Recommendations on feeding feed containing mycotoxins are not the same for all animals. Hogs have little or no tolerance for most mycotoxins, and horses cannot tolerate even low levels of fumonisin, a mycotoxin derived from Fusarium, which are fungi that can produce mycotoxins in cereal grains.
So what should you test for? In the case of corn shipped into our area, that is a difficult question to answer because much of the feed crop isn’t harvested yet. When receiving corn, the worrisome mycotoxins are aflatoxins, especially for dairy producers, because aflatoxins can be transmitted into the milk.
Granted, the interstate transportation of aflatoxin is regulated, but the purchasers of feeds and related byproducts need to be aware of where the feeds came from, when the feed was harvested and whether weather conditions had any impact on the crop.
Aflatoxins are not considered common to corn in the northern states, but cases have been found in South Dakota and Minnesota, and that’s not far away. So be mindful of the origin of your feed shipments. Besides, if we would experience seven to 10 days of 90 to 100 F heat in our area, our corn could become susceptible to aflatoxins, too.
Of course, the corn plant has to make an ear first to have grain for harvest. In the worst drought-stricken areas of the country, the corn and other crops may never mature. Then producers are faced with the challenges of salvaging the standing corn plants and turning them into silage or baleage.
This brings up another potential weather-stressed feed problem: nitrates. Water quality already is a concern because of nitrates, sulfates and total dissolved solids creating potential health issues for livestock. Stunted corn will have nitrates that it was transporting in the stalks to make an ear of corn. Without adequate moisture, the corn plant shuts down seed formation. That leaves a high concentration of nitrate in the stalks. However, if you know the level of nitrate in your feed, you can dilute it with other feeds. So nitrate in feed generally is manageable.
Livestock producers have many ways to utilize those marginal crops for feed, from as basic as placing electrified wire around the field as a temporary fence to making baleage. In 2009, when mold and wet conditions were the challenge, a common practice for cattlemen was to fence and graze standing corn fields not harvested, although I recall concerns about grain overload from livestock munching on the ears.