Feeding High Moisture Corn

Feeding high moisture corn can be advantageous but must be harvested and stored correctly, as indicated in this publication.

• Advantages of High Moisture Corn
• Disadvantages of High Moisture Corn
• Optimum Maturity and Harvest Moisture
• High Moisture Corn Storage
• Ground High Moisture Corn
• Use of High Moisture Corn When Fed With Corn Byproducts
• Feeding Mixtures of Grain Types
• Whole High Moisture Corn
• Reconstitution
• Ground Ear Corn or Ground Snapped Corn
• Feeding Value of Immature or Early Harvest Corn
• Summary
• Acknowledgment

The use of high moisture grain is popular due to the increased costs of drying and handling of dry grain. Using high moisture grains allows greater opportunity to design a system that will minimize harvest, storage and feed processing costs.

Grains such as sorghum and wheat have been stored as high moisture, but corn is the principal high moisture grain stored. High moisture corn (HMC) can be processed and stored as whole shelled corn, ground shelled corn or ground ear corn. When deciding whether to dry or store HMC, consider the following advantages and disadvantages.

Advantages of High Moisture Corn

1. Costs incurred during artificial drying are eliminated.
2. High moisture corn can be harvested two to three weeks earlier than corn harvested for dry storage.
3. Dry matter losses from field and harvesting can be decreased by 3-6 percent for corn harvested at 25-35 percent moisture compared to corn harvested for dry storage.
4. Greater potential exists for the use of higher quality residues by allowing earlier stalk grazing.

Disadvantages of High Moisture Corn

1. Loss of some marketing flexibility compared to dry corn.
2. Additional processing equipment may be needed.
3. Facilities are needed for the entire quantity of HMC to be stored.
4. Spoilage can be a problem and storage losses may be higher than for dry corn if HMC is not properly ensiled and fed at adequate rates.
5. High moisture, fermented corn may require better bunk and feeding management than does dry corn.

Optimum Maturity and Harvest Moisture

Corn is considered physiologically mature when it will yield the maximum quantity of dry matter. Most corn kernels accumulate dry matter until moisture decreases to 30-35 percent; 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. 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 usually are needed to reduce kernel moisture from 50-40 percent. During this time, yield can increase at a rate of one-fourth to three-fourths 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. Moisture content that best satisfies these requirements occurs shortly after physiological maturity is reached. An acceptable range for corn moisture content is 28-33 percent. At this stage corn loses about 1/2 to 1 percent moisture per day in the field. Table I shows the approximate moisture relationship between kernel, cob and the whole ear. Field losses at harvest can be significantly affected by corn moisture content. Harvesting and handling becomes easier as moisture content falls, but ear droppage and downed stalks increase due to wind, stalk rot and insect damage. These losses can be minimized with proper machinery adjustment, and beginning harvest when corn is around 30 percent moisture and finishing before corn is less than 25 percent moisture. If corn is less than 25 percent moisture, greater spoilage can occur unless the corn is stored in oxygen-limited silos.

High Moisture Corn Storage

Storage methods commonly used for HMC consist of two main types. Ground HMC normally is stored in bunker or trench silos, whereas whole HMC is stored in upright oxygen limiting structures. Ground or coarse rolled corn also can be stored in upright structures. The large bagging systems that have been primarily for storing silage also can be used for HMC storage. Fermentation losses for HMC average 3-4 percent of the initial dry matter ensiled but can be two to three times this if ensiled at the wrong moisture for the type of structure used.

Ground High Moisture Corn

Corn stored in bunker silos should be harvested at moistures above 25 percent. The preferred harvesting moisture is around 28-33 percent. Corn stored by this method should be ground or rolled and well packed into the silo. Since proper packing depends on the moisture and particle size, corn that is to be stored in a bunker silo can be coarsely ground (as much as 40-50 percent whole corn passing through). However, as moisture of the corn decreases to near 25 percent, finer grinding may be necessary to achieve proper packing. Finer grinds also permit a slower feeding rate once the silo is opened. If the feeding rate is fast enough (approximately 3 inches removed from the face of the bunker daily) to prevent deterioration as the grain is fed, a coarser grind is recommended. As the silo is being filled, only enough corn kernels need to be ground or broken to permit a firm pack.

Compared to dry corn, the feeding value of ground HMC may vary with roughage level fed and storage method. In a high concentrate ration (10 percent roughage or less), corn stored in a bunker silo will, on the average, produce daily gains 2-5 percent lower than dry corn. Feed efficiencies are similar for both corn types, however.

