PSXIII-19 Feeding One-Year Storage Sorghum Silage Base Diets: Effects of Grain Processing on Performance of Backgrounding Beef Cattle

Abstract

Abstract The aim of the experiment was to evaluate the effect of feeding a one-year stored sorghum silage (SS), grain processed or not at harvest, on ADG, DMI and feed efficiency (FE) of beef heifers. A total of 96 Angus heifers were used in a completely randomized design with 6 pens/treatment of 8 heifers per treatment. Mixed model of SAS was used, and the model included the fixed effect of treatment: SS processed (PRO) or not (NPR), with initial BW used as covariate. Significance was declared at P < 0.05. A dual-purpose sorghum (ADV2450IG, Advanta seeds, Irving, TX) was harvested (Claas Jaguar 930, Harsewinkel, Germany) at the late-dough stage of grain maturity and PRO or NPR were obtained with a specific SS cracker (196 mm rolls of 125 teeth each, 40% speed differential, 1.1 mm roll gap). Each treatment was chopped at 15 mm theoretical length of cut and ensiled in polyethylene ag-bags (60 m long and 2.74 m diameter), for 388 d until starting the feeding trial. Two backgrounding diets containing (DM basis) 90.5% SS either PRO or NPR (31.4±1.4% grain content on average), 6.5% soybean meal (expeller) and 3% supplement (ROC90, Provimi, Argentina) were offered for a 12 d of adaptation and 60 d of experimental period. Diets were adjusted daily to a score of 0.5, using the SDSU 4-point bunk scoring system, and samples were taken for analyses. Initial, middle and final BW was measured, while DMI was calculated from differences between DM offered and refused within each pen (Table). In conclusion, feeding sorghum silage stored for 388 to 460 d, and either grain processed or not, resulted in similar ADG and FE when used as the base of the diet of backgrounding beef heifers.