each of the states of germany has its own local warmblood breeding society, or sometimes more than one. lower saxony is the domain of the oldenburg and hanoverian breeds, the latter being closely linked to the state stud of celle. formerly, the east frisian was also bred in that part of lower saxony, however most of the breeding stock was absorbed into the hanoverian gene pool after the second world war. more recently, the hessen horse was also made into an extension of the hanoverian herdbook. the northernmost region of schleswig-holstein has the holsteiner, while mecklenburg-vorpommern has the mecklenburger. north rhine-westphalia traditionally breeds both the westphalian and rhinelander, which populate the state stud of warendorf and which work in close cooperation.