Analysis shows mycotoxin levels rising in stored 2013 crop

After seven months of feeding the 2013 harvest to their herds,dairy producers may soon find their corn silage and total mixed ration (TMR) arenot quite up to par, as many herds are now facing new challenges due to recent moldand mycotoxin growth in feed during storage.
“The U.S. crops varied considerably from farm to farm and even from field to field. These varied crops were all harvested at the same time and placed into storage, creating silage that is a mixture of maturity and crop stress,” said Dr. Max Hawkins, a nutritionist from Alltech’s mycotoxin management team. “The effects of storage moisture and temperature, oxygen availability and forage management are now being discovered.”
Alltech has continued to analyze corn silage and TMR samples since the September harvest through its 37+ Program. The analysis is performed using LC/MSMS technology and considers the mycotoxin challenge in each sample as a whole, rather than looking at the individual mycotoxins present. According to Hawkins, the analysis more closely reflects commercial production and the challenges facing producers around the world. The company has also developed a Risk Equivalent Quantity (REQ), which assesses and calculates the total potential risk to a given species associated with the mycotoxin group present in a sample.
A total of 104 corn silage samples and 279 TMR samples have been analyzed through Alltech’s 37+ Program from September to March with each month showing an increase in the average number of mycotoxins per sample. For example, corn silage samples have increased in levels of Type B Trichothecenes from 681 parts per billion (ppb) in September to 1720 ppb in March. A cautionary level of Type B Trichothecenes is 1000 ppb and high risk is 2000 ppb for mature dairy cows.
“As a result, producers are likely to see decreased dry matter intake, lower milk production, poor gut health with inconsistent manure and diminished immune response,” Hawkins said. “This places the risk for corn silage well above a cautionary risk level and at or near high risk since October.”
He also reminds producers as storage facilities are emptied this spring that high levels of mycotoxins may be found in the lower levels of the facilities, where the fines and cracked kernels tend to concentrate.
Hawkins recommends these five tips for producers feeding the last of the 2013 harvest:


• Only run aeration fans during the coolest times of day or night. Hold grain at 50F or less and 14 percent moisture or less.
• Mold growth in storage is greater where there are leaks in facilities and where fines and damaged kernels are concentrated.
• The south side and tops of grain bins warm quicker as daytime temperatures begin to increase.
• New mold growth will increase temperature and moisture in surrounding grain.
• Continually monitor stored grain for temperature, moisture and mycotoxins.
“Producers need to keep in mind the risk from mycotoxins to the cow is a moving target and what you feed today is not necessarily what you will feed tomorrow,” Hawkins said.