University of Minnesota Beef Team
Pleasant fall weather conditions and record or near-record corn yields in much of Minnesota have crop farmers smiling this year. This may be a different story, however, for cattle feeders located throughout the state and Midwest, who cringe as corn prices skyrocket once again to potentially record highs.
Many feeders are wondering how high corn prices will go and how long they will stay at these high levels. Buying corn grain can comprise a large majority of feed costs for feedlot producers, especially if corn is the main ingredient in cattle diets. Increased feed costs result in diminished profit potential which may put an end to the recent streak of realized profits for cattle feeders.
Several years ago when corn prices first hit $5 per bushel, feeders were scrambling to find alternative, cost-effective feedstuffs to incorporate into finishing diets. At the time, many feeders first started utilizing corn milling co-products, predominantly distillers grains plus solubles (DGS), in place of portions of corn grain to reduce feed costs and improve profit potential.
The nutrient profile of conventional DGS may vary substantially between and within ethanol plants. Average nutrient concentrations of dried DGS produced in the upper Midwest include 26.5 percent crude protein, 10 percent fat, 3.7 percent starch, and 77 percent total digestible nutrients.
Distillers grains plus solubles are highly palatable to livestock and contain high concentrations of soluble fiber that is readily digested in the rumen and crude protein that escapes ruminal digestion; thus increasing energy and undegradable intake protein in feedlot diets to improve growth performance.
Dietary inclusion levels of ingredients in feedlot rations are largely based on economics and availability of feedstuffs. While DGS is usually more cost-effective and has an equal to or greater feeding value compared to corn, several concerns exist when feeding high levels of conventional DGS in finishing diets.
Some concerns include high and variable sulfur concentrations ranging anywhere from 0.4 percent to over 1.0 percent, which when not managed closely, may pose risks to animal health and performance.
High phosphorus concentrations of conventional DGS are also a concern. Depending largely on the level of solubles added back to the DGS, phosphorus concentrations may exceed 1.0 percent of dry matter, which can lead to increased excretion into the environment.
The relatively high lipid concentration in conventional DGS can effectively increase dietary energy. However, dietary levels of fat greater than 8 percent of dry matter may severely reduce fiber digestion, feed intake, and consequently feedlot performance; thus, fat concentration of DGS typically limits inclusion in feedlot diets.
While conventional DGS is still readily available in the Midwest, technological improvements developed by some corn ethanol companies to enhance efficiency of ethanol production have resulted in production of alternative co-products.
One method implemented by some ethanol companies is pre-fermentation fractionation of the corn kernel. In this process, the endosperm, which includes nearly all of the corn starch, is separated from the corn germ and bran prior to fermentation.
Ethanol plants not only obtain greater efficiencies, but they also gain novel co-products that can be marketed for human or livestock consumption to improve their overall profitability and sustainability.
One co-product derived from this process is dried distillers grains containing markedly higher protein and lower fat concentrations compared to conventional DGS. Typically, low fat distillers grains (LFDG) contains 39 to 44 percent crude protein and 4 to 5 percent fat. Contrary to conventional DGS, no solubles are added back to LFDG; thus, sulfur and phosphorus concentrations are usually lower in this distillers grain.
If readily available to cattle feeders, including LFDG in place of conventional DGS in feedlot diets may allow for higher inclusion and provide added economic and environmental benefits.
To date, there is limited research available evaluating the effects of finishing cattle with LFDG on feedlot performance and carcass characteristics.
In 2008, researchers at Kansas State University fed 13.5 percent LFDG in place of portions of steam-flaked corn to feedlot heifers and reported similar performance and carcass characteristics as heifers consuming a traditional steam-flaked corn-based finishing diet.
Additionally, because of its lower phosphorus concentration, the authors suggested there is less phosphorus excretion into the environment when feeding LFDG in place of conventional DGS. Thus, an opportunity exists to develop feeding strategies that optimize LFDG inclusion in feedlot diets while maintaining feedlot performance and reducing environmental concerns.
Recently in 2010, researchers at the University of Minnesota completed a feedlot experiment evaluating the effects of replacing either portions of dry-rolled corn or 35 percent conventional DGS with 35 percent LFDG on feedlot performance and carcass characteristics of beef steers.
Angus steers averaging 699 lb bodyweight were individually fed one of three finishing diets for 118 days prior to harvest. Diets included 82.5 percent dry-rolled corn, 12.1 percent crude protein, and 3.55 percent fat (Control), 35 percent conventional DGS, 51 percent dry-rolled corn, 17.1 percent crude protein, and 5.96 percent fat, or 35 percent LFDG, 51 percent dry- rolled corn, 22.0 percent crude protein, and 3.53 percent fat. All diets contained 12 percent alfalfa haylage to maintain rumen health and were formulated to supply 300 mg monensin sodium per steer daily.
Dry matter intake after the first 28 days on feed through the end of finishing was lower for steers consuming diets containing LFDG compared to steers consuming Control (21.9 vs. 23.9 lb of dry matter per day). Additionally over the same time period, steers consuming diets containing LFDG tended to have lower daily feed intakes than steers consuming diets containing conventional DGS (21.9 vs. 22.4 lb of dry matter per day).
Steers consuming diets containing conventional DGS had similar dry matter intake as steers consuming Control, however. Although there were feed intake differences, daily gain, feed efficiency, and final live body weight were similar for all steers.
There were no differences due to diet in any carcass characteristics in this experiment, as was also reported by researchers at Kansas State University in 2008.
Although marbling score and percent carcasses grading USDA Prime and Choice were similar among treatments, those carcasses grading in the upper 2/3 USDA Choice category or higher averaged 41.6, 58.5, and 65.6 percent for steers consuming Control, conventional DGS, and LFDG diets, respectively.
Results of this experiment suggest LFDG may successfully replace up to 35 percent of dry-rolled corn or conventional DGS in feedlot cattle diets. Because steer growth performance and carcass characteristics were not compromised even though intake was lower with LFDG, there is potential to realize decreased cost of gain and carcass premiums when finishing cattle with this co-product.
Distillers grains with lower fat concentrations may be fed to feedlot cattle at higher inclusion levels than conventional DGS, thus reducing corn expenses and providing options for cattle feeders to remain economically viable, even as corn prices stay high.
Perhaps then as snow begins to fall and winter sets in, both crop and cattle producers can enjoy friendly conversations about commodity and futures markets over well-deserved, hot cups of coffee.
For more information regarding beef feedlot nutrition or any other beef-related topic, please visit the U of M Beef Team website at: http://www.extension.umn.edu/beef.