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Bunkers, bags or piles: Storage options for high moisture corn and snaplage
What is the best storage option for high-value ensiled feeds like high moisture shelled corn (HMSC), ear corn or snaplage? The answer depends on the definition of the word “best.”
For some, “best” could mean “easiest.” For others, it could be the option that yields the most milk. Hopefully for most, the “best” option is the one that has the greatest positive economic impact on the dairy.
A few studies are helpful in choosing storage strategies, but most tend to concentrate on the best options for silage (corn silage or haylage). For HMSC and snaplage, the stakes are much higher simply because of their value per ton compared to silage.
Dry matter loss
A 10-percent storage and feedout loss based on $40-per-ton corn silage is quite different than a 10-percent loss for $120-per-ton HMSC. For example, according to data compiled by Holmes and Muck at the USDA Dairy Forage Research Center shown below, the average total loss is 23.5 percent for a covered bunker, 25.5 percent for a stack or pile, and 11.5 percent for bags.
| Storage type | Filling, % | Seepage, % | Gaseous, % | Top surface, % | Feedout, % | Total, % |
| Bunker (uncovered) | 2-6 | 0-1 | 9-10 | 9-12 | 3-15 | 24-43 |
| Bunker (covered) | 2-6 | 0-1 | 6-7 | 3-4 | 3-15 | 16-31 |
| Stack (uncovered) | 3-7 | 0-1 | 11-12 | 19-24 | 3-15 | 37-58 |
| Stack (covered) | 3-7 | 0 | 6-7 | 4-6 | 3-15 | 17-34 |
| Bags | 1-2 | 0 | 5 | 2 | 1-5 | 9-14 |
Source: USDA Dairy Forage Research Center
The next chart shows the financial impact of this loss when we use a value of $40 per ton of silage, $100 per ton of snaplage and $120 per ton of as-fed HMSC. Per 1,000 tons of feed, and using average loss for each structure, the numbers for economic loss are as follows:
| Feed | 25.5% avg. loss pile | 23.5% avg. loss bunker | 11.5% avg. loss bag |
| Silage | $10,200 | $9,400 | $4,600 |
| Snaplage | $25,500 | $23,500 | $11,500 |
| HMSC | $30,600 | $28,200 | $13,800 |
As you can see, these loss numbers increase astronomically when you look at high value feeds like HMSC and snaplage. But these are average loses and a good manager can really skew the numbers to their favor by harvesting at the correct moisture and particle size, packing to reduce porosity, covering with good plastic and using an oxygen barrier such as Silostop®, and employing the best inoculant strategy.
Other factors
Dry matter loss is only part of the story when considering a storage unit for HMSC. The initial and annual costs of each structure needs to be considered. Bunkers require the most initial upfront investment, but bags will cost the most to store feed on an annual basis.
Animal performance needs to be a high-priority consideration as well. Performance may differ based on the quality of feed coming from the different structures. If the face of a pile is too large in relationship to daily removal, the management of that face can be a real challenge and feed quality will suffer. Some managers may be better off spending a little more money on the annual cost of bags versus the potential problems caused by feedout issues related to bunkers and piles.
Storage choices really require a comprehensive analysis on a farm-by-farm basis. Scientists at Kansas State University did this research and concluded:
“Costs per ton of milk-production-adjusted silage were compared for silage stored in concrete bunkers, drive-over piles, and plastic bags for an example dairy. Cost per ton was lowest for silage stored in bags if all costs were included for the bunkers. However, if fixed costs of concrete bunkers were ignored, the cost of storing silage in bags was only lower than silage stored in bunkers if milk production for cows fed bagged silage increased slightly.”
Click here for more on this study from Kansas State University.
| Storage option | Advantages | Disadvantages |
| Concrete bunkers | High capacity, smaller footprint, fast unloading rate, stable forage quality if packed correctly, relatively low “out of pocket” cost, utilizes conventional farm equipment | High initial investment, packing influences DM losses, cost-effective for small herds, cost/availabilty of labor, safety concerns |
| Drive-over piles | Low initial capital investment, flexibility of pile quantity, fast unloading rate, utilizes conventional farm equipment | Larger footprint than bunkers, flooring potentially expensive, cost/availability of labor, safety concerns |
| Plastic bags | Low initial capital investment (assuming custom bagging), flexible storage system, small feedout face to manage, Low DM loss if managed properly, feed can be inventoried easily, fewer safety hazards | High annual “out of pocket” expense, largest footprint, flooring potentially expensive, need specialized equipment, small feedout face, cows may ingest plastic, plastic bags not reusable |
Source: Kansas State University
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Feed quality and nutrition Forage Foundations Forage storage and management |