No increase in mycotoxins in properly stored corn silage, research shows
Following the correct ensiling process could slow down DON growth in corn silage.
Fungi that produce DON, such as fusarium species, do not thrive in low oxygen levels or low pH environments. When corn is correctly ensiled, fusarium becomes inactive and can no longer produce DON, a Wednesday OMAFRA field crop report
Corn silage becomes fully fermented after three weeks.
To help prevent DON from spreading in silage once it’s stored, producers should harvest crops when moisture levels are stable, Doug Duffin, a cash crop, beef and poultry farmer in Middlesex County, told Farms.com yesterday.
“For silage, we got it off in time that the moisture is good,” he explained. “It should have acidified, and the VOM will stabilize in it at the level it was when it came off the field.”
Storing corn in a properly sealed silo with adequate packing density and at correct moisture levels contributes to a low pH and oxygen environment that halts mycotoxin growth.
When corn is excessively dry, it is too difficult to pack, which reduces the amount of air that can be excluded from the silo. Inadequate fermentation caused by improper moisture levels leads to “silage pH not dropping far or fast enough to prevent spoilage,” the report says.
Proper moisture levels vary by the type of silo producers use for ensiling. Tower silos pack silage with gravity. With bunker and bag silos, operators must match the rate of silo fill with proper packing time and force to exclude air correctly. In bunker silos, packing must reach a density of at least 240 grams of dry matter/litre (15 lbs DM/ft3).
One litre of packed silage should weigh 640 to 800 grams (40-50 lbs/ft3) or more on an as-fed basis and must be properly sealed to ensure air is kept outside. When oxygen penetrates silage containing fusarium species, the fungi can produce DON.
Since DON is water soluble, it can be “washed out” through seepage from wet silage, researchers suggest.
Yesterday, Farms.com spoke with Drew Thompson, market development agronomist for Pride Seeds, who recommended some sources for information on storing corn silage, one of which can be found here
Farmers should consult their feed adviser or veterinarian about mycotoxin testing in silage after fermentation and before feeding it to livestock.
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