This section looks at the modern state of the Japanese Black Wagyu herd, now challenged by diminishing genetic diversity caused exclusively by intensive selection for a single (meat quality) trait. We skim the Japanese animal science that identifies this challenge to the once proudly unique tsuru of the traditional Chugoku district, and the parallel commoditization and march to uniformity also confronting Japanese Black genetics elsewhere.
Nonetheless, Japanese studies involving prefectural calf market and carcass comparisons have demonstrated significant performance differences between some prefectural herds well into the 21st century. Japanese animal science has called for genetic preservation programs and detailed schemes to modify the selection practices which some see as bringing the breed to a crisis. Illustrative tables are reproduced below.
After reviewing the post-1980s swing to Hyogo (Tajima) bloodlines in the national herd which was the catalyst to challenged genetic diversity, we identify a sire-level swing back to larger Tottori (Kedaka) sire genetics by 2010. Evidence for this can be examined cursory pedigree analysis of prefectural bloodlines within the leading contemporary sires of Japan, which are detailed in the ‘Sire Rankings’ for Japan on this site.
Similarly, more detail on the individual the five key prefectural herds of Chugoku is available in the ‘Key Bloodlines’ subsection.