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A clone is a
genetically identical animal produced from a body cell of the
donor animal. The first animal cloned experimentally was a sheep,
in 1997, by scientists at the Roslin Institute near Edinburgh,
Scotland. The clone, named Dolly, was born in February 1997, the
first living animal cloned from the cell of an adult rather than
from an embryo. Out of 277 cells taken from a ewe’s udder for
cloning attempts, only one was successful.
Later that same year
the first bovine clone was born--a Holstein calf named
Gene--cloned by ABS Global, Inc. in Wisconsin, created by stem
cell culture. Soon after, Japanese researchers delivered a live
cloned calf in a different type of process that could yield
multiple clones from a single fertilized egg.
Today the most commonly
used method is to create a copy of the original animal from skin
cells taken from the living animal. The cells can be used
immediately or frozen for future cloning. But a few years ago a
clone was produced by U. of Georgia scientists (working with the
biotechnology firm Prolina, later purchased by ViaGen) using cells
collected from a dead cow. The clone, named KC (Kidney Cell) was
created from a kidney cell obtained from a frozen beef carcass in
a freezer. She grew up normal and healthy, and was bred
artificially with semen from an Angus bull. In December 2004 she
gave birth to her first calf, named Sunshine--which proved that
cloned animals can reproduce and have normal offspring.
Sheep, cattle, horses
and other animals (including pets) have been successfully cloned;
the first cattle cloned experimentally at Texas A&M were born in
1998 and 1999. One of those was named Second Chance, a Brahman
bull calf born in 1999. He was a clone of Chance--the famous pet
bull owned by rodeo clown Ralph Fisher for 17 years; Chance
travelled with Fisher to many rodeos and had thousands of photos
taken with people sitting on his back. Fisher decided to let
researchers at Texas A&M clone the bull when he grew old, and the
clone was just like the original in disposition and physical
traits.
The cloning process has
been commercially available for cattle producers for several
years, and a number of breeders have cloned their best animals.
Some of the commercially produced clones are now 5 years old.
ViaGen, a company in Austin, Texas, has been cloning cattle for
purebred breeders--and has now cloned several famous bucking bulls
for producers of rodeo stock.
George Owen, of ViaGen, says bucking bull clones include copies of
Panhandle Slim (owned by Scot Accomazzo), Yellow Jacket (owned by
Milt Bradford) and Houdini (owned by Gene Baker). “The Houdini
clone is 4 years old and the Yellow Jacket clones are over a year
old,” says Owen. The Panhandle Slim clones are yearlings.
EXTENDING THE
BREEDING POSSIBILITIES
“For the bucking industry, cloning makes a lot of sense; it’s a
custom fit,” says Owen. The purebred breeders in beef and dairy
breeds can often collect enough semen from a good bull to last a
lifetime, but this is not so easy with bucking bulls. Fertility
can be questionable by the time the bull is retired from a bucking
career. Second, it’s hard to get many cows bred to a bull when
he’s performing. It’s hard to pull him off the road to turn him
out with cows at the right time. And third, AI is not used as much
with rodeo stock as in other aspects of the cattle industry. Most
rodeo cattle are bred by live cover.
Cows that produce
bucking bulls are usually very wild and tempermental; it is
difficult to run them through an AI program. Even if they are
inseminated successfully, conception rate is low due to the stress
experienced by these animals while being handled. Many of the
producers who raise rodeo stock prefer to turn the bull out with
cows rather than try to breed cows by AI. “Many of the top cows
for producing good bucking bulls are not easy to breed with AI.
Their disposition is not the best; they are not easy to work with.
Being able to just turn a bull out with them eliminates the
struggle to breed them by AI. If you can kick out 5 clones of a
bull like Panhandle Slim with all those cows you want to cover,
this takes out the hassle of doing AI,” he explains.
“Gene Baker told me that if he could make several more copies of
Houdini he’d put away the AI tank and not worry about trying to do
that anymore,” says Owen. By using clones, you can keep the
athlete on the bucking circuit and leave his young clones home
breeding all the cows. This is the ideal situation--using the
clones to extend the breeding capabilities of an outstanding bull.
The potential to extend the genetics is exciting. “Purebred beef
breeders are really starting to get into this, but I am pleased
with the number of bucking bull owners who are now deciding to
clone their animals,” says Owen. GOOD INSURANCE - You never know
how long a good animal will last. Having some tissue saved and
frozen (gene banking) so you could clone your best animal makes
good sense, he says. Also, you don’t know how long a good bull
will be fertile (for collecting semen or for live cover) and able
to sire offspring. If you have some clones from him that can
continue on, this is just good insurance.
“Gene banking allows
you to clone that animal later, any time you want. For instance, I
think Houdini was no longer capable of siring calves. His owner
still had some semen in the tank, but he wanted to make sure he
would never run out of Houdini genetics, and cloned the bull,”
explains Owen.
