cows in field



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:

  1. Clay or silicate/montmorillonite-based products (Desert Dynamin, Redmond Conditioner, bentonite, calcium aluminosilicate etc) are effective against aflatoxin, but with little effect on Fusarium toxins.
  2. Low-inclusion rate yeast cell wall extracts, also known as oligosaccharide/beta-glucan yeast cell-wall products (Fuse 207, Check M, Immunowall, FloMatrix, Mycotex etc) are reasonably effective against the Fusarium toxins.
  3. A newer product from Alltech called Integral A+ is made from hydrolyzed yeast and is showing promise in better protecting an animal’s gut on a routine basis, tying up toxins in cattle, horses, sheep, poultry and pigs. It seems to work best when used as a routine ‘safety’ feed inclusion at the rate of 4-8 g/head/day than if used in an emergency or acute situation.

Steps to Minimize Mycotoxin Levels in Grain, Forage and Feed

  1. Always use cleaned, high quality seed that does not carry seedborne diseases. If you plant back your own seed, make sure it was not infected with scab or head blight (Fusarium) the previous year. Fusarium is a very common soil organism, so its presence in seed alone will not guarantee problems, but if weak seed results in a plant that is more vulnerable to stress, this can cause infection and mycotoxin problems. Whenever possible, use disease resistant varieties.
  2. Since fungal infection and mycotoxin development is far more likely on stressed plants, it is very important to focus on reducing agronomic factors in the field that cause stress. This includes soil fertility imbalances or deficiencies/excesses, soil drainage problems, soil compaction, weeds, insects, and diseases. It also includes planting varieties that are suitable in season and will mature fully and reliably under your farm’s conditions. We can’t control weather conditions, but many agronomic factors are under our control.
  3. Harvest at physiological maturity, as soon as the moisture content allows minimum grain damage. This means harvesting shelled corn at 23-25% moisture, ear corn at 25-30%, small grains at 12-17%, and soybeans at 11-15%. The longer grain is left in the field after maturity, the higher the likelihood of fungal contamination. Dry suspected grain to at least 14% moisture as rapidly as possible, at least within 24-48 hours after harvest. Safe, long-term storage can only be achieved at a moisture level of 13.5% or below. Cool grain after drying so hot grain doesn’t absorb moisture from the air.
  4. Adjust the harvesting equipment for minimum grain damage and maximum cleaning. Especially where scab/head blight is evident in the field, the combine should be set for maximum cleaning, with higher blower speeds to remove the small shriveled diseased kernels and broken grain.
  5. If harvested grain contains wet weed or plant material, run it through a rotary cleaner soon after harvest so the moisture doesn’t migrate into the grain. Rotary cleaning also will remove broken and diseased kernels and fines which are more vulnerable to insect and mold damage in storage, and removal of chaff and debris will reduce the possibility of dryer fires. During harvest, we routinely use the rotary cleaner between truck/wagon and grain bin to make sure that grain goes into storage as clean as possible.
  6. Roasting does NOT deactivate mycotoxins, but it may reduce the level by blowing off surface mold. If you roast moldy grain, make sure you run a mycotoxin test after roasting to check if the level is safely reduced.
  7. Thoroughly clean all bins before storage to remove dirt, dust, and old grain. Store in water-, insect-, and rodent-tight structures. Keep grain well-aerated and monitor regularly for mold, insect infestation, leakage, or other deterioration.
  8. For ensiled forages in bags or silos, make sure forage is harvested at the right moisture level, is tightly packed, that oxygen is excluded and the ‘package’ is kept sealed since mycotoxin-causing fungi require oxygen to live. Be prepared to discard forage from around torn areas of Ag bags, as it is more likely to be contaminated. Avoid harvesting dead or moldy plant material in the field.
  9. Use extra care and watch more closely when you harvest grain or forage that you know grew under stress, including grain that is low test weight, frost, insect or flood damaged, harvested immature or at high moisture, or forage or silage that may have been harvested too wet or too dry, dirty or containing significant levels of dead material, or that may not have fermented correctly, or any feed that just doesn’t look or smell right!
  10. If you have reason to suspect mycotoxin problems, contact a forage testing lab and test before feeding it or representing it to a buyer as sound grain. If you must feed contaminated grain, identifying the toxins present will help you choose the most effective toxin binder.
  11. Reduce animal stress from other causes, since stressed and diseased animals are far more susceptible to mycotoxin issues than healthy unstressed animals. Watch your animals for subclinical symptoms that might indicate feed issues.

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,