A popular method of breeding selection with the Wagyu breed is the use of the “16×16” analysis to group animals into one of 4 major groups, and then breeding through a rotation of animals in these 4 groups. This is done to try to create “balance” in offspring, and to avoid inbreeding.
There are 3 major genetic bloodlines of Black Wagyu cattle. Red Wagyu, or “Akaushi” as they are also referred to as, could be considered a 4th major bloodline, as they are considered to be Wagyu, but are distinctly different than the 3 major bloodlines of Black Wagyu cattle. But most people disregard the Red Wagyu/Akaushi when discussing 16×16 Analysis and Wagyu rotational breeding, since many Wagyu breeders consider the Black Wagyu to be a different “breed” than the Red Wagyu/Akaushi, even though they are both considered “Wagyu” in Japan and by the major Wagyu breed associations outside Japan.
The 3 major genetic bloodlines of Black Wagyu cattle are:
- Tajima – consisting of animals of the Tajima/Tajari bloodline, know for smaller size, slower growth, but also known for the best quality marbling.
- Kedaka – consisting of four “minor” genetic bloodlines including Kedaka, Tottori, Okayama and Hiroshima, and known for larger size and faster growth, while also having good marbling, and also known for outstanding maternal characteristics.
- Shimane, sometimes also referred to as “Fujioshi”, consisting of two “minor” genetic bloodlines, Shimane and Itozakura.
Together, the three “major” genetic bloodlines of Black Wagyu cattle include all seven of the “minor” genetic bloodlines.
While this grouping methodology works to simplify the grouping of animals, it is not “perfect science” because there is variation between animals within the minor bloodlines, and certainly the major bloodlines.
The “16×16” analysis identifies the minor bloodlines within an animal down to the “1/16th” level in order to provide a relatively simple method of evaluating genetic similarity or difference between two animals. It can also be used as a simple way of trying to understand what a physical animal might be. For instance, an animal that is very high in Tajima blood wold normally be expected to be smaller, slower growing, below-average maternal characteristics, and above-average carcass marbling. Conversely, an animal that was very high in either Shimane/Fujioshi or Kedaka could be generally expected to be larger, faster growing, with above-average maternal characteristics, and below-average carcass marbling (compared to the average Wagyu animal).
There are two similar “rotational breeding” methodologies utilized in the Wagyu Breed. One was documented by Mr. Shogo Takeda in 2016 and is referrred to as the “Rotational Breeding Model”. The other similar model is the “Sandwich Cross Model”, which was developed in Japan, and described in the Japanese Wagyu Journal by Masakazu Miyashia, DVM in 2007. The intent of these breeding methods is to create balanced females and beef cattle that have consistently high quality carcasses. Outside Japan, the “Rotational Breeding Model” is more popular than the “Sandwich Cross Model”, but the two models are similar.
In the Rotational Breeding Model, animals are grouped into 4 groups (A, B, C or D) and bred in a “rotation” designed to balance the theoretical attributes of one vs. the others. In this method, animals in Group A are
According to Mr. Shogo Takeda, “Super size, good marbling, good milk production, and good calf raising ability are the keys to success in Wagyu breeding!” However, too many breeders are still focusing too heavily on marbling, at the expense of other important traits, “Tajima, Tajima, Tajima,” he said. Under Mr. Takeda’s four-stage Rotational Breeding Model, the emphasis is put on building frame score first, and then marbling. Mr. Takeda maintains that a breeding program based on his rotation technique is more likely to deliver the best overall profitability in the long term.
For each of the Groups: A, B, C, and D, he lists the traits in order of priority and significance.
- Group A – (Shimane- Itozakura Lines) – Large Size, Good Marbling, Excellent Maternal Sire
- Group B – (100% or High Tajima) – Small Size, Best Marbling, Poor Maternal Sire
- Group C – (Kedaka, Okayama, Hiroshima Lines) – Large Size, Good Marbling, Excellent Maternal Sire
- Group D – (High Tajima) – Medium Size, Better Marbling, Average Maternal Sire
This model is based in a broad sense on a “back cross” method. It is recommended to use a different sire from the same group on the second rotation. If you start with high Tajima dams at the beginning, use growth type sires (Group A or C) to increase the body size but pay attention to calving issues when using the larger Group A and Group C sires to breed smaller Group B and Group D females. It is possibly better to flush these dams and use larger recipients to birth the resulting embryo calves. Generally, calves from smaller Group B or D (Terminal sire) animals are smaller than Group A or C’s (Maternal sires).
Some Wagyu breeders plan their breeding with “religious vigor” using the Rotational Breeding Model. Others try to generally stick to the model, but are not as strict, and look more closely at the individual animal, rather than the theoretical group the animal should be in. And once a herd is “balanced” then the lines between the groups become more “blurred” and it is more difficult to assign animals to these 4 groups because they are a genetic blend of all four groups. And then some breeders of Wagyu who cross Wagyu bulls with cattle of other breeds to make percentage Wagyu for terminal beef production prefer their bulls to be heavily weighted on carcass quality vs. size and maternal characteristics because all of the offspring will become beef animals, and therefore maternal characteristics of offspring “don’t matter”, and because in theory there should be some “hybrid vigor” that will help growth when a Wagyu is crossed with a non-Wagyu, which helps with growth and size of the beef animal offspring. And some seed stock producers purposely breed (for instance) pure Tajima or high-Tajima animals together (by way of example) to make next generation animals that are prime examples of Group B or Group D animals to be used in this rotational breeding program in the future. Obviously, if everyone were to utilize this rotational breeding program to produce all of the future animals, then all future animals at some point in the future would be “balance” and there would be no “100% Tajima” or “high Tajima” or other “pure lines” of Wagyu, and thus this rotational breeding concept could not be used. This outcome occurs to some degree in the herds of breeders who follow this breeding methodology over time as their herd of breeding females become more “balanced” after several rotations of this methodology. So this methodology works better in theory if one is breeding “foundation animals” rather than balanced animals that result from years of following this rotational breeding methodology.
And it should go without saying that an essential component of these rotational breeding methodologies (or any selective breeding methodology) is that offspring be evaluated and sires and replacement heifers be selected based upon such evaluation. It is possible that an offspring might inherit the undesirable characteristics of smaller size and slower growth from the Group B and Group D animals paired, while also inheriting the undesirable below-average carcass qualities of the Group A and Group C animals that were paired. Of course, the desired outcome is the opposite (the desirable characteristics inherited from the sire and from the dam), but it is impossible to know what attributes were inherited by the offspring without measurement and evaluation. So evaluation of the offspring and selection of future breeding stock based upon offspring actual attributes after rotational breeding is essential to success.