Milk and meat from cloned cows could hit grocery shelves
in a few years but would the products be safe? Scientists
and consumer advocates disagree on the answer.
The Food and Drug Administration has been wrestling
for more than five years with the question of whether
or not to allow the use of milk or meat from cloned cows,
swine and sheep, with a voluntary ban on such products
in place for now. Cloning companies and many scientists
say the products are safe to eat, while consumer advocacy
groups argue there are unaddressed concerns.
But milk and meat from cloned animals is unlikely to
hit grocery store shelves for a few years. Clones must
grow up before products from them can be used. And since
creating them is expensive, they will likely be used for
breeding, not for direct consumption, experts say.
Reports of abnormalities, higher disease susceptibility
and early deaths of clones have prompted many of the concerns
about using their milk and meat. (Dolly, the sheep that
was the first animal cloned by this process, was euthanized
at the early age of six, though scientists at the institute
that created her stated the disease she was suffering
from was unrelated to her being a clone.)
Some of these abnormalities result from slight changes
that occur when the DNA from the cow to be cloned is being
read and translated by the egg cell from another cow into
which it is implanted — even if clones are genetic
replicas, they aren't quite identical to the original
donor. These so-called epigenetic changes allow us to
tell human identical twins apart, said geneticist Bill
Muir of Purdue University, an author of a 2002 National
Academy of Sciences report on the scientific concerns
of animal biotechnology.
Abnormalities can result in prenatal deaths and deaths
early on after birth, but TransOva Genetics President
David Faber says that this is true of all artificial breeding
processes, including artificial insemination and in vitro
fertilization. Clones that do make it to adulthood seem
to be no different than their peers, Muir stated.
"Generally the animals that have survived have
been perfectly normal," said biochemist R. Michael
Roberts of the University of Missouri, also an author
of the 2002 NAS study.
Some consumer advocacy groups, such as the Center for
Food Safety, remain skeptical. CFS spokesman Jaydee Hanson
acknowledges that some clones do reach adulthood without
abnormalities, but contends that cloning is still an uncertain
science with potentially unknown effects.
"We're not saying that every clone comes out
wrong, but enough of them do" that more stringent
requirements should be used and more testing done, he
One big question on the minds of groups like Hanson's
is how these abnormalities would affect the composition
of milk and meat, whether it could change the nutritional
value or introduce some harmful component.
Muir says that the companies that do cloning
have conducted chemical tests, which they submit to the
FDA, that show that the proteins, fat and other components
in the milk of cloned animals appear to be the same as
in normal milk.
"The milk was ordinary milk," Roberts agreed.
Muir acknowledges that the cloning process could cause
different genes to be turned on , which could cause unknown
substances to be expressed in the clones. The substances could
escape detection because scientists don't know what
to look for.
But, he points out, "there doesn't seem to
be anything harmful."
Hanson, the Center for Food Safety spokesman, says that
though studies have found nothing wrong with the cloned
animal products, that doesn't mean they should be
fed to humans.
"We shouldn’t see what the effects are by
going ahead and feeding them to humans just in case there
aren't any," he said.
Consumer advocates don't think the FDA testing has
been rigorous enough.
"The FDA's done a poor job with the risk assessment,"
Hanson said. He called the FDA's work "a weak
risk assessment with people with a vested interest from
the industry side" participating.
Muir, Roberts and Faber contend that the studies that have
been done are more than adequate to assure the safety
of products from cloned animals.
The main concern that scientists actually had in the
2002 NAS report, according to Muir, was not the effect
of cloned products on humans, but the health of the animals
Young animals were of particular concern because their
immune systems tended to be more stressed, and there was
more risk of them shedding pathogens if they were used
for meat (in veal, for example). But studies and advances
in the last five years have answered many of these concerns,
Some worry that cloning would create a "monoculture"
that is susceptible to diseases because it has no genetic
variation (as is the case with some genetically modified
crops). But as Muir points out, sombe breeds of American
dairy cows today are so inbred that "we already have
that problem, and cloning is not going to make it worse."
Some lines of dairy cows are bred from just a few bulls
and are selected for their high milk production. Such
a high level of inbreeding in these normal cows means
they have weak immune systems and so they are fed antibiotics
(which many consumer groups also object to) because they
have such high rates of infection.
According to Roberts, of all the genetic methods that
the NAS risk assessment examined, "we felt the least
risk was actually from cloned animals."
What to expect
Concerns aside, it seems likely that the FDA's approval
is imminent and inevitable.
Would an FDA approval this week mean that meat and milk
from cloned cows would be on the shelves tomorrow? Probably
not, most experts say.
The first product to enter the market would be cow's
milk. Already, some 500 cloned dairy cows are ready to
produce milk, Muir says.
But its not clear when any of the milk would become
available. Many milk producers, such as Dean Foods Co.,
have said they won't use milk from cloned cows, largely
because of consumer backlash.
Meat deriving from cloned cows would take longer to
make it to market, and because the clones would likely
be used as breeders and not butchered for their meat (since
they would cost up to $20,000 a pop), "it's unlikely
that most consumers would eat a clone directly,"
Consumers would likely eat the offspring of breeding
clones, because breeders aren't interested in clones
for their milk or meat, but for their genes, Faber said.
Cloning: an insurance program
For farmers, cloning is a way to preserve the genes
of their best animals, Muir said. A farmer may breed a
bull with several of his cows, but won't know how
well the offspring will perform until they are grown,
at which point the bull may be gone.
In this way, cloning acts as an "insurance program"
for breeders, Muir says, allowing them to preserve the
genes of cows and bulls to create a clone for later breeding.
"You're putting him on ice and saving him for
later," Muir said.
Some meat companies have echoed dairy producers in saying
they would not use cloned meat, Hanson said, because of
Roberts says that labeling cloned milk or meat so that
consumers could avoid it is unlikely — the FDA has
not mentioned it in any of their draft assessments. He
says the task would be almost impossible, since the milk
that you pour into your cereal isn't just from one
cow. And while he thinks the public has a right to know
where its food comes from, "we know that this milk
and these meats are perfectly safe," he said.
Why concerns persist despite studies that deem cloned
milk and meat safe to consume is something that Muir,
Roberts and Faber chalk up to fear of change and the novelty
of the cloning process and its implications for humans.
Faber says there was similar resistance to using artificial
insemination to breed animals and even to pasteurizing
Cloned livestock "should have been approved years
ago," Roberts said. "It isn't the science
that's held things up. It's the reaction of the
Muir thinks people are made uncomfortable because of
the slippery slope from animal cloning to human cloning
and therefore think that "we're coming closer
to playing God," he said.