Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

Paul R. Middaugh


The intestinal bacterial flora of an animal has a considerable influence on the physiology of that animal. Some bacteria of the intestine are pathogenic and can initiate infections if they gain access to a susceptible individual. Some of the intestinal bacteria can produce potent carcinogens in vitro and can presumably do this also in vivo. Food passing through the alimentary tract of an animal is also chemically modified through the enzymatic action of the bacterial flora. The animal is also protected from some enteric infections through the antagonistic and competitive actions of the established organisms of the normal bacterial flora. Most of the normal alimentary tract flora studies have been conducted with the human. The bovine rumen has also been a popular subject for bacterial flora studies. There have been, however, few studies made of the normal bacterial flora of the intestine of animals, especially the bovine. The studies that do exist are studies of the facultatively anaerobic bacteria of the flora or are studies of the anaerobic bacteria of the flora in which inferior methods of identification and/or anaerobiosis production were used. Recent studies of the feasibility of refeeding animal wastes to utilize nutrients remaining in the wastes have not incorporated a sterilization step for the feces. The omission of a sterilization step is more energy-efficient than is the incorporation of such a step. Unfortunately, little is known about the fecal flora of cattle and such refeeding plans may be beset with considerable difficulties. The organisms may be able to survive oxygen exposure well enough to be viable when the animal consumes the feces. If the organisms are pathogenic, they may be able to cause disease by entering the bloodstream through lacerations in the alimentary tract walls or by initiating an enteric infection. If the organisms are not pathogenic, they may still be able to cause problems by upsetting the normal rumen fermentation. Since such a small amount of data concerning the bovine fecal flora exists, the risk posed by refeeding bovine wastes can not [sic] be evaluated with any degree of accuracy. The purpose of this study is to investigate the normal bovine fecal flora and to evaluate possible hazards of refeeding animal wastes. The objectives of this study are to develop media and methods for quantitatively cultivating the predominant organisms of the bovine bacterial fecal flora, to enumerate and identify the predominant bacteria of the bovine fecal flora, and to determine the die- off rate of the predominant bacteria of the flora when the organisms are exposed to air.

Library of Congress Subject Headings

Feces -- Microbiology
Bacteriology -- Technique
Anaerobic bacteria




South Dakota State University

Included in

Bacteriology Commons