Have you ever wanted to eat a fermented corn plant? No? Yeah, me neither! However, cattle have much different food preferences and diet requirements than we do, and they happen to love fermented corn plants- also known as silage. Luckily for cattle, not only does silage taste delicious to them, but it also fulfills nutrient requirements that they need in their diets. Silage provides both beef and dairy cattle with a highly nutritious, balanced diet. As ruminants, cattle need a lot of forages or roughages in their diet- feeding the whole corn plant to cattle provides them with the forages they need. In feeding livestock, two areas of focus are energy and protein (vitamins, minerals, and water are important, too). Corn silage provides cattle with protein, in the corn kernels, and energy, in the stalks and leaves of the plant.
There are several different types of silage. Many different types of crops can be ensiled (made into silage) and fed to cattle, like legumes, grasses, small grain cover crops, and sorghum, but this blog will focus on corn silage. We know that silage is fermented corn, but let’s dive into how farmers make it.
First, farmers must grow corn- and not just any corn. Corn that produces high yields makes for the highest quality silage—deciding on which corn seed to plant is a decision made far before planting starts. Some seed companies have developed a hybrid seed to grow corn meant to be ensiled. Also, planting corn for silage means planting more corn seeds- the goal is to have approximately 20% more corn plants than if a farmer was growing corn normally. Then, farmers may apply herbicides to control the weeds and wait for the crop to grow.
After the corn has had time to grow, it’s time to harvest. Harvesting corn for silage requires a balance of waiting for the corn to dry enough, but not waiting too long so that it dries too much to pack. Usually, when farmers harvest corn, they can’t store it above 15% moisture, so they must dry it if it’s wetter than that. When farmers harvest silage, they want the moisture to be 60-70%, so it will pack together well to ferment. Harvesting silage takes place before normal corn harvest. Farmers can use various equipment to harvest silage, but the basic concept is that the harvester takes the whole corn plant, chops it into pieces, and then deposits it into another implement, like a semi or a tractor-pulled cart.
Finally, the silage is stored to begin the fermentation process. That process can look different on different farms. The way silage is fermented can also depend on moisture rates. Let’s dive into some options.
Upright Oxygen-Limiting Silos
This option is ideal for low-moisture silage, in the 55-60% moisture range. An upright oxygen-limiting silo unloads from the bottom but gets filled from the top.
Upright Stave Silos
These are the most popular type of silo. Metal bands hold the structure up and keep the silo from collapsing due to the pressure of the silage. This type of storage works best for 60-65% moisture silage.
A silage bag is a popular, low-cost option for storing 60-70% moisture silage. These plastic bags hold the silage while it ferments.
Venting the bags, appropriately filling them, and avoiding rips or tears in the plastic are concerns for farmers while using this storage method.
This type of silage storage is best for wet silage in the 65-70% moisture range. This storage facility has concrete walls on three sides. The farmer dumps the silage and then drives over it with a heavy tractor to pack it down. The farmer will cover the packed silage pile with plastic to protect the pile and tires to hold the plastic down.
What now? The silage must ferment for around three weeks. Fermentation starts when the farmer covers the silage pile or puts freshly chopped silage in the silo. That creates an anaerobic environment (no oxygen) for the silage. Next, the microorganisms in the silage perform an exchange by consuming the sugars and some carbohydrates in the silage and producing organic acids. These acids lower the silage’s pH, which preserves the remaining silage.
After the silage has fermented for around three weeks, it is ready for consumption. The silage has a very distinct, sweet smell when it is done fermenting, and the cattle love it!