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Cow Clones 'a la Natural'
Mario Osava
BRASILIA, (Tierramérica) - Many people
are disappointed when they meet Vitoria
and Lenda, the first cows cloned in
Latin America. ”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 cows, the first cloned in
Brazil, 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, says
Sucupira veterinarian Mauricio Machaim
Franco.
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 realise her starring
role,” jokes Franco.
In contrast, Vitoria, with her white
head and brown body, ”already knows how
to pose for photos,” he says.
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 through copulation
with a bull failed, but the scientists
are awaiting the results of the latest
try, a month and a half 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 her
body's other biochemical processes.
Lenda's mother was a Dutch breed. She
died from haemorrhage 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 utilised, 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 admits.
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 foetuses, and of that portion,
only one to three percent survive. In
vitro fertilisation 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, says
Franco.
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