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Combining distillers grains with low quality forages creates storage solutionBy Jennifer M. Latzke In the business of agriculture the mantra is "waste not, want not." And in an era of high corn prices and rising input costs, livestock producers are learning new methods of reducing waste in their feed rations, particularly when it concerns the use of costly corn, hay and forage. That's why many producers are now looking to adding distillers grains into their cattle feeding rations. Availability growing With more and more ethanol plants going online across the High Plains, many cattlemen are finding they have a source of distillers grains in their backyards. The closer they may be to an ethanol plant, the lower the price may be for this high value feed co-product and its transportation to their facilities. There are challenges to using distillers grains, though. To take advantage of large volume discounts, smaller operations have to find a way to store large quantities of distillers grains bought cheaply in the summer so that they can be fed in the winter. Distillers grains have a tendency to lose quality if they aren't stored properly. Researchers at the University of Nebraska-Lincoln have spent the past two years looking at methods of mixing lower quality hays and forages with distillers grains for long-term storage and the most efficient use as a feed. The resulting "silage" uses up those stocks of poor hay feeders may have leftover from seasons past. And it allows for winter feeding of hard-to-store distillers grains that can be purchased cheaply in the summer.
Challenge to long-term storage Unlike grain or hay or silage that can be stored in bunks, large plastic bags or in open-air facilities, distillers grains pose a bigger problem. Because of their fine particulate matter, dry distillers grains plus solubles (DDGS) tend to blow in windy open-air storage. And, while wet distillers grains plus solubles (WDGS) or modified wet distillers grains plus solubles (MWDGS) won't blow, they have the consistency of "mashed potatoes." Therefore, they cannot be compressed in bags or bunks like traditional silage without the potential for ripping holes in the bags. While MWDGS and wet corn gluten feed can be stored in silo bags under 300 psi or greater on their own, and WDGS can be stored in silo bags under no pressure, it is a less efficient method because of the area the bags will use. "Traditionally, it'll bag, but you can't put any pressure on the bag and it will end up being a foot tall and 15 feet wide," explained Galen Erickson, associate professor and beef feedlot Extension specialist with the University of Nebraska-Lincoln. "If you were to put any pressure on the bag at all it will break and you'll have to re-do it. You can't put distillers grains in a bunker and drive over them to pack them in either. They have a consistency of mashed potatoes." He explained that there is a debate as to whether WDGS or MWDGS should be stored in overhead bins, and that most cattlemen have found success by storing them flat on the ground and covered from the elements. Pelleting or cubing the distillers grains adds to the price of the product, and may not be efficient. "Distillers grains don't make a very good pellet or cube because they tend to fall apart," Erickson said. Shelf life of distillers grains is also a factor in their storage. UNL research found that spoilage will begin in three to 14 days when a pile of wet co-products are exposed to air. Hot ambient temperatures can also shorten the shelf life if distillers grains aren't properly stored.
A solution found The Nebraska study found success by amending distillers grains with forage matter prior to storage in bags or bunks. "Our goal was to find the minimum amount of forage, fiber or bulking material to add into the bag to keep the pressure constant," Erickson said. "What was the minimum amount of forage needed to add to a bunker to let someone drive over it and pack it down?" The project looked at many different forages, including grass hay, wheat straw, corn stalks and even alfalfa hay for use as amendments. The added forage gives the fine particles of wet distillers grains some bulk that will make it easier to pack into a bag, and give it support to allow it to be driven over and packed down in a bunk. Most encouraging, the study found that adding poorer quality forages to distillers grains in storage doesn't hurt the feed value of the roughage. And, is a way producers can get the most out of their hay and forage investments. "This is a good way to get cattle to consume that older forage," Erickson said. "It is a good way to use up low quality forages." The more fibrous the forage, the better it is as an addition to stored distillers grains. The study found that it acts as a binder to the distillers grains, providing more structure to the overall feed and improving its ability to be packed. The study also looked at which distillers grain and forage combination would do best in silo bags, bunkers and open air storage. Basically, lower quality forages with greater neutral detergent fiber content work better. In using silo bags, the Nebraska researchers found that wheat straw or corn stalks, for example, could be mixed in a equation of 12.5 percent straw with 87.5 percent WDGS on a dry matter basis, or, about 5 percent on an as-is basis. If using grass hay, the recommendation is to mix 15 percent hay with 85 percent WDGS. Alfalfa can be used, but it requires 22.5 percent of alfalfa to 78.5 percent WDGS on a dry matter basis. Bunker storage requires more forage material to be mixed with WDGS. A mixture of 40 percent grass hay with 60 percent WDGS on a dry matter basis, easily compacted in the bunker and allowed a pay loader to stay on top of the pile. In general, the drier the distillers grains are, the less forage may be needed to pack them into a bunker. MWDGS, when mixed with grass hay for bunker storage only needs a mixture of 15 percent grass hay to 85 percent MWDGS. Another consideration is the particle size of the forage being mixed. Large pieces of hay or forage won't mix well with the distillers grains, and small particles are better for packing. Researchers at the Texas AgriLife Extension Center in Amarillo, Texas, replicated the Nebraska success. Jim MacDonald, assistant professor of animal nutrition, explained they purchased a load of wet distillers grains in April 2007 and used the Nebraska formula to store them with some alfalfa they had on hand at the center's feedlot. Despite the hot Texas Panhandle summer, the project was a success. "We bagged it in April and didn't open it until September or October," he said. "It was stored for a good six months and through the summer and we didn't observe any negative feeding value." MacDonald and his team are looking to other nearby forage sources in the Texas Panhandle, specifically cotton burrs, that might be acceptable to store with distillers grains. "If you can buy cotton burrs at a large discount, relative to higher quality forages like alfalfa, and improve the digestibility of cotton burrs when combined and ensiled, it may be an economic value," he said.
