Cattle Genetic Resources in Japan: One Successful
Crossbreeding Story and Genetic Diversity Erosion
Mitsuru Minezawa
Animal Genetic Resources
Laboratory, Genebank, National
Institute of Agrobiological Sciences, Japan
Kannondai 2-1-2, Tsukuba,
Ibaraki 305-8602, Japan
I. Beef cattle production background
I-1.
Historical features influencing cattle
production
Besides pigs
and ducks, Sus scrofa and Anas sp., no ancestral domesticated animals naturally inhabited
Japan. Domestic animals, such as pigs, cattle and chickens were
introduced in the late Jomon (~ B.C.
500)
to Yayoi Eras (B.C.
500
–
A.D.
300).
A
Chinese historical book (~ A.D.
250)
described that there were no cattle, horses or sheep in Japan. Because
no descriptions of pigs and chickens were found in the book, the possibility
of their existence could not be denied.
Several
books written in the mid 7th century referred to cow’s milk.
Engishiki (A.D.
927),
written in the Heian Era, is a description of the milk product, “So”,
surmised as condensed milk for medical purposes. A
reference to a presentation of “So” to the government is made in this
book. However, this habit was abolished at the beginning of the 12th
century. The government banned the slaughtering of animals, cattle, horses,
dogs, monkeys and chickens in A.D. 675.
Cattle
and horse slaughtering were abolished again in A.D.
742.
This
suggested that the people of this period ate meat.
After the
prohibitory edict, meat and milk became less common. A
pictorial book, written around A.D.
1700,
introduced dairy products. However,
the main use of domestic animals was for transportation of goods, farming, or
military power. Some
agricultural books introduced a feeding system aimed at manure production.
The
history of domestic animals for practical food production in Japan is
extremely short compared to most other countries. This seems due to two reasons. First,
the climatic conditions in Japan are suitable for grain cultivation and the only purpose for cattle was to assist in rice
cultivation. Second, for a long time Buddhism was predominant in Japan
and prohibited
the eating of meats; especially from four legged animals. The utilization of animal products did not become popular
until the Meiji era; especially in the central region of Japan. Meat has been consumed in Japan for only about 130 years,
the beginning of the Meiji era. Meat
eating has only reached widespread popularity in the last 30 years. Therefore, Japanese cattle were not subject to improvement
techniques for milk and meat production before the mid 1950’s.
The
“Law for Improvement and Increased Livestock Production” was enacted in
1950. The law stipulated that the
government was required to establish the goal of improving and propagating
livestock, stating, “The minister of Agriculture, Forestry and Fisheries
shall set specific goals by species concerning the improvement and propagation
of livestock including cattle, horses, sheep, goats, pigs and other livestock
stipulated according to the related ordinances and publicize each goal”.
In
the Meiji era, many foreign cattle were introduced to Japan and initially
extensively crossbred with the native cattle under the leadership of the
government. Through this, the gene pool for Japanese cattle were
diluted and greatly expanded. After the
initial frenzy of crossbreeding was over, cattle breeders began to
improve and promote their own breeds
without crossbreeding within prefectures. The
unique characteristics of Japanese cattle were then established
as found today. However,
followed by the
introduction and breeding efforts made in each region, most
of genuine Japanese native cattle diminished
and only Mishima and Kuchinoshima
cattle remained in two
islands, Yamaguchi and Kagoshima Prefectures, respectively (Fig. 1).
I-2. Domestic Animals in Japanese daily life
There
are many traditional events related to a variety of livestock that are still
held, particularly in relation to cattle and horses. These include “ushioni”
at the Warei shrine, the cattle festival at Uzumasa, and sacred rites relating
to fieldwork (Tsuda, 2001) in
rural Japan. At these events,
living farm animals play a leading role, but unimproved indigenous livestock
rarely appear. However, improved
breeds are now being utilized even at these traditional events and festivals
(Fig.
2).
Livestock
production now takes place on a large scale. The
presence and awareness of farm animals has gradually faded from ordinary life.
Only a few species have been bred for specific purposes, such as cattle
for bullfights, and Shamo,
Onagadori and Naganakidori as fighting cocks and pet animals.
Dishes using goat and pig meat in Okinawa Prefecture and “kiritanpo-nabe” using
Hinaidori in Akita Prefecture are the forms
of traditional cuisine utilizing traditional Japanese breeds.
Most non-native species have already become familiar in ordinary
Japanese life. With
the exception of chickens, the handing down of these traditional recipes and
breeds does not seem to have led to the protection of native animals.
