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Preventing Mold Growth on Feed in Winter

Have you ever opened a bag of feed that smells a little musty or put your hand in the feed bunk in the middle of the winter and the ration is too hot to touch? If the answer is yes to either of these questions, then there probably was a mold problem that was not addressed. In most cases, by the time most people notice they have a problem with their feed or grain; it is too late to do much about it.

Livestock feeds often contain molds and viable mold spores which are unavoidable contaminants. Under the right conditions, these mold spores will germinate and grow, producing more mold and potential toxins. Mold growth degrades the nutrient value of feedstuffs and negatively impacts palatability which affects animal performance.

When dealing with moldy feed or grains, it is still vital to use a mold inhibitor, such as MoldLess 50% from Brookside Agra. Mold inhibitors are used to kill mold before it starts to form any harmful toxins. Mycotoxins are secondary metabolites of the fungus and nobody really knows why and when mycotoxins are produced. The current thought is that mycotoxins are produced by molds at the end of their life. Generally when one mycotoxin is identified in a feed ingredient, there may be several more present below detectable limits. Therefore, in early stages of mold growth (i.e., before the visible evidence of white, green, or black growth on feedstuffs), mycotoxins are not a major concern. However, when it is white, green or black and fuzzy, it is more likely to be producing mycotoxins and damaging the nutrients in the feed.

“MoldLess is a special formulation of vermiculite and calcium bentonite which causes the active ingredients to be released in a manner to give a quick kill of the mold, plus three to four days of residual activity after the application,” said Brookside Agra Executive Vice-President and General Manager Chad Vaninger. “MoldLess is safe for use on all animal feeds and requires no special equipment for handling or mixing. MoldLess comes in a small, uniform particle size to give complete dispersion throughout the grain or feed mixture. This helps to provide better protection from mold growth and the resulting toxins.”

Poor animal performance due to mycotoxins may be the result of damage to the immune system, whether exerted directly or by attacking the antioxidant defense system, or perhaps through liver and gastrointestinal tract damage. Moldy feedstuffs, even without mycotoxin contamination, tend to reduce feed intake. Regardless, the end result is increased morbidity and mortality, resulting in decreased animal performance.

There are many molds that are not toxigenic (i.e., don’t produce mycotoxins). Unfortunately, those are not the ones we have problems with. Mold species most noted to be a problem are Aspergillus sp. (aflatoxin), Fusarium sp. (vomitoxin, zearalenone and fumonisin), and Penicillium sp. (penicillic acid). Aflatoxins are prevalent in the field during hot, dry years, and also form in stored grains that are not dried properly. Fusarium molds are generally found during cool, wet conditions during the crop growing and harvest seasons. Molds are more likely to develop in feedstuffs when the moisture is over 12% and the ambient temperature is above 54° F (these are generalities and are not intended to be guarantees). While aflatoxins are generally thought to be prevalent in the field during drought conditions, they can also be quite prevalent under storage conditions where the grain contains greater than 12% moisture.

Mycotoxins generally occur in multiples. A sample testing high in aflatoxin will also test positive for other mycotoxins. If mycotoxins are in fact “end-of-life” toxins, then mycotoxin contamination increases with duration of poor storage conditions. By the same token, control of molds or fungus does not necessarily limit the damage or synthesis of the toxin. While limiting mold growth may help reduce mycotoxin development, it does not assure it. Toxin binders, such as Flo-Bond from Brookside Agra, are used in animal nutrition to bind the harmful toxins that have formed to reduce the toxic effect on the animal.

Beef and dairy producers generally only worry about aflatoxin and to a lesser extent T2, DON (vomitoxin) and zearalenone. Swine and poultry producers always worry about all of them. The hidden concern in dealing with these mycotoxins is the damage they do to the gut because they are dermal necrotic agents. The damage to the gastrointestinal system also means that nutrient absorption is compromised. When the mycotoxin is absorbed, it leads to liver damage, certainly a concern for lifetime productivity of animals. A compromised gastrointestinal tract also leads to a compromised immune system.

5 Points to Remember

  1. Visually examine your crops prior to harvest. If damaged grains are found, then assume there is a need to do some mycotoxin screening. Mycotoxin screening kits are very toxin specific. Know which mycotoxins are significant to the animals involved and screen specifically for those mycotoxins so no one wastes their money.
  2. Dry grains as quickly as possible to 12% moisture (sift fines out of the grain bins prior to storage). Broken kernels tend to harbor more molds and mycotoxins than whole grains.
  3. Don’t forget that wet forages can harbor molds and mycotoxins.
  4. Finished feeds which are not immediately fed or feed that will be put into a self-feeder should have a mold inhibitor applied. Mold inhibitors slow down mold growth, but will not totally prevent it or get rid of the toxicity of the existing mycotoxin.
  5. If mycotoxins are found, use a toxin binder. They are used to bind the toxins in the gastrointestinal tract of the animal. This helps to prevent the harmful effects on animal health, improving overall animal performance.

As we begin this fall season and start to harvest grain, protect this year’s crop so it does not lose its overall value. Animal production will be sub-par when moldy feedstuffs are used. Once a feedstuff molds, there are very limited options to redress the problems mold creates. When possible, reduce mold growth to limit mycotoxin production. Remember, it is important to address the issue today. If the problem is not dealt with, it will end up costing more in the long run.