As feeding the 2013 harvest winds down, dairy farmers may soon find their corn silage and total mixed ration (TMR) are not quite up to par due to recent mold and mycotoxin growth during storage.
“The U.S. crops varied considerably from farm to farm and even from field to field,” said Dr. Max Hawkins, a nutritionist from Alltech’s Mycotoxin Management Team. “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. The effects of storage moisture and temperature, oxygen availability and forage management are now being discovered.”
Between September 2013 and March 2014, 104 corn silage samples and 279 TMR samples were analyzed. Each month showed 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.
Alltech analysis 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. The company’s Risk Equivalent Quantity (REQ assesses and calculates the total potential risk to a given species associated with the mycotoxin group present in a sample.
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 50 degrees Fahrenheit or less and 14% 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.