Biochemical profiles such as antioxidants and reactive oxygen species differ among the seasons as well as collection times. Winter season have higher concentration of antioxidants and lower level of ROS than summer season in bovine species in tropical climate. Similarly antioxidant level is higher and ROS level is lower in night as compared to day time in bovine species. Thus winter had greater beneficial effects than summer season on health and wellbeing of the bovine species in tropical countries. This book will be very useful to the scientists working in the biological rhythm of animals, animal breeders and dairy farmers in tropical countries.