Animal Science Department


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Sudbeck, K. M. 2014. Effects of feeding distillers grains throughout a yearling heifer beef production system on meat quality attributes and effects of OmniGen - AF with ractopamine hydrochloride on animal performance and beef carcass characteristics of feedlot steers. M. S. Thesis. University of Nebraska, Lincoln.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Animal Science, Under the Supervision of Professor James C. MacDonald. Lincoln, Nebraska: December, 2014

Copyright (c) 2014 Kelby M. Sudbeck


Heifers (n = 229; 225 kg ± 2) were used in a 2 x 2 x 2 factorial to determine the effects of longterm exposure to corn distillers grains plus solubles (DGS) on meat quality characteristics. Factors included supplementing 0.91 kg (LW) or 2.3 kg (HW) modified DGS (MDGS) while grazing corn stalks; 0.6% BW dry DGS (SS) daily or none (NS) during summer grazing; and finishing diet containing 40% wet corn gluten feed (CGF) or 40% MDGS (DGF) on a DM basis. An interaction was observed within CGF for discoloration, with SS increasing discoloration 30%; but no differences between SS or NS from DGF cattle. Discoloration scores for DGF increased compared to CGF d 6 - 7 and d 4 - 6 for steaks aged 7 and 21 d, respectively. Supplementing with DGS did not further reduce the color stability of retail beef of DGF finished cattle; however, DGS supplementation prior to finishing can affect beef quality when DGS are not included in the finishing diet. In the second study, crossbred steers (n = 336) were utilized in a 2 x 3 factorial evaluating duration of OmniGen – AF supplementation (0, 28, or 56 d) at 4 g / 45.5 kg BW and supplementation of ractopamine hydrochloride (RAC) at 300 mg/ steer daily for the last 28 days of finishing or no supplementation. No Omnigen – AF by RAC interaction or OmniGen –AF effects were observed for any feedlot performance or carcass characteristics measured. Supplementing RAC increased ADG 0.5 kg, increased FBW 10.0 kg, and increased LM area 0.9 cm2 compared to NORAC.

Keywords: Beef, Discoloration, Distillers, OmniGen – AF, Ractopamine hydrochloride

Advisor: James C. MacDonald

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