History of Wagyu (Japanese Black)
The origins of domesticated Japanese Black cattle are unclear. However, a recent study on Mitochondrial DNA and Evolution of Japanese Black Cattle conducted by Mannen, Tsuji, Loftus, and Bradle, suggests that the modern Japanese Black cattle DNA sequences are descended from a mixture of early migrants from the original domestic centers of West Asia and a locally domesticated strain of wild oxen. The data further suggests that there was an ancient interchange of DNA with European cattle, perhaps a legacy of the first introduction of domesticates to East Asia over 5,000 years ago.
According to cited references, in North East Asia (including China, Korea, Japan), the earliest domestic cattle in the region were more than likely classified as Bos taurus and appear between 5,000 and 6,000 years ago, several thousand years after primary wild oxen domestication in West Asia. The extinct wild ox is thought to have been distributed locally, but whether its domestication led to North East Asian cattle, or if these were introduced from older exotic domestic stocks, is not known.
Further, around the second century A.D., cattle migrated from North China via the Korean peninsula to Japan. This cattle movement was accompanied by the introduction of rice cultivation. Both genetic and morphological studies have illustrated that native Japanese cattle are Bos taurus and are representatives of the "Turano-Mongolian" type. However, no further genetic information is available concerning the origins of the Bos taurus populations of North East Asia.
At the end of the 19th century, cattle of several European breeds were imported into Japan for the purpose of upgrading native breeds. According to the researchers, it is possible that some of this exotic genetic material retains an influence in modern Japanese cattle. However, the original importation strategy failed because hybrid cattle required more feed than natives and became less active for draft. The implementation of a resulting government policy quickly eliminated crossed cattle from herds to re-create completely pure breeds. Japanese Black cattle now have little influence from this 19th century genetic cross.
After World War II, Wagyu cattle were used less and less for farming purposes as they were being quickly replaced with farm machinery. In 1961, the Japanese government enacted the Agricultural Fundamental Act, and Wagyu cattle became an official beef breed. Since this time the Japanese farmers in partnership with the government have continued to improve the breed, now with a focus on the highest quality beef production. The intra muscular fat that provided the working energy for long days in the field at draft now sets Wagyu beef apart from all other beef in the world. The Japanese government has declared their Wagyu as a national treasure and has closed exports of genetics.