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This Article Full Text Full Text (PDF) All Versions of this Article: jas.2009-1853v1 87/11/3791    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Loken, B. A. Articles by Lardy, G. P. PubMed PubMed Citation Articles by Loken, B. A. Articles by Lardy, G. P.

Growing rate of gain on subsequent feedlot performance, meat, and carcass quality of beef steers¹

B. A. Loken^*, R. J. Maddock^*,2, M. M. Stamm, C. S. Schauer, I. Rush, S. Quinn and G. P. Lardy^*

^* Department of Animal Sciences, North Dakota State University, Fargo 58108-6050; and Hettinger Research Extension Center, North Dakota State University, Hettinger 58639; and University of Nebraska Panhandle Research and Extension Center, Scottsbluff 69361

² Corresponding author: Robert.Maddock{at}ndsu.edu

Eighty Angus and Angus x Simmental steer calves were used in a completely random design to determine the effect of rate of BW gain during the backgrounding period on subsequent feedlot performance, carcass characteristics, Warner-Bratzler shear force (WBSF), and sensory analysis. Animals were stratified by BW and allotted randomly to 1 of 10 pens (5 pens/treatment). Dietary treatments were formulated for an ADG of 0.91 kg/d [low BW gain (LG), 1.06 Mcal of NE_g/kg] diets and 1.25 kg/d [high BW gain (HG), 1.19 Mcal of NE_g/kg]. Steers were fed 70 d during the growing period. The LG diet consisted of 52.5% barley silage, 39.0% whole shell corn, and 8.5% supplement, whereas the HG diet contained 43.9% barley silage, 47.4% whole shell corn, and 8.7% supplement (DM basis). Initial BW (226 kg) was not different (P = 0.70) between treatments. Steers fed the HG diet had increased ADG (1.67 vs. 1.40 kg/d; P < 0.001) compared with steers fed LG diet. Dry matter intake was greater (9.49 vs. 8.35 kg/d; P < 0.001) for steers fed the HG vs. LG diet. Total backgrounding cost ($/animal) was less (P < 0.001) for those steers fed LG diet compared with HG diet ($126.00 vs. $140.35, respectively); however, total cost per kilogram of BW gain was not different (P = 0.24; $0.485/kg of BW gain). After the backgrounding period, steers were fed a common finishing diet for 135 d. During the finishing period, LG steers had similar (P = 0.12; 10.73 vs. 10.35 kg/d) DMI compared with those fed HG diets; however, ADG was not different (1.55 kg; P = 0.72) among treatments. Hot carcass weight, marbling score, 12th-rib fat, LM area, and USDA yield grade were not different (P > 0.12) between treatments and averaged 363 kg, Sm³⁰, 1.33 cm, 83.8 cm², and 2.7, respectively. There were no differences (P = 0.77; 3.63 ± 0.12 kg) in WBSF tenderness of rib-eye steaks. Percent cooking loss was increased in LG diets (P = 0.017). No differences were observed in consumer sensory analysis of tenderness, juiciness, and flavor intensity (P 0.276; 5.43 ± 0.12, 5.07 ± 0.13, and 5.17 ± 0.05, respectively). These data suggest that feeding steers diets that differ in energy concentration and result in ADG of 1.4 and 1.7 kg/d during the growing period results in minimal changes in subsequent finishing performance and does not affect meat quality.

Key Words: finishing • growing • meat quality • rate of gain • steer • tenderness