Each fall, producers are faced with the challenges of putting up high
quality corn silage and high moisture corn. One key factor that can have a
big impact on silage and high moisture corn is mold, which can greatly
reduce the palatability and quality of the feed. However, there are steps
that can be taken to reduce or eliminate the presence of mold in your
harvested corn.
1.
Inspect your silo before beginning harvest.
Seal
any cracks and repair damaged doors. This will help make a better seal and
improve your silage fermentation.
2.
Start harvesting at the right maturity and moisture content for your
storage structure.
For
high quality silage, harvest should start when the kernel's milk line,
also called starch line, is one-half to two-thirds of the way down the
kernel. Denting can vary from hybrid to hybrid, so it is important to
monitor the corn closely near harvest. When the kernel milk line is at
this stage, whole-plant moisture levels generally range from 65 percent to
70 percent, which is a good compromise among starch content, sugar
content, stover digestibility and moisture content. To
get the best results, it is recommended to have a whole plant moisture
test done by your local testing lab.
The
desired theoretical length of cut (TLC) for most crops is one-quarter to
one-half inch, though this can vary based on the type of silo, the
amount of silage fed and the extent of processing. This length promotes
good compaction and fermentation of the silage and yet allows for ease
of unloading from an upright silo. If you will be processing your
silage, you may need a longer TLC - from three-quarters to an inch - to
avoid too-short particles that do not provide enough effective fiber for
cows. This can suppress butter fat production, as well as cause several
metabolic disorders. If your silage is dryer, you may need a finer chop
to insure better packing.
4.
Fill rapidly.
Ensile
crops immediately after chopping. Add Crop Cure® at the
appropriate rate.
5.
Distribute evenly.
Silage
that has been spread evenly will have improved packing, and it will
increase the silo capacity as well as assure equal distribution of
Crop Cure®.
6.
Pack and cover silage well.
The
last loads that you harvest should be higher in moisture to allow for
more compaction. This reduces air space, a major cause of spoilage and
mold growth. Packing should occur throughout filling when storing
crops in bunker silos. Use heavier tractors or wheeled bulldozers to
increase packing capacity, and pack at a minimum rate of 800 to 1,000
hour-pounds per ton.
7.
Seal securely.
Once
the trench or bunker is filled and packed, cover it immediately.
Studies at Kansas State University show leaving a bunker uncovered is
equivalent to using 30 percent of the top three feet of silage as your
silo cover. Currently, the most effective covering material is
polyethylene. Tires, used to keep the plastic in place, should be
placed close enough to touch - about 20 to 25 tires per 100 square
feet.
8.
Leave the silage covered for 21 days to allow for the fermentation
process to complete.
9.
Test feed samples.
Laboratory
analysis will help determine the feed value and will help you
incorporate your feedstuffs into a balanced ration.
10.
Manage feedout carefully.
Feeding
silage too slowly and/or disrupting bunker faces can account for 30
percent to 50 percent of your total dry matter losses. To minimize
losses caused by mold and yeast growth, start by matching silo
dimensions to the amount of feed removed daily. At least 5 inches
should be removed from the silage face per day. If the bunker is too
wide to accomplish this, divide it in half and feed from one side.
Next, fine-tune your removal technique. To avoid oxygen penetration of
the silage, remove loose silage from the floor and take care not to
fracture the face. Also, remove only enough silage for the day's
feeding.
Finally,
pay close attention to the feed once it hits the bunk. Clean bunks and
start over with fresh feed at least once per day. Adding more feed to
spoiled feed can cause serious intake and contamination problems.
Improve
the Quality of your High Moisture Corn
There
are many factors that can effect the quality of your high moisture corn
at harvest and feed-out time. You will need to consider ear corn versus
shell corn, the moisture level at which it is harvested, processing, and
your method of storage. Following is information that can help you to
make the most of your high moisture corn and help you control mold in
your stored feed.
HMSC
vs. HMEC
High
moisture shelled corn (HMSC) and high moisture ear corn (HMEC) have
similar energy values, despite the higher fiber levels in HMEC. HMEC
will yield 12-20% more dry matter per acre at harvest than HMSC. HMEC
has a tendency to trap more air, has a higher chance of mold and
mycotoxin contamination, and separates more when fed. HMEC has much
higher energy than dry ear corn because the cob harvested at higher
moisture is more digestible.
Moisture
Level
The
recommended kernel moisture for both HMSC and HMEC is 26-32%. The cob in
HMEC increases total ear moisture by about 4-6 points. The cob which
represents about 12-20% of the dry matter of the corn ear, contains
approximately 1½ times the moisture content of the kernel. Harvest
recommendations are based on the following factors:
(1)
minimizing field, harvesting, and storage losses
(2)
providing favorable conditions for fermentation during storage
(3)
optimizing feeding value
Harvest
can typically begin once corn has reached physiological maturity which
is indicated by the formation of a black layer at the tip of the kernel.
Kernels at black layer will vary from 28-35% moisture depending on
hybrid and environmental conditions. Harvesting grain at higher than the
recommended moisture contents will reduce dry matter yields and can lead
to extensive fermentation, resulting in increased energy loss during
storage. Harvesting below the recommended moisture range also reduces
dry matter yields due to increased ear drop and weather damage and makes
it more difficult to pack and exclude air. Entrapped air increases the
risk of mold growth and/or excessive heating which will lead to nutrient
loss. It is important to add Crop Cure to your corn at the appropriate
rate to help reduce mold growth and improve the quality of your grain.
Producers
should consider adding water during ensiling if moisture content drops
below 25% for HMSC or below 32% for HMEC. Specific moisture guidelines
for various structures are located below:
HMC
MOISTURE GUIDELINES
Silo Type
Crop
Upright
Bag
Bunker Oxygen-limited
HMSC
(whole)
--
--
--
22-28
HMSC
26-32
26-32
26-32
--
HMEC
32-38
32-38
32-38
32-38
Processing
HMSC
not stored in an oxygen limiting structure should be processed.
Incorporate the use of a hammer mill, roller mill, or blower with
recutter attachment so that at least 90% of the kernels are cracked.
Avoid grinding
corn
too fine. HMEC can be picked and processed with a tub grinder or hammer
mill before ensiling. Cobs should be broken into pieces 1/2 inch or less
to prevent separation in the silo.
Feedout
Losses
Once
ensiled HMC is re-exposed to oxygen during feedout, aerobic (oxygen
loving) microorganisms will begin to grow and metabolize nutrients in
the grain. Generally, the first sign of aerobic spoilage is heating. In
order to minimize this aerobic loss, it is essential that that producers
remove a minimum of 2-4" of material in conventional structures
each day during cool weather and as much as 4-6" in the heat of
summer. Losses from aerobic deterioration can be significant (5-10%) if
proper management is not followed. Losses are usually 2-4% higher for
HMEC compared to HMSC. Applying Crop Cure at the correct rate at time of
harvest and storage will help reduce the heating that can occur.
