Growing conditions have been ideal for corn in several parts of North Dakota this year, and many livestock producers are preparing to produce corn silage.
“Even under ideal conditions, dry-matter losses between the time that corn is harvested and when the silage is consumed by animals can approach 15 percent,” cautions North Dakota State University Extension livestock environmental stewardship specialist Miranda Meehan.
“With poor harvest and management, these losses can be in excess of 50 percent,” she notes. “Therefore, proper harvest and management are important to ensure you are maximizing the amount of good-quality silage available for feeding your livestock.”
Harvesting corn silage at the appropriate moisture level is key to getting proper fermentation for preservation and forage quality, according to Carl Dahlen, an associate professor in NDSU’s Animal Sciences Department. Moisture levels outside of the ideal range will lead to improper fermentation, which can impact packing and feed loss through spoilage.
Traditional indicators of when to start chopping silage, such as when corn reaches the 50 percent milk line, can be deceiving with different silage hybrids. Dahlen and Meehan recommend producers harvest based on whole-plant dry matter. For bunkers and piles, they recommend a moisture content of 60 to 70 percent.
Based on a producer survey NDSU Extension conducted, the majority of corn silage in North Dakota is harvested during September.
“If you are utilizing a custom harvester, it is important to keep the harvester updated on the status of your crop so it can be harvested at optimal conditions,” Dahlen says.
When harvesting, having the chopper set at the proper length and clearance between the processing rolls is important when using a kernel processor. Particle size influences digestibility.
To obtain optimal digestibility, researchers found that approximately 90 percent of the particles should be between 0.31 and 0.75 inch. Kernel processing equipment on choppers can ensure that a greater proportion of particles falls into the ideal range. The equipment breaks down large pieces of cob and stalk, helping achieve an ideal particle size and enhancing silage compaction.
Meehan and Dahlen advise that prior to harvest, producers should select a location for the silage pile and determine the proper pile size. Factors to consider when selecting a location include:
- Distance to water well
- Snow movement/drifting
- Distance to feeding area
- Space to maneuver equipment
- Ability to exclude livestock and wildlife
Follow these steps to size the pile:
- Calculate the pounds of silage to be fed daily.
- Divide by 40 to determine the volume of silage to be removed daily in cubic feet.
- Establish a daily removal rate from the face of the pile.
- Divide the volume to be removed (Step 2) by the removal rate (Step 3). This is the cross section of the pile.
- Set an average pile depth, realizing the peak will be higher.
- Divide the cross section (Step 4) by the average depth (Step 5) to determine the average width of the pile. If this seems too narrow, adjust the average depth and/or the removal rate.
“A critical step to ensure quality silage is the packing process.” Dahlen says. “An anaerobic environment is required for appropriate silage fermentation, and packing removes air between silage particles.
“Excess air remaining between particles (poor packing) leads to excess spoilage and mold growth,” he adds. “Once piles are well-packed, consider covering the pile to further enhance silage quality and reduce spoilage. Remember that the amount of visible spoilage seen on top of piles (up to 16 inches in a survey of producers) is lost feed.”
Once silage is fermented and feeding starts, producers should pay particular attention to managing the feeding face of horizontal silos and silage piles. Once fermented silage comes in contact with air, additional heating and spoilage can occur.
Dahlen recommends keeping the silage face as straight as possible and removing at least 6 inches of silage from the entire face of the pile on a daily basis. Producers can use this concept to determine the appropriate dimensions of silage piles.
“Corn silage can provide a high-quality feed for livestock if it is harvested and ensiled properly,” Meehan says. “Careful planning of the harvest, pile size and location, and feeding management can ensure quality and reduce the amount of silage lost due to spoilage.
“Considering the high variability in quality due to harvest conditions, harvest methods and ensiling methods, we recommend that producers test forage quality to ensure they are meeting animals’ nutritional requirement,” she adds.
Contact your local NDSU Extension office for more information about corn silage.