|COX-O'NEILL, J - University Of Nebraska|
|Hales Paxton, Kristin|
|ULMER, K - University Of Nebraska|
|RASBY, RICK - University Of Nebraska|
|PARSONS, J - University Of Nebraska|
|DREWNOSKI, MARY - University Of Nebraska|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2017
Publication Date: 12/1/2017
Citation: Cox-O'Neill, J.L., Hales, K.E., Ulmer, K.M., Rasby, R.J., Parsons, J., Shackelford, S.D., Freetly, H.C., Drewnoski, M.E. 2017. The effects of backgrounding system on growing and finishing performance, and carcass characteristics of beef steers. Journal of Animal Science. 95(12):5309-5319. https://doi.org/10.2527/jas2017.1934.
Interpretive Summary: The abundance of diverse forage resources in the Midwest, provides cattle producers many different options to background calves prior to placing them in a feedlot and finishing them out for meat harvest. This 2-yr study evaluated growing and finishing performance, as well as carcass characteristics of spring-born steers backgrounded using 3 different systems using feedstuffs readily available in the Midwest: 1) grazing corn residue and supplementing dried distillers grains, 2) grazing a late summer planted oat-brassica forage mix, or 3) fed a corn silage-based diet in a drylot. Oat-brassica forage consisted of 57% oat, 27% turnip and 16% radish. During backgrounding, the ADG of calves fed in drylot was greater than both groups of grazing steers. At the start of finishing, body weight of steers that had grazed the oat-brassica forage mix was greater than steers fed in drylot or grazing steers fed distillers grains. The finishing diet was fed for 160 d across all treatments and 12th rib fat and calculated yield grade did not differ among treatments. Finishing phase feed efficiency was greater for cattle fed in drylot. Finishing phase feed efficiency did not differ between backgrounding treatments. The lower cost of gain associated with the grazing systems may make these backgrounding methods economically competitive.
Technical Abstract: The objective of this 2-yr study was to evaluate growing and finishing performance, as well as carcass characteristics of spring-born steers backgrounded on 3 different systems, using feedstuffs readily available in the Midwest: 1) grazing corn residue and being supplemented with dried distillers plus solubles at 2.68 kg DM/steer 6 d/wk (RESIDUE), 2) grazing a late summer- planted oat-brassica forage mix (CCROP), or 3) being fed a corn silage-based diet in a drylot (DRYLOT). Steers (n = 715) were stratified by BW (278 kg ± 23 yr 1 and 291 kg ± 91 yr 2) and assigned to treatment and replicate (4 replications per treatment per yr). Steers assigned to DRYLOT were fed a corn silage-based diet for 54 d in yr 1 and 52 d in yr 2 before being transitioned to the finishing diet. Steers assigned RESIDUE and those assigned to CCROP grazed 65 d in yr 1 and 66 d in yr 2 and then were fed a corn silage-based diet for 21 d in yr 1 and 33 d in yr 2 before being transitioned to the finishing diet. During backgrounding, the ADG (SEM 0.022) of steers arrigned to DRYLOT (1.48 kg/d) was greater (P < 0.01) than that of steers assigned to both CCROP (1.05 kg/d) and RESIDUE (0.87 kg/d) and ADG of steers assigned to CCROP was greater (P < 0.01) than that of steers assigned to RESIDUE. At the start of the finishing period, BW of steers assigned to CCROP (381 kg) was greater (P < 0.01, SEM 2.5) than that of steers assigned to DRYLOT (361 kg) and RESIDUE (366 kg). The finishing period lasted 160 d or all treatments. Both 12th rib fat (P = 0.89) and calculated yield grade (P = 0.39) did not differ among treatments. Finishing G:F of steers assigned to DRYLOT (0.162 kg/kg) was greater (P < 0.01, SEM 0.0015) than that of steers assigned to RESIDUE (0.153 kg/kg) and CCROP (0.153 kg/kg), which did not differ (P = 0.79). In yr 1, HCW of steers assigned to CCROP (402 kg) was greater (P < 0.01, SEM 2.1) than that of steers assigned to both RESIDUE (389 kg) and DRYLOT (391 kg), which did not differ (P = 0.40). The difference in HCW is most likely a result of differences in BW at the start of the finishing phase in yr 1. However in yr 2 HCW of steers assigned to CCROP (400 kg) and RESIDUE (397 kg) did not differ (P = 0.26, SEM 2.1) but were greater (P < 0.01) than that of steers assigned to DRYLOT (367 kg), despite the fact that steers assigned to RESIDUE entered the finishing phase at a lighter BW than steers assigned to CCROP. Marbling was greater (P = 0.01, SEM 3.9) for steers assigned to DRYLOT (429) than for steers assigned to RESIDUE (414), although steers assigned to CCROP (424) were not different (P >/= 0.10) from steers assigned to DRYLOT or RESIDUE. When cost and price scenarios from the last 5 yr were conducted, no treatment appeared to be consistently superior in terms of cost of gain or net return. Therefore, all 3 systems appear to be viable options for producers.