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[JULY 21, 2005]
URBANA -- Livestock producers should consider
several guidelines when making decisions in the next few weeks when
and if to harvest their drought-stressed corn silage and consider
purchasing barren corn from grain farmers, said Mike Hutjens,
University of Illinois Extension dairy specialist.
"Several areas in the Midwest are under moderate to severe
moisture stress," he said. "Some corn has not pollinated, some
corn is fired, and other corn has not reached the critical
stages that will impact corn yield and quality."
--When deciding to cut the corn crop for silage, determine
ear development and stage of maturity. If the corn plant has
green tissue remaining, allow it to grow and mature, adding
nutrients. Once the crop is down to 30 percent to 40 percent dry
matter, successful ensiling can be achieved (be sure to add an
inoculant). If a sample of chopped corn silage is squeezed
tightly in a grip and water runs out between fingers, the silage
is over 70 percent moisture and too wet. Running a dry-matter
test using a Koster tester, microwave or commercial lab will be
--The yield of corn silage will depend if cob formation has
started. Purdue University suggests one ton of wet corn silage
(70 percent moisture) per foot of barren or immature corn plant
excluding the tassel.
--Nitrate levels can be a concern. The level nitrates in the
lower one-third of the corn stalk can contain over 5,000 parts
per million nitrate-nitrogen, while the top one-third of the
stalk and leaves contain less than 160 parts per million.
--The feed value of the corn silage is reduced 80 percent to
90 percent depending on the amount of corn grain in the
drought-stressed corn silage. Barren stalks will feed similar to
high-quality grass silage or hay.
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--Making corn forage as hay will be difficult as the corn stalk will
be wet (over 70 percent moisture) and difficult to dry down. Hay
curing also does not reduce nitrate levels, while corn silage does
reduce nitrate levels due to fermentation by 35 percent to 50
percent. Testing for nitrates by a commercial lab is highly
recommended after fermentation has been completed.
--Grain managers may sell drought-stressed and barren corn to
livestock producers. Based on the quality and tonnage in the field
and adjusting for harvesting costs, a price can be calculated. Using
a guideline of one ton (wet basis) per linear foot, one acre of corn
silage standing at 5 feet (excluding the tassel) could provide five
tons of wet corn silage times 30 percent dry matter, or 1.5 tons of
forage dry matter. Subtracting harvesting costs (higher than normal
for corn silage due to lower yields) of $8 per ton of wet corn
silage, or $40 an acre, if the corn forage is worth $80 a ton of dry
matter, the value per acre could be $120 per acre minus harvest
costs of $40. Values should be adjusted based on individual
situations. The recommended approach is to weigh actual chopper
boxes of silage and test the silage for quality to determine a price
per ton and per acre.
--Some grain producers may consider plowing down the corn stalks
for fertility. The nutrients in the corn stalks are estimated to be
worth $25 per acre.
--Drought-stressed corn silage is an alternative for livestock
producers. But producers should be sure to balance rations for lower
levels of starch and reduced dry-matter intake potential.
[News release from the
University of Illinois College
of Agricultural, Consumer and Environmental Sciences]