Artificial insemination of cows based on detected estrus is still a regular practice included in most reproductive management programs in the United States and elsewhere. Traditional methods of estrus detection are time-consuming, repetitive, and require qualified labor. In recent years, there has been an explosion in the development and adoption of automated estrus detection systems for dairy farms, especially those monitoring individual changes in physical activity. This article will discuss the potential benefits of using automated estrus detection, limitations of programs relying solely on insemination at detected estrus, and ideas for integrating activity monitors into effective reproductive programs.