Editor's note: Dr. Roy “Mike” Watkins passed away March 3, 2013. This is the last article he submitted for publication during a decades-long career. Hot, dry, drought conditions in the summer of 2012 set the tone for crops across the Corn Belt and beyond. Corn yields were significantly reduced as noted in the continual decline in USDA crop yield projections.

Of equal if not greater importance was the amount of grain contaminated with mycotoxins, especially aflatoxins. Not only was there more corn contaminated with aflatoxins, but the levels have been high.

The purpose of this article is to discuss the aflatoxin aspect of the 2012 crop which not only cost many dairymen a great deal of grief but a lot of money as well. Even though aflatoxins dominated the mycotoxin scene, other mycotoxins including DON (vomitoxin) and zearalenone have been found in many areas.

Measures that can be taken for managing the different mycotoxins in feeds are presented. Understanding the different analytical methods available for qualitative mycotoxin detection is also essential to determine how and where contaminated feedstuffs can be used.

The potential for aflatoxin contamination, especially in a growing season like that of 2012, should be of actionable concern for all dairymen. The mold aspergillus flavus is the main aflatoxin-producing mold, but other aspergillus strains can produce aflatoxins.

Under the right conditions, these molds produce aflatoxins in crops while still in the field (field molds). Drought is a major stressor and a strong predictor for aflatoxin production, particularly when nighttime temps remain above 70 degrees F at silking.

Other adverse conditions, including lodging, hail damage and insect damage, can cause these rather ubiquitous molds to produce aflatoxins. Moreover, aflatoxins can be produced by these molds when crops are stored under conditions that permit mold growth (storage molds).

Crops under stress and crops improperly stored are more susceptible to these molds and subsequent aflatoxin production. To paraphrase Forrest Gump, “you never know when you will get aflatoxins.” So, knowing how to minimize the risk and how to manage contaminated feeds can make or save money depending on one’s point of view.

FDA does not allow an adulterated feed (or food) to be remediated (made whole again), and mycotoxins are considered adulterants. However, they do realize that there are times, like 2012, when they must work with states by granting special variances permitting the blending of aflatoxin-contaminated grains.

Thus, blending allows for the greater use of contaminated feedstuffs. Lactation rations should not contain more than 20 ppb aflatoxins; however, rations for other species and animals with particular productive functions can be fed rations containing higher levels of aflatoxins with reduced risk.

Having said that, it still behooves dairymen to periodically invest in testing in both bought and homegrown grains, silages and finished feeds for aflatoxins and other mycotoxins, regardless of the crop year.

Few dairymen test for aflatoxin or other mycotoxins until there is a problem. Consequently, not testing this year has caused the loss of a considerable quantity of milk, in volume and dollars, because the milk was “dumped.”

Seldom was it just one or two days’ milk production that was dumped. It took some dairies a week or so to get the problem under control. No matter what size the dairy, losing the revenue from even one day’s production is an attention-getter.

Understand that aflatoxins are known carcinogens, and therefore, the levels in feed and food are regulated by the FDA. Milk has been dumped because it contained more of the aflatoxin metabolite AFM1, which also is carcinogenic, than allowed by the FDA.

AFM1 at or above 0.50 ppb is considered an adulterant and poses a risk to consumer health. Therefore, the milk cannot be sold into the human food market but must be destroyed.

Dairymen should know that approximately 2 percent of the aflatoxins consumed by lactating cows will be excreted in the milk as the metabolite aflatoxin AFM1.

They should grasp the fact that this is why the maximum level of aflatoxins in lactation rations should not exceed 20 ppb (20 ppb x 0.02 = 0.40 ppb). Thus, feeding more than 20 ppb risks having the milk rejected and dumped.

While aflatoxins have received most of the attention this year, deoxynivalenol (DON or vomitoxin) and zearalenone have been a problem for numerous dairies. They have been in corn, wheat and barley from the Atlantic seaboard across the Corn Belt and north into Canada.

Likewise, fumonisins also were found in much of the corn. These toxins are present in some areas because, as with aflatoxins, weather and other conditions were right to trigger fusarium mold growth and subsequent mycotoxin production.

