Mares carrying cloned embryos at home in Oklahoma

Sunday, November 13th 2005, 1:11 pm

By: News On 6

PURCELL, Okla. (AP) _ While some of the mares jockey for position around the hay feeder filled with alfalfa, others check out the human visitors to their pasture, leaning forward to have their muzzle or ears scratched, searching handbags for an edible goodie.

The more than 30 healthy looking horses in this one pasture are all shapes and sizes and include an Appaloosa, a couple of bays, chestnuts, a paint and a Palomino.

None of the mares have a name, and their only identification is two plastic collars with numbers. The other thing these mares have in common is they each has been impregnated with a cloned embryo produced by ViaGen, an Austin, Texas, company that specializes in cloning horses, cattle and pigs. The mares are due to deliver in February.

ViaGen contracts with Purcell-based Royal Vista Southwest, which provides horses to carry these embryos, which are produced in a process where the DNA-bearing nucleus of a horse's cell is placed into an unfertilized egg, which has had its nucleus removed. The implanted DNA drives the egg to develop into an embryo, which is placed in a mare, which carries it to term and gives birth to a genetic clone of the animal whose DNA began the process.

Iran Polejaeva, chief scientific officer with ViaGen said the company has successfully produced clones in seven different animal species.

The first cloned horse was born in 2003 in Italy. In 2005 Texas A&M University created the first cloned horse in the United States.

ViaGen is cloning performance type horses for $150,000, for customers who want to continue their horses genetic makeup.

Currently these do not include thoroughbred racing horses.

The Jockey Club, which regulates the registration of thoroughbreds, will not allow any foal to be registered that is produced by the process of artificial insemination, embryo transfer or transplant, cloning or any other form of genetic manipulation.

The health of the breed is better served with natural breeding, said Bob Curran, Jr., Vice President of Corporate Communication for the Jockey Club.

``Because the technology is so new, the health ramifications of cloned foals need to be studied,'' Curran said.

The Jockey Club uses parentage verification along with DNA testing to make sure the foal has been naturally bred.

Michael San Flippo, spokesman for the American Veterinary Medical Association said endurance horse racing allows cloned competitors, as does the equine sports of show jumping, polo, carriage horse racing and dressage.

``In dressage most of the animals are geldings and they can't reproduce, so when you have an outstanding horse, then you can use the cloning process to preserve the genetic lines,'' Polejaeva said.

Polejaeva said that it has taken awhile but they are now having a very good success rate of collecting a tissue sample from the donor, culturing it in the laboratory, removing the existing material from an egg and injecting the cultivated cells into the egg. ViaGen laboratories then cultures the new embryo for about six days and with the next step being transferring one embryo into a surrogate.

Mark Walton, president of ViaGen, Inc. said they are not anticipating any of the colts to have any health problems, saying ``the clones are identical twins separated by time.''

``Cloning is just another reproductive technology,'' said Polejaeva, similar to embryo transfer or artificial insemination.

ViaGen does not have any brood stock so the embryos are shipped to Oklahoma where technicians at Royal Vista Southwest, places the embryo into a mare that is on the proper cycle to receive the embryo, said Jim Bailey a veterinarian and an owner of Royal Vista Southwest.

Bailey said they screen the mares for reproductive soundness, make sure they are healthy, are gentle and used to human contact and that the social order in the herd has been established.

``The secret to good stock is to keep them stress free,'' Bailey said.

``Most of these mares would go to slaughter if they were not being used for embryo transfers.''

He said the mares are kept outside, even during the winter and only taken into a barn at night when it comes closer for them to deliver a colt.

``We keep a really close watch on them when it get close to their delivery day because we only have a small window of opportunity of about 25 minutes to an hour to help with the delivery in case there is a problem,'' Bailey said.

Bailey is excited about the biological technology that allows reproductive technology as cloning and embryo transfer.

``In the past two years we have been making progress by leaps and bounds, so who knows where this technology will advance in the next two,'' Bailey said.