Corn ear molds are often noticed late in the season and during harvest. This week Ive used an excerpt/summary of a piece my co-workers Madalyn Shires, Connie Tande and Connie Strunk put together.
Molds (which are fungal plant pathogens) produce mycotoxins, but molds by themselves do not cause problems for animals, though they can be problematic in grain storage as they continue growing and reproducing thus producing more mycotoxins. The mycotoxins produced by these molds can cause significant problems for livestock and significant reduction of grain price.
Mycotoxins with higher prevalence in corn are Aflatoxin (reduced performance/death more prevalent in drought), Zearalenone (ZEN/ZON) (reproductive problems), and DON/Vomitoxin (feed refusal). Fumonisins and T-2 toxins may occur in South Dakota, but far less frequently. We often see DON and ergot issues in wheat, other small grains and grasses.
Hot weather and drought stress conditions promote the production of aflatoxin. The prime conditions for this fungal toxin development occur when the temperature is greater than 70 degrees F at night and the corn grain is in the latter stages of grain fill during drought stress. The mold found on corn is gray-green to olive-green in color, and the two most common fungi that produce this toxin are Aspergillus flavus and Aspergillus parasiticus.
Aflatoxins are a concern for livestock producers since the toxins are harmful and potentially fatal to livestock. They are also carcinogenic to other animals and humans. Most commonly, aflatoxins negatively affect feed efficiency and reproduction, can be excreted into milk, and suppress the immune system of livestock. The most common type of toxin, aflatoxin B1, is a carcinogen. This can become a concern as it can appear in milk when corn with aflatoxin concentrations over 20 ppb (parts per billion) is fed to dairy cows. The legal limit for aflatoxin in milk, according to FDA regulations, is 0.5 ppb (aflatoxin M1).
There are a few options for reducing mycotoxin levels in contaminated grains at receiving areas. Heating grain and using dust capture systems are both good examples; however, a common method is to mix in mycotoxin-free grain to help reduce/dilute the overall mycotoxin levels whenever the grain is processed into livestock feed.
Typically, elevators do not accept corn with aflatoxin concentrations of 20 ppb. In addition, the Food and Drug Administration has an action level of 20 ppb for aflatoxins in corn that regulates interstate commerce. This is the level at which federal agencies may take action, including the seizure of the corn or prohibition of its sale.
Producers wishing to have their grain or feed tested to be used in animal feeding operations or to determine how to properly store grains potentially contaminated with mycotoxins can contact the SDSU Plant Diagnostic Clinic in Brookings at 605-688-5545. Read more about mycotoxins here.
Hay quality testing
Do you typically send in your livestock feedstuffs for quality analysis? To ensure that livestock nutritional needs are met adequately throughout the winter months and to make efficient use of resources, quality testing feed is key. One commodity that is easy to overlook is dry hay; testing dry hay is relatively simple and the small cost of analysis can help avoid much larger issues.
Testing hay is not terribly difficult, but does take some foresight. It is important to begin by making sure you core multiple bales and do so in lots. A lot is often hay put up under similar conditions/timing can be sampled and compiled together for testing. Samples should represent each field and each cutting; consider additional lot separations if there are differences in species, mixture, stage of maturity, rain damage, harvest loss, insect or disease damage, and season. A great deal of variation can happen between cuttings, fields, or types of forage.
Once you determine how to group hay into testing lots, youre ready to sample. Dry hay sampling is typically completed with a hay probe that is ~18 or longer. There are different styles of hay probes, but most use the same basic principles to collect a sample the core turns into the bale (manually or by motorized power), sampling multiple layers of hay, and is removed from the bale when the sampler reaches max capacity.
Tools needed to adequately sample dry hay are the following: hay probe, clean bucket, and labeled sample bag. Hay probes should be placed on the round side of the bale and cored toward the center of round bales, or cored from the butt end of square bales. Core several random bales: approximately 20 cores from small square bales per lot, or multiple samples from ~12 different large round bales/lot (while taking at least 20 cores overall). For each lot of samples, combine the core samples in a pail, mix them together and place the cores into a labelled gallon size plastic bag and seal. Learn more about proper forage methods in this article/video.
Samples can be dropped off or shipped to a variety of forage testing labs found across the region. Go here for a list of feed and water testing labs in South Dakota and the surrounding area.
Need a hay probe? Check with your nearest SDSU Extension regional center for free short-term check-out of a hay probe, or with your local feed store or feed sales representative.
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