October 4, 2001

Dairy Specialist Offers Advice on Storing High Moisture Corn

The increased cost of handling dry feed grains has prompted livestock producers to use more high moisture grain, notes a North Dakota State University dairy specialist.

"For dairy producers in particular, storing grains with high moisture contents is one practice that can improve their competitive position and reduce costs," notes J.W. Schroeder, of the NDSU Extension Service. "Using high moisture grains allows greater opportunity to design a system that will minimize harvest, storage, and feed processing costs."

Grains such as barley and wheat can be stored at high moisture levels, but corn is the principal high moisture grain stored. High moisture corn can be processed and stored as whole shelled corn, ground shelled corn, or ground ear corn, Schroeder notes. When deciding whether to dry or store high moisture corn, consider the following advantages and disadvantages:

• Costs incurred during artificial drying are eliminated.
• Corn can be harvested two to three weeks earlier than corn harvested for dry storage.
• Dry matter losses from field and harvesting can be reduced by 3 to 8 percent for corn harvested at 25 to 30 percent moisture compared to corn harvested for dry storage.
• Greater potential exists for the use of higher quality residues.

• Loss of some marketing flexibility
• Additional processing equipment may be needed.
• Additional storage facilities may be needed.
• Spoilage can be a problem and storage losses may be higher than for dry corn if high moisture corn is not properly ensiled and fed at adequate rates.
• High moisture, fermented corn may require better bunk and feeding management than dry corn.

Corn is considered physiologically mature when it yields the maximum quantity of dry matter. Most corn kernels accumulate dry matter until moisture decreases to 30 to 35 percent, although some hybrids may be mature at 40 percent moisture. "Postponing harvest to decrease corn moisture does not increase yield or energy per acre and often increases field losses," Schroeder notes. Corn kernels that have started to dent have about 50 percent moisture and are in a medium soft stage, but are not mature. Twelve to 16 days is usually needed to reduce kernel moisture from 50 to 40 percent. During this time, yield can increase at a rate of 1/2 to 3/4 bushel per acre per day.

"Optimum moisture in corn should allow for easy harvesting, lower field losses, excellent packing, proper fermentation, and more desirable animal performance," Schroeder says. "Moisture content that best satisfies these requirements occurs shortly after physiological maturity is reached. An acceptable range for corn moisture content is 25 to 30 percent. At this stage corn loses about 1/2 to 1 percent moisture per day in the field."

Schroeder notes that ground high moisture corn is normally stored in bunker or trench silos and whole high moisture corn is stored in upright oxygen-limiting structures. Ground or coarse rolled corn can also be stored in upright structures. The large bagging systems that have been primarily for storing silage can also be used for high moisture corn storage.

High moisture corn going into storage at kernel moisture above 35 percent will result in the kernels cracking during handling with augers and blowers. This kernel breakage results in more of the starch being broken into fine particles. "The starch in fine particles is more soluble and will ferment very rapidly in the rumen," Schroeder notes. "This rapid starch fermentation can result in a more acid rumen environment and potentially cause rumen acidosis and digestive upset. Cattle that consume in excess of 18 pounds of high moisture corn per day are more susceptible to digestive disorder from the wet corn."

The term "fines" represents foreign matter and the floury starch particles in the corn. According to Schroeder, there are no published values on what level of fines should be in high moisture corn or what is excessive. A producer’s experience may be the best indicator.

"Rolling or grinding high moisture corn before storage is often done, but, with corn at about 35 percent moisture, that may not be necessary," Schroeder says.

If producers are considering rolling or grinding the corn before placing it in storage, Schroeder advises them to check the extent of kernel cracking and the amount of fines appearing in the silo. "With corn kernel moisture of 35 percent and above, normal combining, auguring, and blowing of the grain will probably crack or break the kernels sufficiently for adequate air exclusion and fermentation," he says. "With horizontal storage, rolling may be necessary if few fines are present after combining. However it is likely that wet corn will have adequate fines."

Also keep in mind wet grain exerts more pressure on the silo than corn silage, so conventional concrete stave silos may require additional hoops or the silo must not be completely filled. Before filling, hang a sheet of polyethylene behind the unloading doors on the silage chute as air leakage around the doors causes drying and spoilage.

"High moisture grain not only offers many advantages during harvest, but when properly stored makes excellent feed," Schroeder says. General harvesting and storage recommendations include:

• 25 to 30 percent kernel moisture – Follow usual harvesting and handling procedures that have been done in previous seasons.
• 30 to 35 percent kernel moisture – Can be harvested as high moisture corn. Watch for excessive kernel breakage and the occurrence of "fines" and "flour" particles. If excessive "flouring" is visible, different handling procedures need to be implemented to minimize kernel breakage.
• 35 to 40 percent kernel moisture – Excessive kernel breakage will likely occur and handling procedures that minimize breakage should be implemented. Mixing of dry corn with high moisture corn going into storage would be an option to reduce total moisture to more acceptable ranges.
• About 40 percent kernel moisture – Questionable moisture range for storage and feeding. Mixing with dry corn before storage is recommended.

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Source: J.W. Schroeder, (701) 231-7663, jschroed@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu

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