The aim of the project is the introduction of precision breeding for endangered domestic breeds, with the help of breeding parameters selected from real-life. With this objective, for the first time the OG wants to record, with researchers and practitioners, the features of four endangered Schleswig-Holstein domestic breeds. For the German Red Pied (Rotbunte Rind) cattle and the Angeln cattle (Angler Rind), the basis for a cow training sample will be developed to derive the relationship between genotype and phenotype with the parameters of calving, milking, udder health, and fertility. For the Angeln Saddleback (Angler Sattelschwein) and the German Whiteheaded Mutton (Deutsche Weißköpfige Fleischschaf), the development of performance characteristics for fattening and meat quality is planned in the project. The development of an app for the collection of health data, for example for the German Whiteheaded Mutton, is intended for testing by practitioners in the project. It can be extended to other populations if found to be successful.