Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: March 19, 2004
Publication Date: July 26, 2004
Citation: Ferrell, C.L., Berry, E.D., Freetly, H.C., Miller, D.N. 2004. Influence of genotype and diet on steer performance [abstract]. Journal of Animal Science 82(Suppl. 1):42. Technical Abstract: Objectives were to evaluate genotype and diet effects on steer performance during the growing period and subsequent responses to a high concentrate diet during the finishing period. Fifty-one [MARC III (M; 14) and Brahman cross (Bx; 37)] steers were allotted to eight pens and individually fed chopped bromegrass hay (BG; N=26; DM=0.85, CP=9.5%, ME=2.19 Mcal/kg) or a corn silage based diet (CS; N=25; DM=0.51, CP=11.9%, ME=2.75 Mcal/kg) for 119 d (PD1) followed by a high corn diet (HC; DM=0.79, CP=11.7, ME=3.08 Mcal/kg) to a target wt of 560 kg (PD2). Data were analyzed by ANOVA with genotype, diet (BG, CS), and the two-way interaction included. The interaction was not significant. Initial (273 kg) and final wts (559 kg) did not differ due to genotype or diet, but wt of BG (325 kg) steers was less than CS (384 kg) steers at the end of PD1. ADG and intake of DM, CP, and ME were less (P<0.05) for Bx than for M during PD1, PD2 and total, but efficiency of M and Bx was similar (P>0.40). Carcass wt, marbling, quality grade, and REA were similar (P>0.12), but Bx steers had greater backfat (1.26 vs. 0.87 cm) and yield grades (P=0.07) than M steers. During PD1, daily DMI (6.91 vs. 7.11 kg) was similar, but CP (0.66 vs. 0.85 kg) and ME (15.2 vs. 19.5 Mcal) intake of BG was less (P<0.001) than CS. DMI/gain (21.5 vs. 6.9), CP intake/gain (2.06 vs. 0.83), and ME intake/gain (47.1 vs. 19.2) were greater in BG. CS manure accumulated more total VFA but less branched-chain VFA and aromatics than BG manure. When fed the HC diet (PD2), feed intake, ADG, and efficiency were improved (P<0.02) in the BG vs. CS steers. Shedding of E. coli 0157 was associated with reduced DMI and ADG (P<0.10). Over the total study, ADG was lower (0.97 vs. 1.03 kg), and DMI (8.50 vs. 7.62) and DMI/gain (8.09 vs. 7.17) were greater in BG than in CS fed steers, but neither CP intake/gain (0.86 vs. 0.84) nor ME intake/gain (22.2 vs. 21.1) differed. Carcass weight, backfat, and yield grade were greater (P<0.04) for CS than for BG, but marbling, quality grade, and REA did not differ.