Pay attention! Aflatoxin more dangerous than you may think

Special to The Post

When aflatoxin is discussed in a cow-calf producer meeting, the response is usually glazed eyes, feet shuffling, whispering, trips to the coffee pot or a combination of these activities. This lack of interest is because aflatoxin is not considered a serious threat to commercial cattle producers. It can be a problem, however, in feeding home-grown grain or from improper feed storage.

According to Erick Larson, Extension corn specialist at Mississippi State University, aflatoxin is a naturally occurring toxic chemical by-product of fungal growth. The two responsible fungi, Aspergillus flavus and Aspergillus parasiticus, are found in grains such as corn, milo and wheat; tree nuts; and oil seeds such as cotton, soybeans and peanuts.

The fungi are spread by air-borne spores and produce aflatoxin in crops during seed development or during crop storage and handling. Heat, drought, high humidity and insect infestation predispose crops to aflatoxin-producing fungi.

Aflatoxin is nasty stuff. It causes diseases such as aflatoxicosis in livestock, wildlife, domestic animals and humans throughout the world. Dogs are one of the most susceptible spe-cies. Aflatoxicosis, however, can be a problem for livestock, particularly young animals, and there are instan-ces of wildlife and birds affected by aflatoxin in deer corn and birdseed.

Effects of aflatoxin include cancer, liver damage, decreased egg and milk production, immune suppression, gastrointestinal dysfunction, anemia, jaundice, reduced reproduction and a decrease in feed consumption and efficiency.

Group 1 carcinogen

Aflatoxin is a Group 1 carcinogen and is transferred to humans through contaminated milk and other foodstuffs. Group 1 carcinogens are those known to cause cancer on the basis of human experience.

"Aflatoxin presence in corn is consistently a challenge in Central and South Texas, as well as along the Red River valley in the northern part of the state," says Ben Jones, associate director of the Office of the Texas State Chemist.

"The 2011 crop year was no exception. The widespread, extended drought stressed corn plants statewide and may have played a role in the increased presence of aflatoxin in the south plains around Lubbock and in other panhandle areas not usually concerned with the problem," Jones said.

"The prevalence of aflatoxin was greater in counties that produce corn, but the levels were manageable. The Office of the Texas State Chemist collected 356 samples of corn during harvest and the majority contained less than 100 parts per billion," Jones said.

"Prevention of aflatoxin in corn is difficult," Jones said. "Scientists are working on the development of aflatoxin resistant hybrid corn seed and the application of non-toxin producing fungi strains to compete with toxin producing strains in the corn plant."

"Solving the problem in corn will not rid the agricultural and food industries of aflatoxin, however, because it can occur in other grains, grain by-products, oilseeds and oilseed products. Reducing risk through testing, labeling and channeling grain containing aflatoxin to the appropriate animal species is currently the best way to protect livestock producers," Jones said.

The Food and Drug Administration accepts the following maximum aflatoxin levels in feed for various livestock classes:

* 300 parts per billion for corn and peanut products intended for finishing beef cattle.

* 300 parts per billion for cottonseed meal intended for beef cattle, swine, or poultry (regardless of age or breeding status).

* 200 parts per billion for corn or peanut products intended for finishing swine of 100 pounds or greater.

* 100 parts per billion for corn and peanut products intended for breeding beef cattle, breeding swine, or mature poultry.

* 20 parts per billion for corn, peanut products, and other animal feeds and feed ingredients, but excluding cottonseed meal, intended for immature animals.

* 20 parts per billion for corn, peanut products, cottonseed meal, and other animal feeds and feed ingredients intended for dairy animals, for animal species or uses not specified above, or when the intended use is not known.

"The amount of aflatoxin an animal can tolerate varies with age, sex and health of the animal," said Jeff Ball of The Samuel Roberts Noble Foundation. "Younger animals are most susceptible to aflatoxin poisoning. Pregnant and growing animals have slightly more resistance than young animals, but less resistance than mature animals."

"To diminish risks, ask your feed supplier if they sample and test their incoming ingredients for the presence of aflatoxin," Jones said. "Do their purchase contracts specify feed ingredients with no aflatoxin or levels appropriate for the type of livestock for which the feed is produced? Livestock producers can also ask to see aflatoxin analysis results, collect samples and send to a commercial laboratory for analysis, or contact their feed control agency if they suspect a problem."

Since moldy feed may indicate possibilities of aflatoxin presence, it is important to avoid mold growth by storing feedstuffs in dry, well-ventilated areas. Do not feed hay and supplements in larger quantities than will be consumed by livestock in one or two days. Remove uneaten feed from troughs prior to spoilage.

"When growing grain, it is important to use management practices that promote good plant health," Missis-sippi State's Larson said. "Healthy plants discourage aflatoxin development. Good management practices are timely planting, adequate fertility, good weed and insect control, supplemental irrigation, suitable plant population and hybrid selection.

"Aflatoxin producing fungi approach dormant levels when grain moisture drops to about 12 percent, especially when air temperatures decline to around 55 degrees Fahrenheit," Larson said. "If you plan to dry grain yourself, do not harvest more than you can dry within these conditions."

Research has shown that approved binders, when mixed at low rates with feed, bind aflatoxin and reduce its effect on animals and hu-mans. Texas is the only state that permits the use of bin-ders in custom mixed feeds.

For additional information, visit otscweb.tamu.edu or call 979-845-1121.

Aflatoxin is enough of a threat to livestock that proper feed management is warranted and closer attention to the speaker during the next presentation on aflatoxin.