II. Japanese native cattle breeds’ description
In 2000, there were a total of 2,824,000 beef
cattle and 1,764,000 dairy
cattle in Japan. The beef cattle can be classified into two categories, indigenous
and non-indigenous
cattle. The
former includes 1,700,000
Japanese beef cattle, named Wagyu, and the latter involves 461,000 non-indigenous dairy cattle and 663,000 corresponding crossbred animal. Wagyu includes four breeds, Japanese Black (93.9%), Japanese Brown
(4.2%), Japanese Poll (trace), and Japanese Shorthorn cattle (1.0%). Each breed that developed its own history and distinct characteristics will be described follows. However,
exotic cattle breeds contribute most milk production and more than 99% of the dairy cattle are Holsteins. Production from the two genuine Japanese native
cattle is in trace proportions
(Statistical Data Related to Livestock Improvement, 2001).
II-1 Mishima cattle (Fig.
3)
Mishima Island is situated at latitude 34°46'
N and longitude 131°8' E with an area of 7.8 km2 in the
Sea of Japan. Mishima
Island is small and with a restricted flat area. The rice fields are therefore small and
terraced. Mishima
cattle are suitable for small landholding farmers because of its small body
size and good temperament. The first official record indicated that 350 cattle were
annihilated for rinderpests in 1672. After that, a new herd was established. Four hundred thirty-three cattle were recorded
in 1739 and about 400 cattle had been kept up to the Meiji Restoration in 1868. Mishima cattle can be thought of as the original type of Japanese Black
cattle. They were designated a natural monument in Japan
in 1928. After this designation, Mishima cattle have been kept as
farm animals and for in situ conservation.
More than 300 female Mishima cattle were kept
up to 1961. The
number decreased after that and only 33 females remained in the middle of the
1970s (Furukawa et al., 1997).
The number of females has gradually increased to nearly 100 in 2002.
Mishima is classified as late
maturing cattle with dark brown coat color and
small horns as well as narrower
body compared to the modern Japanese Black. The
average wither height, chest girth and body weight of a mature Mishima female (60 months old) are 112.8 cm, 152.1 cm and 261.1 kg, respectively (Harada et al., 1996).
II-2. Kuchinoshima
feral cattle (Fig. 4)
Kuchinoshima island is situated at latitude 29°58' N and
longitude 129°55' E with an area of 13.3 km2 at the north end of Tokara Isles 200 km south
from Kyushu.
A record, written in 1727, indicated the existence
of domesticated cattle in Kuchinoshima (Tomita, 1996). However, Hayashida and Nozawa (1964) suggested that
these feral cattle were descendent from cattle of
Kagoshima during 1918 and 1919 and that had escaped from pasturage.
The population size of Kuchinoshima feral cattle
was 44
- 66
individuals in 1999. However,
there were two Kuchinoshima cattle
populations with
20 and 24 animals
in 2001, respectively, conserved at Kagoshima University and Nagoya
University. The body size of the Kuchinoshima cattle is smaller
than the Mishima cattle.
The average wither height and body length of a
mature female are about 110 cm and 120 cm, respectively. The coat color is mainly black with a white
spot in the belly and/or four limbs with brown color occasionally occurred.
II-3. Japanese
Black (Fig.
5)
Most Japanese Black cattle were crossbred, producing a
modern type of this breed. In the
Chugoku district, several pre-crossbred strains (Tsuru) were developed during
the Edo era (1600
– 1876). The primary function of these cattle was carrying firewood
for steel production and used as draft animals. After
the Meiji restoration in 1867, the government encouraged the introduction of
foreign cattle breeds for crossbreeding with native cattle to improve body
size and milk production. As
shown in Table I, various breeds were introduced and crossbred with regional
native cattle. In consequence, the genetic diversity of the indigenous
cattle was greatly expanded.
After the mid 1950’s, agricultural machinery
predominated and chemical fertilizer was more popular in agriculture,
supplanting and reducing draft cattle use. This
forced a shift in the reason for raising these cattle to beef production.
The Japanese Black is now found in all regions of Japan. This breed has increased in number in the Kyushu and
Hokkaido regions. However, in
the Chugoku region, which was once the main production region for this breed, the number of this
breed has decreased.
The characteristics of the
breed include dull black coat and skin, small to medium body size with withers height and body weight being 124 cm,
420 kg and 137 cm, 700 kg in mature cow and bull, respectively.
This breed has horns, but no humps. The milk yield over 180 days is about 1000 kg.
Compared to the other Japanese indigenous breeds, the Japanese Black
are noted for their capacity to produce high degree of fat marbling beef with a thin fat layer beneath the skin and surrounding the
internal organs.
II-4. Japanese
Brown
The Japanese Brown breed has two distinct strains and reared
mainly in Kumamoto and Kochi
prefectures, respectively.
The developmental processes of these strains are quite
different and usually described separately:
II-4-a.
