Late planting, immature corn and the cost of drying wet corn have many producers considering harvesting some type of high-moisture corn this year. Which method you choose is a factor of what harvesting equipment you have available or personal preference.
- High-moisture shelled corn and/or corn and cob meal (which has some of the cob) is harvested with a combine, and adjustments allow various amounts of cob in the grain.
- High-moisture ear corn (earlage) is usually harvested with a corn picker.
- Snaplage is harvested with a forage harvester with a kernel processor and has a snapper head. The kernel processor should be set to crack all of the kernels and break the entire cob into pieces smaller than a thumbnail.
There's renewed interest in harvesting earlage or snaplage because you harvest an additional 10 to 15 percent digestible dry matter per acre. Most storage structures will work for each type, but upright silos need to be in good condition with enough reinforcement rings.
Moisture guidelines for harvesting high-moisture corn are 28 to 32 percent for shelled corn; 30 to 35 percent for ear corn; and 35 to 40 percent for snaplage. Harvesting in these ranges assures that there will be adequate moisture for fermentation and allow for good packing. Harvesting drier than these guidelines increases the risk of molds and poor fermentation.
Harvesting corn at a high moisture rate will increase the rate of ruminal digestion compared to dry corn. Also, the longer high-moisture corn is fermented, up to approximately six months, the faster the rate of digestion and the greater the extent of starch digestion.
Feed testing laboratories can provide information on starch digestibility and energy value of the corn. Changing the amount fed, feeding in a total mixed ration and additional buffer are strategies that may be needed.
Snaplage tends to have the most variability as a feed. Variables such as grain moisture, cob moisture, corn hybrid and machine settings will change the amount of husk and stalk harvested. It is better to error on the wet side and a finer chop so not to have too many large pieces of husk, stalk and cob. More frequent monitoring of dry matter, neutral detergent fiber and starch content is suggested with snaplage.
If you've had a frost or hard freeze, harvest timing will be critical due to the rate of dry-down of the plant and grain. Check for black-layer development first. If the corn has not black-layered, the cob will remain soft, with adequate moisture. Once mature corn has had a killing frost, dry-down can progress quickly if weather conditions are favorable. If the corn was immature and still is wet, watch for possible development of field molds.
For more information about livestock feed requirements for dairy and beef cows, visit the Extension website at www.extension.umn.edu/dairy and www.extension.umn.edu/beef. For additional educational resources for corn producers, visit www.extension.umn.edu/corn.
Jim Paulson is a dairy educator with University of Minnesota Extension.