If you have an animal
worth more than $15,000 (the cost of cloning the animal) and it’s
insured, there is no reason to not gene bank that animal. “If he
dies tomorrow, I can make you another copy of him for $15,000,
which is what your insurance money would pay you,” he says. It
only costs $1500 to collect the tissue for gene banking, and you’d
have the future possibility of cloning that animal at any time in
the future.
Some bulls are worth a
lot more than $15,000 and there’s a lot of risk in that
investment. “Why risk a loss, when for $1500 you can have the
possibility of replacing him,” explains Owen. He feels that anyone
who buys an expensive bull should take a skin sample for gene
banking, before they ever put that bull out with a cow or collect
him. “Even if a bull doesn’t die, he won’t be able to breed cows
if gets injured,” he says.
ADVANTAGES OF
CLONING A COW
Most people think in terms of cloning a famous bull, but the
advantages are even greater when cloning a top cow. “I think
cloning will level the playing field between the bulls and the
females,” says Owen. A bull can be extended through use of AI and
frozen semen, but the cow can only be flushed so many times, to
produce multiple calves, and it’s difficult to do this.
“But if I made 10
copies of an exceptional cow, at a year of age I could flush each
one of those heifers to a different bull. I’d have 10 different
matings, the first time around. I’d flush that heifer til she
couldn’t be flushed any more. Let’s say we get 5 flushes out of
her that year. If you do the math on that, you’d have 50 different
matings in which you’d have a result--calves on the ground--in 12
months. By the time the clones are 18 to 24 months old you’d know
which matings nick the best,” explains Owen. Then you could
concentrate on those and produce multiple offspring from that
cross, for the rest of her life.
The advantage of
cloning a cow is that you can extend her breeding potential. “In
one year, I can make more matings than you would in a lifetime
otherwise. And you wouldn’t have to keep them all. You could sell
embryos, sell an interest in one or 2 and pay for the process.
This is really where it will take off and be beneficial. There are
some good maternal genetics out there, for producing great bulls.
You could clone your best cow a few times and extend her
productivity beyond imagining. We have some Longhorn breeders who
are doing this. They pick their top cow and make 5 copies of her,
then they can find that magic mating a whole lot quicker. It
really pays for itself that way,” says Owen.
CLONES MAY NOT LOOK
EXACTLY ALIKE
“It doesn’t matter what the clones look like; they are genetically
identical with the original animal, regarding what they will
produce when bred. We had a Longhorn breeder try to corner us on
that question. He said, if it doesn’t make any difference what
they look like, which clone would you buy, if one had little horns
and one had long horns? And I said I’d buy the cheapest one I
could, because they are all exactly the same genetically. I’d buy
the one with the little horns, for a lot less money, for she’s
going to flush exactly the same thing as the more expensive
heifer,” says Owen.
“It’s hard for people
to grasp that concept, but we tell them not to worry about what
she/he looks like, because the genetics are still the same. They
don’t all look exactly like the original; there may be a little
variance,” he explains. Even identical twins don’t always look
exactly the same. You might get brockle-faced or spotted twins
whose spots are a little different.
The white markings on
an animal, whether cattle or horses, can be a little different on
the clone than they were on the original. “For instance, we
produced a clone of Scamper, the famous barrel horse, and it has a
blaze face--and Scamper didn’t. But obviously Scamper had a little
bit of white somewhere or it wouldn’t show up; the possibility was
there. It has to be there in order to come out in the clone. But
that’s often the first question we get,” he says. Even the uterine
environment plays a role in what the results are with certain
inherent traits.
“When the little switch
gets turned on and off for color, or white markings, it varies in
utero, with each calf or foal that is created. You’ll notice in
our ad, using the clones of Panhandle Slim, they are all 98
percent identical. The shape of their spot may be different, but
the actual spot location is the same. There is also a black spot
on the left tailhead of every one of those calves. Each one has a
little differently shaped black spot, but it’s there. It’s
actually a little creepy, how much they do look alike, because of
the unique markings on the original bull--with the black nose and
the black eyes.”
UNCANNY SIMILARITIES
“It’s amazing how similar the clones are. The Panhandle Slim
calves act like one. They stick together and do the same things.
They are usually all together in a group, or paired in twos. In
the photo for our ad they are all lined up, looking at you. They
always stand like that--together. Scot told me that one day when
he was working the cattle, one of those clones would come out of
the group and come toward him and paw the ground, and act really
mean. If Scot just stood there, the calf would give up in a couple
minutes and walk back to the group, and another one would come out
and do the same thing, pawing the ground,” he says.
“We had creep feeders
when we had the Panhandle Slim calves, and it was spooky; two of
the clones would go in the creep feeder and the others would stay
out in front, watching and guarding. As soon as the first two
would come out, the next two would go in, and they would just
rotate guarding and eating,” says Owen.
They are like identical
twins, only more of them. If you’ve ever observed twins, you know
how closely they think alike, and it’s uncanny how much alike they
are, almost like they share the same brain and know exactly what
the other is thinking or doing. One might be sound asleep when the
other twin goes to nurse the cow, and the sleeping calf will
suddenly come awake, realizing it’s dinner time, and get up to go
nurse, too--not wanting to miss out.
