The Red and White Dairy Cattle Association (RWDCA) began registry procedures in 1964 in the United States. Its first members were Milking Shorthorn breeders, who wanted a dairy registry for the cattle they had bred in prior years, including some red and white Holsteins. When Milking Shorthorn breeders were looking for potential outcrossing individuals to improve milk production, red and white Holsteins came into the picture, since the red colour factor is the same for both breeds. The RWDCA had adopted an "open herd book" policy, and the Red and White Holstein became the major player.