|Cox, J - University Of Nebraska|
|Ulmer, K - University Of Nebraska|
|Rasby, R - University Of Nebraska|
|Drewnoski, Mary - University Of Nebraska|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 12/22/2015
Publication Date: 3/7/2016
Citation: Cox, J.L., Hales, K.E., Ulmer, K.M., Rasby, R.J., Shackelford, S.D., Freetly, H.C., Drewnoski, M.E. 2016. Effect of backgrounding system on feedlot performance and carcass characteristics of beef steers [abstract]. Journal of Animal Science Supplement. 94(Supplement 2):173-174.
Technical Abstract: 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 was 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 OBF and CRD not differing (P = 0.87) but were greater (P = 0.05) than DGR. Calculated yield grade of OBF (3.48) and DGR (3.49) didn’t differ (P = 0.88) but was greater (P = 0.01) than CRD (3.29). Marbling score tended (P = 0.06) to differ among treatments, with DGR (423) and OBF (419) not differing (P = 0.59), but DGR was greater (P = 0.02) than CRD (402) while OBF tended (P = 0.06) to be greater than CRD. 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 didn’t differ from calves fed a corn silage based ration during backgrounding.