Animal Science Department


Date of this Version

Spring 5-9-2014


Ahern, N.A. 2014. Comparision of wet or dry distillers grains plus solubles to corn as an energy source in forage-based diets and in vitro forage standard development based on in vivo digestibilities utilizing brome hay, prairie hay and meadow hay. 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 Professors Terry J. Klopfenstein and Galen E. Erickson. Lincoln, Nebraska: May, 2014

Copyright (c) 2014 Nerissa Ann Ahern


Four growing experiments were conducted to evaluate the use of dry rolled corn (DRC) and either dry (DDGS) or wet distillers grains plus solubles (WDGS) as energy sources in high forage diets. In Exp. 1, steers were fed a blend of sorghum silage and alfalfa hay and supplemented 1 of 4 inclusions of WDGS, DDGS or a MIX (67% WDGS: 33% Straw). In Exp. 2, Exp. 3 and Exp. 4, steers were fed diets including WDGS, DDGS or DRC at different inclusions, replacing sorghum silage and grass hay. In Exp. 1, WDGS, DDGS and MIX produced greater ending BW, ADG and G:F compared to the basal diet. Increasing distillers grains improved ADG and G:F in forage based diets. Data from Exp. 2 - 4 were pooled and ADG was regressed against inclusion thereby allowing the energy value of WDGS to be calculated relative to that of DRC. The energy value of WDGS was 137% and 136% of DRC when fed at 15 and 30% of the diet DM, respectively.

In vitro digestibility and in vivo digestibility estimates are highly correlated but absolute values differ. Therefore, our objective was to determine in vivo digestibilities of 5 forages and use these forages as standards for in vitro digestibility procedures when in vivo estimates are needed for unknown forage samples. Eight in vitro runs were conducted using 5 hay standards and 6 forage samples with unknown in vivo digestibilities in order to predict actual in vivo values from in vitro estimates. Runs were evaluated using either regression equations or standard mean adjustment. Using regression equations increase forage*run variation. Forage*run variation decreased using the standard mean adjustment. Standard mean adjustment appears to be a valid method to adjust IVOMD values and estimate in vivo digestibility.

Advisors: Terry Klopfenstein and Galen Erickson