[1] Work on breeding the Hays Converter began in 1959, and it was officially recognized by the Canadian beef industry under the Canada Livestock Pedigree Act in December 1975.
The Holstein cattle were chosen due to their good strong feet and ability to produce milk with a high butter-fat content, allowing calves to grow faster.
Lastly, the Brown Swiss cattle were chosen due to their perfectly shaped udder and ability to produce milk up until the end of lactation.
[6] Once the crosses began, Hays selected for the traits he wanted, and any offspring that did not make the cut in one way or another would have their tails docked and were shipped off to a processing plant.
These traits included high growth rate, sturdy build, good carcass quality, easy calving and excellent milk production.