The prerequisite for sustainable dairy production is persistent lactation and high yield. The trend is fewer but bigger herds with increasing level of automation, like automatic milking (AM). To increase the efficiency in AM, automatic cluster take off can be done at high milk flow levels and with reduced prestimulation, which we consider have negative impact on udder emptying. In AM each udder quarter is milked separate. However, the knowledge of optimal use of AM, for instance with quarter milking and how the routines influence udder emptying and production is insufficient. The aim with the project is to evaluate how prestimulation and cluster take off, in combination, shall be practiced for efficient milking in sustainable production. For a better understanding of the importance of the routines, we will study if milk fat is involved in the regulation of milk synthesis. With this new knowledge routines can be developed for better use of AM, optimal milk extraction and better economy.