Feeding Aflatoxin-Contaminated Corn to Beef Cattle

    First and foremost, it is important to note that the following information is in regard to feeding aflatoxin-contaminated corn to beef cattle and does not have any validity for selling corn.  For interstate commerce, there are very strict guidelines with regard to aflatoxin-contaminated corn.
    Aflatoxin can result in a reduced appetite, reduced growth or milk production, rough hair coat, immunosuppression as well as many other possible symptoms.  Depending on interactions with other mycotoxins (realizing that when mold is present there are probably several different mycotoxins being produced), aflatoxin concentrations as low as 100 parts per billion (ppb) may be toxic to beef cattle.  However, the toxic level is generally considered to be between 300 and 700 ppb.  A good rule of thumb would be to use 200 ppb as a target concentration to stay below.  Obviously, all people have differing ideas on degree of risk, as an extension employee I would rather error on the side of caution.
    The 200 ppb concentration is a number that would be for the total diet; therefore, if you were supplementing brood cows with 4 pounds of corn per day and they were consuming an additional 24 pounds of hay then the corn could actually contain as much as 1,400 ppb aflatoxin and the cows total intake is still at the 200 ppb level.  However, be aware that some cows will get more than 4 pounds when group-feeding and also you may get to high enough levels that the grain is actually unpalatable to the cows and they wont consume 4 pounds of it.
    Various strategies for reducing the effects of the aflatoxin include the following:  ammoniation, blending with aflatoxin-free grain, screening and addition of clays.  Again, all of these strategies are for on-farm feeding not for sale of corn.  Ammoniation of the grain with anhydrous ammonia at a rate of approximately 3/4 pound per bushel of corn has been shown to destroy the aflatoxin.  It is best to do this with the corn on concrete and under plastic not in a grain bin.  Once the anhydrous has been put into the stack the process takes about three weeks at which time the plastic is removed and remaining anhydrous allowed to escape.  CAUTION - Anhydrous ammonia is dangerous!  Blending with uncontaminated grain simply is a dilution technique.  Screening may be beneficial in that most of the aflatoxin is in the broken kernels, tips and otherwise damaged pieces.  Once the corn has been screened it can be re-tested to see what the new aflatoxin level is, probably reduced.  Research has shown some benefit from incorporating small quantities of clays (e.g., bentonite at .5%;10 pounds per ton) for binding the aflatoxin so that it is carried on through the digestive tract and into the manure rather than absorbed into the body.  Does not always work.
    A key factor in all of this is that the analysis is accurate, which starts with getting a good, representative sample of the corn.  Once the sample is obtained it will need to be sent to a testing lab.  Below you will find a list of some labs that can measure aflatoxin as well as other mycotoxins.  I am unfamiliar with their costs.  Im sure there are many other labs as well, this just happens to be the list that I have.
    One in-state lab that I am aware of that will also measure aflatoxin is the Peanut Inspection Service in Dothan, AL.  Their phone number is 334-792-5185.

A&A Laboratories Inc.
1000 Backus Ave.
Springdale, AR 72764

A&L Analytical Labs
411 N. 3rd St.
Memphis, TN  38105

18246 Waller Rd
Fulton, IL 61252

Anitox Corp.
1055 Progress Circle
Lawrenceville, GA  30043

Central Analytical Laboratories Inc.
101 Woodland Hwy
Belle Chasse LA  70037

Diversified Laboratories Inc
3810 Concorde Parkway
Chantilly, VA 20151

Woodson-Tenent Laboratories
1331 Union Ave, Suite 1500
Memphis, TN 38104