Currently, fusarium mycotoxins are not excreted at levels of concern in milk, even when fed at high levels. This does not mean that animal health and performance are not affected. All mycotoxins, as noted by a prominent mycotoxin researcher, at most any level adversely affect animal health and performance, causing economic losses, and therefore should be effectively dealt with.

Understandably, there is a general misunderstanding about how to manage mycotoxins in feeds. This is rather natural, since aflatoxins were the first mycotoxins recognized – as was, shortly thereafter, that they can be “bound” with “binders.”

Even though for many years binders were all that was known for managing mycotoxins, there has been a lot of progress in the intervening years between the ’60s and today. It is now known that not all “binders” are really effective.

More significantly, it is now known that not all mycotoxins are bindable. This lack of current understanding still leads dairymen to spend money on “binders” that are either not effective or are added to feeds containing non-bindable mycotoxins (see Figure 1 ).

Essentially, binders are compounds, such as certain bentonites, other clays and HCSAS (hydroxy calcium sodium aluminosilicates), which have a large surface area structure and polar sites which attract and bond to polar sites on the mycotoxins.

Ultimately, a bound mycotoxin is not absorbed from the digestive tract into the bloodstream where it can alter organ and cell function to impair health.

Efficient binders also must remain bound to the mycotoxin at both low and high pH (3 to 7.0) as the complex moves through different regions of the GI tract and is finally eliminated in manure.

Some cautionary notes need to be made at this point. Activated charcoal (carbon) is an excellent binder. The problem is that it binds everything: mycotoxins, vitamins, trace minerals, drugs, etc. So if it is used, it should not be fed for extended periods of time, which may not be feasible when the barn is full of contaminated grain.

Similarly, some functional feed ingredients, such as pellet binders, which may have some binding capacity, added at high levels can bind essential nutrients. They may also occupy space needed for essential nutrients. Another old practice: “dilution is the solution,” works for a while, but as noted earlier, at any level mycotoxins are harming animal health and productivity.

Subclinical effects difficult to diagnose and tend to go unrecognized. The fact is that most of the damage mycotoxins do to animals and the dairyman’s pocketbook is from subclinical levels of contamination.

As seen in Figure 1, a number of the major mycotoxins are not manageable with binders. Non-bindable mycotoxins may have some polar sites, but these sites are not exposed where they can “bind” to a binder. For some two-plus decades it has been known that there are organisms which can deactivate mycotoxins.

These organisms produce enzymes that render the mycotoxin nontoxic. Rumen bacteria capable of deactivating DON and other like mycotoxins have been isolated, propagated and the deactivating enzyme identified.

Now the enzyme is commercially available to help manage DON, Ac-DON, T-2 and like mycotoxins. Commercialization of enzymes originally produced by termites (deactivate zearalenone and ochratoxin) as well as enzymes produced by soil organisms that detoxify fumonisins are now or soon will be found in commerce.

Knowing which analytical method is most accurate and appropriate for determining the mycotoxins present in feedstuffs is important so dairymen get accurate results for the money they invest. Let’s discard an old method that never was good; that is using a “black light” to detect aflatoxins. The toxin itself does not fluoresce, although the mold may; however, a lot of things, including rat urine, fluoresce.

Commercially available tests have been developed for analysis of specific feedstuffs, generally grains or grain byproducts. Using these tests indiscriminately on materials they were not intended or validated for can lead to inaccurate results and a poor expenditure.

Having said that, there are a number of excellent commercially available rapid test kits for analyzing aflatoxins in grains and milling byproducts. These test kits are commonly used by grain elevators for analyzing incoming grain.

These quantitative methods allow grain elevators to analyze grains quickly and accurately. The tests, often referred to as strip tests, can be bought for different levels of detection (LOD), which allow elevators to properly segregate lots of grain for later distribution and adhere to regulations.

That is, grain with no aflatoxin detected is not mixed with contaminated grain, and similarly contaminated grains can be segregated into bins containing low (over 20-50 ppb), medium (over 50-100 ppb) and high (over 100-300 ppb) levels of aflatoxin.

ELISA test kits offer reasonably quick analysis, reasonably low LOD and are economical compared to more sophisticated methods. ELISA tests were developed for specific feedstuffs, essentially grains. Using them otherwise can give inaccurate results.

