The Rumen and Its Microbes

The Rumen and Its Microbes is a contribution to the ecology of this important microbial habitat. Relatively few microbial habitats have been subjected to a thorough quantitative ecological analysis. The rumen fermentation is peculiarly suitable because of its relatively constant and continuous nature and because of the very rapid rates of conversion of organic matter. Although analysis of the ruminant-microbe symbiosis is still far from complete, knowledge is sufficient for formulation of principles and for identification and measurement of important parameters. The first eight chapters of the book include a description of the rumen and its microbes, their activities, and the extent of these activities. This basic biology provides a framework in which applications to agriculture can be evaluated. These applications are discussed in the last four chapters: host metabolism, variation in the rumen, possible practical applications, and abnormalities in rumen function.

Preface

Chapter I Introduction

Chapter II The Rumen Bacteria

A. Diversity of Kinds

B. Distribution

C. Morphology

D. Cultivation

E. Total Numbers of Rumen Bacteria

F. The Kinds of Rumen Bacteria

G. Nutrition

Chapter III The Rumen Protozoa

A. Morphology and Classification

B. Transfaunation

C. Distribution of the Protozoa

D. Microscopic Examination and Counting

E. Nutrition and Growth

F. Influence of Various Factors on the Numbers of Protozoa in the Rumen

G. Digestion of the Protozoa

H. Relationships between the Protozoa and Bacteria

Chapter IV Ruminant Functions Related to Rumen Microbial Activity

A. Fistulation

B. Ingestion and Deglutition of Food

C. Structure of the Ruminant Stomach

D. Development of the Rumen-Reticulum

E. Salivary Secretion

F. Stomach Movements

G. Absorption

H. Additional Characteristics of the Rumen

I. Summary

Chapter V The Rumen as a Continuous Fermentation System

A. Introduction

B. Characteristics of Continuous Fermentation Systems

C. Passage of Digesta through the Rumen

D. Expected Extent of Digestion in the Rumen, Based on In Vitro Fermentations and Continuous Fermentation Theory

E. Significance of Rumen Turnover in the Ruminant Economy

F. Divergence of the Rumen from the Continuous Fermentation Model

Chapter VI Quantities of Carbohydrate Fermentation Products

A. The Metabolic Significance of Carbohydrate Fermentation

B. Measurements of the Rumen Carbohydrate Fermentation

C. Stoichiometry of the Rumen Fermentation of Carbohydrate

D. Conversions of Certain Intermediates in the Rumen Fermentation

Chapter VII Conversions of Nitrogenous Materials

A. Proteins

B. Ammonia

C. Utilization of Urea

D. Rumen Synthesis of Amino Acids

E. Nature of the Microbial Protein

F. Quantity of Microbial Nitrogen Available to the Host

G. Thermodynamic Limitations on Protoplasmic Synthesis Imposed by Anaerobiosis

H. Summary

Chapter VIII Vitamins and Minerals

A. Vitamins

B. Other Organic Nutrients for Rumen Microorganisms

C. Inorganic Foods

Chapter IX Host Metabolism in Relation to Rumen Processes

A. Carbohydrate Metabolism

B. Nitrogen Metabolism

C. Fats

D. Appetite

Chapter X Variations in the Rumen

A. Influence of Kinds of Feed

B. Influence of Quantity of Feed

C. Other Factors

D. Summary

Chapter XI Possible Modifications in Ruminant Feeding Practices

A. Nitrogen Sources for Microbial Synthesis

B. Use of Carbohydrates for Microbial Synthesis

C. Other Nutrients Influencing Microbial Synthesis in the Rumen

D. Importance of Balanced Nutrients

E. Rumen Inoculation

F. Importance of Turnover

G. In Vitro Evaluation of Feedstuffs

H. Rumen Neutralization of Toxins and Production of Antibiotics

I. Problem of Excess Energy

J. Selection of Heritable Nutritional Traits

K. Rumen Contents as a Tissue

L. Conclusion

Chapter XII Abnormalities in the Rumen

A. Bloat

B. Acute Indigestion

C. Nitrate Poisoning

D. Ammonia Toxicity

E. Hypomagnesemia

F. Enterotoxemia

G. Ketosis

H. Poisonous Constituents of Plants

References

Index