|Macdonald, Jim - TEXAS AGRLIFE RSCH|
|Jenkins, Karla - TEXAS AGRILIFE RSCH|
|Mccollum, F. Ted - TEXAS AGRILIFE EXT|
Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: November 30, 2008
Publication Date: March 16, 2009
Citation: MacDonald, J.C., Jenkins, K.H., McCollum, F., Cole, N.A. 2009. Effects of level of alfalfa hay in steam-flaked corn-based diets containing 25% sorghum wet distiller's grains [abstract]. In: Abstracts of 2009 Midwest Section of American Dairy Science Association Conference, March 16-18, 2009, Des Moines, Iowa. Abstract No. 267, p. 84. Technical Abstract: Two hundred forty crossbred yearling steers (379 +/-19 kg) were blocked by weight and used in a completely randomized design study to determine effects of 25% wet distiller's grains (WDG) derived from sorghum in steam-flaked corn (SFC) based diets, and to determine effects of level of alfalfa hay (7.5, 10, and 12.5%; LOW, MED, HIGH, respectively) diets containing 25% WDG. A SFC control diet with 0% WDG and 10% alfalfa hay (CONT) was included to calculate the energy value of WDG. Contrasts included CONT vs. MED, and linear and quadratic effects of level of alfalfa hay within WDG diets. The WDG replaced cottonseed meal and partially replaced SFC, supplemental fat, and urea while the alfalfa hay was exchanged with SFC. Inclusion of WDG tended to increase DMI (10.4 vs. 10.9 kg for CONT and MED, respectively; P = 0.17), reduce ADG (1.89 vs. 1.80 kg for CONT and MED, respectively; P = 0.15), and significantly decreased gain:feed (0.181 vs. 0.166 for CONT and MED, respectively = 0.03) resulting in carcasses that tended to be lighter (418 vs. 410 kg for CONT and MED, respectively; P = 0.18). The calculated energy density of the WDG was 73% the value of the SFC used in this study. Increasing level of alfalfa hay in diets containing 25% sorghum WDG tended to linearly increase DMI (10.5, 10.9, and 11.0 kg for LOW, MED, and HIGH, respectively; P = 0.16) and linearly decrease gain:feed (0.170, 0.166, and 0.161 for LOW, MED, and HIGH, respectively; P = 0.16), with no change in ADG (P > 0.73) when animal performance was calculated on a carcass-adjusted basis. Increasing alfalfa hay resulted in carcasses with linearly reduced fat thickness (1.65, 1.58, and 1.46 cm for LOW, MED, and HIGH, respectively; P = 0.03), and a tendency for linearly reduced YG (3.37, 3.35, and 3.17 for LOW, MED, and HIGH, respectively; P = 0.17) and linearly reduced dressing percentage (65.4, 65.1, and 64.2% for LOW, MED, and HIGH, respectively; P = 0.09). While the inclusion of 25% sorghum WDGS appears to dilute the energy density of the diet and may negatively impact animal performance, inclusion of roughage at a level equivalent to 7.5% alfalfa hay appears to be adequate in diets containing 25% sorghum WDG.