The lower gains experienced with HMC may be due to a more rapid ruminal digestion of the corn starch, resulting in a greater chance of digestive disturbances, such as acute or subclinical acidosis, occurring. Past research results from Oklahoma show that cattle fed processed grains are more predisposed to acidosis conditions. Recent research results from the University of Nebraska–Lincoln Northeast Research and Extension Center have shown that the decreased performance observed with ground HMC occurred primarily during the step-up or adjustment period — the period in which cattle normally have the greatest chance of developing acidotic problems. Once cattle were on the high concentrate ration, performance was similar regardless of corn type fed.

The more rapid ruminal starch digestion primarily is due to the increased solubilization of the corn starch as a result of the fermentation process. As starch becomes more soluble it is digested more rapidly and possibly to a greater extent than less soluble starch. Grinding or rolling corn also increases the rate of starch digestion. Too rapid starch digestion will lower ruminal pH and increase acidosis-related challenges.

Use of High Moisture Corn When Fed With Corn Byproducts

Using products such as wet corn gluten feed (WCGF) to replace corn in finishing diets has been shown to improve feed intake and daily gain while maintaining or improving feed efficiency. Most of this research has been done with dry-rolled corn replacement, although it has been shown that there are improvements in feed efficiency when other corn types are used and WCGF is included in finishing diets (Table II).

Table II. Effect of corn processing when fed with wet corn gluten feed (University of Nebraska–Lincoln).
	Processing methoda
25% WCGF	DRC	FGC	FRC	RHMC	GHMC	SFC	Whole
ADG, lb Feed:gain ratio, DM NEg (corn), Mcal/cwt Fecal starch, %	4.23 5.49b 70.0 19.2b	4.35 5.29c 73.4 11.8c	— — — —	4.21 5.13d 76.4 10.6cd	4.24 5.05d 77.7 8.4d	4.33 4.91e 80.4 4.1e	— — — —
	Processing methoda
32% WCGF with calves	DRC	FGC	FRC	RHMC	GHMC	SFC	Whole
ADG, lb Feed:gain ratio, DM	4.24 5.52c	4.17 5.32d	— —	4.15 5.26de	— —	4.25 5.18e	4.18 5.92b
	Processing methoda
22% WCGF with yearlings	DRC	FGC	FRC	RHMC	GHMC	SFC	Whole
ADG, lb Feed:gain ratio, DM	3.98b 6.09bc	— —	3.95b 6.15b	4.02b 5.97c	— —	4.22c 5.54d	— —
aDRC = dry rolled corn, FGC = fine ground corn, FRC = fine rolled corn, RHMC = rolled high moisture corn, GHMC = ground high moisture corn, SFC = steam flaked corn, whole = whole corn. b,c,d,eMeans with different superscripts differ (P < 0.05).

The increased availability of wet distillers grains plus solubles (WDGS) has led to a greater number of feedlot producers and nutritionists incorporating this feed into finishing diets similar to what has been done with WCGF. Incorporating WDGS into feedlot diets results in better performance, with optimum feed conversion observed when included between 25-35 percent of the diet.

Cattle fed WDGS and HMC as the concentrate source yielded better feed conversion and higher marbling scores than cattle fed the same amount of WDGS with other corn types. Overall, WDGS is an excellent feed ingredient for finishing diets. It appears that fine grinding or not processing corn at all (whole corn) is not as favorable as using DRC and HMC in diets containing approximately 30 percent WDGS.

In other studies conducted at the University of Nebraska–Lincoln, it has been shown that inclusion of 25 percent wet corn byproduct was insufficient to overcome the subacute acidosis associated with 0 percent roughage. Thus, the inclusion of other sources of fiber or roughage is recommended in diets containing WCGF or WDGS.

Feeding Mixtures of Grain Types

Adding dry corn to the ground HMC ration may lower the incidence of acidosis and improve steer gains and feed efficiencies. When compared to steers fed only ground HMC or dry corn, results of studies conducted in Nebraska and Oklahoma have shown that mixtures of these corn types improve steer weight gains and feed efficiencies 5-10 percent.

Feeding grain combinations (ie: steam-flaked grain sorghum (SFGS):HMC) resulted in a 5-6 percent positive associative effect for daily gain and gain efficiency. Significant benefits (positive associative effects) also are found when SFGS was fed in combination with DRC.

