Hidden danger: Beware of gasses produced by silage

When I was a young boy, I saw something odd when I entered the silo equipment room on our farm just days after the silo was filled.

As I opened the door, there was a brown cloud of gas hovering just above the floor. I did not know it at the time, but that brown gas could have killed me.

The brown gas was nitrogen tetroxide. It is a byproduct of the fermentation process in a silo. Even the plastic silage bags popular now on modern farms can accumulate those deadly gasses during fermentation.

Nitrogen tetroxide is heavier than the air we breathe. Just hours after contents of the silo or bag begins to ferment, the gas can collect in dead air spaces at the base of a silo, such as our equipment room.

When a door or window opens, the fresh air flowing in allows the gas to creeps out, like smoke hugging the floor.

If you have ever watched the 1956 movie “The Ten Commandments,” the scene of the cloud creeping across the Egyptian landscape to strike down the firstborn children is a very accurate depiction of the way the gas moves.

There is a second deadly silage gas: nitrogen oxide. It may be more sinister because it is invisible and odorless. Victims may not even know they are being exposed.

Both of these gases have taken the lives human and livestock alike without warning. They destroy your lungs in a similar fashion to mustard gas weapons during some wars.

That’s why it’s best to keep doors and windows open around silo rooms and attached storage areas until the danger has passed.

Harvest is meant to feed families, not take lives away. A little attention to detail during silage-making time can make a lot of difference.

Tips For Better Feed

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.

Chopping Time

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 6 to 8 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.

Jeff Burbrink is the Purdue Extension educator for agriculture and natural resources in LaGrange County.