But we have a tremendous opportunity to save money (lower feed cost) by making higher-quality silage.The management of our silage operations can determine whether we make a profit or not in tight years. This article will demonstrate the financial impact of improving silage quality, and then I will give you three key steps to improving your profitability by improving your silage quality.
Forage is the foundation of a dairy cow’s diet. The amount of energy and protein a cow consumes through her forage determines how much energy and protein must be supplemented by concentrates. As the quality of forage increases, both energy and protein in the forage increase.
As we feed higher-quality forages, we decrease the amount of energy and protein we must supply or purchase through concentrates. We are able to save money on purchased commodities when we buy, produce and/or ultimately feed higher-quality forages.
The goal of silage making is to preserve a feed that is not available throughout the entire year and retain as much of the original quality and quantity as possible.
Dry matter loss, by definition, is not visible. The evidence of dry matter loss can only be seen when you have a surface you can use to compare the size of a silage mass at harvest with variable time points post-ensiling. This is possible in upright tower silos and may be possible in bunker silos if the silage is not filled above the top of the wall.
However, it is not possible to visually see two or three feet of silage missing in a pile that is 20, 25 or more feet high. To get true dry matter loss numbers, every load of forage must be weighed and the dry matter checked when it is put into the pile, and again, when it is removed from the pile, which is not practical on most commercial dairies.
Research has clearly identified the main drivers of dry matter loss. We now can estimate dry matter losses in silage piles with good accuracy. Even though it seems unlikely, a great proportion of silage piles in the western United States have dry matter losses above 15 percent, and too many even have dry matter losses greater than 25 percent.
Table 1 shows the economic impact dry matter loss has in terms of tons of silage lost, dollar value of silage lost, acres of harvested silage crop lost and actual price of silage after accounting for shrink or losses. The table shows that decreasing shrink from 20 percent to 15 percent in 10,000 tons of harvested corn silage valued at $50 would save $22,500, or 17 acres of forage assuming 30 tons per acre of forage (20 acres of forage if yield is 25 tons per acre).
Additionally, decreasing shrink from 20 percent to 15 percent would decrease the actual as-fed price of corn silage from $62.50 to $58.82 per ton.
In a diet feeding 40 pounds of corn silage per cow per day, that would mean a ration cost savings of more than seven cents per cow per day. These economic calculations are only showing the value of saving the quantity of silage that was lost and assumes no loss in quality.
Dry matter loss in silage starts with the loss of the most soluble and highest-quality nutrients. Dry matter loss means nutrients such as sugars, starches and soluble proteins are lost. Cellulose, lignin and ash are lost only minimally.
Furthermore, dry matter loss will increase the concentration of lower-value nutrients such as fiber and protein bound to fiber while decreasing the concentration of higher-value nutrients.
Dry matter loss means less feed is available to feed. This lost feed must be replaced with other feed. Often this other feed is purchased. If the replacement feed is grown by the dairy, it represents extra cost that wasn’t necessary had there been less dry matter loss.
It also may mean the opportunity to sell feed that was lost. Additionally, because the higher-value nutrients were lost, we have to replace them if we want to continue providing the plane of nutrition the cows need to perform at optimal levels. Yet these higher-quality nutrients are more expensive to replace, which will in turn increase your cost.
There are several sources of dry matter loss in silage. The most obvious dry matter loss is silage that has spoiled and is not fed. This is typically found at the ends of piles and on the top of piles. Other sources of dry matter loss include aerobic respiration and fermentation during the filling stage of ensiling.
This loss results from delayed or insufficient packing of the forage when filling a silage mass. Dry matter loss from silage effluent (runoff) occurs when silage is harvested and preserved at too high of a moisture content. This silage “juice” is the most soluble and highest-quality nutrients in the forage.
A secondary fermentation can cause extremely high dry matter loss and result in feed that is very unhealthy to cows. This occurs when the amount of acid production is inadequate to sufficiently drop the pH and stop the growth of harmful clostridial bacteria.
Significant dry matter loss can occur during storage as well as feedout through the process of aerobic deterioration. This occurs at three main stages: when forage is not packed, not sealed well or when the silage face is not properly managed.
There are three key steps that you can take to decrease dry matter loss. These three steps have been adapted from presentations by Dr. Keith Bolsen, professor emeritus of Kansas State University and forage management consultant with Keith Bolsen and Associates.
• Step 1 – Increase silage dry matter (DM) density. Dry matter loss is directly related to the dry matter density of the silage. As we increase DM density of silage, we decrease DM loss in that silage.
Key factors to increase DM density include: chopping forage at the correct DM for the forage type, chopping the forage to the appropriate particle size, processing the forage when appropriate, spreading the silage in thin layers when filling a horizontal silo, putting enough weight on the silage when packing and limiting exposure to oxygen by filling the silage quickly.
• Step 2 – Properly seal your forage. Extensive deterioration occurs when silage is exposed to oxygen. This deterioration leads to DM loss as well as decreased animal performance and potential health problems.
Covering and sealing with 6-mil to 8-mil polyethylene plastic with UV protection should be considered the minimum to prevent excessive DM losses. A newer oxygen barrier technology is available that has much lower oxygen permeability than polyethylene.
• Step 3 – Manage the face and rate of feedout. Silage feedout is another key time to influence silage DM loss. Piles should be sized to feed through the silage faster than oxygen can spoil the silage. Strive to feed across the entire face daily and remove 9 to 12 inches per day during cooler weather and 12 to 18 inches per day during warmer weather.
Shave silage down the face or from the side and never lift the loader bucket into the silage mass, as this will increase oxygen penetration into the face of the silage mass. Additionally, a silage facer may be a good alternative to using a loader.
The major key in making good-quality silage is to avoid the spoilage that occurs when oxygen allows bacteria, yeasts and molds to grow and deteriorate the silage. We have tremendous control over how much dry matter loss occurs during storage.
Decreasing dry matter loss in silage results in more silage available to feed, higher-quality silage available to feed and less need to replace lost silage with other costly feeds. PD
Photos by PD staff.
Progressive Dairy Solutions