High Moisture Corn, Ear Corn and Snaplage
Originally written September 14, 2015. Last updated
October 22, 2015
High moisture corn is, as the name implies, corn harvested before the kernels dry down, usually processed by a roller mill or hammer mill, packed into an appropriate structure and allowed to ferment. High moisture ear corn is similar to high moisture corn but it includes some portion of the cob. Snaplage includes the grain, cob, and shuck (husk leaves and shank).
Many producers use harvest options that reduce
cost or spread the harvest window.
For livestock producers, harvesting
corn as high-moisture grain is one
option that will eliminate grain
drying costs and produce a
product that makes excellent
feed for ruminant animals.
High-moisture corn (HMC), high moisture ear corn (HMEC) and snaplage offer
many advantages for producers who
feed beef or dairy cattle. However,
successfully using high-moisture corn
requires attention to harvest timing,
processing, storage conditions and
High-moisture corn refers to corn
harvested at 24 percent or greater
moisture, stored and allowed to
ferment in a silo or other storage
structure, and used as feed for
Estimating the Value of Wet Ear Corn--A Suggested Starting Point
UWEX Bulletin A3410
Usually harvested at 28-32% kernel moisture
Equivalent Price/Ton of High Moisture
vs Price per Dry Bushel: conversion tables for converting wet ear corn
and wet shelled corn to its dry corn price equivalent. Developed by Jeff
Key, Winnebago County and Gary Frank, Center for Dairy Profitability
over dry grain harvesting
Spreads work load
Reduces harvest losses
HMC is more palatable than dry corn
High-moisture corn is similar
in energy and protein content
to dry corn.
- Elimination of grain drying costs.
- Yields typically are increased
due to less ear drop in the field.
- Longer-season (greater relative
maturity) corn can be grown with
greater yield potential.
- The ability to use an immature crop;
- High-moisture corn allows 2 to 3 weeks earlier corn harvest than dry grain, between corn silage and dry grain potentially spreading
the workload during harvest.
- Earlier availability and longer window
for cattle grazing corn residue.
- The ability to minimize sorting by adding moisture to the diet.
- Loss of marketing flexibility. High-moisture corn is marketable
only through livestock. Since it has
fermented, high-moisture corn
cannot be marketed for ethanol
production or other uses typical
for dry corn.
- More storage and processing
- Potential higher spoilage and storage losses.
- High-moisture corn tends to
ferment faster in the rumen and
requires better bunk management,
compared with dry corn.
More likely to be associated with acidosis.
The approximate dry matter composition of HMC, HMEC and Snaplage.
||High Moisture Corn
||High Moisture Ear Corn
|Crude protein, %
Advantages of high moisture ear corn and snaplage over high moisture
shelled corn include:
Increased tonnage harvested per acre. Can harvest 15-20% more feed/acre with HMEC than with
Milk production/lb of feed is slightly better for HMEC
Cows donâ€™t go off feed as often with HMEC.
Digestible and effective fiber - all the components of high moisture corn, high moisture ear corn and snaplage are highly digestible. Corn cob and husk have the added benefit of containing effective fiber. Effective fiber helps protect the rumen from acidosis. The effective fiber contained in these ingredients reduces the amount of forage that needs to be included in the ration to maintain optimal rumen health.
- Mycotoxin concentration in the cob portion. Avoid harvesting moldy or damaged corn as ear corn or snaplage.
- The need for increased storage capacity to handle the extra volume coming from the cob and husk.
High-moisture corn should be
harvested at 24 to 33 percent moisture
for optimum storage (maximum
moisture of 40 percent). Harvesting
corn at these moisture levels may
require adjustments to harvest equipment
to ensure grain is removed from
the cob uniformly. Some damage to the
grain is acceptable because it still will
need to be processed prior to ensiling.
Handling and processing of HMC for good packing and
95% of the kernels should be cracked or broken
Cob pieces shouldnâ€™t be larger than 1/2 inch
Grinding too fine will result in floury HMC
Most high moisture corn is processed (rolled or ground) before going into the storage unit. The two exceptions to this rule are shelled corn being stored in an oxygen limiting unit and corn that is excessively wet (near 35% kernel moisture). Take care not to over process corn that is over the desired moisture level. It is easy to get excessively fine high-moisture corn that may result in rumen acidosis, fat test depression, off-feed problems or an increased incidence of displaced abomasums. As the corn approaches optimum moisture content, increase the degree of processing.
