Marc meets his clone, another on the way

June 16, 2010

by Laurie Dixon

Thirty-year-old Marc has bonded well with his clone, Mouse, but little does he know another little DNA twin is on its way.


Mouse is shown outside the hospital barns about a week after his birth.


Mouse with his owner, Kit Knotts of Cocoa Beach. © Sarah Carey

Mouse is a living tribute to dressage champion Marc, a stallion who has been in the ownership of Kit Knotts, of Cocoa Beach, Florida, for 24 years.

Knotts could not be happier with her new lipizzaner colt, a DNA copy of Marc.

In fact, another surrogate mare is already pregnant with Marc's next cloned twin.

Knotts made the decision to clone Marc after a futile nationwide hunt to find another horse she really wanted.

The technology that made Mouse possible was pioneered at Texas A&M University's College of Veterinary Medicine and Biomedical Sciences in 2004, and it was there the cloning of Marc took place.

The cloning of Marc's second twin also took place there and the mare is expected to journey from Texas A&M to the University of Florida's Large Animal Hospital in mid-August for management by equine specialists.

Mouse's mum, Minnie, travelled to the University of Florida for management of the later stages of her pregnancy, and the wee colt became the first test-tube baby delivered at the university.

"There have been several issues with cloned offspring, and while this isn't the first cloned foal, there are few in the world," said Margo Macpherson, an equine reproduction specialist and associate professor at Florida.

"So the fact this baby is alive and is currently thriving is a very good thing."

Nearly six weeks after Mouse's birth on May 5, and a month after his discharge from the Large Animal Hospital, he is a happy, healthy, bucking foal enjoying the good life at his home in Cocoa Beach.

Although veterinarians worried that Minnie would give birth prematurely, a situation that would have meant almost certain death for the foal, the mare held on to carry Mouse to term.


A common abnormality of cloned foals. Typically the umbilicus lacks the natural breaking point and is thickened and edematous. This foal had to have his umbilicus removed at about a week of age. © Dr Aime Johnson/Equine Science Update
The clinic was well prepared for Mouse's arrival.

For example, veterinarians knew that, for unknown reasons, many cloned foals have needed oxygen support at birth, so they planned ahead of time to start administering oxygen therapy immediately after the foal was born.

They knew an intravenous catheter was going to be required shortly after birth for administration of plasma, as staff were aware that the mare's colostrum quality was poor prior to her going into labour.

Plasma was given to transfer the parent's antibodies to build the foal's immune system.

Mouse's birth proceeded without incident. Minnie passed her placenta within an hour of foaling, and the foal was sitting up and alert within five minutes - all good signs.

As time progressed, however, Mouse was unable to stand without assistance. At that point, veterinarians administered antibiotic therapy, supportive fluid therapy and regular feedings of the mare's milk.

Within the next few days, additional problems were diagnosed, similar to those seen in premature foals.

University of Florida equine surgeons operated on Mouse to remove his umbilical remnants, eliminate a urinary problem and remove a blood clot from his bladder. In about a week, the infections had greatly improved.

Knotts was at Mouse's side throughout his treatment.

"I think the whole team approach we have is so outstanding," Knotts said of the care Mouse received. "It's not just the doctors; it's the students and the nurses, even the stall cleaners. They're just the most amazing crew I have ever encountered."


Mouse meets Marc, from whom he was cloned.