|COX, J - UNIVERSITY OF NEBRASKA|
|HALES PAXTON, KRISTIN|
|ULMER, KRISTEN - UNIVERSITY OF NEBRASKA|
|RASBY, R - UNIVERSITY OF NEBRASKA|
|DREWNOSKI, M - UNIVERSITY OF NEBRASKA|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2015
Publication Date: 7/1/2015
Publication URL: http://handle.nal.usda.gov/10113/61748
Citation: Cox, J.L., Hales, K.E., Ulmer, K.M., Rasby, R.J., Shackelford, S.D., Freetly, H.C., Drewnoski, M.E. 2015. Effect of backgrounding system on beef calf performance [abstract]. Journal of Animal Science. 93(Supplement s3):885.
Technical Abstract: In the Midwest, opportunity to integrate cattle production into cropping systems abounds. Two winter forage sources are corn residues and double cropped cool season annuals planted after corn silage harvest. The objective of this study was to evaluate backgrounding spring born calves using these feed resources. Composite MARC II steer calves (n = 355) were stratified by BW (277.6 ± 0.52 kg) and genetic line and assigned to 1 of 3 backgrounding treatments: 1) corn residue grazing with distillers supplementation (CRD), 2) oat-brassica forage grazing (OBF) or 3) drylotting on a grower ration (DGR). Each treatment had 4 replicates. Calves on CRD were supplemented 6 d a week with 2.77 kg DM/hd of dried distillers grains mix containing 2% limestone (DM basis). The OBF was planted in early September and the forage produced consisted of 28% purple top turnip, 14% daikon radish and 59% oats (DM basis). The initial forage mass of OBF was 3516 ± 121 kg DM/ha and calves were stocked at 1538 ± 37 kg forage DM/hd. Both CRD and OBF calves were given access to a free choice mineral containing 1.32 mg monensin/g. The grower ration consisted of 25% alfalfa hay, 51% corn silage, 20% wet distillers grains and 4% supplement containing 732 mg monensin/kg (DM basis). All calves were consuming the grower ration prior to initial weights. The CRD and OBF calves were removed from grazing after 64 d when the OBF biomass was 1769 kg DM/ha and calves were fed the grower ration for 6 d and then weighed. The free choice mineral intake of the CRD calves (173 g/hd/d) was greater (P < 0.01; SEM ± 9.6) than OBF calves (121 g/hd/d). The backgrounding phase of DGR calves ended after 54 d when they reached 365 kg BW. Intake of DGR calves during backgrounding was 8.27 ± 0.031 kg/hd. During the backgrounding phase, the ADG of the DGR calves (1.57 kg/d) was greater (P < 0.01; SEM ± 0.034) than both OBF (1.00 kg/d) and CRD (0.75 kg/d) and ADG of OBF was greater (P < 0.01) than CRD. Although the calves drylotted and fed a grower ration had a greater rate of gain, the lower cost of gain associated with the grazing systems make these backgrounding methods economically competitive.