Abstract #692

# 692
Effect of yearling beef steer frame score, grazing sequence, and delayed feedlot entry on steer performance, carcass measurements, and system economics.
Songul Senturklu*1,2, Douglas G. Landblom1, Robert J. Maddock3, Steve I. Paisley4, 1North Dakota State University, Dickinson Research Extension Center, Dickinson, ND, 2Canakkale Onsekiz Mart Universitesi, Animal Science Department, Canakkale, Turkey, 3North Dakota State University, Animal Science Department, Fargo, ND, 4University of Wyoming, Animal Science Department, Laramie, WY.

Ninety-six yearling beef steers divided into 2 frame score groups and identified as small frame score (SF: n = 48, Avg. 3.40; Range 1.58–4.13; 1/2RA × 1/4LO × 1/4AN) and large frame score (LF: n = 48; Avg. 5.31; Range 4.48–6.65; 1/2SM or 1/2SH × 1/4AN × 1/4RA) were randomly assigned to replicated pens or fields (3) on May 1 to evaluate an extended grazing and delayed feedlot entry system (GRAZ) compared with a feedlot direct (FLOT) system. Growing and finishing for the FLOT treatment and final delayed finishing of the GRAZ treatment steers was at the University of Wyoming (UW), SAREC feedlot, Lingle, WY. FLOT steers were on feed 216 d and GRAZ steers were on feed 74 d. GRAZ steers grazed a sequence of native range (113 d), pea-barley intercrop (30 d), and unharvested corn (77 d) before being moved to the UW-SAREC feedlot. Grazing and feedlot total days was 294 d. Data were analyzed using the MIXED procedure of SAS. For the GRAZ-LF and GRAZ-SF steers, grazing gain, ADG, pasture grazing cost, annual forage crop expenses, and grazing cost/kg gain was 243 kg, 1.10 kg/d, $285.05/steer, and $1.17/kg; 211 kg, 0.96 kg/d, $278.04, and $1.32/kg, respectively. Compared with the LF steers in the feedlot, SF steers grew slower, consumed less feed, were equally efficient, but feed cost/kg of gain was higher. HCW for SF steers was lighter, and marbling score was greater for SF steers (Table 1). LF steer carcass value was greater and system net return was greater for the LF frame steers (Table 1). Managing grazing cost and delaying feedlot entry reduced DOF and enhanced LF and SF GRAZ system profitability. Table 1. Performance data for beef steers
Days on feed2162167474
Gain, kg3432881591405.560.0001
ADG, kg1.591.332.151.890.0350.0001
DM feed/steer/d, kg9.398.6212.1810.760.370.002
DM feed/kg gain, kg5.906.465.705.700.300.52
Feed cost/kg gain, $1.882.071.381.390.0180.001
HCW, kg36731837432810.60.001
Fat depth, cm0.890.990.640.820.0740.05
REA, sq cm82.674.881.374.81.350.004
Marbling score5786245526150.08
Carcass value, $1,728.551,515.662,004.381,763.6857.250.0005
System net return, $67.95−1.62500.65350.08

Key Words: frame score, delayed feedlot entry, grazing system