|MCCOLLUM, III, F.|
Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/2002
Publication Date: 3/17/2003
Citation: Hough, B., Greene, L. W., McCollum, III, F. T., Bean, B. W., Cole, N. A., Montgomery, T. Performance of Feedlot Heifers Fed Corn Silage or Brown Midrib Forage Sorghum Silage as The Roughage Portion of a Finishing Diet. Available from: http://www.asas.org/midwest/2003/03mabs.pdf. Midwestern Section of the American Society of Animal Science. No. 297. 
Technical Abstract: One hundred twenty six cross bred heifers (average BW = 315 kg) were used to determine the performance of heifers fed brown midrib forage sorghum silage (BMRS) vs. corn silage (CS) as the roughage source in a finishing diet. Silage was stored in 4.5 m diameter silage bags. Heifers were blocked by weight and previous grazing program, and randomly assigned to one of three diets, 10% (DM basis) CS (C10), 10% (DM basis) BMRS (S10), and 7.5% (DM basis) BMRS (S7.5) in a randomized block design. Other diet ingredients consisted of steam flaked corn, choice white hog grease, and supplement. Diets were formulated to include CS and BMRS at equal levels of DM inclusion (C10 vs. S10), and equal NDF concentrations (C10 vs. S7.5). Heifers were housed in 18 pens (n=7/pen), and fed in fence-line bunks. Carcass characteristics were determined after harvest. Heifers fed either the S10 or S7.5 diets gained 11.3% faster (P<0.03) than those fed C10 (1.38 and 1.38 vs. 1.24 kg/d, respectively). Feed intake (8.5, 8.8, and 8.7 kg/d for C10, S10 and S7.5 respectively) was not different (P=0.43) across treatments. Gain efficiency (gain/intake) was greater (P<0.01) for the heifers fed S10 and S7.5 compared to those fed C10 (0.158 and 0.158 vs. 0.148, respectively). Heifer performance was not different (P>0.10) for heifers fed S10 vs. S7.5. No differences in carcass characteristics were detected (P>0.10). Due to storage of the silages, the CS contained noticeable mold on the face of the silage when feeding, which may have affected subsequent heifer performance. Results indicate that BMRS as a roughage source will not affect performance of heifers fed a high concentrate finishing diet when compared to those fed CS.