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MYCOTOXIN ALERT 2017
Just In: Mycotoxin Alert Update!
By Mary-Howell Martens
In New York, and in the northeast, there are emerging 2 new sources of mycotoxin problems this summer.
Straw, especially wheat straw and triticale straw can be a potent source of vomatoxin and some of the other lesser known Fusarium toxins, but the nastiness that is emerging is a toxin most of us have previously not heard about called Gliotoxin, caused by the fungus Aspergillus (but a different species than the Aspergillus that causes aflatoxin). This has been measured at high levels in straw in Cayuga County, NY. If a cow eats their bedding, especially after the bedding gets wet, this can be ingested.
The significant thing here is that the toxin contains sulfur. Why is that important? Because of a situation I helped sleuth out a month ago when an organic dairy farmer had a milk sample come back positive for sulfa drugs. He had no idea where it might have come from. Eventually, we got the old 2016 crop ear-corn in his crib tested and it had detectable levels of aflatoxin. Doing a little research on this, it appears that the common CHARM test used on milk has some cross-sensitivity, so aflatoxin and apparently gliotoxin can throw a positive sulfa result, even if no sulfa is present. Of course though, it is illegal to feed dairy cows feed exceeding 20 ppm (parts per billion) alfatoxin because it can come through, in a particularly potent form, in the milk and aflatoxin is carcinogenic.
Now here’s the next ringer. Haylage in New York is testing positive for Penicillium mold this summer! That is a greenish slimy mold that develops when haylage is harvested too wet and not stored anaerobic enough. Guess what antibiotic Penicillium toxins can mimic? Yes indeed folks, positive penicillin test in organic milk.
The other thing is that these toxins are causing haemorragic bowel symptoms in some New York herds. Generally that is associated with an infection like salmonella, but it appears that DON (vomatoxin) and gliotoxin can cause the symptoms, bloody manure, etc.
Please also be warned that we have been rejecting loads of New York grown triticale grain due to elevated vomatoxin. The level for concern with cows is 5 ppm (parts per million) and we tested one load, grown by a really excellent farmer who is very attentive to detail and quality, that tested 13 ppm. That can cause some serious symptoms, from general immune system depression to actual bleeding and death.
What can farmers do? Fortunately, there are yeast cell wall products that bind up many of these toxins and let the cow eliminate them in a non-toxic form. These are allowed for organic, OMRI listed generally, and can be fed at a ‘safety’ routine low-inclusion level without tying up nutrients like the older clay binders do.
I was at a training at Cornell 2 weeks ago and several conventional feed mills say they are recommending safety toxin binders. These mycotoxins are a real serious problem with distillers’ grain coming out of the ethanol plants - the ethanol process really concentrates the toxins and all kinds of toxins are being found. Corn gluten meal also is risky because it concentrates toxins. We organic farmers don’t use those products, but we do have to worry about other feed sources, especially this year any forage you may have harvested a little wet, and any triticale and wheat that have not been tested. It remains to be seen what corn and corn silage will be like, but many New York experts are worried, especially silage.
Heads up, folks. Mycotoxins may not be easy to detect or realize you have in your feed, especially your hay/baleage/haylage/silage, but mycotoxins are real, and they can do real damage.
Mycotoxins are toxic chemicals produced by certain types of fungi that grow on plant material, both in the field or in storage. Mycotoxins are a common problem worldwide, indeed, it is estimated that globally, over 25% of field crops are affected annually with mycotoxins. In Europe, Napoleon’s defeat in Russia may not have been due as much to cold or military skill, but rather to mycotoxin-contaminated grain fed to horses and men.
At a recent meeting with other feed mill operators and regulators, mycotoxins are definitely on everyone’s mind, as a feed and food hazard that is increasing with changing weather patterns and especially with the amount of distillers’ grain from ethanol production that is fed on conventional dairies. Mycotoxin levels can be significantly concentrated and increased in distillers’ grain. Conventional dairy farmers are also concerned about all the corn for silage that was planted late and ‘mudded in’.
This year’s extended wet cool spring created nearly ideal conditions for mycotoxin development in small grains, forage and possibly silage. At Lakeview Organic Grain, we test all incoming grains in-house before taking delivery, rejecting loads that test above 3 ppm vomatoxin. In all the years we have been buying and testing grain, we have never seen such high levels as this year in New York-grown organic grain, especially in triticale. The loads we rejected at harvest are probably still out there, looking for unsuspecting buyers, some with levels of vomatoxin that were literally “off the charts” for our testing protocol.
This is not a new risk, several years ago a study from Vermont estimated that over a 10 year period, nearly all dairy farms in that state will experience mycotoxin-related issues, even though most will not connect symptoms to actual cause. Increasingly erratic weather, though, has caused significant crop stress, making it difficult for many of American farmers to ignore mycotoxins, especially as they see more low-grade and serious animal health problems, poor quality forage and rejected grain. The fact that the Midwest also experienced an excessively wet spring this year suggests that much of the American grain crop, especially small grains like triticale, wheat and barley, is at risk.
Many types of feedstuffs can develop mycotoxins, including grains, haylage, baleage, silage, dry hay, and high moisture corn. Infection is most common on plants grown under stress, especially when damaged by insects, birds, mites, hail, early frost, heat and drought stress, windstorms, and other unfavorable weather. Mycotoxins can also form or increase when grains and forages are harvested and stored at undesirably high moisture levels, when grains are put into storage dirty, if plastic ag bags get torn or damaged, or if storage facilities leak. Forage mold inhibitors, acids or bacterial inoculants generally do not reduce mycotoxins already present in baleage or silage, and though drying or roasting grains will stop further development and may blow off some surface contamination, it will not deactivate the toxins that are there.
