Rotational Breeding Guide

For breeders the rotational breeding system promoted by Mr. Shogo Takrda is a great tool to use. The system is used to create well balanced cattle that do well in the cow herd and also, deliver the best overall profitability.

As a point of reference, the following major strains and sub strains of Japanese Black Wagyu commonly have these traits respective to them:

  • Okayama; Shimomae: Large Frame
  • Sub-strains: Shimomae, Kiyokuni, Fujiyoshi, Itozakura
  • Shimane: Outstanding structure, strong length, depth, and good milking
  • Sub-strains: Itozakura
  • Tottori: Large frame, superior meat/marbling, quality, good milking
  • Sub-strains: Eiko, Kedaka
  • Hyogo; Tajima: Superior marbling, most popular
  • Sub-strains: Yasumi Doi, Kikumi Doi, Oku Doi, Shigakananemi, Shiroiti, and Kanemon


SCD typing in Wagyu is designed to aid in the selection of cattle with the inheritable genetic coding that produces a superior fat composition. Stearoyl CoA Desaturase (SCD) is the protein that is encoded by the SCD gene and is the enzyme that changes saturated fatty acid (Stearic Acid) that generates a harder fat with a higher melting point into an unsaturated fatty acid (Oleic Acid) that results in a softer fat with a lower melting point. Not only is unsaturated fat healthier, it is more desirable and pleasing to the palate. DNA sequences in Wagyu cattle are placed into two classifications of amino acids: A (Alanine) and V (Valine). Wagyu carry a genetic mutation that changes Valine to Alanine, the presence of A type amino acids have lower melting point of fat. The preferred SCD designation is AA ; Eighteen percent of Wagyu are designated as AA, 74% VA, and 8% VV.


 Calpains are the enzymes that weaken muscle fibers during the break down of proteins. Calpastatin is the enzyme that regulates the activity of Calpains; the balance between Calpain and Calpastatin regulates the muscle growth. Genes in DNA sequencing attributed to the tenderness are calpain (CAPN1) and calpastatin (CAST). Muscle mass in cattle is in a continual cycle of synthesis and breakdown. Increasing muscle mass occurs when the rate of synthesis is greater than the rate of breakdown of proteins in the muscle tissue. After harvest, the calpains continue the breakdown of protein in the muscle fibers resulting in the natural process of “tenderizing”. Higher levels of calpastatin result in the reduction of the amount of calpains and inhibit the breakdown of proteins, thus the meat will be less tender. The relationship between calpains and calpastatin after harvest is the natural process of improving beef through aging.

Wagyu Tenderness is passed down through heredity and selective breeding. The incorporation of tenderness traits in DNA validation testing is designated by a number on a scale of 1 to 10; with the most tender being “10”. Fifty-nine percent of the population of Wagyu cattle have scores of 1 to 5 and 41% have scores of 6 to 10.


1= 5.0%

3= 20.0%

4= 27.5%

 5= 6.5%

 6= 16.5%

 7= 16.75%

 8= 1.0%

 9= 4.75%

 10= 2.0%