2008 Annual Report 1a.Objectives (from AD-416) The objectives of these cooperative research projects are to. 1)evaluate the effects of dietary roughage concentration on the feeding value of distiller's grain in steam-flaked corn based beef cattle finishing diets;. 2)evaluate the effects of corn processing method and feeding of distiller's grains on eating quality of beef; and. 3)determine interactions of grain processing method (DRC and SFC) and wet distiller's grains cereal grain source (sorghum and corn) on site and extent of nutrient digestion. The purpose of this study is to replace samples lost due to a freezer break down. 1b.Approach (from AD-416) Two beef cattle feeding trials will be conducted. In Experiment 1, yearling steers will be utilized in a randomized complete block design with four experimental treatments. Experimental diets will include three levels of roughage (7.5%, 10.0%, and 12.5%) included in diets containing 25% wet distiller's grains (DM basis). The fourth treatment will be a control with no distiller's grains, 10.0% dietary roughage, and 13.5% CP. The roughage source will be alfalfa hay. All diets will be formulated to be equal in fat and calcium and be adequate in degraded intake protein concentration. There will be 6 pens per treatment. Samples of feed ingredients will be collected weekly and analyzed for dry matter, protein, fat, fiber, and sulfur. All pens within a block will be marketed at one time when the average 12th rib fat thickness is estimated to be 0.50 inch and carcass data will be collected by trained personnel. Statistical analysis will be conducted using the general linear procedures of SAS: contrasts of interest will be control with 10% roughage vs. wet distiller's grains with 10% roughage as well as linear and quadratic effects of roughage level in diets containing 25% wet distiller's grains. In Experiment 2, crossbred steers weighing approximately 650 pounds will be individually fed in a Calan gate system to determine effects of distiller's grain inclusion and corn processing method on marbling, shelf life, and consumer acceptance of beef loins, animal performance, and to determine if blood glucose concentrations are related to marbling attributes. Treatments will be arranged in a 2 x 2 factorial . Factors will be inclusion or absence of wet distiller's grains and corn processed by steam flaking or dry rolling. Distiller's grain inclusion will be from 35 to 45% depending on distiller's grain availability, storage, and other logistical issues. Serum glucose concentrations will be monitored for each animal prior to feeding and at five time points post-feeding during four periods of the finishing study. Animal performance (dry matter intake, average daily gain, feed efficiency) will be monitored and carcass data collected. One loin from each animal will be purchased at the time of slaughter and shipped to College Station, Texas for analysis of taste panel acceptance, shelf life, fatty acid concentration, fatty acid profile, and activity of enzymes associated with marbling. 3.Progress Report This agreement consists of four studies, all of which have been started. Metabolism study 1 compared wet distiller's grains with solubles (WDGS) from different feedstocks (corn and sorghum) in diets utilizing different corn processing methods (dry-rolling and steam-flaking). This study was completed. However, the freezer that stored the samples failed and the rumen fluid, urine, duodenal fluid, and feces were lost. We are working to repeat that portion of the study in the winter of 2008. However, the in situ portion of the study has been completed and suggests that the WDGS derived from corn has greater digestion than does the WDGS derived from sorghum. We are analyzing the neutral detergent fiber (NDF) fraction to determine if this difference is due to differences in the NDF fraction of the WDGS sources, or if it is simply due to differences in NDF content. Results also suggest that calves fed diets containing 20% sorghum WDGS have greater ruminal fluid pH, thereby supporting reduced digestibility of sorghum WDGS. The second metabolism study investigates the interaction of supplemental dietary fat and fat from the WDGS. This study has been completed and the samples are being analyzed. They are safely stored in new freezers. The third study was a feeding trial that investigated level of roughage in diets containing 25% sorghum WDGS. There was a linear reduction in feed efficiency with increased roughage level, suggesting reducing roughage from 10% to 7.5% may be beneficial in diets containing sorghum WDGS. Additionally, comparing the diet with 10% roughage and 25% sorghum WDGS to the SFC control with 10% roughage suggests the sorghum WDGS has an energy value 73% that of SFC. The fourth study was an individual feeding study that investigated the impact of including 35% corn WDGS in dry rolled corn- and steam-flaked corn-based diets on animal performance and meat quality. The animal performance from this study suggests the WDGS derived from corn had an energy value 110% that of SFC. However, several response variables were reduced in steers fed 35% WDGS, including ultrasound estimated marbling, indirect estimates of delta 9 desaturase activity, and a ratio of monounsaturated:saturated fatty acids in the longissimus muscle. Additionally, steaks from steers fed 35% dietary WDGS were darker and had slightly higher levels of lipid, especially after 5 days of storage. Tentative results of studies have been reported as a paper presented to the Plains Nutrition Council (published as a proceedings paper) and a presentation to the American Society of Animal Science (published as an abstract). The ADODR and lead investigator are in regular contact via e-mail, phone and face-to-face contacts. The ADODR monitors cooperator expenditure of funds through semi-annual reports from the cooperator and via contacts with the lead investigator.