How much have the domestic Japanese Black Wagyu herds of today lost prefectural differentiation and become genetically homogenous, with performance consistency?
Although the identification of a threatening genetic convergence towards a homogenous, inbred Japanese herd has fueled a prominent thread in Japanese Black Wagyu scientific discussion since the 1990s, Japanese science of the early 21st century has also presented evidence that economically important genetic differences remain between the remnant sub-populations of the five historic Chugoku ‘Black Wagyu cradle’ prefectures of southern Honshu – probably most significantly in female populations.
According to scientific literature published as recently as 2002, modern Chugoku ‘cradle’ prefectures continue to support unique tsuru cows and differentiated genetics with substantially varying performance characteristics. These prefectural characteristics are deemed sufficiently important to rate everyday mention in major Japanese sire catalogues, with comments such as “Good with Fujiyoshi female” being commonplace.
Prefectural genetic origins (those of genetic founder animals) identified in pedigrees are therefore important in everyday selection in Japan – perhaps not as important as progeny test results or EBVs based on carcass results, but an important part of the mix nonetheless.
There is no reason whatsoever why founding genetics data should be less important in non-Japanese, global Japanese Black herds, given the fact that Australian and American pedigrees retain this prefectural origin data and also given that most exports took place in and around the time frames of the studies referenced in this review.
In fact, given the lack of any comprehensive selection tools based on hard carcass data, the combination of pedigree analysis with phenotype review is the logical starting point for any analysis of a fullblood Japanese Black animal in Australia or the United States.