High-moisture corn should be
processed (ground or rolled) prior
to storage. Grinding or rolling
and subsequent packing of the corn
facilitates oxygen exclusion in the silo.
The goal with processing should be to
have no more than 5 percent fines and
no more than 5 percent whole kernels.
For feeding purposes, rolling is the
preferred method of processing
(compared with grinding) because
rolling will result in less fines and
lower probability of acidosis due
to rapid fermentation when feeding.
While grinding may lead to faster
ruminal fermentation and greater risk
of acidosis, this problem is an issue
only when feeding greater than
50 percent of the grain as HMC
in a feedlot diet. With the increased
feeding of wet distillers grains, the
risk of acidosis from feeding ground
high-moisture corn is greatly reduced
due to the reduction in total ration
starch content. Likewise, most dairies
finely grind the high-moisture corn
to facilitate greater ruminal digestion,
and since grain is generally less than
50 percent of the diet, acidosis is
not a problem.
All high moisture corn feedstuffs must be harvested at an appropriate moisture level and properly ensiled. The corn cob contains higher moisture than the corn grain so high moisture ear corn and snaplage should have higher moisture levels than high moisture corn by itself. Cob digestibility falls off dramatically as the crop matures and moisture levels fall. Moisture testers are available to estimate the moisture of the corn grain. On average snaplage will run about 5% higher moisture content than high moisture corn. Ideally snaplage will be harvested when the corn grain itself tests over 28% moisture.
Ideal moisture levels at harvest
|High Moisture Corn - Bunker, Bag %
|High Moisture Corn - Oxygen Limited Silo , %
|High Moisture Ear Corn, %
High moisture corn can be stored either whole or ground and in upright or bunker silos. Whole high moisture corn is commonly stored in upright silos. High moisture corn should be ground if it is to be stored in a bunker silo. There is no advantage to grinding high moisture corn beyond the ability to store it in bunker silos. High moisture ear corn needs the cob fraction to be reduced to Â½ inch or less to insure adequate packing and consumption by the animals.
At moisture levels below 27 percent,
water may need to be added to
facilitate packing and fermentation.
A good rule of thumb is to add
3.5 gallons of water per ton of corn
for each percentage point the corn
is below 27 percent moisture.
For corn stored above 40% moisture, an undesirable fermentation may take place and yeast may proliferate along with high ethanol levels. Animal acceptance may be poor with this type of fermentation. Additionally, harvesting high moisture shelled corn above 32% kernel moisture for oxygen limiting silos equipped to handle high moisture shelled corn may result in unloading problems.
Bunker or Trench Silo
This is the best option for large
volumes of corn harvested in a short
period of time but will require a
large-volume roller or hammer mill
to process grain rapidly. Packing is
done with tractors, which may be
equipped with a dozer blade or
front-end loaders. The face of the
bunker must be kept fresh to avoid
heating, so the width of the highmoisture
corn bunker should match
the rate of use. Multiple narrower
bunkers may be more useful than one
wide bunker silo. Bunkers constructed
of a cement base and sides will reduce
spoilage better than earthen structures
and provide a firm surface for
equipment throughout the year.
Proper packing of the high-moisture
corn in bunker silos also is critical to
Proper packing, covering and
facing will reduce spoilage losses
and improve acceptability of the
high-moisture corn in the feed bunk.
A minimum density of 45 pounds of
dry matter per cubic foot is desirable
for good-quality high-moisture corn.
Packing grain in bunker silos can be
dangerous, so be sure an experienced
and safe tractor operator is operating
the packing equipment.
Also, all bunker, trench and pile
structures should be covered with
plastic to create an anaerobic environment
and minimize spoilage. Plastic
covers should be inspected periodically
and any holes or tears repaired.
Plastic Silage Bags
Bags are filled with
a specialized bagger that also will
process the corn to reduce oxygen
inclusion as it stuffs the bag. Pressure
can be varied to accommodate different
feed products. Baggers are available
for rent or purchase. Bags come in
different sizes and lengths.
