Forage quality is No. 1.
You want to keep it that way, but you also realize that you can’t lock corn silage in an impenetrable vault at harvest.
However, you do have some control over forage quality between harvest and feedout. Storage time is a perfect opportunity to monitor corn silage to maximize dry matter quality at feedout and to troubleshoot quality problems so that you get better results at the next harvest.
Here are two practices that you can implement during storage to maintain the future feeding value of corn silage.
1. Estimate dry matter loss
Stored corn silage that is subject to air penetration results in dry matter loss. Dry matter loss means you not only get less silage, but also poorer-quality silage.
One way that you can minimize this problem is to estimate dry matter loss.
It’s not always practical to determine dry matter loss by weighing every load going into storage and comparing it to what you feedout, says Ken Griswold, dairy extension educator with Penn State Cooperative Extension.
A more practical way to estimate dry matter loss is to measure silage density during storage.
“We know that density is inversely related to dry matter loss,” Griswold says.
During the past six years, Griswold and Paul Craig, extension agronomist with Penn State, have taken measurements on 65 different farms to determine corn silage density. They use a gas-powered drill to obtain 2-inch “core” density samples from different locations on a bunker face.
The goal, says Griswold, is to use the core density of silage to estimate how much dry matter loss you have in the silo. That information tells you how good of a job you did packing the crop and can be used to make adjustments in packing and sealing procedures at the next harvest.
Aim for a minimum of 14 pounds of dry matter per cubic foot of silage during packing, Griswold says.
2. Monitor retained heat
Excessive heating in silage also can lead to spoilage and reduce forage quality.
Infrared thermography is a way to monitor heating, or secondary fermentation, during storage. The use of this technology to monitor silage temperature is relatively new, though it has been used in other thermal-sensing applications like monitoring cow body temperature.
Heat-sensing digital cameras capture the temperature of the silage at various locations in the bag or bunker, says Mike Hutjens, extension dairy specialist at the University of Illinois. This gives you an idea of the secondary fermentation and dry matter losses that you may be up against.
The “pictures” reflect the fermentation characteristics of the silage. For example, how well packing was done or how well an inoculant did its job to reduce secondary fermentation.
“In effect, it’s telling you that if you have a lot of thermal imagery on the top of your bunker, that’s not nearly as stable as the bottom,” Hutjens says.
Though its application is promising, thermal-sensing equipment is expensive.
Another option is a temperature probe or “spike” thermometer, which also can be used to monitor silage temperature.
Learn more about these tools and why it is so important to keep your silage’s retained heat below 95 degrees F during storage at: www.dairyherd.com/nutrition.