Animal Science Department


First Advisor

Galen E. Erickson

Second Advisor

James C. MacDonald

Date of this Version



Jones, R. M. 2017. The effects of feed additives in beef finishing systems and the effect of rumen degradable protein supplementation in corn residue grazing systems with the use of distillers on growth performance. 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 Master of Science, Major: Animal Science, Under the Supervision of Professor Galen E. Erickson and James C. MacDonald. Lincoln, Nebraska: December, 2017

Copyright 2017 Robert M. Jones


One receiving trial evaluated the effect of the feed additive monensin (trade name: Rumensin) on steer growth performance in the receiving period while evaluating the effects of two receiving vaccinations on morbidity and mortality of newly received calves. No differences were observed in growth performance, morbidity rate or mortality rate between treatments for the first 28 d of receiving. A finishing trial evaluated the effect of the feed additive ractopamine hydrochloride (trade name: Optaflexx) on feedlot growth performance and carcass characteristics of crossbred yearling steers fed to differing degrees of finish. Feeding ractopamine hydrochloride at 300 mg improved ADG, G:F, and HCW regardless of days on feed (i.e., degree of finish). A growing trial evaluated the performance effects of grazing steers on corn residue supplemented with modified distillers grains plus solubles (MDGS; 1.4 or 2.3 kg/d) with or without urea (0 or 0.05 kg/d). No differences were observed in growth performance suggesting that supplemental urea is not necessary when supplementing at least 1.4 kg MDGS to steers grazing corn residue.

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