Animal Science Department

 

First Advisor

Galen E Erickson

Date of this Version

Summer 8-2018

Comments

A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Animal Science (Ruminant Nutrition), Under the Supervision of Professor Galen E. Erickson. Lincoln, Nebraska : August, 2018

Copyright © 2018 F. Henry Hilscher Jr.

Abstract

Six studies were conducted to evaluate effects of corn silage harvest, hybrid, and concentration in growing and finishing diets. Experiment 1, evaluated corn silage DM (37 or 43%) and replacing corn grain with silage (15 or 45% of diet DM) in finishing diets. Experiment 2, evaluated corn silage DM (37 or 43%) and response to rumen undegradable protein (RUP) supplementation in growing diets. Experiment 3, evaluated nutrient digestibility of 37 or 43% DM corn silage at two different intakes. Experiment 4, 5, and 6 evaluated three corn silage hybrids: a standard hybrid control (CON), a brown midrib (bm3) hybrid (BM3), and an experimental bm3 hybrid (BM3-EXP) with a soft endosperm trait. Experiment 4 evaluated the three hybrids and concentration (15 or 45% of diet DM) in finishing diets, while Exp. 5 and 6, evaluated the same three silage hybrids in growing diets. In Exp. 1 with finishing cattle, as DM of silage increased from 37 to 43%, there were no differences (P ≥ 0.30) in DMI, ADG, or G:F. In Exp. 2 with growing cattle, as DM of silage increased from 37 to 43%, ADG and G:F were reduced (P ≤ 0.04). Increasing supplemental RUP in the diet increased (P £ 0.05) ending BW, ADG, and G:F linearly. In Exp. 1 and 4, as concentration of silage in the finishing diet increased from 15 to 45%, ADG and G:F decreased (P ≤ 0.04). In Exp 4, BMR-EXP had the greatest ADG and G:F at 15% silage. At 45% silage, both bm3 hybrids had greater (P ≤ 0.05) ADG than CON, but G:F was greatest for cattle fed BM3 (PP < 0.01) for steers fed the BM3 and BM3-EXP compared to the CON. In Exp. 6, steers fed both bm3 hybrids had greater (P < 0.01) NDF and ADF digestibility than the CON. Delayed silage harvest decreased performance in growing diets, but did not affect performance of finishing cattle. Silage hybrids containing the bm3 trait improved performance, and improvement was most evident with large concentrations of silage.

Adviser: Galen E. Erickson

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