Q: I’ve heard that distillers’ grains plus solubles (DGS) are quite variable in nutrient content. Is this true? If so, is it a concern, and what can I do to manage this situation?
A: In short, the answer is “yes”, DGS can be quite variable in nutrient content. A more detailed answer considers the factors that make up that variation. First, the feed grains that are used to make ethanol (such as corn and grain sorghum) are themselves variable in nutrient content. This source of variability is difficult to control and is magnified in the DGS because the nutrients that remain after starch is removed from grain are concentrated in the DGS. Second, some ethanol plants add variable amounts of the solubles portion back to the grains themselves. This source of variability can change from day to day, depending on both marketing conditions for the DGS and current supply of byproducts at the plant. Third, research indicates that variation between ethanol plants is another source of variation. Not every plant has the same degree of commitment to distillers’ grains quality.
Whether or not variability of DGS is a concern is a more difficult question to answer. In many ways, it depends on the level of DGS that the producer wants to feed; when more DGS are fed, the concern about variability becomes greater.
Moisture content is of primary concern because it is related directly to the value of the byproduct; if everything else is equal, higher moisture feeds are less valuable that dryer feeds simply based on the value of what the producer is buying. Sulfur is another nutrient that has gain particular attention in this area.
In general, sulfur levels in DGS have risen historically. High levels of sulfur have be shown to lead to toxicity symptoms, which can include reduced performance and it severe cases, death of animals.
The best way to manage the variability of DGS is through quality control measurements. First, a prospective DGS customer should ask for a historical record of the nutrient content in an ethanol plant’s DGS supply. Once a supplier of DGS has been selected, a regular program of quality control at the producer level should by utilized. Data from both sources should be evaluated by a trained nutritionist. He or she can assist in determining the quality of a DGS source.
As DGS continue to become more readily available, more supply options become available and those plants who cannot supply a consistent supply of quality DGS will most likely be undervalued in terms of price until the situation is corrected.
Having said all of this, the issue of quality control in DGS is becoming more widely recognized within the ethanol industry and the level of consistency will continue to improve.
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Source: Dr. Ryan A. Mass, Ph.D., Lallemand Animal Nutrition