The dairy sector in the EU faces many challenges as a consequence of political, economic and societal developments. Many countries are responding to these changes by exploring the possibilities and constraints of scaling up and intensification. This also holds for Flanders and the Netherlands, wheredairy farming systems are already intensive. This paper describes high output dairy farming systems in the Netherlands and Flanders and discusses their problems, solutions and perspectives associated with grassland and forages. The dairy farming systems are generally characterised by high fluxes of nitrogenand phosphorus through the systems. Research has led to a strong decrease in mineral losses to the environment in practice. The decrease in grazing is another concern of high output systems. Many activities have been initiated with the aim of stabilisation of the number of dairy cows grazing. Further scaling up of farms and intensification is thought to be possible in the Netherlands and Flanders because of high soil fertility, favourable weather conditions, a good infrastructure and well-educated farmers.