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Be Careful How You Interpret Mycotoxin Results

Dr. John Doerr, Ph.D., PAS, Dpl. ACAP - Vice President, Science and Technology - Agrarian Solutions

Recently I wrote about our mycotoxin testing service.  I hope you took that one to heart and, if new to us, have since tried it out.  In that article I published some data we’ve collected as we do 1,000-1,500 tests per year for US customers and a significant additional number for clients in Canada.  Agrarian is expecting to publish update summaries of mycotoxin findings at regular intervals in 2020.  Sounds foolproof! 

But a major issue is how you interpret the results you get back or see on our reports.  Recently I opened a trade e-zine to find an article on protecting livestock from mycotoxins.  Not a bad piece; some good information on obtaining a sample of shell corn for testing and a good bit of numbers... “guidance levels” for various mycotoxins in livestock and poultry.  That’s when I groaned, not because the author had mis-reported any of them, but because in a short article there was no room to put in a few caveats about those numbers.  

The ‘guidelines’ were quoted from a piece written by a major mid-West university, which in turn was citing a state chemist’s office.  Ultimately the real source was FDA.  So, go to those tables (I’m not reprinting them here...pretend!) of data, put yourself in the shoes of a busy dairyman or dairy nutritionist, and tell me how much aflatoxin is okay for your milking herd.  A quick glance to the ‘maximum” level column says “20 ppb”.  Ah, but that’s for corn and peanut products.  What percent of a dairy cow’s ration is ‘corn’ or ‘peanut’ products?  Right!    Now drop down several lines.  There’s a guidance for cottonseed...max = 300 ppb.  But only beef cattle, swine, or poultry are mentioned.  Guess we never feed cottonseed to dairy cows!  How many other commodities are not included?  The guidelines don’t speak about TMR.  So, now add the sources of aflatoxin in the feed.  It could amount to a good bit.  I’ll now remind you that a typical Holstein herd consuming a TMR with 25 ppb aflatoxin B1 will excrete sufficient aflatoxin M1 in the milk to cause rejection by a milk processor.  Bottom line: don’t look at ‘max’ levels as being safe to feed.

Also, read all of the table for a given toxin and species, not just the big number.   The “All other animals” category DON guideline (only spot open for dairy cows) says 5 ppm (5,000 ppb) DON.  But a bit less obvious is the phrase... ‘not to exceed 40% of the diet’.  Some will miss that and assume the 5000 ppb is okay.  But, now we’re down to a ration with 2,000 ppb DON.  While that’s significantly better, guess how much below par on just milk production those cows will be consuming that amount of DON!  We know research has shown herds start losing lbs/day at around 300 ppb DON.

So, FDA specs are a safe bet to quote in print, and they have real meaning for the mission of that agency (that humans aren’t affected by contaminated milk, meat, or eggs).  Keep in mind none of the guidelines takes into account multiple toxins and their interactions, nor other stressors that face farm animals.  Be cautious, therefore when you see such information; don’t assume it is telling you a particular level of one mycotoxin is safe for you to feed.  It certainly doesn’t account for the multiple toxin challenges that are routine on farms.

If a dairy wants to manage well for mycotoxins, it will have to use a fairly broad-spectrum weapon on the farm.  If you need a legally binding limit for purposes of interstate commerce of ration ingredients, by all means keep the FDA guide in your pocket for ready reference.  But if you are looking for performance and improvement in a dairy herd, you will have to be much more conservative and proactive in your strategy.  Want some realistic solutions?  Take a moment to chat with your Select Sires salesperson or get in touch with an Agrarian Solutions representative.  We’ll give you the straight story on mycotoxins in dairy operations and proven solutions to let dairymen weather the problems Mother Nature brings to us in the form of fungal toxins.  And by the way, Agrarian is running a 10% discount on DTX!  Now that’s a broad-spectrum solution!  Get in touch for details (and don’t wait, this is for December only)