Clear a flat space of rocks and debris,
and make sure the space is large
enough for equipment to move around
to fill bags. Be sure to inspect bags
and plastic bunker covers for tears
or holes because oxygen penetration
in these areas can cause additional
spoilage. In addition, producers
should monitor bags and bunkers
for evidence of wildlife depredation
and take necessary steps to reduce
depredation and silage losses.
Whole high-moisture grain may be
stored in certain types of oxygen limiting
silos. One advantage of these
structures is that corn can be stored at
lower moisture levels (22 to 26 percent
moisture) than in bunker or plastic
bag storage structures.
Check with the manufacturer to be
sure your silo is designed to handle
whole high-moisture grain prior
to placing grain in the structure.
Certain additives may be beneficial
in reducing fermentation and feedout
losses in HMC. Lactic acid bacteria
inoculants that have been developed
specifically for high-moisture corn
should be considered when the corn
has been frozen or is harvested below
the optimal moisture content. The use
of acid preservatives may be warranted
if substantial ear mold damage has
occurred and mycotoxin production is
prevalent in the standing crop. When
considering the use of an additive for
high-moisture corn, be sure to ask the
manufacturer for research data to
support efficacy claims.
High moisture corn offers some unique preservation challenges compared to corn silage because it ferments more slowly and less extensively while containing high levels of starch, which promotes aerobic deterioration. Any aid to hasten fermentation, use up available oxygen, and inhibit yeast growth (once exposed to oxygen) is beneficial in the ensiling process. Several options are currently available to producers.
Standard bacterial inoculants
High moisture corn inoculants have been available for many years. These primarily produce lactic acid during the fermentation process (homofermentative) and increase the speed of fermentation, while reducing dry matter loss. They may also increase animal performance. Choose an inoculant that has been specifically developed for ensiling high moisture corn. Specific strains of bacteria may not grow well on all crops and across a wide range of moisture contents. Thus, a corn silage inoculant may or may not work well under the drier conditions of high moisture corn. Most standard high moisture corn inoculants were developed to improve fermentation. For this reason, aerobic stability during and after feed-out may not be significantly improved. In fact, some standard lactic acid producing bacterial inoculants may actually improve fermentation but decrease aerobic stability (heating at feedout). With all 3 inoculants, it is important to follow the manufacturer's application rates. Typical
rates are between 100,000 and 500,000 colony forming units (cfu) per gram of high moisture corn.
Lactobacillus buchneri is a unique bacterial inoculant that has been developed to improve aerobic stability of silages and high moisture corn by reducing the growth of yeasts. The net result is grains inoculated with L. buchneri are more resistant to heating when exposed to air as compared to untreated silages. L. buchneri was originally isolated from naturally occurring aerobically stable silages. It is a heterofermentative bacteria that produces both lactic and acetic acid during fermentation. Silages treated with an effective dose (600,000 CFU/gram of wet corn) of L. buchneri have higher concentrations of acetic acid and lower levels of lactic acid than untreated silages.
The beneficial impact of L. buchneri appears to be related to the production of acetic acid. Although the precise mechanism has not yet been determined, it is likely that aerobic stability is improved because acetic acid inhibits growth of specific species of yeast that are responsible for heating upon exposure to oxygen. As a result, the temperature of fermented feed inoculated with L. buchneri does not readily rise upon exposure to air and tends to remain similar to ambient temperature for several days, even in warm weather. Using L. buchneri often results in a slightly higher dry matter loss during fermentation compared to standard homofermentative bacterial inoculants.
L. buchneri is a well-researched, highly effective inoculant to use for high moisture corn preservation in all storage units. Use of L. buchneri improves aerobic stability and this is important if high moisture corn removal rates need to be reduced because of mycotoxins or excessively degradable starch.
Preserving high moisture corn with propionic acid or propionic acid mixtures (propionic, acetic, benzoic) has been a proven effective practice for many years. However, it is more costly than simply using a standard inoculant and requires specialized equipment to apply. There are several situations where the use of propionic acid to reduce pH and preserve corn makes good sense. In years past, some producers have successfully used concrete or wood floors/bins to store high moisture corn. In this case, it's a must that corn be treated with propionic acid. Applying propionic acid at the proper rate reduces the pH of preserved corn to about 4.0 and inhibits the growth of harmful microorganisms. The cost of treatment is usually comparable to that of on-farm drying.
