German warmblood

(The Trakehner, while a warmblood horse from Germany, has a closed stud book and thus, like the Thoroughbred and Arabian, is considered a "true" breed.)

Formerly, the East Frisian (Ostfriesen) 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.

North Rhine-Westphalia traditionally breeds both the Westphalian and Rhinelander, which populate the State Stud of Warendorf and which work in close cooperation.

[2] Historically, each of the southern states had a very distinct population: Rhineland-Palatinate was a center for the breeding of elegant Anglo-Arabian riding horses, Baden-Württemberg bred Arabians and Arab-influenced riding horses at the State Stud of Marbach, and Bavaria was home to the ancient heavy warmblood Rottaler.

Of late, these three regions have combined their breeding and marketing efforts, so the modern Bavarian Warmblood, Württemberger, and Zweibrücker are increasingly indistinguishable.

Similarly, the eastern states of Berlin-Brandenburg, Saxony-Anhalt, Saxony, and Thuringia have begun hosting a common stallion inspection.

[3] The four popular breeds of German Warmbloods are bred with a focus towards their intended discipline, such as hunters, jumpers, and dressage.

On the other hand, Oldenburgs and Hanoverians are bred with a similar clustering pattern in the PCA (principal component analysis) and iHS (integrated Haplotype Score) selection signatures, leading them to have shared breeding.