Crops grown in stressful conditions, like this year's drought, are more susceptible to mold growth, and consequentially, mycotoxins. Hog producers need to take extra precautions when feeding corn that may be mycotoxin-infected, says Bob Thaler, South Dakota State University Extension Swine Specialist.

“We know that this year's grain crop will be poorer quality than normal, and may be contaminated with molds. I encourage hog producers to begin preparing today, and that also means conserving the remaining high-quality 2011 corn crop for sows and nursery pigs. They need to test their feed as it comes in or when they harvest it to determine if it is infected with mold and what types of molds,” he says.

Corn can be infected by more than 200 varieties of mold, however, Thaler explains that only a few of these varieties produce mycotoxins which is produced by the mold, and can lead to feed refusal, abortions and even death.

The three molds Thaler says hog producers need to test for are aflatoxin, vomitoxin (DON) and zearalenone.

Aflatoxin:Aflatoxin is not typically seen in South Dakota, and appears around about every 10 years. Alflatoxin can kill hogs at very high levels, so Thaler says when a test shows that feed is positive for the mycotoxin; producers should add binders to the feed.

“Binders control the majority of the problem for aflatoxin,” Thaler says.

Vomitoxin (DON):Thaler expects DON to be the most common mycotoxin to show up in grain this harvest. Although it does not kill animals or cause problems with the reproductive cycle, like its name suggests, vomitoxin does cause feed refusal.

“If animals eat more than 1 ppm they will begin vomiting and will go off feed, which then reduces gain and sow performance,” Thaler says.

If this is found in tested feed, Thaler says producers need to blend it with clean grains so that the total level in the diet is below 1 ppm. He says mycotoxin binders are not as consistently effective against other mycotoxins besides aflatoxin, and if producers are considering a binder, Thaler says they need to use one that has university research to back it.

“Unfortunately with vomitoxin and zearalenone, there are commercial binders available, but their effectiveness varies, and we've not been able to find one that will consistently and completely alleviate the symptoms,” Thaler says.

Zearalenone:This mycotoxin's estrogen-like effects will disrupt a sow's reproductive cycle causing abortions if it reaches levels above 1 ppm.

Reserve Clean Grain & Other Blending Tips

Because the level and type of mycotoxins found in a field of corn can vary greatly throughout the field, Thaler encourages producers to take a number of samples from every section of the field, and combine them into one sample for testing. The samples then need to be placed in a cloth or paper bag and sent to a qualified lab for mycotoxin analysis.

He encourages pork producers to review the data and if they have any questions on blending, consult their nutritionist or an SDSU Extension specialist.

“Before producers can begin blending below 1 ppm, they need to know what specific mycotoxin they are dealing with and what level it is in the first place,” he says.

If producers have clean grain on hand, Thaler says they need to hold it back to feed to their sow herd and nursery pigs and for blending.

“Grow-finish pigs can handle higher levels of mycotoxins, and pork producers will more than likely need clean grain to blend with infected grain to bring the levels down,” Thaler says.

For a list of testing labs and more information on this topic,