The objective of this study is to clarify how modification of the dairy herd can improve the performance of automatic milking systems in Hokkaido. It is focused on the refuse time and milk flow speed, and calculates the daily milk yield and profit, by eliminating the nonconforming cattle and introducing new cattle. From the results, it is possible to secure additional milking time by changing the dairy herd to speed up the milk flow rate. It is found that milking efficiency can be improved. This is more effective than cattle culling to reduce the number of refusals.
