Ethanol production and its byproducts have changed significantly over the past 20 years. For dairy farmers, that means distillers grains (DDGs) in the feed bunk today might look quite different from those used a decade ago. While the volume of DDGs remains strong, new technologies are shifting their nutritional profiles and how they fit into dairy rations.
On a recent episode of “The Dairy Podcast Show,” Kurt Rosentrater, associate professor at Iowa State University, shared insights on how new ethanol byproducts are changing the feed landscape.
New Technology is Changing What’s in Your Feed
Ethanol plants have evolved from simply meeting production mandates to focusing on efficiency and product value. Around 2010, many began installing centrifuges to remove corn oil from DDGs, improving the consistency of fat content, something nutritionists appreciate.
“Consistency of the oil separation and the fat content of the distillers products has been really good for the last decade,” Rosentrater adds
Producers then sought to separate or concentrate protein, fiber and oil more cleanly, but these nutrients often stick together in the drying process. Some plants tried “dry fractionation”, which means separating fiber from the starch and protein before drying, but this process is expensive and uncommon.
More recently, new liquid-phase separation techniques, done after fermentation but before drying, have allowed better concentration of protein, fiber and oil. “
There are about a dozen ethanol plants that have installed these fractionation or separation systems,” Rosentrater says. “It’s a significant investment, multiple millions of dollars, and it’s happening not just in the U.S., but also in Europe and Brazil.”
These high-protein products often don’t fit the traditional definition of DDGs and might be called corn fermented proteins or mechanically extracted corn fermented proteins. This creates challenges for nutritionists and producers to decide which product to use and how.
“As a scientist and nutritionist, we have to ask: What do I use? How do I use it? What’s it going to cost? And is there any economic benefit for me to use this?” Rosentrater says.
More Than a Byproduct
DDGs have grown beyond a niche feed ingredient to a staple in dairy rations nationwide.
“We’re right now sitting about 33 to 35 million tons per year, and we’re not landfilling it, and we’re not burning it, we’re using it,” Rosentrater notes. This represents a success story for sustainability, as DDGs use a byproduct that might otherwise be wasted, providing a protein and energy source already embedded in corn processing.
This link between ethanol and animal agriculture highlights how interconnected supply chains are today. As the ethanol industry looks to stay competitive, feed ingredients will remain central to its future.
DDGs and Soybean Meal Can Work Together
Soybean meal, another staple protein in dairy diets, once was significantly more expensive than DDGs, but that price gap has narrowed. In fact, soybean meal has reclaimed its spot as the top feed ingredient by volume in the U.S.
Rosentrater points out that the two ingredients complement each other well, especially in nutrient balance and digestibility. However, DDG prices can be volatile due to export markets, especially China, which can cause swings of several hundred dollars per metric ton in a short time.
“When China enters the market, prices spike. When they exit, prices drop. That kind of volatility makes it really hard for farmers and nutritionists to plan around,” he says.
While some ethanol plants are adopting high-protein technologies, traditional DDGs remain in demand and will continue to be a core ingredient for livestock operations.
Make the Most of Your Ration
Rosentrater emphasizes that feed ingredient value isn’t just on paper. It depends on the rest of the ration, location and relative costs.
“Is it enough to say my feed ingredient performs as well as soybean meal?” he asks. “Or are we looking for added benefits like better feed conversion or lower total feed cost?”
Successful operations stay flexible, adjusting feed choices with market conditions. Poultry integrators will buy DDGs when prices are favorable and avoid them when they aren’t; dairy producers face similar decisions.
Looking ahead, rising domestic demand from new soybean processing plants and sustainable aviation fuel production could complicate feed costs further.
“If all the soy crush plants come online like they’re supposed to, we may not be able to export as many soybeans as we do today,” Rosentrater says. “Whether or not it happens, it shows how interconnected all of this is.”
For now, staying informed remains key. That means asking questions about ingredient origins, costs and how they support your production goals.
As ethanol production evolves and new technologies reshape what lands in the feed bunk, ongoing collaboration between producers, nutritionists and suppliers will be a must.
“The industry is so dynamic, there have been so many changes,” Rosentrater says, “but I contend that there’s still a lot of work that needs to be done to understand how to best use these high protein or fiber products in dairy rations.”
