This book provides a broad perspective on understanding bovine fertility, focusing on the classification and interpretation of bovine sperm defects. Building upon the success of its first edition published in 1989, this new edition has been significantly updated and expanded to reflect developments over the past three decades. The chapters cover topics such as the normal and abnormal development of bovine sperm, the mechanisms behind sperm defects, and the impact of these defects on fertility. Special attention is drawn at advances in genomic research and the use of sperm quality biomarkers and genetic screening tests in the assessment of bull fertility. In addition to this, the work explores critical periods for sexual development in bulls, such as early gestation and pre-weaning. This monograph is intended for researchers and students in the field of animal reproduction, veterinarians, and animal scientists. It provides a deep understanding of bovine fertility, a topic that is crucial for anyone working in livestock production or related fields. The knowledge gained from this book will be beneficial to those seeking to improve livestock productivity and thus contribute to global food security.