Whole High Moisture Corn

Shelled corn can be stored whole in oxygen limiting silos and bins. Research has shown that steers fed HMC stored whole and fed whole gain approximately 5 percent faster and are 5 percent more efficient than steers fed DRC in high concentrate finishing rations. Rolling whole HMC prior to feeding resulted in a 1-2 percent improvement in gain and feed efficiency over steers fed the whole corn.

With oxygen limiting structures corn can easily be stored at a much lower moisture than is needed for bunker stored corn. Optimum moisture for corn stored under this type of structure is between 22-26 percent moisture.

High moisture corn also can be stored whole in other types of structures by treating it with organic acids. Such organic acids can be used to treat HMC stored outside, particularly in low rainfall areas. Steer gains and feed efficiencies may be improved 1-3 percent over DRC when fed organic acid treated corn; however, the extra cost of the acid and its application must be considered before using this method of preserving and storing HMC.

Reconstitution

A summary of research conducted at South Dakota, Indiana and Nebraska has shown that reconstituting corn results in little, if any improvement in gain and feed efficiency when the corn is fed in high concentrate rations. With the costs incurred in drying the corn and then reconstituting it, harvesting HMC from the field and storing it in that form appears to be more economical. Adding enough moisture for adequate fermentation also is a problem, since moisture content of 25 percent or more is desirable for proper reconstitution. Reconstitution of milo has been shown to be much more beneficial, however, and should not be discarded as a processing method for it. Reconstitution of grains also may add flexibility to the feeding operation due to the lower inventory of grain that is needed at one time when compared with traditional HMC.

Ground Ear Corn or Ground Snapped Corn

Ground ear corn (corn and cob only) appears to have 6-10 percent greater feed value when stored as high moisture feed than when fed dry. This improvement may be largely due to increased palatability of the feed. Approximately 13 percent of the dry matter of high moisture ground ear corn is found in the cob (Table III). This is more roughage than necessary for maximum rate and efficiency of gain in finishing rations. Thus, additional grain should be added to a ground ear corn ration once the cattle are started on the finishing ration.

Ground snapped corn (cob and shuck included) will have 5-10 percent more roughage equivalent than ground ear corn and thus would be fed at a lower level than ground ear corn in a finishing ration. In finishing rations, 8-12 percent roughage is generally recommended. At 8 percent roughage equivalent, ground ear corn would be included at about 40-50 percent of the total ration if no other roughage is included since it is about 15 percent cobs. Ground snapped corn is about 25 percent cob and shuck and would be included at 30-40 percent of the ration dry matter.

Before ensiling, high moisture ear corn needs to be properly processed. For best results, reduce cob pieces to 1/2 inch in diameter to assure good packing and adequate consumption when fed. Harvesting the cob requires about 50 percent more storage capacity compared to storing the grain only. Where storage capacity is limited or more expensive structures are used, the improvement in feed utilization and the feed value of the cob may not always offset the additional cost of harvest and storage.

Feeding Value of Immature or Early Harvested Corn

When corn has been planted late or growth halted because of an early frost, the harvested grain may be immature and the nutritional value considerably different than that of corn reaching maturity. The composition of corn harvested at various maturities is shown in Table IV. In general, immature corn is higher in protein than mature corn, but similar in energy. Test weight is lowered considerably depending on degree of immaturity.

Immature corn that is incapable of being shelled can be harvested as ear or snapped corn, but will have a lower energy value than mature snapped corn. As corn progresses from the milk stage to full maturity, the percentage of corn in a corncob mix increases from approximately 60-80 percent of the total dry matter. Snapped corn harvested in the dough to early-dent stage of maturity will have 90-95 percent the energy value of mature snapped corn. After mid-dent, the energy value is similar to mature snapped corn. In the typical beef cattle ration, the digestibility of immature corn is expected to be similar to the digestibility of mature corn.

Summary

If properly stored, high moisture corn is an excellent feedstuff for feedlot cattle. Even though it has enhanced feed value when compared to dry rolled corn, additional feed value can be obtained by mixing and feeding it with dry rolled corn or corn byproducts.

Acknowledgment

The authors would like to acknowledge the work and contributions of the original co-authors of this publication, Paul Guyer, extension beef specialist, and Rick Stock, extension feedlot specialist.

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Index: Beef
Feeding and Nutrition
1974, 1983, Revised November 2006