During the past 50 years, selective breeding, improved herd management, and modern milking technology have all played an integral role in boosting productivity on US dairy farms. Since 1993, California has vigilantly guarded its title as the top dairy state. With the size of the state’s dairy cow herd roughly 40 percent larger than Wisconsin’s—the country’s next largest producer—at the end of 2016, California’s production title is safe for now. Even so, Wisconsin's dairy productivity is exploding, owing to increased investment in infrastructure and herd management. What’s more, Wisconsin's milk cows gained the yield crown in 2015, albeit attributed primarily to feed quality (California drought). As California’s dairy farms recover, you can track whether Wisconsin’s cows are able to hold on to their yield title.