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Document Type

Dissertation - University Access Only

Award Date

2014

Degree Name

Doctor of Philosophy (PhD)

Department

Dairy Science

First Advisor

Kenneth F. Kalscheur

Abstract

Dried distillers grains with solubles (DDGS) is a co-product of ethanol industry and traditionally fed as an alternative to soybean meal and corn. It has been recognized as an excellent source of energy, attributed to having high concentrations of digestible neutral detergent fiber (NDF) and fat. The dairy industry utilizes approximately 40 to 45% of DDGS produced in the United States. However, still there are challenges to overcome when feeding DDGS to lactating dairy cows. Greater concentrations of highly degradable non-forage fiber and polyunsaturated fatty acids and less physically effective non-forage fiber are considered as the negative qualities associated with DDGS. Five studies were conducted to overcome challenges of feeding DDGS to lactating dairy cows. The overall objectives of the all studies were to increase the efficiency of utilizing DDGS as a feed ingredient in lactating dairy cow diets and decrease the feed cost. The first study evaluated the effect of replacing starch from corn with non-forage fiber from DDGS and soybean hulls on nutrient flow to the omasum, ruminal nutrient digestibility, total tract nutrient digestibility, and nitrogen partitioning of lactating dairy cows. Results from the study suggested that when lactating dairy cows are fed DDGS to replace starch from corn, they derive energy through digesting non-forage fiber and crude fat of DDGS. The second study evaluated the effect of concentrations of forages and DDGS on production performance of lactating dairy cows. Results suggested that when lactating dairy cows were fed DDGS at 18% on DM basis with adequate forage fiber (>21%), cows had greater milk production without having any adverse effects such as milk fat depression. The third study evaluated the effect of concentrations of forages and DDGS on ruminal fermentation and nutrient digestion in lactating dairy cows. This study demonstrated that DDGS had different degradation patterns and rate of passages with low and high forage concentrations. The fourth study evaluated the effects of concentrations of forages and DDGS on in situ degradability of DDGS. This study demonstrated that non-forage fiber of DDGS had less degradability with low forage diets whereas it had greater non-forage fiber degradability with high forage diets. The fifth study was conducted to evaluate the effect of DDGS on the fatty acid composition of rumen digesta and milk when fed with different forage concentrations. This study demonstrated that forage and DDGS concentrations in the diet change the fatty acid composition of rumen digesta and milk. Variations in the trans fatty acids in the milk and rumen digesta were not sufficient to explain the variations observed with milk fat concentration and yield. Finally, it was concluded that DDGS is not an effective fiber source to maintain milk fat concentration. But feeding DDGS at 18% of DM with sufficient forage fiber to lactating dairy cows maintain healthy rumen conditions and greater milk production without having any adverse effects such as milk fat depression at a lower feed cost.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds
Distillers feeds
Fiber in animal nutrition
Lactation
Forage

Description

Includes bibliographical references (pages 250-278)

Format

application/pdf

Number of Pages

302

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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