 In the 1970s, the breed began to be revived through increased public interest. Breed societies have been established in the United States, Canada, the Netherlands, France, and Germany, and in 1996 the first World Shire Horse Congress was held in Peterborough. The first use within the breed of artificial insemination through frozen semen was with several Australian mares in 1997. Between the 1920s and 1930s and today, the Shire has changed in conformation. The Clydesdale was used for crossbreeding in the 1950s and 1960s, which changed the conformation of the Shire and most notably changed the feathering on the lower legs from a mass of coarse hair into the silky feathering associated with modern Shires. At the peak of their population, Shires numbered over a million. In the 1950s and 1960s, this number declined to a few thousand. In the United States, the Shire population dropped significantly in the early part of the 20th century, and continued to decline in the 1940s and 1950s. Between 1950 and 1959, only 25 horses were registered with the US registry. However, numbers began to increase, and 121 horses were registered in the US by 1985.