Kumamoto
strain (Fig. 6)
The Kumamoto cattle is a red
colored strain in Kumamoto
prefecture originally developed from imported Korean cattle. After the late 1900’s, this breed was crossbred with many imported foreign breeds such as the Simmental and Devon breeds. A large body size crossbred cattle
was produced when Simmental cattle was used. The features
of this breed are high weight gain rate and large rib eye area.
The body weight of mature females and males are 600 kg and 950
kg, respectively.
II-4-b. Kochi strain
The Kochi strain was developed from crossing the Simmental
with Korean cattle introduced from Kyushu Island. This crossbreeding period was substantially shorter than
that for the Kumamoto strain. This reduced
the dilution of the original breed’s characteristics, retaining important
differences. These cattle have a yellow-brown coat, which is much
lighter than the Kumamoto strain. The cattle with black skin at horns, hoofs, eyelids, muzzle, tongue,
switch and anus are more valuable due to its similarity to typical of the original Korean breed. The beef production performance of this strain is similar
to that of the Kumamoto strain. The body
weight of mature females and males are 600 kg and 950 kg, respectively.
II-5. Japanese Poll
(Fig. 7)
This breed has been developed since 1916 from a cross
between the indigenous cattle with Aberdeen Angus bulls imported from
England. Furthermore, Japanese Poll
cows were crossed with Japanese
Black bulls to improve meat quality in 1975. Therefore, it can be
expected that not many
pure bred Japanese Poll cattle remained currently. However, neither
performance nor progeny tests have been practiced since 1986. The phenotypic characteristics
include hornless and black coat
color with withers height and body weight being
122 cm, 450 kg and 137 cm, 800 kg in mature cows and bulls,
respectively.
II-6. Japanese
Shorthorn (Fig. 8)
This breed is the result of crossbreeding begun in 1871
between the imported dairy Shorthorn cattle and indigenous
cattle in the northern parts of Honshu Island (Tohoku region). It is claimed that this breed can utilize the rough summer
grazing available in the mountainous parts of this region better than other
breeds. They are distributed mainly in the Tohoku and Hokkaido
regions.
The coat color of this breed is a deep red-brown that is
darker than the Japanese Brown.
The
Japanese shorthorn seems superior to the Japanese Black for milk production,
forage intake and growth rate. The
withers height and body weight of mature females and males are 128 cm, 500 kg
and 140 cm, 800 kg, respectively.
III. Genetic analysis
of Japanese native cattle breeds
and populations
III-1. Genetic variability of
Japanese Cattle
The genetic
variability of three breeds, Japanese Black, Japanese Brown and Japanese
Shorthorn, is almost the same as that of Holsteins from several indices
estimated using the blood type, blood protein, milk protein and microsatellite
DNA polymorphisms as genetic markers. Mishima
cattle revealed low genetic variability,
which accounted nearly half of the other breeds
(Abe et al., 1977;
Kato, 2002). Kuchinoshima Feral Cattle also
showed
the same level of genetic variability as Mishima cattle using the same set of
microsatellite DNA loci (Kato, 2002).
In the mtDNA,
inherited through the maternal line, 24 haplotypes were observed based on 18
mutations in the Japanese Black (Mannen et al.,
2000). Only
two haplotypes were found in the 6 maternal lines known for Mishima cattle
(Shi et al., 2002).
Abe et
al. (1977) reported that the Japanese Poll possessed slightly lower
genetic variability than the other Wagyu breeds. However,
the population size of this breed has recently been drastically reduced. The
level of variability also seems to have been decreased to a critical level.
P.poly, the
average heterozygosity and average number of effective alleles in each breed
and population are shown in Table 2. The values
for these indices in the Japanese native cattle populations are clearly lower
than that in the other three Wagyu breeds.
The average
number of effective alleles of the Holstein, Kuchinoshima
Feral and Mishima were 2.51,
1.48 and
1.40, respectively. The average heterozygosity was 0.521, 0.242 and
0.209, respectively. It is clear that the genetic
variability of Japanese pure native cattle is quite low (Table 2).
III-2.
Genetic
relationship among Japanese native breeds and populations estimated from
genetic distance
One
hundred forty two alleles from 23 microsatellite loci were found in the three
Wagyu breeds, two pure Japanese native populations and the Holstein breed.
Only 58 alleles were observed in the Mishima and Kuchinoshima
population. Forty-five
of 58 alleles are shared with other groups, the three Wagyu breeds and
Holstein. Twelve
alleles are shared with only the Wagyu breeds. Only
one allele was specific to the Mishima population. Therefore,
it is suggested that many genes inherited from the past native Japanese cattle
population still remain in the present Japanese beef cattle breeds.
