–By Liz Morrison
Hog farmers around the globe are benefiting from AURI-funded research on feeding distillers grains, an important ethanol coproduct.
Feed trials at the University of Minnesota, supported by AURI, the Minnesota Pork Board, and the Minnesota Corn Research & Promotion Council, are generating “powerful information” that is widely used by the pork industry, says Al Doering, AURI senior associate scientist and director of AURI’s coproducts lab in Waseca. Minnesota research is also helping to win international acceptance for distillers grains as a high-quality swine feed, Doering says.
Responding to the changing ethanol industry
Energy content of distillers grains is a major focus of the AURI-sponsored research— after the starch portion of the corn kernel is made into ethanol. This nutritious animal feed is usually dried and sold as distillers dried grains with solubles, or DDGS.
In the past, DDGS usually contained 10 to 12 percent corn oil, which supplies energy in livestock diets, says Gerald Shurson, professor of Animal Science at the University of Minnesota. In the last decade, ethanol plants have started extracting some of the oil from distillers grains, selling it as a separate feed ingredient or as a biodiesel feedstock.
In 2014, about 85 percent of ethanol plants were extracting distillers corn oil, according to the Renewable Fuels Association, a national organization focused on expanding the production and use of American-made renewable fuels and bio-products worldwide. Today, the oil content of DDGS typically averages around 8 percent, Shurson says, although it varies widely by plant, ranging from 5 to 12 percent. This variability affects the nutritional value of the feed and makes it hard to formulate consistent diets, he says. Nutritionists and pork producers needed new tools to manage these changes in DDGS nutritional content.
With funding help from AURI and the corn and pork producers’ associations, Shurson and his research team devised and tested a set of equations to calculate the amount of digestible and metabolizable energy in DDGS from any given ethanol plant. Shurson found that the corn oil content of DDGS is not an accurate indicator of how many calories the pig can actually digest and use.
“Contrary to what most people believed, we found that we also needed to include other components of the feed, like protein and fiber, to determine the metabolizable energy content,” he says. “We conducted a series of experiments that demonstrated these effects and enabled us to develop energy prediction equations.”
Additional studies at the U of M quantified the effects of feeding swine diets containing lower-oil DDGS on pork belly fat quality and firmness. Reducing the amount of unsaturated corn oil in DDGS is actually an advantage for pork packers, Shurson says, yielding firmer belly fat, which improves the appearance and shelf life of bacon.
Shurson’s findings are now being used throughout the pork industry to formulate diets and maintain high dietary DDGS inclusion levels, Doering says. For example, NutriQuest, a leading Iowa-based animal nutrition company, uses Shurson’s energy equations as the basis for its weekly analysis of digestible nutrients in distillers grains from more than 140 U.S. ethanol plants.
This research has also been very valuable to the U.S. Grains Council, which is developing export markets for DDGS, says Tommy Hamamoto, manager of U.S. Grains Council operations in Japan.
Japanese hog producers, for example, don’t feed high levels of distillers grains — in part because of a perception that DDGS make belly fat too soft, Hamamoto says. The U.S. Grains Council is educating the swine industry abroad “on the characteristics and benefits of DDGS.”
Shurson’s energy calculation equations and fat quality data have helped “manufacturers to understand the value of reduced-fat DDGS,” and encouraged them to offer distillers grains as an option for pork producers, Hamamoto says.
Exports of distillers grains surged to record levels in 2014, accounting for nearly one-third of U.S. production. But in Japan and other regions of Asia, “the use of DDGS has a lot of room to grow,” Hamamoto says.
Further expanding the use of DDGS
- Another important study sponsored by AURI, the Minnesota Pork Board and the Minnesota Corn Research & Promotion Council dispelled industry fears about a possible link between DDGS and a nutrient deficiency in pigs called Mulberry Heart Disease, or MHD. Feeding trials at the University of Minnesota including sows and nursery pigs found no relationship between high levels of fat-damaged DDGS in their diets and MHD. In fact, no pigs developed nutritional deficiencies involved in MHD, Shurson says.
- Other significant research is laying the groundwork for new swine feeding systems that can make use of low-cost liquid or wet feed ingredients, such as corn distillers solubles, wet distillers grains, and dairy processing waste. In studies at the University of Minnesota’s Southern Research and Outreach Center in Waseca, pigs fed liquid diets that included wet ethanol coproducts grew as well or better than pigs fed a conventional dry diet, says research leader Sam Baidoo, associate professor, Department of Animal Science at the University of Minnesota.
These and other AURI-sponsored research studies are helping livestock producers make “informed decisions regarding corn DDGS in swine diets,” Doering says. “They also help ethanol processors understand the value and impact of DDGS for livestock producers.”
AURI and swine feed trials
Idea to reality: Research was needed to overcome the barriers to increased use of corn ethanol coproducts in swine diets.
AURI’s role: AURI and its partners have funded many feed trials at the University of Minnesota to help pork producers successfully incorporate DDGS in pig diets.
Outcomes: Research is increasing the use of corn ethanol coproducts in the pork industry, both in the U.S. and abroad. One of the most significant outcomes is the development of a DDGS metabolizable energy prediction model, now in wide use. Another set of studies dispelled a potential link between DDGS in swine diets and Mulberry Heart Disease.
Partners: University of Minnesota, Minnesota Corn Growers, National Pork Board, Minnesota Pork Board.
AURI feed trials help add value to ag coproducts
AURI feed trials are aimed at adding value to agricultural coproducts, says Al Doering, AURI scientist in Waseca. The goal is to expand the use of low-value ag products and help farmers take advantage of the state’s abundant supplies of alternative feeds, such as distillers grains.
Here’s a brief summary of some recent AURI-funded swine feed studies:
- Effects of reduced-oil DDGS on digestible and metabolizable energy in growing pigs.
- Development and validation of metabolizable energy equations for DDGS in swine diets.
- Relationship between DDGS in the diet and Mulberry Heart Disease in pigs.
- Effects of different DDGS inclusion rates on pork belly fat quality.
- Effects of feeding low-oil DDGS on pig growth and fat quality.
- Use of glycerin, a biodiesel coproduct, in sow and growing pig diets.
- Development and testing of economical methods of processing low-oligosaccharide, high-protein specialty soybean meal.
- Effects of feeding growing pigs wet distillers grains and liquid ethanol coproducts.
- Demonstration of a versatile liquid hog feeding system that can handle liquid ag coproducts, such as thin stillage and dairy processing waste.
- Use of ensiled beet pulp in swine diets.
- Effects of feeding whey protein to heat-stressed growing pigs.