Dairy farms need to reduce nitrogen (N) emissions, but strategies are lacking. N emissions are difficult to measure, thus, milk urea (MU) was proposed as a proxy. MU is heritable and a breeding value (BV_MU) is available. However, neither MU nor BV_MU has been applied so far, because the linkage of MU variation and N emissions is unclear. This project investigates this linkage to enable (combined) feeding and breeding strategies with MU and BV_MU for dairy farmers and the government to mitigate N losses.