subsequent crop is at higher risk. In time, this favors those strains capable of producing the higher toxin levels under wider ranges of environmental conditions. Expect, then, that whatever the winter of 2010-11 brings, spring warming plus the broader range between day and night temperatures will likely produce a typical round of increased spoilage/mycotoxin contamination of stored feedstuffs (silage, shell corn, etc.).

And, always keep in mind that when we submit samples periodically for testing, we are testing for a tiny number of the many possible contaminating mycotoxins in feedstuffs. A growing number of investigators are now cautioning that dairy issues are likely correlated to two of the toxins produced by a species of Penicillium which thrives in corn silage. Mycophenolic acid and roquefortine C occur almost as frequently as DON and often in amounts significantly higher than that ‘marker’ toxin. Even worse, except for the generic symptoms (lowered milk production, irregular manure, increasing SCC, reproductive failures) responses specific to mycophenolic acid and roquefortine C have not been determined. Also, there are no rapid, antibody-based assays for those two toxins and commercial labs are not prepared to offer test options for them. Even a low test for DON (e.g., <500 ppb), a Fusarium toxin, should leave us wondering if some other potentially more devastating fungal poisons are present in our silage. Producers need to be considering now, as winter is just fixing its grip on the country, how they will prepare for and deal with those circumstances so that herds are not impacted by sudden shifts in background mycotoxin levels during the spring. The most successful remedy to-date is the application of specific L-Form bacteria that inhabit the cow’s intestinal epithelium and act as gatekeepers, scavenging absorbed toxin and signaling the normal epithelial cell’s own regulatory systems to exclude more toxin.