Livestock producers depend on forages to feed their herd throughout the year. So it’s more than just growing and harvesting—it’s ensuring that it stores well while waiting to be used. But preserving good, nutritive silage takes work.
Understanding the Difference Between Silage and Hay
Silage is stored at 55%-70% moisture and has high soluble sugar content. It is tightly packed so that no oxygen can enter, which can quickly lead to spoilage. Fermentation creates the acids necessary to preserve the silage. It is usually stored in piles or bunks near where it will be used.
In contrast, hay is stored at approximately 12%-25% moisture and has low soluble sugar content. The bales are loosely bound, so oxygen enters, but preservative acids can be added to help with longer-term storage. In addition, hay is packaged in smaller units to be easily transported or sold.
The Basics of Silage
Silage is a way of storing high-moisture forage to use as a food source. The key to silage is the fermentation process, in which soluble sugars are converted to preserving acids. The goal is to reduce the loss of valuable dry matter. Acids, ammonia and gasses such as carbon dioxide (CO2) all play a role in this preservation process. Preservation is complete when the pH of the silage is below four.
Factors That Impact Silage Quality
There are four primary considerations for encouraging fermentation and protecting quality.
1. Harvest Timing
Silage should be harvested when moisture levels are between 60%– 65%. This moisture level correlates to the mid-dent stage in corn, or 50% milk line. Harvesting at the correct moisture helps to ensure adequate carbohydrate content for fermentation. Naturally occurring bacteria produce 44-88 pounds of organic acids per ton of silage to reduce pH to around four. This process requires 2%-4% of the raw forage material.
PRO TIP: Preventing the occurrence of butyric acid fermentation is important. Butyric acid-producing clostridium is active above 70% moisture. This type of fermentation leads to increased dry matter loss and hurts overall animal performance. Feeding this silage can result in reduced milk production, diarrhea, ketosis and mastitis.
2. Filling and Packing
Packing is the most cumbersome step during filling, but it is the most critical process for silage quality. A best practice is to fill it with uniform 6-inch layers. Overall packing density should be at least 14 pounds per cubic foot.
PRO TIP: Adding a silage inoculant can reduce dry matter loss by 5%. That’s like saving 5 acres out of every 100!
3. Silo Sealing
Air exclusion is vital to preserving silage. Air can penetrate 11- 40 inches per day from the silage surface, and silage piles can have up to 35% dry matter loss due to a large amount of surface area. Covering a silage pile can reduce dry matter loss from 46% to 8%.
A mold layer of 5-6 inches translates to a loss of 1-2 feet of original silage—that can be 15%-20% of the original ensiled material. Animals know the difference too. Holstein’s fed uncovered alfalfa silage consumed on average 12% less and gained 42% less than when fed covered silage.
PRO TIP: If your silage pile is warm, it means that work is still being done and nutrients are being lost. Something is doing work and eating the nutrients! Covering a pile and having good face management is one way to help keep your pile cool as long as possible.
4. Fermentation
Fermentation is all about the acid. The faster the pH is reduced, the more nutrients are saved. Slow fermentation causes more degraded proteins and increased amounts of ammonia. At high pH (>5), mold and yeast increase, leaving more potential bacterial survivors that can be reactivated upon silo opening.
PRO TIP: Using a quality inoculant ensures that the beneficial microbes are in place to fully utilize the soluble sugars to rapidly reduce the pH. In haylage - the soluble sugars disappear in 72 hours regardless of what we do. This means that we have a small window to convert the soluble sugar to preserving acids.
Watch Out at Feed Out
At feed out, losses can occur from secondary decomposition. These losses are caused by mold and yeast being re-activated by oxygen once the bunk is opened. Loosely packed silage allowing air penetration and high external temperatures also encourage this process. Dry matter losses can reach 10%-20% in a few days.
An Inoculant That Gets It Done
Anchor™ for Silage is a state-of-the-art inoculant blend that uses Agnition’s patented Microbial Catalyst® to lower pH levels in forage and lock in nutrients. Anchor for Silage drives efficient fermentation while reducing dry matter loss and enhancing palatability. It’s also highly soluble and easy to apply. The key is how Anchor for Silage stimulates the beneficial bacteria already present in the silage to encourage a rapid drop in pH. The best part? Anchor for Silage can be safely stored at room temperature thanks to encapsulation technology - meaning that there is no need for a fridge or freezer