This is especially true if they are used on mixed feeds. Complex feeds such as TMRs containing fermented components (i.e. silages) produce complex matrices (compounds that interfere with analysis) when the extract is removed from the prepared sample.

Special “clean-up” procedures are required before the sample material is applied to the ELISA test. If not “cleaned up,” the results may not be trustworthy (false positives, false negatives or inordinately high values).

Despite the fact that most ELISA tests are conducted in commercial laboratories, this may not assure that it is being used correctly. Some due diligence by the person submitting the feed sample should be done to assure the lab is using the procedure correctly. Ask questions: What material was the test developed for? How was the sample prepared before testing?

For many years, HPLC (high-pressure liquid chromatography) was the gold standard for mycotoxin analysis. It still is an important method for quantitative mycotoxin analysis and will continue to be used, mainly because buying an HPLC system is no small investment.

However, technology marches on and now LC-MSMS (liquid chromatography-mass spectrometer mass spectrometer) is quickly taking center stage. The costs of analysis by LC-MSMS are somewhat comparable to HPLC. The LOD is lower and, technically, more than 200 mycotoxins and analytes can be detected.

Practically speaking, what do you do with that much information down on the farm? Another thing to keep in mind is that just because a mycotoxin can be measured doesn’t mean it can be managed with a feed additive.

Nevertheless, knowing that there are multiple mycotoxins in a feed (DON, T-2, NAV, ZON, etc.) can help explain why the health and performance impact of the major toxins is greater than can be explained by their analysis alone. That is to say, mycotoxins can interact to increase their toxic effects on animals.

These interactions can be additive (2+2=4) or as is often the case, it can be synergistic (2+2=7).

Table 1 , page 55, presents an example of the mycotoxins that can be measurable in a single analysis by LC-MSMS in a commercial laboratory.

Technology is great, but it must be understood and used properly. Dairymen know this and work hard to stay current and use technology to remain as profitable as possible.

Therefore, they should realize that mycotoxin management has moved beyond binders alone; even though the term binder is used generically like Kleenex is for tissue, know there is a difference.

Dairymen and other animal producers will, as pressure requires, recognize and adopt the new knowledge and technology available for managing mycotoxins in contaminated feeds.

Question: Why is an insurance policy on a truck or a tractor accepted as an investment, yet adding a product that insures animals are protected from mycotoxins considered a cost?

In both cases the effort is to protect the business and maintain a healthy bottom line. In the end, it makes sense to test for mycotoxins on a routine basis just as feeds are analyzed for nutrient composition.

Regardless of whether it is the nutritionist or the owner that is responsible for feed quality, managing mycotoxins requires the same discipline in assuring feed quality and animal performance. Knowing the mycotoxins in the feed is a first step in being able to effectively manage the risk they pose.

As noted earlier, some mycotoxins, mainly aflatoxins, are readily managed with an effective binder. However, the risk posed by non-bindable mycotoxins cannot be managed with a binder. These mycotoxins are manageable with newer technology products containing specific enzymes that deactivate non-bindable mycotoxins.

In the end, a multidisciplinary approach using a product containing a binder and mycotoxin-deactivating enzymes is a sensible, convenient and cost-effective approach to managing the risk from mycotoxins.

Too often, mycotoxin testing and/or using an appropriate mycotoxin risk management product is viewed as an expense, which is understandable with the current milk price outlook. However, for many dairymen, had they taken these actions it would have been a good investment.

If you don’t think of these measures as good investments, just talk to any dairymen who dumped a week’s milk production because testing or adding an appropriate feed additive was too expensive. PD

Mike Watkins
Ruminant Technical Service Manager
Biomin America

In memorium
Watkins will be remembered with love as a husband, father, grandfather, uncle, father-in-law, brother-in-law, colleague and friend. His educational accomplishments included bachelor's and master's degrees from Texas A&M University . Watkins received his Ph.D. in nutrition from Mississippi State University .

During his career, Watkins was an associate professor at Stephen F. Austin State University in Nacogdoches, Texas; director of technical service for Diamond V in Cedar Rapids, Iowa; a nutritionist for Dairy Manufacturers in Prosper, Texas; and most recently the ruminant technical service manager at Biomin America in San Antonio.

Biomin employees and staff express their gratitude for their connection to Watkins' noble life – one that was lived with grace, integrity and humility.