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Document Type

Dissertation - University Access Only

Award Date

2004

Degree Name

Doctor of Philosophy (PhD)

Department

Dairy Science

First Advisor

Arnold R. Hippen

Abstract

Research to date has focused on increasing the supply of glucose precursors in transition dairy cows to reduce ketosis. Ketones and ketone bodies represent energy sources for body tissues; therefore, conserving blood glucose for lactose synthesis in the mammary gland. This led to the hypothesis that transition cows might benefit from diets formulated to stimulate rumen epithelial ketogenesis or dietary ingredients supplying ketone precursors. A series of experiments were conducted to study the impact of diets formulated to increase the supply of ketones (via feeding lactose, glycerol, or an alphaamylase enzyme preparation) or ketone precursors (feeding Ca soaps of longchain fatty acids) on the carbohydrate status of transition dairy cows. Feeding lactose to lactating dairy cows increased ruminal butyrate and plasma betahydroxybutyrate (BHBA) without placing cows at risk for developing ketosis. Additional experiments were conducted using transition dairy cows. All comparisons were made against control cows fed a corn-based concentrate mix. Feeding glycerol decreased precalving feed intake, increased concentrations of rumen butyrate and plasma BHBA while plasma glucose was decreased. Feeding lactose to transition dairy cows resulted in more consistent prepartum DMI, increased proportions of ruminal butyrate, and concentrations of BHBA in plasma without affecting the glycemic status. Transition dairy cows fed an alphaamylase enzyme preparation had greater concentrations of glucose and BHBA in plasma. Feeding propionate and fat in sufficient quantities decreased fat mobilization as reflected by decreased NEFA concentrations in plasma postpartum while plasma BHBA and glucose were unaffected. With the exception of cows fed glycerol, lactation performance was unaffected by diets formulated to increase the supply of ketones or their precursors in transition dairy cows. It is concluded that formulating diets to increase the supply of ketones via rumen epithelial ketogenesis increases plasma BHBA while minimally affecting the carbohydrate status and performance of transition dairy cows.

Library of Congress Subject Headings

Livestock
Biological Sciences
Carbohydrate
Diets
Ketones
Transition Dairy Cows

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

218

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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