The following is from Jeff Burbrink, LaGrange County Extension educator, ag and natural resources.
We are nearing corn silage harvest. Corn silage is one of our most important feeds for dairy and beef operations. The quality of that silage can have a significant impact on animal performance, milk production, and feed efficiency throughout the year. While many management decisions contribute to producing high-quality silage, harvesting at the proper moisture remains one of the most important.
Silage that is harvested too wet can create several problems. Excess moisture increases seepage losses, carrying valuable nutrients out of the storage structure. In addition to reducing feed value, seepage can create environmental concerns if it
reaches nearby water sources. Silage harvested too dry presents a different challenge. Dry forage is more difficult to pack, allowing oxygen to remain in the pile or silo. Poor fermentation and increased spoilage can reduce feed quality and lower digestibility.
Each storage system has an ideal moisture range. Horizontal bunkers and piles generally perform best when silage is 65% to 70% moisture. Conventional tower silos are best filled with silage at 63% to 68% moisture, while oxygen-limiting silos perform best between 55% and 60%. Silage bags typically store well at approximately 65% moisture.
Fortunately, determining moisture does not require expensive equipment. Commercial moisture testers provide quick results, and the microwave method remains an accurate, low-cost option for producers willing to spend a few extra minutes. The important point is to measure moisture rather than rely on appearance alone.
Knowing when to begin harvest also requires monitoring crop maturity. Sampling fields at full dent, when the milk line first becomes visible, provides a good starting point. Under normal conditions, whole-plant moisture declines approximately one-half to three-quarters of a percentage point each day, allowing producers to estimate when fields will reach the desired harvest range.
The size of the chop is also important. Generally, a length of cut between three-eighths and three-fourths of an inch allows for the best fermentation, although adjustments may be needed depending on crop moisture and storage method. Proper kernel processing is equally important. Kernels should be cracked, and cob pieces should be no larger than thumbnail size to improve starch availability and overall digestibility. As corn matures beyond the half milk line, thorough kernel processing becomes increasingly important.
Once harvest begins, filling storage structures efficiently helps preserve forage quality. In bunker silos, packing density is one of the biggest factors affecting fermentation. Filling in thin layers of six to eight inches while maintaining a progressive wedge helps remove oxygen and create the anaerobic conditions needed for successful fermentation. Well-packed silage should approach approximately 14 pounds of dry matter per cubic foot.
As busy as silage season becomes, safety must remain a priority. Harvest equipment is powerful, and field activities often attract children who are curious about the machinery. Operators should remain aware of everyone working around equipment and make sure children observe harvest from a safe location away from moving vehicles and machinery.
There is also a safety risk after harvest. Silage can product deadly gasses as it ferments. I will write more about that next week.