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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Livestock Nutrient Management Research » Research » Publications at this Location » Publication #268543
Title: Utilization of wet distillers grains in high-energy beef cattle diets based on processed grain

Author
item GALYEAN, MICHAEL - Texas Tech University
item Cole, Noel
item BROWN, MIKE - West Texas A & M University
item MACDONALD, JIM - Texas Agrilife Research
item PONCE, CHRISTIAN - Texas Tech University
item SCHUTZ, JEN - Texas Tech University

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/15/2012
Publication Date: 9/15/2012
Citation: Galyean, M.L., Cole, N.A., Brown, M.S., MacDonald, J.C., Ponce, C.H., Schutz, J.S. 2012. Utilization of wet distillers grains in high-energy beef cattle diets based on processed grain. In: Makkar, Harinder P.S., editor. Biofuel Co-Products as Livestock Feed - Opportunities and Challenges. Food and Agriculture Organization of the United Nations: Rome, Italy. p. 61-76.

Interpretive Summary: Distiller's grains (DG) are a co-product of the grain-based bio-ethanol industry. The starch in the grain is fermented to ethanol leaving a wet product (65% moisture) that is high in protein, fat, fiber, and minerals. Distiller's grains are used extensively by beef cattle feeding operations in the United States, including the Southern Great Plains. Our regional research consortium comprised of Texas Tech University, West Texas A&M University, Texas AgriLife Research, and the USDA-ARS, has been conducting research focused on utilization of wet DG in feedlot diets based on steam-flaked corn (SFC), and possible environmental effects. Effects of DG on feedlot cattle performance are influenced by source, and concentration of DG in the diet. In SFC-based diets, DG concentrations of 15 to 60% of the dry matter (DM) decreased gain efficiency, with the effects seemingly related to the fiber content of the DG and associated changes in ruminal DM, and neutral detergent fiber (NDF) digestibility. Wet DG contributes a unique source of fat to the diet; however, our findings indicate that fat contained in sorghum DG, and in a commonly used commercial source (yellow grease – an animal-vegetable fat blend) are utilized in a similar manner. Exchanging DG for SFC and oilseed meals typically increases the total dietary concentratin of crude protein (i.e. nitrogen),phosphorus, and sulfur. Our results indicate that between 0.52 and 0.78% urea was needed to optimize feedlot performance with diets containing 15% wet DG, but added urea was not beneficial when the diet contained 30% DG. The relative difference in energy value of wet DG, and the basal grain it replaces seems to provide a reasonable explanation for differences in feedlot performance reported among different grain processing methods. High concentrations of sulfur (S) in finishing diets can potentially affect animal health, and performance, and is a practical concern with high dietary concentrations of DG. Manure production varies with the concentration of DG in the diet, basal grain processing method, and other dietary ingredients. The quantity of manure collected, and the protein (P) excreted in manure from feedlot pens will increase with addition of DG to the finishing diet. When applied to meet crop P requirements, farm land required to utilize the manure increases approximately 20% for each 10% increase in wet DG in the diet. Greenhouse gas emissions from feedlots using DG are variable, and need further study. Overall, our results suggest that DG can be a useful source of energy, and protein in feedlot diets, but optimal concentrations of DG are less in SFC-based diets than in diets based on dry rolled corn.

Technical Abstract: Distiller's grains (DG) are used extensively by beef cattle feeding operations in the United States, including the Southern Great Plains. Our regional research consortium has been conducting research focused on utilization of wet DG in feedlot diets based on steam-flaked corn (SFC). Effects of DG on feedlot cattle performance are influenced by source, and concentration of DG in the diet. In SFC-based diets, DG concentrations of 15 to 60% of the DM decreased gain efficiency, with effects seemingly related to the neutral detergent fiber (NDF) content of wet DG, and associated changes in ruminal DM and NDF digestibility. Thus, the exchange of starch for fiber plays an important role in digestion, and animal performance as DG is added to an SFC-based diet. Wet DG contributes a unique source of fat to the diet; however, our findings indicate that fat contained in sorghum DG, and in a commonly used commercial source (yellow grease–an animal-vegetable fat blend) are utilized in a similar manner. Exchanging DG for SFC, and oil seed meals typically decreases degradability of CP, and often increases the total dietary crude protein (CP). Our results indicate that between 0.52 and 0.78% urea was needed to optimize feedlot performance with diets containing 15% wet DG, but added urea was not beneficial when the diet contained 30% DG, presumably reflecting recycling of excess CP in 30% DG diets. Although interactions between DG concentration, and grain processing method have been reported, our results with SFC- vs. dry-rolled corn-based diets have not provided evidence of an interaction. The relative difference in NEg concentration between DG, and the basal grain it replaces seems to provide a reasonable explanation for differences in feedlot performance among different grain processing methods. High concentrations of sulfur (S), and their effects on health and performance of feedlot are a practical concern with addition of DG to feedlot diets. In our work, feed additives like ionophores, and antibiotics did not increase in vitro ruminal H2S, but H2S production is clearly responsive to dietary S concentration. Manure production varies with the concentration of DG in the diet, basal grain processing method, and other dietary ingredients. The quantity of manure collected, and the protein (P) excreted in manure from feedlot pens will increase with addition of DG to the finishing diet. When applied to meet crop P requirements, farm land required to utilize the manure increases approximately 20% for each 10% increase in wet DG in the diet. Greenhouse gas emissions from feedlots using DG are variable, and need further study. Overall, our results suggest that DG can be a useful source of energy and protein in feedlot diets, but optimal concentrations of DG are less in SFC-based diets than in diets based on minimally processed corn.