Introduction

Japanese fullblood Wagyu production is based on intensive management with minimal use of pasture.  Virtually all joining is by artificial insemination. AI sire selection is extremely rigorous, starting with highly structured testing of potential AI bulls.  The limited diversity of sires is a core foundation of the consistent maintenance of desired carcass traits across the national herd, aptly illustrated by the extraordinary influence of a single bull in recent carcass competition results. The key production trends are towards increased growth and carcass weights with maintenance of high marbling.