M ycotoxins, toxic compounds produced by various kinds of molds, are rearing their ugly heads again this year. Mycotoxins form when mold spores in the environment proliferate in grains and feeds that are damaged by drought conditions, insect damage, or improper storage. Common mycotoxins include aflatoxin, zearalonone and deoxynivalenol (DON) or vomitoxin. All of these compounds can cause detrimental effects in the animals that consume them, depending on the level present in the feedstuff. Effects can include decreased feed intake, reduced feed efficiency and adverse health and reproductive problems.
Due to the challenging growing conditions nationwide this past summer, aflatoxin problems are more common this year, especially for dairy cattle. A small percentage of the aflatoxin a cow consumes enters the milk produced. Since aflatoxins are potent carcinogens and can cause liver damage, there are established regulatory levels in milk. Pennsylvania dairy farmers have already had loads of milk rejected this year due to the presence of aflatoxins in the milk.
So what can you do as a dairy producer? The main sources of aflatoxins in dairy feedstuffs are corn grain, corn byproduct feeds, and corn silage, although oilseed products like cottonseed have also been implicated. It is important to check with your feed providers to make sure that feed you purchase has been checked for aflatoxins levels. Another important practice is to work with your veterinarian and nutritionist to check the feed you produce on your farm. Just because you do not see mold, it does not mean mycotoxins are not there. Even if you do see mold, it does not necessarily mean you have mycotoxins. Testing is they only way to make sure.
If mycotoxins are present in your feed, you may need to use binders, dilute feeds, or not use some feeds depending on the levels present and how sensitive your herd is to mycotoxins. Which binder do you use? It depends on the type of mycotoxin and you may need to use more than one at the same time. There are many mycotoxins, and labs only test for a few of them, but a general rule of thumb is that the presence of one mycotoxin usually indicates the presence of several types. For example, clay binders are usually very good at binding aflatoxins, but not as good for zearalonone. So if you have both types present, you may need to use a clay product and another product together for better coverage.
Remember, the most important way to prevent and control this problem is to talk with your veterinarian and nutritionist to devise a program for your farm.