The genetic distance estimated
from the blood type, protein and DNA polymorphism shows that the Wagyu and
Holstein have a close relationship. The Japanese
native cattle, Mishima and Kuchinoshima reveal a relatively large distance
from the Wagyu and Holstein groups. The genetic
distance between the Mishima and Kuchinoshima is greater than that to the
Japanese Black and Japanese Brown (Table 3).
Although many alleles shared
with the pure Japanese native are still left in the Wagyu breeds, Japanese
beef cattle breeds are rather close to the Holstein breed presumed from the
genetic distance. While the Wagyu originated from native
Japanese
cattle, they
differ greatly genetically from their origin because of crossbreeding with
exotic breeds in the early breed development stage.
The
large genetic distance between the two
Japanese native populations is believed partially
due to a genetic drift in different directions after introduction to both
islands. This
also suggests the existence of geographical differentiation in the past
Japanese cattle population. Other
phenotypical differences were reported in these two populations
too.
The
coat colors of the two populations are different, as described above. The
meat quality of Mishima cattle is similar to the Japanese Black, which is
famous for marbled meat. The
Kuchinoshima produce lean meat. The
muscular marbling in the Japanese Black is deemed to have crossed
with indigenous cattle in
the
Chugoku district where the Japanese Black developed and Mishima cattle
originated.
IV. Perspective
on Japanese native cattle
Four beef cattle breeds, the Japanese Black, Japanese
Brown, Japanese Poll and Japanese Shorthorn were established in Japan and considered
as indigenous
to Japan, although they were initially extensively crossbred with foreign
breeds in the early 1900’s. The
breeds used for crossing and the selection criteria varied significantly from
prefecture to prefecture. Consequently, a number of distinct strains were
established. At present, however, the genetic diversity is decreasing
due to the concentration around a limited number of Japanese Black strains
noted for their superior meat quality. After the
liberalization on beef importation in 1991, other breeds, with meat quality
thought difficult to discriminate from foreign beef breeds, are decreasing
steeply.
Japanese native cattle could therefore be categorized into
three groups: (i) not at risk, Japanese Black; (ii) presently not at
risk but potentially endangered, Japanese Brown and Japanese Shorthorn; (iii) at risk,
Japanese Poll, Mishima and Kuchinoshima feral
cattle. From the
genetic conservation point of view, the systematic conservation of minor
Japanese breeds and minor strains of Japanese Black is recommended using
frozen semen and embryos for future genetic resource demands such as emergency
measures or as supplemental measures for in
situ and live animal conservation.
From the sustainable cattle breed viewpoint and for making
full use of Japanese natural resources without environmental damage, it is
necessary to develop appropriate rearing systems for these cattle breeds and
the two indigenous populations. The
Japanese Brown in Kumamoto and Japanese Shorthorn in the Tohoku region have
superior grazing traits compared to the Japanese Black. The Japanese Brown was
bred and grazed in grasslands located in mountainous-hilly areas.
In 2000, direct payment systems to the mountainous-hilly areas started
in accordance with the Basic Law on Food, Agriculture and Rural Areas.
In Aso, this grant is used to promote animal production focusing on the
maintenance and management of grasslands and the Japanese Brown cattle.
References
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and utilization
of beef cattle genetic resources
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T., Oishi, T.
and Komatsu, M. 1977.
Genetical
constitution
of Japanese cattle as determined by the gene
frequencies
of blood groups
and protein types.
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S.
and Nozawa,
K. 1964.
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K.
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H.,
Kawasaki, J.,
Ishida, T.,
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Table 1. Foreign
breeds crossed with native cattle in each Prefecture
|
|
Prefecture
|
Foreign breed
|
|
Japanese Black
|
Kyoto
|
Brown Swiss
|
|
|
Hyogo
|
Shorthorn, Devon, Brown Swiss
|
|
|
Okayama
|
Shorthorn, Devon
|
|
|
Hiroshima
|
Simmental, Brown Swiss, Shorthorn, Ayrshire
|
|
|
Tottori
|
Brown Swiss, Shorthorn
|
|
|
Shimane
|
Devon, Brown Swiss, Simmental, Ayrshire
|
|
|
Yamaguchi
|
Devon, Ayrshire, Brown Swiss
|
|
|
Ehime
|
Shorthorn
|
|
|
Ohita
|
Brown Swiss, Simmental
|
|
|
Kagoshima
|
Brown Swiss, Devon, Holstein
|
|
Japanese Brown
|
Kochi
|
Simmental, Korean Cattle
|
|
|
Kumamoto
|
Simmental, Korean Cattle, Devon
|
|
Japanese Poll
|
Yamaguchi
|
Aberdeen-Angus
|
|
Japanese Shorthorn
|
Aomori
|
Shorthorn
|
|
|
Iwate
|
Shorthorn
|
|
|
Akita
|
Shorthorn, Devon, Ayrshire
|
