Corn silage has always been a major feed component in dairy and beef cattle rations. However, this year's weather is making harvesting corn silage a challenge for many areas of Iowa.
Northwest and northeast Iowa had excess rain early in the crop season, which delayed corn planting. With late planting, producers in northern Iowa may not be challenged as much with the 2018 harvest, yet.
Using good harvesting and storage practices are important for getting quality corn silage every year, but it’s even more important in years like 2018 when wet weather is delaying silage harvest.
Weather not cooperating
Eastern Iowa was dry in the spring allowing early planting. That part of the state is now challenged to get the silage harvested before the crop becomes too dry, especially with the heavy rains in September keeping the silage harvesters out of the field.
Southern Iowa has been extremely dry all summer and is finally getting some much-needed rain, but it’s too late to impact grain crops.
While every area of the state has had different growing conditions in 2018, all those conditions have been challenging. Iowa State University Extension beef specialist Denise Schwab says a few basic principles of corn silage harvest are critical to pay attention to, if you want to harvest and store a high-quality corn silage feedstuff.
Harvest silage at proper moisture content
According to ISU Extension dairy specialist Hugo Ramirez-Ramirez, the No. 1 priority for high-quality silage is to harvest at the right moisture content. The bacteria that convert the plant sugars into lactic acid need the right moisture to drive fermentation. Ideally, the plant should be at 35% dry matter or 65% moisture to facilitate packing the silage to exclude oxygen and promote fermentation.
What options do producers have when the plant gets drier than this? One might be to switch the storage method.
Retired ISU Extension forage specialist Steve Barnhart says the optimum silage moisture at harvest ranges from 55% to 60% (40% to 45% dry matter) for upright oxygen-limiting silos; 60% to 65% for upright stave silos; 60% to 70% for bags; and 65% to 70% for bunkers.
“Pay particular attention to moisture measurements,” Barnhart says.
Agronomists tend to talk in terms of moisture level while animal scientists tend to focus on dry matter levels.
Harvest as silage or earlage?
Another option suggested by Dan Loy, ISU Extension beef feedlot specialist, is to switch from silage to earlage or snaplage. Earlage or snaplage is harvested at closer to 62% to 65% dry matter. Earlage or snaplage is similar in protein levels but higher in energy value than traditional corn silage, so ration modification is needed, but it may provide a better feed storage option for corn that dries down prior to chopping.
Chop length and kernel processing are important for dairy producers. Ramirez-Ramirez suggests a theoretical length of ¾ inch if using a kernel processor, or shortening the cut to ¼ to ½ inch without kernel processing.
University of Nebraska research showed a 7% improvement in finishing cattle feed-to-gain by kernel processing. As the corn plant gets drier, smaller particle size may aid in improved packing and fermentation, but it also needs to offset the cost of the additional processing.
How about using silage inoculant?
Inoculants with lactic acid-producing bacteria will help speed the drop in pH to around 4, thus improving the fermentation process. This is particularly important in situations where an efficient fermentation process may be compromised. As standing corn becomes dryer, using inoculants in the silage becomes more important.
Whether it is silage, snaplage or earlage, Ramirez-Ramirez recommends that producers look into using inoculants that contain Lactobacillus buchneri. This microorganism has been shown to improve shelf life of the feedstuff or increase aerobic stability during the feed-out phase. This translates into less heating and less spoiling once the silage is open.
Packing silage when storing
Packing also is critical and becomes more of a challenge with dry silage. Packing eliminates oxygen, which aids in the anaerobic fermentation process. Silage density needs to be 14 to 16 pounds of dry matter per cubic foot to exclude oxygen. Bunkers and piles should be packed in layers no more than 6 inches at a time.
Density is dependent on crop type, moisture, chop length, type of structure, delivery rate, packing weight and time. With dry silage, you should err on the side of extra packing time and weight.
The final and most important practice for quality silage is to seal and cover the silage, both to prevent the entrance of oxygen and to keep rain from infiltrating the silage when stored.
With less-than-ideal chopping and packing situations, consider adding both an oxygen barrier layer as well as a plastic cover. The oxygen barriers are special thin films that don’t allow oxygen penetration, whereas the traditional plastic silage cover prevents water infiltration. Both need to be weighted down to prevent air infiltration. If using old tires, be sure they all are touching other tires to get full coverage of the plastic.
“These good practices are important for getting quality silage every year, but even more important in years like 2018 when wet weather is delaying silage harvest,” Schwab says.
Source: Iowa State University