“What’s really amazing,
with clones, is the different recip cows that gave birth to them
seem to mother them all. They let all of them nurse. There are
enough similarities that the cows seem to accept them all,” says
Owen. In a normal herd situation you sometimes find a cow that
will accept another calf or be tolerant of another calf suckling,
but in the recip groups raising clones, there’s a much higher rate
of cows tolerating all the other calves.
THE CLONING PROCESS
Cloning is just another reproductive tool like AI, embryo
transfer, in vitro fertilization, etc. that is now available to
breeders. They can bank their best genetics, for future use. Gene
banking is the process of taking a tissue sample (biopsy) from a
donor animal and preserving these cells in a frozen state, for
future cloning. Cloning is simply creating a twin of the original
animal; they are twins, separated only by time.
The first step is to
take a small tissue sample (usually skin) from the animal to be
cloned. “Tissue samples from a horse are usually taken from the
neck. What we usualy do with cattle is take the sample from the
ear with an ear punch, or sometimes out of the skin flap under the
tail head. When you take it out of the ear, it leaves a small
notch; it just looks like they’ve lost an ear tag.”
They use a little anesthetic when removing a tissue sample from
the tail. “With horses, you stitch up the area on the neck where
you took the biopsy, but on a bull we just use a little adhesive
if the owner wants us to, on the tailhead. Most people don’t worry
about the looks of the ears,” says Owen. Most cattle have some
slits and raggedy ears anyway, so the owners don’t really care if
a notch is removed--about the size of a pencil eraser.
The sample is chilled
and sent to the ViaGen lab, where the cells are grown in culture,
producing fibroblast (connective tissue) cells. These cells can
then be frozen and kept for future use, or used immediately for
cloning. “We put the tissue samples into a growing solution, and
grow them into millions of cells, then freeze them in different
vials,” he says.
“Whenever you want to
clone the animal you’ve gene banked, we thaw those cells and make
the cloned embryos. Once you have the animal gene banked, it’s
just like semen and embryos; as long as we keep them frozen in
nitrogen for you, they are good forever.”
For the actual cloning,
DNA from the donor animal’s cells is transfered (in a process
called nuclear transfer) into flushed eggs from which all genetic
material has been removed (enucleated). This produces an embryo
containing the complete genetic makeup of the animal to be cloned.
“You just take the DNA out of egg, put yours in, make the egg
think it has started to grow, and it’s an embryo,” says Owen. The
new embryos are grown in an incubator for a few days, then
transfered into a recipient female, just as you would for a normal
embryo transfer. The recip female carries the embryo, and after a
normal gestation the cloned calf is born.
CONTROVERSY OVER
CLONING
Cloning is another step in reproductive technology, enabling
breeders to reproduce their best genetics. “Some people confuse it
with genetic modification, but it’s not. Nothing is modified; it’s
just another copy of the same animal. There’s a big argument right
now about labeling milk and meat from cloned animals, but how are
you going to do that when you can’t tell the difference? Are you
going to label the milk and meat produced from AI created animals
or those from embryo transfer? This is just another reproductive
technology,” he says.
“At present it’s
voluntary removal of cloned animals from the food chain, and this
has held back some beef and dairy producers from using cloning.
Swine producers and some of the dairy people won’t be doing much
cloning until it’s cleared by the FDA. The public needs to
understand, however, that you won’t see many clones in the food
chain. No one will spend $15,000 to raise an animal for meat! You
won’t be eating a cloned hamberger. The purpose of cloning is to
get offspring from the clone, not for food. The people who want
natural food should be in favor of cloning. If we can clone a high
producing animal (like a milk cow that produces 50,000 pounds of
milk or a fast growing beef animal--to use as a bull to sure a lot
more just like him) that does it naturally and doesn’t need the
hormones that people don’t want, wouldn’t this be a welcome
improvement?”
This will probably be
the main thrust of cloning, to extend the best genetics for
efficient, natural meat and milk production, creating more animals
that can do it without growth hormones, antibiotics, etc. “We are
cloning bucking stock because we like the entertainment of rodeo,
but the long range goal is in food production. For instance, you
could take the best yielding steer from a producer who’s tracked
it all the way through, and clone it. You could take the top
carcass and bring it back as a bull, and breed a lot more top meat
animals,” he explains.
Right now, we have to
wait awhile before we know our best genetics. “But when you’ve
traced an animal all the way through the steps and it’s in the top
5 percent for all desired traits like birthweight, weaning and
yearling weight, feed conversion, etc. and then finally has the
ultimate carcass, we can pull tissue from these calves as they are
going along. When we get to that end product we can put it in
motion for cloning. What we’d like to see is an a major integrated
beef company order 100 cloned bulls (that were created from top
performing steers) to supply their producers. It would make a lot
more uniformity for the desired end product, and with more feed
efficiency. I would think the people who want natural beef would
be excited about this possibility.”
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