Australian Wagyu Forum

Japanese AI Bull Selection

Modern sire selection practice typically combines Fujiyoshi, Kedaka and Tajima bloodlines to achieve a superior overall feed investment performance. (See Average Bloodline Composition of Calf Market Sires). The process of selecting AI bulls for the Japanese national Wagyu herd is managed by LIAJ.

(Livestock Improvement Association Japan) LIAJ is a corporate body made up of members from 42 prefectures, the Wagyu Registry Association (Zenwa), the Japanese Holstein Association, and the Agricultural & Livestock Industries Corporation.

LIAJ manages breeds bulls, manages progeny testing, publishes results, distributes semen, distributes veterinary drugs and manages traceability systems. Production of candidate bull calves is also undertaken by individual prefecture breed organisations and private breeding centres. About 40 new candidate bulls are entered into the progeny test every year.

The progeny test system consists of:

  • The Direct Examination(not compulsory)physical measurement of candidate AI sire performance commences at 12 months. Candidates are fed for two months with a uniform ration of 10% soybean meal, 20% Millrun, 35% Barley and 35% Corn. This enables objective measurement of both daily gain and feed efficiency. The young bull then enters the Indirect Examination phase with mating to a group of 8-35 female contemporaries.
  • The Indirect Examination (compulsory)focuses on progeny performance in both grow-out and carcass characteristics. Key parameters include:

Progeny Performance Measurement

    1. Daily Gain
    2. BMS
    3. Loin Diameter
    4. TDN Requirement
    5. Subcutaneous Fat
    6. Slaughter Yield
    7. Carcass Weight
    8. Rib Thickness
    9. Meat Grading (4~5 %)

Test progeny are usually slaughtered at less than 24 months of age.  Results of the completed tests bulls are published by ALIJ with an estimated Standard Breeding Values derived from the objective measurement process.

The entire selection cycle can take up to three years.  Semen doses for new sires are generally priced from $10 ~. Established sires can remain in catalogues for many years, with some going back to 1993. Straws for ‘Super Sires’ can be priced to $1,000. Semen availability is then publicised in local prefecture bull catalogues, by the ALIJ and private breeding centres. Distribution is undertaken by registered artificial insemination technicians and registered veterinarians.

Note that selection for maternal characteristics/milking ability is limited as this is not an important requirement within the overall production regime. However, this does NOT mean Wagyu females cannot feed calves.  Some prefecture bloodlines are noted for superior milking, but outside prefecture line-bred herds, assessment of individual animals is the best way to select for maternal capabilities.