Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/4/2009
Publication Date: 7/12/2009
Citation: Ponce, C.H., Brown, M.S., Cole, N.A., Maxwell, C.L., Silva, J.C. 2009. Effects of ruminally degradable nitrogen in diets containing wet corn distiller's grains and steam-flaked corn on feedlot cattle performance and carcass characteristics [abstract]. Journal of Animal Science E-Supplement 2:190. Interpretive Summary:
Technical Abstract: Assessment of degradable nitrogen (N) needs in diets containing wet corn distiller's grains with solubles (WCDGS) is needed to aid the cattle industry in managing feed costs. Yearling steers (n = 525; initial weight = 373 +/- 13 kg) were housed in 54 pens (9 to 10 steers/pen) and received treatments in a 2 x 3 + 1 factorial. Factors included WCDGS (15 or 30% of DM) and non-protein N (NPN; 0, 1.5, or 3.0% of DM) from urea. The control diet without WCDGS contained 3.0% NPN (1.06% urea) and cottonseed meal. Steers were fed twice daily for 129 d and WCDGS was obtained three times/week from a local plant. Final shrunk BW was less (P < 0.02) for 30% WCDGS than for the control or 15% WCDGS. Overall DMI was not different (P > 0.31) between the control diet and 15 or 30% WCDGS, but overall DMI increased linearly (P = 0.04) as NPN increased. Overall ADG and gain efficiency were affected by both WCDGS and NPN (interaction, P < 0.12). Overall ADG for steers fed 15% WCDGS was greater for 1.5 and 3.0% NPN than for 0% NPN (P < 0.07, quadratic); however, ADG was not influenced by NPN for 30% WCDGS. Overall ADG was not different between the control and 15% WCDGS, but ADG was lower (P < 0.02) for 30% than for 15% WCDGS. Overall gain efficiency among steers fed 15% WCDGS was greatest for 1.5% NPN and least for those fed 0% (P < 0.07, quadratic), whereas gain efficiency decreased linearly (P < 0.09) as NPN increased in 30% WCDGS diets. No interactions between WCDGS and NPN were evident for carcass traits. Dressing percent was greater (P < 0.01) for the control diet than for 15% or 30% WCDGS (65.1, 64.2, and 63.9% for control, 15% WCDGS, and 30% WCDGS, respectively). Hot carcass weight was not different between the control and 15% WCDGS (P = 0.44), whereas carcass weight was less for 30% WCDGS than for 15% WCDGS (P < 0.01). Other carcass measurements were not different among treatments. Data suggest that optimum performance occurs between 1.5 and 3.0% NPN when diets contain 15% WCDGS, and with 1.5% NPN or less when diets contain 30% WCDGS.