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Does Silage Make Sense for You?

By: Cody Welchons, Ph.D.
Nutritionist, Livestock Nutrition Center

As everyone is all too aware, the cost of doing business is rising. Whether it’s feed ingredients, fertilizer, or labor we have had continuous discussions lately about ways for producers to operate more cost efficiently. One of the common topics we discuss is the potential use of silage in someone’s feeding program. Anecdotally, as mixer wagons become more widespread, the amount of silage being put up has also increased. For many, the ability to grow or purchase silage for their feeding operation can bring great value, but it’s also important to understand what exactly you are getting and how to properly store and handle it to maximize your investment.

What is Silage? – Silage is the name given when a whole plant, whether it’s a grain or grass, is harvested at a dry matter of 30-40% and preserved by a fermentation process which lowers the pH to the point of acidification. The most common types of silage for our region would be corn silage, sorghum and forage sorghum silage, and small grain silages such as wheat, triticale, or oats. The whole plant is chopped, packed, and then, preferably, sealed for a period of 4-8 weeks prior to feed out during which time there is rapid drop in pH to “pickle” the system. From this point on, proper storage is important to keep air out to maintain a stable, high-quality product.

Benefits and Downsides – The use of silage lends many benefits to backgrounding and cow-calf operations. While the process of harvesting silage is a significant investment in time and resources, the ability to have a large store of a high-quality feed can reduce the producers reliance on purchasing hay and other feed ingredients through the winter when prices are at their highest as silage can make up a significant portion of diets for both cows and growing animals. Additionally, silage can act as a conditioning agent for your ration which can take the place of a separate conditioning agent such as water or a molasses based blend.

Most of the potential downsides to using silage are to do with harvesting and storing the silage properly to minimize shrink and decreases in forage quality associated with spoilage. Harvesting silage at the correct moisture level is important because if harvested too early (too much moisture) fermentation is much quicker and can be excessive leading to decreased nutrient density. Conversely, harvesting silage too late (too little moisture) can lead to slow and restricted fermentation leading due to insufficient water limiting the growth of microbes in the silage. Therefore, something to consider is the impact that waiting on a custom harvester can have on your silage crop if they must come too early or too late. After harvesting, proper packing and storage of silage minimizes dry matter loss due to aerobic spoilage. Even under the best management, dry matter losses of silage will be 10-15% while under poor conditions losses can be more than 25%. When purchasing silage from someone else’s pit, its still important to consider potential shrink after the silage is delivered to your location.

Valuing Silage – The largest determinant of whether a given silage is a fit for your operation likely lies in the cost. To accurately compare the cost of nutrients in silage to alternative feedstuffs such as soyhulls or wheat midds, you need to have a cost per ton along with an accurate dry matter of the silage. From here, you can evaluate the cost per unit of energy and cost per unit of protein on a dry basis and compare that to other potential feeds. In the case of silage, we will likely always be comparing it on a cost per unit of energy as protein levels in most silages are deficient for growing animals. To note, at this time there is very little silage available from last years crop and no new crop silage has been put up yet. Additionally, prices of all commodities are much higher than in recent years, therefore, the prices below are purely for illustration rather than representative of prices we may see this year.

From Table 1 we can see that when corn silage costs $80/ton delivered and has a dry matter of 35%, the equivalent price of soyhulls (roughly equal in energy to corn silage on a dry basis) would be $201/ton.

Table 2 shows the same evaluation for sorghum silage compared to soyhulls. In this scenario, the energy values aren’t equal and must be evaluated on a price per unit of energy. With sorghum silage costing $60/ton at 32% dry matter the equivalent price for soyhulls would be $233/ton. Vital to point out is that the dry matter and energy density of silage can vary widely so prior to making an evaluation of whether silage is the correct choice for your operation is to have a sample analyzed so that you have accurate information to make decisions with.

Silage can be a viable roughage and energy source for your operation. However, its important to evaluate the cost benefits of silage correctly to accurately determine if silage is the value that it may seem when only looking at it from an as-fed cost per ton. Additionally, we have to consider the potential for greater shrink and take that into account when making growing or purchasing decisions.