Most of the clinical disease events in a dairy cow’s life occur during the transition period, defined as the period three weeks before and after calving. It is believed that almost all cows experience some immune dysfunction during the peripartum period, and that this combined with nutritional disturbances or certain management practices leads to a variety of metabolic and infectious disease events. This chapter addresses the best way to monitor the health and management of cows during the transition period and discusses a number of factors that can affect herd transition health, including the intrinsic characteristics of the cows, limitations and challenges associated with the housing and environment in which cows are placed and interactions with caregivers. While this chapter does not focus on nutrition per se, many of the risk factors will manifest themselves as changes in the availability or need for nutrients.