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Mycotoxins Prevalent in 2022 Corn Crop


The 2022 corn crop is essentially all stashed away in the bin and the bunker. Are potentially damaging levels of mycotoxins in storage with it?


Alltech, Inc. recently shared mycotoxin data in its 2022 Alltech U.S. Harvest Analysis. Dr. Max Hawkins, global technical support specialist for Alltech’s mycotoxin management program, recapped mycoplasma particulars of this year’s corn grain and silage harvest.


Perhaps the only good news about drought is that it lowers the likelihood of mycotoxin contamination. But in the regions of the country blessed with more moisture, more mycotoxin is an unfortunate side dish. Hawkins said the most common mycotoxin family – fusarium – favors moisture and moderate temperatures around harvest time.


Hawkins manages an extensive annual mycotoxin screening program for Alltech, which this year checked for 54 individual mycotoxin species. Corn silage sampling started in mid-August; corn grain in late September. Both included samples collected through mid-November.


All samples were tested for mycotoxins before they were ensiled or stored.


A total of 302 corn silage samples averaged 7.3 different mycotoxins per sample, with some samples containing up to 15 different mycotoxins. At least 2 mycotoxins species were found in 100% of the samples.


Corn grain showed similar results, with 95 samples averaging 7.0 mycotoxins per sample, and, again, at least 2 mycotoxins in all of the samples.


The mycotoxin species found at the highest levels was type-B trichothecenes, often referred to as the “DON group.” When it was present, it averaged about 1,700 ppb, with some samples exceeding 12,000 ppb.


Alltech ruminant specialist Bryan Sanderson said evidence of mycotoxin overload in lactating dairy cows includes fluctuating feed intakes; inconsistent milk production; ambulatory issues caused by joint swelling; manure inconsistencies; and abortions.


Heifers, whose digestive and immune systems are less developed, may be even more sensitive to mycotoxins. Sanderson said they may show signs of mycotoxin damage through premature mammary swelling, inconsistent feed intake, and abortions.


The Alltech experts advised a comprehensive mycotoxin monitoring program starting at harvest. Hawkins advised checking stored feed every 6-8 weeks, as well as every time a feed source is changed. Sanderson said that includes purchased feedstuffs, which should be monitored and rejected if mycotoxin limits are exceeded.


They said it’s important to develop a complete control program based on test data to determine appropriate inclusion rates of feedstuffs. While the DON species often are the most harmful, Hawkins said even “low-risk” mycotoxins can impact cattle performance and health if they are consumed at high levels. “’Low-risk’ does not equal ‘no-risk,’” he stated.


Hawkins also said even “clean” samples coming out of the field are at risk of harboring mycotoxins later, which is why ongoing monitoring is important. Excellent silage packing, face management, and rapid feed inventory turn-over can help deter mycotoxin growth over time.


“All mycotoxins have a chance to increase in storage,” he advised. “The crop is never going to get any better than the day you put it in storage. Hopefully it stays the same, but it’s got a great opportunity to get worse.”


By MAUREEN HANSON

December 13, 2022


dairyherd.com


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