The rapid expansion of the U.S. ethanol industry and the resulting increased production of distillers’ dried grains with solubles have offered pork producers a feed ingredient that has the potential of reducing overall diet costs.
In most regions of the United States, corn quality for the 2010 harvest was excellent and DDGS quality ran higher than in 2009, when wet and late harvest conditions increased mycotoxin issues. This has led to the opportunity to incorporate higher DDGS levels in nearly all swine diets.
Indeed, DDGS offers an excellent source of energy and digestible phosphorus for pigs and can be incorporated into diets for all production stages. However, the ethanol byproduct must be used judiciously to avoid undesirable consequences in carcass yield and fat quality.
With feed prices hitting record highs, maximizing DDGS dietary inclusion rates can help manage feed costs and preserve profit potential. Studies show that DDGS can be fed in concentrations up to 30 percent for growing pigs. You must exercise caution, however, in order to ensure that your DDGS advantage isn’t erased by performance losses or penalties from your packer.
Although the DDGS price is rising along with corn, it must be valued in terms of what it replaces in a diet. “Besides replacing some of the corn, you can also replace some soybean meal and some phosphorus, as well,” says Craig Rowles, DVM, Elite Pork Partnership, Carroll, Iowa.
Rowles finishes 150,000 hogs annually. As his experience with DDGS has increased, he is gradually increasing inclusion levels.
“We start including DDGS in the late-nursery diets at around 20 percent and go on up to a 30 percent inclusion level by the mid-finishing phase,” Rowles says. A few weeks prior to marketing, Rowles reduces the DDGS level to 15 percent to avoid a decline in carcass yield or issues with soft fat.
Packers are increasingly using iodine values to measure the levels of unsaturated carcass fat. Excessive DDGS levels in swine feed can push fat iodine values past acceptable levels. Although limited, research has shown that the maximum acceptable iodine value should be 70 grams to 75 grams per 100 grams of fat. Some packers have set their maximum iodine value at 73 grams per 100 grams, while other packers do not specify a maximum iodine value but have specific recommendations for maximum DDGS rates in late-finishing diets. So, before formulating those diets, ask your packer for DDGS recommendations.
How much DDGS to incorporate into your swine diets depends on several variables. “The DDGS levels producers use depend on potential cost savings, regional availability, packer guidelines for carcass fat quality, growth rate goals, as well as their pigs’ baseline iodine value,” says Joel DeRouchey, Kansas State University Extension swine nutritionist.
Feeding DDGS in nursery and grower diets can start impacting carcass fat quality as well as reduce carcass yield of market pigs. Since acceptable iodine values vary among packers, maximum DDGS inclusion rates will vary as well. “The key to predicting iodine value accurately is having the actual farm baseline of pigs fed known diets throughout finishing and the resulting carcass fat iodine value,” DeRouchey says.
“In all reality, the concern is fat quality, of which softness is one indicator,” says Roger Johnson, pork quality director, Farmland Foods. “Including higher levels of alternative feedstuffs, particularly those that contain elevated levels of unsaturated fatty acids such as DDGS, results in unsaturated fat depots.”
When diets contain excessive DDGS levels, problems first surface in the bellies. “Since bacon and other belly products contain high fat levels, increasing the unsaturated fat levels in these depot regions contributes to processing and handling issues all the way to the end-user,” Johnson says.
Fat quality is an important issue due to the value contribution of the belly to overall carcass value in both domestic and export markets. Johnson points to challenges that develop when the fat in bacon becomes more unsaturated:
• Slicing performance suffers. Soft fat will not maintain the slice thickness, and that impacts the slice counts that foodservice and retail bacon customers demand.
• Shelf-life and storage stability decline. Unsaturated fats have greater potential to develop rancidity and off-flavor.
DDGS and Fat Cells
The quality of fat is related to the physiological maturity of the fat cell and type of lipid within the cell. “If pigs are marketed prior to physiological maturity, they will have more potential for fat-quality issues,” Johnson notes.
Advances in swine genetics can delay fat cell maturation. “Swine genetic-improvement programs have shifted the targeted market weight of most commercial lines, and the use of lean-growth feed additives has helped delay fat cell maturation as well,” Johnson says.
Feeding excessive DDGS levels in the finisher can add to the fat cell issue and soft fat may result. “As a pig reaches its market weight potential, the fat cells become filled with the excess energy that’s consumed in the form of fat,” Johnson adds. “Remember, a pig is what it eats.”
Production conditions that result in reduced or less than optimum feed intake also can result in reduced fat quality. “Over-crowding, summer heat stress, health issues or inadequate water consumption reduce feed intake and reduce the maturation level and quality of the fat depots,” Johnson says.
Withdrawing DDGS prior to slaughter can help reduce the adverse fat-quality issues. “We suggest if DDGS levels exceeding 20 percent are fed in the grow/finish period, that levels be reduced in the month prior to slaughter,” says Mark Whitney, University of Minnesota Extension swine specialist. “It can help minimize the impact on carcass fat quality.”
DDGS for Sows
Studies show that DDGS can be fed in concentrations up to 30 percent in lactating sows and up to 50 percent in gestating sows without impacting animal performance. “While the data is more limited in sows, the negative effects on carcass fat quality of feeding high DDGS levels (50 percent) in gestation is somewhat reduced,” DeRouchey says. “Sows are not in a growing stage and not depositing large amounts of fat. Carcass fat unsaturation increases when they are fed DDGS but not to the same extent as found in growing and finishing pigs.”
In sows heading for slaughter, however, fat-quality issues have begun showing up. “Fat quality is an emerging concern now that we see many sows being fed high DDGS levels,” Whitney says. “Increasing the unsaturated/saturated ratio of the fat in a carcass adversely affects emulsification properties that are important to the processor to achieve texture and appearance for sausage and other ground-type products.”
DDGS Feeding Recommendations
DDGS quality can vary among ethanol plants and should be measured and monitored. Ask your source for information on moisture, crude protein, crude fat, crude fiber and lysine. A nutrient profile will help you determine if the final diet will require rebalancing. When incorporating DDGS, the diets must be formulated on a digestible-lysine basis.
The National Swine Nutrition Guide offers the following guidelines on DDGS inclusion rates by production phase:
Based on available data, the rule is for every 10 percent DDGS that’s fed throughout finishing, carcass fat iodine value increases 2 grams per 100 grams. So, if the baseline of a herd fed a corn/soybean meal-based diet has an iodine value of 66 grams per 100 grams, pigs fed 30 percent DDGS would have an estimated carcass fat iodine value of 72 grams per 100 grams.
While supplementing swine diets with DDGS may reduce your feed bill, there are many variables to consider prior to setting your inclusion rates. Be sure you are tracking all of the potential consequences. If carcass yields are shrinking or your packer is discounting your hogs for soft fat, the bargain may become costly.