The milk source belt in China is mainly distributed in the internationally recognized high-quality dairy cattle feeding belt with mid-temperate monsoon climate (40-47 degrees north latitude). This feeding belt runs through the grassland belt in the northeast, northwest and north China, including most provinces in the "Three North" area and Jiaodong Peninsula, where 70% of cows and more than 60% of raw milk are concentrated. These areas are called "golden milk sources" because they are suitable for raising cows, with large milk output and high quality.