 In the early 1930s, the United States Department of Agriculture (USDA) entered into an agreement with the Ministry of Foreign Affairs in Denmark for the purchase of 24 Danish Landrace to be used for swine research studies, with the stipulation that they would not be commercially propagated as a pure breed.Landrace was subsequently used in numerous comparisons with American breeds.In 1949, upon USDA petition, Denmark released the United States from its breeding restrictions.