Animal Science, Department of


First Advisor

Matthew K. Luebbe

Second Advisor

Galen K. Erickson

Third Advisor

James C. MacDonald

Date of this Version

Fall 11-26-2019

Document Type



Conroy, B.B. 2019. Impact of feeding distillers grains or isolated components in distillers grains to growing and finishing cattle, and the comparison of protein content and in-situ digestibility of feeds commonly used in feedlot diets. MS 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 Professors Matthew K. Luebbe, Galen E. Erickson, James C. MacDonald. Lincoln, NE: Novembner 2019

Copyright 2019 Brianna Conroy


The use of distillers grains originating from biofuel production has become widely used in feedlot diets. Distillers grains has been identified as having an increased feeding value relative to dry-rolled corn, in recent years the composition of distillers grains has begun to change due to greater refinement in the ethanol production process. Two feedlot trials were conducted to evaluate the contribution of fat, fiber, and protein from distillers grains in the diets of growing and finishing cattle. Growing steers were fed a grass hay-based ration, including a corn control diet compared to a diet containing modified distillers grains plus solubles, or one of four additional treatment diets. Finishing steers were fed a corn-based ration, including a control diet without distillers grains compared to a diet containing wet distillers grain plus solubles, or one of four additional treatment diets. Live performance was improved when cattle were fed diets containing either wet or modified distillers grains plus solubles compared to dry-rolled corn. It was determined that protein in WDGS and MDGS, when overfed to provide energy, is important to the improved performance of growing and finishing cattle. A third, in-situ experiment evaluated rumen undegradable protein (RUP) values for feedstuffs typically used in feedlot diets using the mobile bag technique. Bags were ruminally incubated for 16 h or 28 h and refluxed in neutral detergent solution (NDS) or not refluxed in neutral detergent solution. Application of NDS can be used as an effective method to remove excess microbial N, however, physical and chemical characteristics of feed ingredients, along with diet composition and rate of passage, should be considered when measuring N content post rumen incubation to avoid inaccurate RUP measurements.

Advisors: Matthew K. Luebbe, Galen E. Erickson, James C. MacDonald