Experts estimate there are over 300 fungal toxins which can contaminate crops, but several are distressingly common and damaging. In the Northeast, the common soil fungus, Fusarium, causes ear-rot in corn, and scab or head blight in wheat, barley, oats, and rye, and produces several mycotoxins, including vomitoxin (DON), fuminosin, T2, and zearalenone. Fusarium can also infect ensiled/bagged forage and silage. The risk increases when corn/forage is harvested late (especially after frost), gets moldy or lodged in the field, is rained on or sours in the windrow, or is not adequately packed to exclude oxygen. Silage corn cut after a frost or late in the season is often too dry to pack well, impairing normal fermentation and allowing Fusarium, already present on the corn, to proliferate. Fusarium and its toxins can continue to increase if grain is put into storage above 14% moisture.
Several species of the Aspergillus fungus produce aflatoxin, which is most commonly seen in hotter, drier areas of the South and southern Midwest. Though we rarely see aflatoxin on Northeast-grown grain, last year’s drought resulted in aflatoxin in some New York ear corn that was not fully mature when harvested; the plants had died of drought stress before the kernels finished developing. The cow health issues and strange milk test results were very confusing until the farmer tested the ear corn remaining in the crib and found significant aflatoxin. Aflatoxin is extremely potent, at the parts per billion (ppb) levels.
Greenish-colored Penicillium is most commonly seen in silage and can produce several different toxins. Ergot toxins (from the mushroom fungus Claviceps) have also caused problems mostly on rye (St. Anthony’s Fire). Byproducts can also contain mycotoxins, with products containing peanuts being notorious for aflatoxin problems.
How do you know whether your grain/forage contains mycotoxins? If feed is visibly moldy, that is a pretty good clue. Just as you wouldn’t eat moldy food, neither should your animals.
However, it usually isn’t that simple. Not all molds you can see produce toxins, and not all grain/forage containing toxins looks moldy. For that reason, although we rarely see moldy grain, we do test often for mycotoxins. There are accurate lab tests available – Dairy One does a nice 6 mycotoxin scan, but these are expensive and slow, and tests are only as accurate and representative as the sample was, so they are usually not done unless there is good reason to suspect a problem.
What makes us suspicious? We generally test grain that is light test weight, poorly matured, off-color, musty, dusty, harvested excessively late, has many broken or damaged kernels, or just doesn’t look/smell/feel right. We also randomly test other samples of each grain during the season to get a baseline and to check our assumptions. A slight pink coloration to the grain can indicate the presence of Fusarium. We usually recommend testing all on-farm feed supplies if a farmer complains of ‘typical’ mycotoxin symptoms in their animals. We also recommend that, if you must feed forages that are moldy, slimy, off-smelling, or otherwise not quite right, you test them first. Traditionally, aflatoxins have been detected by placing grain under a ‘black light’, but that is not a reliable test for the Fusarium toxins.
At high levels, mycotoxins can cause liver damage, internal hemorrhaging, cancer, abortion, and reproductive failure in animals, but even at a fairly low levels, they can strongly suppress an animal’s immune system, resulting in other opportunistic infections, such a salmonella, clostridia, and E coli to ‘break through’, causing diarrhea, mastitis, and other production/health problems. Some mycotoxins are estrogen-like, interfering with cycling, conception and fetal development.
The subclinical effects of mycotoxins are more insidious and difficult to identify. Feed with mycotoxins can result in reduced feed intake, impaired rumen functioning, elevated SCC, poor vaccine take, reduced milk yield and butterfat, reduced weight gain, and impaired reproductive function in both females and males. The problem here, of course, is that other factors can cause similar low-grade symptoms, which is why farmers may not connect symptoms to cause. But, if you see such symptoms, mycotoxins in feed and forage are one of the first things to address. Animals under stress for other reasons and young animals tolerate significantly lower toxin level than healthy adult animals.
There are ‘threshold’ levels of concern for different mycotoxins depending on the animal species being fed. According to Dairy One, ruminants can tolerate a total toxin level of around 5 parts per million (ppm) of vomatoxin while other experts caution not to exceed 1-2 ppm. Pigs, chickens and young animals are much more sensitive. The acceptable threshold for organic human food grains is essentially zero.
Other mycotoxins are of concern at a much lower tolerance level. New York State has issued a warning that it is illegal to use feed with aflatoxin levels above 20 ppb in dairy feed, because the toxin can be transmitted into the milk. Animals destined for slaughter or breeding can be fed higher levels, up to 300 ppb aflatoxin for finishing beef steers.
It is important for livestock farmers to recognize that as far as the animal is concerned, it is the total cumulative intake level of all mycotoxin-infected feed that counts. Even if each individual feed/forage item tests ‘below threshold levels’ (including baleage, silage, grain, ground feed, high moisture corn, ear corn etc.), if eaten together by one animal, the overall level may exceed the threshold and adverse effects will be seen. Also, frequently contaminated feed/forage contains more than one toxin, further complicating the decision of whether you have reached a level for concern.
While there are products available to ‘bind’ or adsorb toxins, none are 100% reliable, so it is best to avoid feeding suspect feed whenever possible. If you need to use a toxin binder, try to match the correct binder to the toxin present. In the feed industry, mycotoxin binders are often termed ‘flow or anti-caking agents’ to avoid making actual efficacy claims. Binders allowed under organic standards fall into 3 primary categories:
Steps to Minimize Mycotoxin Levels in Grain, Forage and Feed
For more information, this article from South Dakota State University has good information:
Mary-Howell Martens can be reached at Lakeview Organic Grain, Penn Yan, NY, 315-531-1038, firstname.lastname@example.org.