Wagyu Breeding In Japan

- Breeding Strategies
- Traditional Lines
- Modern Lines
   - Okayama
   - Shimane
   - Tottori
   - Hyogo (Tajima)
- Modern Wagyu Substrains

Breeding Strategies

Breeding strategies for Black Wagyu in Japan have changed considerably since the closed herd situation maintained by individual prefectures through the nation in the past.  Outside Hyogo (home of the Tajima strain), each prefecture today uses semen from a range of herds in other prefectures to produce AI sires within highly structured selection programs.

The objective is to capture superior traits from outside herds and express these in enhanced next generations.  For example, Okayama prefecture has focussed on Kedaka genetics to improve carcass weight and marbling.  Across Japan, many sires express the Kedaka bloodline of Hirashigekatsu (bred in Tottori) over the Tajima genetics of Yasufuku.

In the end, however, all combinations are assessed against a uniform JMGA carcass grid that measures key traits such as marbling, meat colour and yield.

For a scientific look at the contemporary Japanese Black Wagyu genetics scene see Sasaki et al:2006 and Kahi & Hirooka:2005.

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Traditional Regional Breeding Lines (Tsuru)

Distinctive lines or strains (Tsuru) of Black Wagyu have been bred in individual prefectures of Japan over centuries. High levels of inbreeding have been used to improve and fix the ability of each line.   Australian Professor John Longworth published a fascinating look at traditional Japanese methods in 1983. See a partial reproduction on the UK-based Lucie’s Farm website.

By prefecture, following is a listing of the oldest “Tsuru” in Japan.

• Okayama – Takenotani-zuru
• Shimane – Tokura-zuru
• Hiroshima – Iwakura-zuru 
• Hyogo – Syusuke-zuru

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Modern Japanese Lines

The dominant Black Wagyu strains of today are founded on the Tsuru strains and, in modern Japanese breeding; a complex balance of genetics from different lines is combined in efforts to produce ‘Super Sires’.  Much emphasis is placed on breeders’ own Super Cows (Tsuru Ushi) in selection.

Following are the major contemporary prefecture lines in Japan:

Okayama (Shimomae)

Okayama Wagyu was founded on a large framed sire, Dai 13 Hanayama . His lineage was subsequently divided into separate lines as follows:  Shimomae Line (Okayama), Kiyokuni line (Okayama) Fujiyoshi line (Okayama) and Itozakura line (Shimane).

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Shimane

The following are the modern Shimane substrains:
Itozakura Line: This line traces back to Dai 6 Fujimori, an Okayama bull of outstanding structure, with strong length, depth and good milk. The line is well represented in Australia through female progeny of the modern Shimane substrain foundation sire Dai 7 Itozakura.

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Tottori

The following are the modern Tottori herd substrains:

Eiko Line: Founded on the large frame sire, Eiko, with good meat quality and milking ability.  There are number of females from this line in the Australian herd.

Kedaka Line : This line commences with an Eiko son, Kedaka, from a Nakadoi and Kumanami line dam. Kedaka was a large framed bull with superior meat quality (especially marbling) and good milking ability. Kedaka sired the super bull “Dai 20 Hirashige”, very popular in Japan from 1985 to the present day. There are only a few Kedaka line bulls available to the Australian breeder.  (See table of available sires in Wagyu Genetics In Australia).

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Hyogo (Tajima)

Tajima lineage Wagyu are the most popular Black Wagyu in Australia, with a good representation of sires.   Genetic disease has been identified in this lineage in Japan and rigorous genetic testing is undertaken.  There are several substrains.

Nakadoi Line : More than 90% of bulls in the Hyogo-line belong to the Nakadoi-line, renowned for high marbling ability.  The Nakadoi line can be broadly separated into the Yasumi Doi, Kikumi Doi and Oku Doi lines.

• Yasumi Doi Line:  An early maturing type producing very high marbling and excellent meat flavor.  Tendency to lower weight gain.  Body type features narrow hip and narrow shoulder.
• Kikumi Doi Line (aka Kikuteru Doi):  Later maturing and known for good marbling and meat colour. Body type features good depth and length. Good maternal characteristics and volume of milk. Narrow hip is a body feature.
• Oku Doi Line: Founded on the sire, Okudoi, a son of Tajiri out of a daughter of Shirokiyo (Shiroiti Line). Good marbling ability, medium growth. 
• Shigekananemi Line (aka Kumanami Line): The Shigekannenami line is recognised for good growth and a well-balanced structure. The leading sire Fukumasa expresses broad shoulder and good weight gain while Shigeshigenami progeny are known for very good marbling ability despite narrowness of the shoulder.

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Modern Wagyu Substrains

The following is an extended list of modern Wagyu strains available to Japanese breeders.  Genetic availability for many is nonexistent outside Japan.

• Substrains
• Okayama
• Kiyokuni Line
• Shimomae Line
• Oocya Line
• Nakaya Line
• Adachi Line
• Fujiyoshi Line
• Shimane
  • Itozakura Line
• Kurahana Line
• Tottori
• Eiko Line
• Yuhou Line
• Kedaka line
• Hyogo
• Nakadoi Line
• Yasumi Doi Line
• Kikumi Doi line
• Okudoi Line
• Kumanami Line
• Shiroiti Line
• Kanemon Line

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