The field of veterinary bacteriology plays a major role in veterinary medicine, human health and economics. Several major groups of bacteria are considered very significant in animal health and welfare. Some of these bacteria are very pathogenic, their severe pathogenicity cause different kinds and levels of infections to livestock, pets and wildlife. The present book comprises of ten chapters with emphasis introduction to bacteriology, structure of bacteria, mycobacterium, brucella, yeast, ruminant nutrition of animals, zoonotic and bacterial diseases, nutrition in animals, changes in activities of enzymes, energy and metabolism and pseudomonas. This book is highly useful for the students, teachers and researchers of veterinary bacteriology and continues to fill an important niche in veterinary education.