Frosty the Frozen Embryo

A crisp, white coating of frost is hard to find in Florida as late as March. But on March 11, 2003, a different kind of sparkle landed on the ground at Peterson and Smith Equine Reproduction Center in Summerfield, Florida. His name was Frosty, and he had been frozen, thawed and foaled.
The flashy sorrel colt is a result of frozen embryo transfer, a new twist to embryo transfer. According to his birth announcement, Frosty was a frozen first for Florida, and he is the first frozen embryo transplant to be born in the Southeastern United States.

“ Embryo transfer in horses has been around for quite some time,” said Dr. Philip M. Matthews, director and co-owner of Peterson and Smith Equine Reproduction Center. “It’s been done commercially for about 20 to 25 years.”

Transfer Technology
Embryo transfer is a meticulous process. A donor mare is bred; the embryo is carefully tracked to her uterus, flushed at the right age and immediately transferred to a recipient mare, Matthews said.
The recipient mare must be in a similar stage of her cycle as the donor mare or she will reject the embryo, Matthews said. The recipient mare then carries the embryo to term.

What makes Frosty so special, though, is that he was frozen. In frozen embryo transfer the embryo, once taken from the donor mare, is prepared to withstand freezing, and is then frozen in liquid nitrogen by a cell freezer machine, Matthews explained. Preparation and freezing takes place typically within one hour from removal of the donor mare.

“ We can freeze it, we can put it in a tank, and then we can just find a recipient mare at some later date,” Matthews said. “We can then follow her at that time until she’s at a stage of her cycle that we want her to be and then do the transfer. So it takes a lot of pressure off of the recipient management when we have a frozen embryo.”

The embryo is taken from the liquid nitrogen, placed in a six-step thawing process and then transferred to the recipient mare, Matthews explained.

Fresh, Frozen Foal
Peterson and Smith decided in 2002 to practice the freezing and thawing technique on the center’s mares before offering the service to clients, according to Matthews. The center harvested some embryos and then transferred one thawed embryo to a recipient mare. The mare carried the pregnancy to prove that the entire process – from harvesting and freezing to thawing and transferring – would result in a live foal.

The resulting foal was Frosty, and, fortunately, he does not show any signs of frostbite.
Frosty’s sire is Arabian stallion, and his dam is a Thoroughbred mare, both selected without special concern for bloodlines, but the result was a good-looking colt and the confirmation that Peterson and Smith could successfully freeze, thaw and transfer embryos.

In 2003, Peterson and Smith froze approximately one dozen embryos and transferred one, Matthews said. That recipient mare is about 90 days in foal (as of early November 2003). The remaining embryos will be transferred in 2004.

Frozen embryo transfer requires some cold cash, though. If the customer uses their own recipient mare the cost is $1,500 to $2,000. However, if Peterson and Smith provides the recipient mare the price jumps to $4,500 to $5,000.

Frosty was raised by his surrogate mother and has since been weaned. The frisky colt munches on Seminole Feed Blue Ribbon 12. Peterson & Smith will donate him to the Marion County 4-H Equine Specialty Club, which is holding a membership drawing to see who will take him home.
“ The plan is that they’re going to be keeping a journal or record of him,” said Paul Vrotsos, director of operations for Peterson and Smith. “So they’ll continue to keep in contact with us as far as what he’s doing.”

The member who wins Frosty will definitely have a cool story to tell. Although Florida weather is not exactly chilly, Frosty will take care of putting a nip in the air.

Want to know more about Frosty? Email editor@ecmagazine.net if you’d like to read more stories about Florida’s first successful frozen embryo foal.

Ginger Larson is a junior at the University of Florida, majoring in agricultural communication.
She enjoys writing and photography and, of course, cheering on the Gators.