The oldest sheepdog was born in 1691, according to the National Sheepdog Foundation.

The oldest shepherd dog was born on May 31, 1842, according the Foundation. 

The oldest wolfhound, a mix of the two breeds, was born about a decade earlier.

The youngest of the four breeds is a mix between the German shepherd and the American pit bull terrier, which was born some 50 years earlier, according The National Sheepdogs.

The National Dogs Association, which has about 2,500 members, estimates that there are at least 700 sheepdogs around the world.

The group says it has seen a surge in interest in breeding dogs since its foundation began working to breed sheepdogs in the early 1990s. 

In 2011, the National Dogs Alliance reported that the number of dogs in the United States with a pedigree had more than doubled since 2005. 

 The breeders have also been working to improve their breeding techniques.

In 2014, the organization announced that it was working to introduce breeders to the International Standard for Standardization for Standardized Pup Training. 

The National Dogs Foundation says it is working with the American Kennel Club and the National Institute of Standards and Technology to set standards for the breeding of sheepdogs.

It is hoped that the American breeders and the international breeders will develop standards that are consistent with the national breed standards for sheepdogs and will provide a uniform breeding program that will make it easier for the American public to adopt and live with a sheepdog. 

“The International Standard of Standardization, a collaborative effort between the American Society for the Prevention of Cruelty to Animals and the World Health Organization, provides the international standard for the care, welfare, and management of the world’s domestic and wild animals,” the foundation says.

“This international standard will facilitate the adoption and training of sheepdog breeds that meet the health, safety, and welfare requirements of the United Kingdom, the United Nations, the European Union, and other nations.”