Storing Wet Distillers Grains in the Summer for Fall and Winter Feeding
Wet distillers grains (WDGS) are a good source of energy (108% TDN) and crude protein (30%) (dry matter basis). Therefore, they are a popular commodity for beef cattle supplementation.
In the western part of Nebraska, ethanol plants and therefore ethanol co-products are not as abundant as in the central and eastern parts of the state. Additionally, in the fall when cow-calf producers begin thinking about supplementing cowherds or newly weaned calves, feedlots in the area are receiving cattle and demand for co-products like WDGS increases. Smaller cow-calf producers often feel the pinch of tight supplies.
Because many feedlots reduce inventory during the spring and most stocker/yearling cattle are grazing grass, feedlot demand for WDGS decreases in the summer months, which is typically reflected in the price as well. Therefore, summer is a good time for cow-calf producers to purchase WDGS for later use in the fall and winter. The main concern producers typically have with purchasing WDGS in the summer is how to store a wet (65% moisture) product in the heat.
To reduce spoilage and shrinkage, producers likely will want to consider storing WDGS in an agricultural bag or in a bunker. Limiting air exposure to the WDGS will help reduce spoilage and shrink, but some methods are more labor intensive and expensive than others.
Bagging WDGS alone– Bagging is a common storage method for many types of grains, forages, and byproducts. Bagging WDGS is a very effective way to reduce exposure to air. However, storing WDGS in an agricultural bag requires a specific bagging machine, and leasing or owning one will increase the cost of the WDGS. Another important consideration when bagging WDGS is that the pressure the bagger puts on the product to fill the bag will break the bag due to the lack of structure associated with the wet by-product, causing the WDGS to ooze out and expose the product to air, increasing spoilage. If no pressure is applied, the WDGS filled bags will be long and flat, but filling and handling must be done carefully to avoid breaking the bag.
Bagging WDGS as a mix with roughage - Research has shown that adding about 12.5% ground wheat straw on a dry matter basis (5% on an as is weight basis) adds enough structure to prevent the bag from rupturing. If a less structural type roughage such as grass hay were used, about 15% on a DM basis would be necessary to prevent rupturing the bag.
Bunker Storage of WDGS – When storing WDGS in a bunker, roughage may or may not be added. Adding 30-40% ground roughage (DM basis) makes packing the pile easier if a producer wants to remove air pockets by compacting, as is done when making silage. However, mixing roughages in with WDGS takes time, labor, and equipment that may not be available during the summer if other operations such as farming are a priority.
Types of Bunkers for WDGS storage – A concrete bunker is a great way to store WDGS or a WDGS/roughage mix because the sides are sturdy, the wetness of the product does not turn the floor to mud, and it is easy to cover. However, concrete bunks are expensive to build and may be in use for silage storage if they are already in place. Making a bunker out of hay bales is another option to consider. Heavy plastic could be used to line the bottom and cover the makeshift bunker or a layer approximately 4 inches thick of ground residues or hay could also be used to help soak up moisture and prevent solubles from leaching into the ground. Another layer of ground hay or residue could be used to cover the pile and the roughage or tarp could be secured with old tires in the same way many silage piles are preserved.
Keeping the pile covered well and feeding off the smallest surface area possible, much like silage, will help reduce shrink and spoilage.
Some mold is likely to grow on exposed WDGS. However, analysis of these molds has not revealed any mycotoxins, and appears safe for cattle when blended in with other feeds.
For more information and visuals of storage and packing methods please see “Storage of Wet Co-products".
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