Tips for success When storing distillers grains in these manners, cattlemen have to pay particular attention to avoid trapping air pockets in the bag or bunk. "Oxygen is the enemy," Erickson said. "Just like silage or high moisture corn, the pile will spoil. If you add too much forage, or if the distillers grains are too dry, you can also run the risk of spoilage." Basically, if a cattleman has any experience with traditional silage, this concept isn't much different. The study could not define the exact amount of anaerobic fermentation that occurs in storage, but scientists pose that it is likely minimal because of the highly acidic conditions. A cattleman can tell if the stored combination has been exposed to air if he detects a strong, foul odor, Erickson said "That's a sign there's been too much air and not the right type of fermentation," Erickson said. "Also, if you see a lot of visible spoilage, molding or dark color that's an indication of too much spoilage." It's normal to have some on the surface of the mixture if it's stored in a bunker silo, he added. And, the study tested the feed mixture for various toxins and didn't find evidence of too high rates. "In general, the feeding value of distillers grains is not changed much by storage, and I'd argue not at all," Erickson said. "For cows, this feed is pretty good quality." Depending on the cow's production phase it may be necessary to offset the good quality feed with lower quality roughage to keep her from fattening up, he added. For calves, a mixture of distillers grains and forage works well as a growth ration, or when they move on to feed lots. "You can feed 40 to 50 percent on a dry basis to calves," Erickson said. With dairy cattle, it's suggested to keep the mixture to 20 to 30 percent of their dry matter. Research has also found that feeding distillers grains works better in finishing cattle diets with dry rolled or high moisture corn, Erickson said. It's performance is lower when added to rations with steam flaked corn.
Lab testing and calculations are key While distillers grains may be more readily available, Erickson reminded producers that they still need to calculate their feeding costs before using them. It's especially important, he said, to look at the feeding value of distillers grains and the cost of other available feeds. And, compare them on a dry tonnage basis, he said. "Wet distillers grains at $60 per ton may sound cheap, but if you divide that out based on 30 percent dry matter, it almost triples the price when compared to corn," he said. To better calculate costs, UNL offers Cattle CODE, a downloadable calculator, at http://beef.unl.edu/byproducts.shtml. When purchasing distillers grains, cattlemen should monitor the moisture content they're paying for. "You can't always tell the moisture content by visual appraisal," Erickson said. "It may look very wet, but it may not be high in water. And, you don't want to pay for too high of water content, either. Have a lab analyze a sample." Erickson strongly advised cattlemen to use commercial laboratory testing to analyze the fat and sulfur content as well. "The fat level is very important," he said. "Make sure it's 10 to 12 percent fat or corn oil. And, monitor the sulfur level so that you don't overfeed and get into toxicity issues." Sulfur content is also an issue in Texas distillers grains. MacDonald and his team compared the sulfur in Nebraska distillers grains and more local Texas distillers grains and found the sulfur in the Texas product was half that of the Nebraska product. However, water in Texas tends to have some sulfur in it. And in the heat of the Texas summer, cattle that are drinking more may need less of the stored distillers grains. Laboratory testing is even more important if an ethanol plant changes its processing technology. It's important that cattlemen understand the processing their ethanol plant uses before purchasing distillers grains. "It will only get more confusing as we get into a future with more and different types of distillers grains," Erickson said. "They're not all created equally." Despite the challenges, though, storing distillers grains with forage amendments may be one more way cattlemen can reduce their feeding costs. Erickson and some of his colleagues from the University of Nebraska-Lincoln, Iowa State University, the North Central Region SARE, South Dakota State University, Kansas State University and the Natural Resource Conservation Service will be offering demonstrations of mixing and storing distillers grains during the Ethanol Co-Products Storage and Utilization Conference. The seminar will be at the Christenson Research and Education Building near Mead, Neb., May 19 to 20. For more information about the conference, call John Hay at the University of Nebraska at 402-472-0408. For more information on feeding distillers grains or corn gluten feed to beef cattle, visit http://beef.unl.edu or www.nebraskacorn.org. UNL scientists have also put out several brochures regarding utilization and storage of corn co-products. They can be found at http://beef.unl.edu/byproducts.shtml. Jennifer M. Latzke can be reached by phone at 620-227-1807, or by e-mail at jlatzke@hpj.com. 5/19/08 Date: 5/15/08
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