Title: Effects of corn processing method and dietary inclusion of wet distiller's grain with solubles on carbon-nitrogen balance of finishing cattle Authors
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: February 18, 2011
Publication Date: July 10, 2011
Citation: Hales, K.E., Cole, N.A., MacDonald, J.C. 2011. Effects of corn processing method and dietary inclusion of wet distiller's grain with solubles on carbon-nitrogen balance of finishing cattle [abstract]. Journal of Animal Science. 89(E-Suppl 1):196. Technical Abstract: The growing ethanol industry in the Southern Great Plains has increased the use of wet distiller's grains with solubles (WDGS) in beef cattle finishing diets. Effects of corn processing method and WDGS on carbon (C) and nitrogen (N) balance were evaluated in four Jersey steers using respiration calorimetry chambers. A 2 x 2 factorial arrangement of treatments was used in a Latin square design. The factors consisted of corn processing method (steam flaked corn [SFC] or dry-rolled corn [DRC]) and inclusion of corn-based WDGS (0 or 30% on a DM basis). Thus, the four treatment combinations consisted of: (1) SFC-based diet with 0% WDGS (SFC-0); (2) SFC-based diet with 30% WDGS (SFC-30); (3) DRC-based diet with 0% WDGS (DRC-0); and (4) DRC-based diet with 30% WDGS (DRC-30). Diets were balanced for DIP and fat. Total C (including gaseous-C) excretion (P < 0.01) and methane-C (P < 0.04) were greater for cattle consuming DRC than SFC-based diets, and cattle consuming SFC diets retained a greater (P < 0.01) quantity of C than those consuming DRC diets. Inclusion of WDGS did not affect (P > 0.52) C balance, except that cattle consuming diets containing 30% WDGS excreted more (P < 0.01) C in the urine than cattle consuming diets with no WDGS. No differences in N balance were detected (P > 0.19) between grain processing methods, although apparent N digestibility was greater (P = 0.02) for cattle consuming DRC- than SFC-based diets and N retained tended (P = 0.10) to be greater for cattle consuming DRC than SFC-based diets. Due in part to greater N intake, cattle consuming diets containing 30% WDGS excreted more (P = 0.01) total N and excreted a greater (P < 0.01) quantity of N in the urine. Apparent N digestibility (g/d and % of N intake; P < 0.03) and N retained (P < 0.05) were also greater in cattle consuming 30 compared to 0% WDGS. From these results we conclude that finishing cattle excrete a greater amount of C when fed DRC compared to SFC-based diets, and that dietary inclusion of 30% WDGS increases urinary N excretion when diets are balanced for equal DIP concentration.