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Brazil's Cow Clones 'a la Natural' |
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By Mario Osava*
Tierramérica
visited the home of the two cows cloned in Brazil. So far, Vitoria
and Lenda are healthy. The lessons learned from their cloning could
contribute to the use of embryos in human regenerative therapy,
say scientists.
BRASILIA - Many people are disappointed when
they meet Vitoria and Lenda, the first cows cloned in Brazil. "They're
just like any others," tends to be the reaction when one first sees
the two at the experimental farm of Sucupira, 30 km from Brasilia.
Vitoria, 32 months old, and the calf Lenda, born Sep. 4, were the
stars of "field days" held Oct. 29-30 by the Genetics Resources
and Biotechnology Institute (Cenargen) of the governmental Brazilian
Agricultural Research Corporation (Embrapa), to show off its livestock
research to students, journalists, farmers and ranchers.
Covering 1,393 hectares, the Sucupira farm is where Cenargen, one
of Embrapa's 40 research institutes, conducts studies involving
cattle, goats, pigs and horses.
The two cloned cows graze in pastures like the others. They do not
receive any special treatment but are under close observation, Arlindo
Ferreira Oliveira, who is in charge of their care, told Tierramérica.
This life in the open countryside provides more useful information
than if they were confined in barn stall, says Rodolfo Rumpf, head
of the experiment as animal reproduction coordinator at Cenargen.
Lenda, white with large black spots, is still just a baby. But on
Oct. 29, just 55 days old, she tipped the scales at 110 kg. She
weighed 45 kg at birth, Sucupira veterinarian Mauricio Machaim Franco
told Tierramérica.
The "adoptive" mother, whose womb was used for gestation, is "very
protective". The cow never leaves Lenda's side and rejects strangers.
And Lenda "has yet to realize her starring role," jokes Franco.
In contrast, Vitoria, with her white head and brown body, "already
knows how to pose for photos," he said.
Vitoria has matured without suffering any diseases, despite the
disadvantages of her breed -- the Simmental, of Swiss origins --
in a warm climate that fosters parasites. Also, her hoofs frequently
crack, making her vulnerable to infections, but Oliveira says that
she always "comes out just fine."
Now she is being tested for her reproductive ability. The first
attempts to impregnate her in the natural way failed, but the scientists
are awaiting the results of the latest try, 40 days ago. If Vitoria
still is not pregnant, the next step will be artificial insemination,
Oliveira says.
Premature aging, which affected the famous cloned sheep Dolly in
Scotland, is not a concern in Vitoria's case because she was created
from an embryonic cell, that is, new genetic material, Rumpf explained
to Tierramérica.
But Lenda was cloned from adult tissue cells, with already defined
characteristics, which is why her development is being monitored
very closely. The scientist said they are tracking her weight, metabolism
and other biochemical processes in her body.
Lenda's mother was a Dutch breed. She died from hemorrhage when
she suffered serious cuts from a barbed-wire fence. The owner offered
the cow's ovaries to Cenargen, seeking to preserve the animal's
fertility and high milk output, at least genetically.
But the ova were damaged in transit and were not suitable for producing
embryos in vitro. Instead, the cells surrounding the eggs were utilized,
a technique that has proved successful in cloning experiments in
New Zealand, said Rumpf.
Because these are somatic cells, as they were in Dolly's case, and
not sex cells, premature aging is a real danger.
The emergency solution led to an important scientific advance. Cenargen
is trying to perfect the reproductive technique of cloning and then
"multiply animals that are genetically superior," says Franco.
Lenda allowed a second step, as a copy of an animal with known positive
traits, while "Vitoria is a shot in the dark," and may not repeat
the characteristics of the original cow, he explains.
Another objective is to clone Vitoria. The first attempt in 2002
produced embryos from cells taken from the cow's ear. In April,
a normal, healthy calf was born, but died two days later as a result
of ingesting uterine liquid during the caesarean delivery. A second
try was interrupted at eight months gestation due to water retention.
According to Rumpf, none of these setbacks really undermines cloning
as a reproductive technique. Two other embryos created from Vitoria's
skin cells are currently in gestation.
Cenargen also plans to make transgenic clones, introducing genes
from other species into the original genetic material in order for
the cloned cows to produce "medicinal milk".
The mammary glands are "natural bioreactors", excellent manufacturers
of substances that boost resistance to certain diseases, says the
researcher.
But it is essential to improve the efficiency of cloning, Franco
admitted.
Unlike other methods of artificial reproduction, cloning is based
on a cell from a single adult, so the offspring has its identical
genetic makeup.
Only five percent of cloning attempts produce fetuses, and of that
portion, only one to three percent survive. In vitro fertilization
is effective in about 50 percent of gestations.
A key factor is ensuring the receptor cows have "strong maternal
capacity", like the cows that carried Lenda and Vitoria to term.
They have a developed bone structure strengthened from previous
births and are less likely to reject the clone embryo.
The scientist believes that the effort is justified in having proven
that somatic cells preserve the genetic memory, and having contributed
to the use of embryos in human regenerative therapy.
In addition to being a tool of scientific study, cloning could increase
livestock production by selecting for exceptional animals. Lenda
is one such example.
Indeed, there is already a demand for animal cloning. But it could
be many years before the technique is efficient enough to meet it,
says Rumpf, adding that the Brazilian public has been receptive
of animal cloning in general.
The cloning projects have not meant high costs for Cenargen, which
has an infrastructure for preserving genetic material and for other
types of artificial reproduction.
Sucupira is home to the Brazilian Animal Germplasm Bank, with genetic
material from domesticated species in danger of extinction. Preservation
is the principal goal of the institution's biotechnology program,
Rumpf says.
Among the 200 cattle on the research farm there are breeds adapted
to local conditions and some that are in danger of extinction. Animals
of great genetic value and receptor cows for all types of reproduction
round out the herd, said Franco.
* Mario Osava is an IPS correspondent.
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