|MAXWELL, CASEY - West Texas A & M University|
|BROWN, MIKE - West Texas A & M University|
|COUFAL, BILL - West Texas A & M University|
|WALLACE, J - West Texas A & M University|
|SIMROTH-RODRIGUEZ, J - West Texas A & M University|
|PRATT, S - West Texas A & M University|
Submitted to: Proceeding of Plains Nutrition Council Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2010
Publication Date: 4/22/2010
Citation: Maxwell, C., Brown, M., Cole, N.A., Coufal, B., Wallace, J., Simroth-Rodriguez, J., Pratt, S. 2010. Effects of roughage source and dried corn distiller's grains concentration on feedlot performance and carcass characteristics of finishing beef steers [abstract]. In: Proceeding of Plains Nutrition Council Spring Conference, April 22-23, 2010, San Antonio, Texas. Pub. No. AREC 10-57, p. 106-107.
Technical Abstract: Physical attributes of roughages used in finishing diets may impact the extent of ruminal digestion of dried distiller's grains (DDG) and growth performance. Crossbred steers (n=380) were adapted to a common finishing diet, blocked by BW, implanted with Revalor-S (120 mg of trenbolone acetate and 24 mg of estradiol), and assigned to treatments of roughage source (sorghum-sudan hay [Hay] or sorghum-sudan silage [Silage]) and DDG concentration (0 or 20% of diet DM). Cattle were housed in 40 soil-surfaced pens with at least 16.7 m2 of pen space and 30.5 cm of bunk space/animal. Roughages were included on an equal NDF basis. All diets contained 3.4% non-protein N from urea (1.2% urea) and cottonseed meal was utilized as a protein source in 0% DDG diets. Cattle were fed twice/d for 108 d (initial BW = 905 +/- 27.81 lb). Steers fed 20% DDG ate 4.1% more DM than steers fed 0% DDG (23.93 vs. 22.99 lb, P = <0.01), but silage or hay did not influence DMI (P = 0.56). Overall shrunk ADG on a live basis was not altered by treatment (P > 0.56). Gain efficiency on a live basis was not altered by silage or hay (P = 0.77), but steers fed 0% DDG were 2.8% more efficient than steers fed 20% DDG (P <0.01). There was a roughage source x DDG interaction for carcass-adjusted ADG and gain efficiency, dressing percentage, hot carcass weight, and LM area (P < 0.07). Adjusted ADG was increased 7% by silage with 20% DDG (P = 0.05), but forage source did not alter ADG when 0% DDG was fed (P = 0.38). Adjusted gain efficiency was reduced (P = 0.03) 4.6% by hay with 20% DDG, but efficiency was not altered (P = 0.63) by forage source at 0% DDG. Dressing percentage was reduced by hay at 20% DDG (63.0 vs. 62.5, P = 0.02) and increased by silage at 20% DDG (62.5 vs. 63.4, P < 0.001). Hot carcass weight was not altered by DDG with hay (P = 0.37), but was increased 16 lbs with 20% DDG when silage was fed (P=0.05). The LM area was increased by silage with 20% DDG (P = 0.02), but forage source did not alter LM area at 0% DDG (P = 0.29). Marbling score was higher when DDG was fed with either silage or hay (380 vs. 390, P = 0.06). Results suggest that rate of gain on a carcass basis can be improved by feeding DDG with silage, whereas forage source was less important when no DDG was fed.