Tokyo - Japan's internationally recognized success in cloning cattle has come from years of work in the quest to protect and nurture a livestock industry where meat sells for up to $170 a kilogram ($77 per pound).
Japanese researchers announced earlier this month that they had cloned eight calves from one adult cow.
Since the first two arrived in July, 24 have been born, with many more expected, according to Japan's Ministry of Agriculture, Forestry and Fisheries. Of the group, however, 10 have died.
“We think there may be as many as 50 scheduled to be born by the end of next March,” said Hiroto Takahashi, an official in the ministry's Animal Production division.
Japan's achievements are more remarkable for the fact that, despite all its manufacturing and technological prowess, it has rarely been in the vanguard of scientific innovation.
But a lot is at stake.
One of the largest forces driving Japan's cloning efforts, researchers agree, is the quest for top-quality animals for meat production.
“The goal is to efficiently reproduce the best animals,” said Yoko Kato, a researcher at Kinki University in central Japan and a member of the team that cloned the eight calves.
“As things are now, even though you think a calf born from a good bloodline will probably turn out well, you can't be sure. Cloning allows you to make a lot of good copies.”
Writing in the journal Science on December 8, Kato's team, led by Yukio Tsunoda, described how they took the eggs from 10 different Japanese beef cattle and removed their nuclei.
They then got 10 cells from another cow. All were from the reproductive tract -- some from the cumulus cells, which nourish the eggs as they develop in the ovaries, and some from the lining of the oviducts, which carry eggs from the ovaries to the uterus.
As have other cloners, they “starved” the cells for three to four days until they entered a quiescent phase, then took out each nucleus, where most of the genetic material is found.
They transferred nuclei into hollowed-out eggs and tricked the eggs into developing as if they had been fertilized.
They picked 10 of these and implanted them into five cows. All five became pregnant and eight female calves were born. Four died soon after birth, but the researchers think outside causes were to blame, not the calves' genes.
Although Kato said she could not pin down why Japanese researchers were so successful compared to those overseas, she felt that superior Japanese in-vitro cultivation skills -- used during the period the eggs develop but before they are implanted in the cow -- were likely to be at least partly responsible.
Chikashi Tachi, a professor of Animal Biotechnology at Azabu University in Tokyo, agreed that technical skills did indeed play a large role.
But he said this should not necessarily be taken as a sign that Japanese research itself is breaking new ground.
“Once it became obvious that you could produce animals by nuclear transfer, it then became a matter of engineering, a Japanese specialty -- although it is certainly a great achievement to produce cloned cattle,” he said.
Noting that researchers in the United Kingdom first started cloning research more than 30 years ago, he added: “There's a long tradition necessary to do really creative work, and while we are putting a lot of emphasis on basic research, there's still a tremendous gap.”
None of this comes cheaply, but Japan's beef industry is used to spending large sums to gain perfection.
The highest-quality beef, called “shimofuri,” or fallen frost, comes from cows that are fed beer and massaged by hand so their fat spreads evenly throughout the meat.
In contrast, the livestock industry overseas can produce meat for so much less than in Japan that cloning, at this point, seems more expensive than it is worth.
Tachi said there is another reason for cloning in Japan - the elimination of possibly damaging recessives from the gene pool.
“Japanese cattle, particularly the native breeds that are the target of the cloning efforts, have been bred relatively narrowly, and there is the chance of bad genes accumulating.”
“But cloning, from a guaranteed cow, would eliminate this.”
In addition to the high death rate, a number of hurdles remain. Kato said researchers remain unsure how many different types of cells may actually be successfully cloned.
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