Title: Effects of wet corn distiller's grains with solubles (WCDGS) and non-protein nitrogen on growth performance and carcass characteristics of yearling steers Authors
|Ponce, Christian -|
|Brown, Mike -|
|Maxwell, Casey -|
|Coufal, C. Bill -|
|Silva, Jason -|
Submitted to: Beef Cattle Research in Texas
Publication Type: Experiment Station
Publication Acceptance Date: September 30, 2009
Publication Date: April 1, 2011
Citation: Ponce, C.H., Brown, M.S., Cole, N.A., Maxwell, C.L., Coufal, C., Silva, J.C. 2011. Effects of wet corn distiller's grains with solubles (WCDGS) and non-protein nitrogen on growth performance and carcass characteristics of yearling steers. Beef Cattle Research in Texas 2009-2010, Texas A&M University, College of Agricultural and Life Sciences Publication. p. 59-65. Interpretive Summary: Wet distiller's grains with solubles (WDGS), a by-product of the grain bioethanol industry, are frequently used in beef cattle feedlot diets. The WDGS contain high concentrations of crude protein and ruminally undegradable protein (which is protein that is not degraded by bacteria in the rumen of cattle). Bacteria in the rumen of cattle need ruminally degradable forms of protein in order to grow, multiply, and digest carbohydrates (starch and cellulose) in the diet. However, the amount of ruminally degradable protein needed in beef cattle finishing diets that contain high concentrations of WDGS is not known. Therefore, a study was conducted with 525 beef steers to determine the optimal concentrations of ruminal degradable protein in diets that contained 15 or 30% WDGS. Urea was used as the supplemental source of ruminally degradable protein in the diets. Based on animal performance (feed dry matter intake, average daily gain, and gain efficiency), the optimal concentration of urea in the diet was 0.5 to 1.0% when diets containing 15% WDGS and 0.5% or less when diets contained 30% WDGS. These results can be used by nutritionists to formulate diets for finishing cattle so that they can attain optimal animal performance while also reducing the quantity of dietary nitrogen that is lost to the environment.
Technical Abstract: Wet distiller's grains with solubles (WDGS) contain high concentrations of crude protein and ruminally undegradable protein. The requirement for dietary ruminally degradable protein in steam-flaked corn-based beef cattle finishing diets that contain high concentrations of WDGS is not known. Therefore, 525 yearling steers (average body weight = 822 lb) were fed diets that contained 15% or 30% WDGS and three concentrations of supplemental urea (0, 0.52 or 1.06% of dry matter equal to 0, 1.5 or 3.0% non-protein nitrogen (NPN)). A control diet containing no WDGS and 3% supplemental NPN was also fed. Dry matter intake increased linearly (P <0.04) as NPN increased but was not altered by WDGS. Overall average daily gain (ADG) for steers fed 15% WDGS was greater for 1.5 and 3.0% NPN than for 0% NPN (P < 0.07); however, ADG was not influenced by NPN when the diet contained 30% WDGS. Overall ADG was not different for the control and 15% WDGS, but ADG was lower (P < 0.02) for diets containing 30% WDGS than for diets containing 15% WDGS. Overall gain efficiency (ADG:dry matter intake) among steers fed 15% WDGS was greatest for 1.5% NPN and lowest for 0% NPN (P < 0.07); whereas, gain efficiency decreased linearly (P < 0.09) as NPN increased in the 30% WDGS diets. Dressing percentage was greater (P < 0.01) for the control diet than for the 15 or 30% WDGS diets. Results suggest that optimum performance occurred when 15% WDGS diets contained 1.5 to 3.0% supplemental NPN and when 30% WDGS diets contained 1.5% or less supplemental NPN.