The burden and challenges of cow health monitoring is growing as qualified personnel becomes scarce, labor costs rise, and herd sizes increase. Minimizing disruption of cow routines is also important to support improved performance. In response to industry needs, availability of automated health monitoring systems has exploded. Most of the systems use wearable or non-wearable sensors to monitor one or more behavioral, physiological, or performance parameter associated with cow health. Rumination, activity, lying behavior, body temperature, and milk yield features are used alone or in combination to generate alerts that indicate potential health problems. Dairy managers are most interested in best use of these technologies to improve herd management.