|PONCE, CHRISTIAN - West Texas A & M University|
|BROWN, MIKE - West Texas A & M University|
|MAXWELL, CASEY - West Texas A & M University|
|WALLACE, J - West Texas A & M University|
|COUFAL, BILL - West Texas A & M University|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 5/7/2010
Publication Date: 7/12/2010
Citation: Ponce, C.H., Brown, M.S., Cole, N.A., Maxwell, C.L., Wallace, J.O., Coufal, B. 2010. Effects of non-protein nitrogen in diets containing 15% wet distiller's grains with solubles and steam-flaked corn on feedlot cattle performance and carcass characteristics [abstract]. Journal of Animal Science Supplement. 88:E-Supplement 2, Paper W340, p. 697.
Technical Abstract: Our previous data suggest that the non-protein nitrogen (NPN) need in diets with 15% wet distiller's grains with solubles (WDGS) for optimum growth performance may be slightly less than in 0% WDGS diets. The objective of the present study was to more clearly define the NPN need in diets with 15% WDGS. Steer calves (n = 296; initial BW = 344 kg) previously grown for approximately 75 d were adapted to a common finishing diet, blocked by BW, and assigned to 36 soil-surfaced pens (18 m**2 of pen space and 33 cm of bunk space/animal). Treatments included a control diet without WDGS (contained 3% NPN from urea, and cottonseed meal) and 15% WDGS with either 1.5, 2.25, or 3.0% NPN (0.52, 0.78, and 1.04% urea, respectively). Steers were implanted on d 1 with Revalor-XS and were fed twice daily for 165 d. The WDGS was obtained 3 times/wk from a local plant, and grain composition of WDGS averaged 22% sorghum and 78% corn. Overall DMI was 6.1% higher (P = 0.001) for steers receiving WDGS than for the control. Similarly, steers fed WDGS had 8% greater ADG (P < 0.008) on either a live or a carcass-adjusted basis than the control. However, overall gain efficiency on either a live or adjusted basis was not different among treatments (P > 0.15). Dietary NPN concentration did not influence growth performance (P > 0.21). Hot carcass weight was 10.9 kg lighter for the control than for 15% WDGS (P = 0.01), whereas dressing percentage tended (P = 0.12) to increase in a linear manner as NPN increased in diets with WDGS. Remaining measured carcass characteristics were not altered by treatment (P > 0.16). The control group tended to have (P < 0.12) fewer average Choice and higher and more low Choice carcasses than those fed WDGS, but the distribution of remaining quality and yield grades did not differ among treatments. Data suggest that growth performance may not be improved by including more than 1.5% added NPN in diets with 15% WDGS derived from a blend of corn and sorghum grains.