Corn silage is a popular choice for winter feeding throughout the Midwest. The feed is very palatable, a good source of energy, and is highly digestible. Along with these attributes, its popularity is also based on high yield and tonnage per acre.
Harvesting and storing corn silage for feed is dependent on anaerobic fermentation. The fermentation process converts soluble carbohydrates to acetic and lactic acid which lowers pH and preserves the feed. Pack density and proper sealing of the container is important to providing the anaerobic environment needed for the process to take place.
Harvesting at the correct moisture will be crucial for achieving good pack density. The whole plant moisture should be between 60 and 70%. Storage structure will impact what end of that range you want to be on. Bunkers or pit silo storage will need to be moister to ensure a very good pack. Bagging or upright silo storage can accommodate a little dryer material. Chop length is also a factor. Ensuring chop length remains short is vital to a good pack and proper fermentation of the corn silage
A good way to measure moisture in the field is to grab a handful of silage and attempt to make a ball. If the ball holds shape and there is a lot of free juice the silage is approximately 75% moisture. If the ball holds shape but there is little juice the moisture is likely 70-75%. If the ball falls apart slowly, the moisture is likely 60 to 70% moisture. When the silage will not make a ball for even a short period of time the moisture is poor and likely below 60%.
As corn silage harvest quickly approaches, producers need to refresh their minds with harvest and storage management strategies to ensure the greatest return on their investment.
A complete review of harvest and storage management is available in a paper entitled "Management and Storage Alternatives for Corn Silage" authored by Dr. Nathan Pyatt and Dr. Larry Berger