By Candace Pollock
In a year when overly wet conditions and a head scab outbreak are significantly impacting Ohio’s wheat crop, there is no room for assumptions that grain is toxin-free and safe to feed to livestock.
To avoid any health problems in cattle, swine, poultry and other animals, growers are highly encouraged to test the grain for vomitoxin levels before any of the feed or grain byproduct is destined for consumption.
“Farmers shouldn’t think that it’s OK to handle or feed scabby grain without actually testing and knowing how much toxin is in it,” said Pierce Paul, an Ohio State University Extension small grains specialist and plant pathologist. “I always emphasize testing.”
Wheat in some portions of Ohio is experiencing upwards of 60% incidence of head scab -- a disease that attacks the wheat during flowering under wet, humid conditions. The disease can impact yields. The fungal pathogen that causes head scab also produces mycotoxins (most notably vomitoxin) in the grain that can be unsafe for livestock if consumed in high levels.
“Much of Ohio’s wheat crop is testing positive for vomitoxin, with results ranging from 1 part per million to as high as 10 parts per million,” said Stan Smith, an OSU Extension program assistant. “In some cases the grain elevator is accepting the wheat after discounting the price anywhere from a nickel per bushel up to more than a dollar per bushel. In some cases the wheat has been rejected at any price by the elevator.”
The situation, while not ideal for wheat growers, may be an opportunity for livestock producers, who value wheat for its higher protein content compared to corn. However, livestock producers must recognize the sensitivities of each livestock species to vomitoxin before incorporating any wheat grain into feed rations.
The U.S. Food and Drug Administration has just revised its guidelines for rationing vomitoxin-infected feed to livestock. Wheat containing up to 10 parts per million of vomitoxin can be fed to adult beef cattle with the stipulation that the total ration should not exceed 10 parts per million for beef cattle and should not exceed 5 parts per million for adult dairy cattle. For calves and other animals except swine, wheat containing vomitoxin at up to 5 parts per million can be fed if it composes no more than 40% of the diet. Wheat containing 5 parts per million vomitoxin can be fed to swine if it composes no more than 20% of the diet. The new FDA Guidance for Industry document can be found in its entirety here.
Bill Shulaw, an OSU Extension beef and sheep veterinarian, said that swine are most susceptible to vomitoxin-infected grain, while beef cattle have the highest tolerance. However, vomitoxin isn’t the only mycotoxin produced by the Fusarium pathogen that farmers have to worry about.
“Hence, the importance of testing the grain suspected of being contaminated,” said Shulaw. “Although swine are the most susceptible to the effects of vomitoxin (vomiting and feed refusal) and cattle are more resistant, some of the other mycotoxins produced by Fusarium species, such as T-2 toxin or fumonisin, can cause clinical and subclinical disease. If farmers plan to feed wheat or other grain they suspect has mycotoxin contamination, testing a representative sample would be wise.”
The occurrence of head scab in wheat does not automatically mean vomitoxin, but high levels of scabby kernels in harvested grain are suspect and should be tested.
For more information on mycotoxins, log on to http://beef.osu.edu/library/mycotoxins.html. Information on head scab and vomitoxin can be found at http://agcrops.osu.edu and http://beef.osu.edu/beef/beefJune3010.html.