The proper application rate depends on two factors: 1) the moisture content of the grain, and 2) the intended length of storage. Rates are based on pounds of actual acid. It's most economical to treat corn with acid when kernel moisture is near 30 percent. It typically takes 10 to 20 lbs. of actual acid to fully preserve a ton of high moisture corn.
Another situation where acid may prove beneficial is when an upright silo is being filled but not fed from for an extended period of time. In this case, producers often only apply acid to corn that will fill the last 5 to 10 feet at the top of the silo. It is at the top where spoilage is most likely to occur as a result of oxygen infiltrating the grain. Again, determine rates based on length of storage and moisture.
High moisture feedstuffs have different feeding characteristics compared to similar dry feeds. High moisture corn ferments faster in the rumen than dry corn and traditionally was thought to add to the difficulty of getting animals started on feed and offer slightly less performance especially early in the feeding program. Currently, the popularity of corn distillers grain and corn gluten feed programs have minimized or eliminated that concern. The lower starch content of corn co-product based diets decreases the risk of rumen acidosis. High moisture corn may be more valuable in modern corn co-product diets than in traditional corn pellet diets. Combinations of dry corn and high moisture corn offer 5 to 10 percent greater weight gains and feed efficiencies than either one alone.
High moisture ear corn offers 6 to 10 percent greater feeding value than dry ear corn. High moisture ear corn and snaplage include a digestible fiber portion and a rumen effective fiber portion that helps meet the roughage needs of the animals.
The energy content of high-moisture
corn is similar to dry-rolled corn. However, high-moisture
corn typically has higher ruminal
and total tract digestion than
dry-rolled corn. The higher ruminal
digestion rate means producers need
to pay particular attention to bunk
management when feeding
Proper bunk management includes
taking care to thoroughly
mix all ingredients in the ration,
including ionophores or other
supplements; feeding at the same
time each day; adjusting feed
delivered to intake of the animals;
and observing cattle for signs of
acidosis or feed refusal.
In addition, because of its moisture
content, high-moisture corn is prone
to more rapid deterioration in
the bunk than dry-rolled grain.
In addition, increased spoilage
losses can occur during storage,
especially during the summer, if the
high-moisture grain is not properly
packed, covered and managed.
Immature corn may be harvested
effectively as high-moisture corn
for feed. Research indicates
light-test-weight, immature corn
harvested and fed as high-moisture
grain produced equal performance
as mature corn grain in feedlot steers.
Analyze grain for nutrient content
to more accurately formulate rations
because light-test-weight corn often
contains more protein than heavy corn.
When pricing corn, producers
should take into account differences
in moisture level, particularly with
high-moisture corn. Dry corn typically
is traded at 15.5 percent moisture.
High-moisture corn can have moisture
levels from 24 to 33 percent, which
necessitates adjustment to a constant
A useful series of calculators and apps to make
this conversion can be found
For beef cattle and dairy producers,
harvesting corn as high-moisture
grain offers many advantages.
Nutrient content and moisture
of high-moisture corn may vary
depending on harvest timing,
yield, variety and other factors.
To reduce storage and spoilage
losses, proper processing and storage
recommendations should be followed
with particular attention to kernel
processing, oxygen exclusion/proper
packing and covering bunker silos
to reduce spoilage.
Take care when feeding high-moisture
corn because it does have a faster
ruminal digestion rate than dry
corn. Consequently, better bunk
management typically is required
for successful feeding.
Calculators and apps for pricing high moisture corn
Buchanan-Smith, J., T.K. Smith, and J.R. Morris. 2003. High Moisture Grain and Grain By-Products, p. 825-854, In D. R. Buxton, R. E. Muck and J. H. Harrison, eds. Silage Science and Technology. American Society of Agronomy, Crop Science Society of America, Soil Science Society of America.
Hoffman, P.C., R.D. Shaver, and N.M. Esser. 2010. The Chemistry of High Moisture Corn. Proc. 2010 4-State Dairy Nutrition & Management Conf., Dubuque, IA.