380
Effect of backgrounding system on feedlot performance and carcass characteristics of beef steers

Wednesday, March 16, 2016: 8:30 AM
302-303 (Community Choice Credit Union Convention Center)
Jordan L. Cox , Department of Animal Science, University of Nebraska, Lincoln, NE
Kristin E. Hales , USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE
Kristen M. Ulmer , Department of Animal Science, University of Nebraska, Lincoln, NE
Richard J. Rasby , Department of Animal Science, University of Nebraska, Lincoln, NE
Steven D. Shackelford , USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE
Harvey C. Freetly , USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE
Mary E. Drewnoski , Department of Animal Science, University of Nebraska, Lincoln, NE
Audio File Recorded Presentation (mp4)
Abstract Text: The objective of this study was to evaluate feedlot performance and carcass characteristics of steers that were backgrounded using 1 of 3 treatments: 1) corn residue grazing supplemented 6 days a week with 2.77 kg DM/hd of distillers (CRD), 2) oat-brassica forage grazing (OBF) or 3) drylotting on a grower ration (DGR). Steers (n = 355) were stratified by BW (277.6 ± 0.52 kg) and assigned to treatment and replicate (n = 4 reps). The OBF forage consisted of 28% purple top turnip, 14% daikon radish, and 59% oats (DM basis). The grower ration contained 51% corn silage, 25% alfalfa hay, 20% wet distillers, and 4% supplement (DM basis). The CRD and OBF calves grazed for 65 days and then were fed grower ration for 21 days while DGR was fed grower ration for 54 days before being transitioned to the finishing ration. At the start of finishing, BW of OBF (381 kg) was greater (P < 0.01) than DGR (365 kg) and CRD (365 kg). The finishing diet was fed for 160 d and consisted of 55.8% dry-rolled corn, 32.3% wet distillers, 8.7% corn silage, and 3.2% supplement. Finishing DMI of OBF and CRD were not different (P = 0.39) but were greater (P ≤ 0.01) than DGR. Finishing ADG (P = 0.63) and 12th rib fat (P = 0.65) at harvest didn’t differ among treatments. However, HCW of OBF (402 kg) was greater (P < 0.01) than both CRD (389 kg) and DGR (391 kg). The LM area tended (P = 0.06) to differ among treatments, with CRD, OBF, and DGR having a LM area of 85.2, 85.0, and 82.8 cm2, respectively. Calculated yield grade of OBF (3.48) and DGR (3.49) did not differ (P = 0.88) but were greater (P ≤ 0.01) than CRD (3.29). Marbling score tended (P = 0.06) to differ among treatments; with DGR, OBF, and CRD having marbling scores of 423, 419, and 402, respectively. Calves backgrounded by grazing oat-brassica forage produced more pounds of carcass than calves fed a corn silage based grower ration and calves grazing corn residue receiving distillers. Additionally, based on marbling, the quality of the carcass produced by grazing oat-brassica forage did not differ from calves fed a corn silage based ration during backgrounding.

Keywords: Backgrounding, Brassicas, Carcass quality, Corn residue, Feedlot

See more of: Ruminant Nutrition: Feed Additives
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