An extensive fattening system with steers was established in order to defend the unique “Zickentaler Moor” within the scope of the project “rund ums moor”. From April to November the steers were pasture-fed and hay was additionally submitted to them followed by grass silage and hay in the winter months. In the last three to four months before slaughter the steers fattening was finished by grass silage, hay and 3-4 kg triticale per steer and day. Different breeds were tested in order to find the most suitable breed or crossing for the local conditions and the fattening system. There were significant differences between the breed groups in carcass weight. The interaction between breed group and year of slaughter was also significant. Apart from the fattening period, the net daily gains and the breed group also had a significant effect on the carcass weight. There were also differences regarding the interaction between the breed group and the net daily gains. In addition, differences in fat classification and conformation classification could be found between some breed groups. The reason for establishing the extensive steer fattening system was the recultivating concept of the project “rund ums moor”. This concept schedules the minimization of the eutrophication. The extensive management of the society “Rinderweide am Zickentaler Moor” ensures a higher nutrient output than input on the managed land around the “Zickentaler Moor”. The calculated “Hoftor-Bilanz” from the year 2010, showed a negative nitrogen balance of -2,133 kg. The nitrogen balances of the whole centre zone and the border zone of the years 2003 and 2010 showed a change in balance due to restructuring of the cultivation. Both balances from the centre zone and the border zone were negative.