Mare to Give Birth Live Online; Human ICSI Helped Her Conceive

March 13, 2012— -- My Special Girl, an 11-year-old red thoroughbred, will soon deliver her first foal, and anyone with an Internet connection can witness the live birth via the live Foal Cam in her stall at the neonatal intensive care unit at Penn Vet's New Bolton Center outside Philadelphia.

So far, tens of thousands around the world have visited the site, and once the little one arrives, the public is invited to participate in a naming contest.

The mare, a former race horse and surrogate mother, was due in mid-March after a typical 340 days, but because gestation length is unpredictable in the world of horses, the foal could be born in 10-and-a-half months or 13 months.

In horses, birth takes place quickly and usually at night, so the foal can escape from potential predators. The foal will stand up and nurse within the first hour and can trot and canter by the next day. The newborn's legs are almost as long -- up to 90 percent as long -- as the adult parent.

Equine fertility is also different from human reproduction, so experts from the University of Pennsylvania's Medical School are working alongside veterinarians to perfect in vitro fertilization in the lucrative field of horse breeding.

Penn Vet is one of only a handful of veterinary hospitals in the United States that is pioneering a procedure that is successfully used to treat infertility in humans -- intracytoplasmic sperm injection, where a single sperm is injected into a mature egg. Within eight days, the developed embryo is implanted into a surrogate mare.

"It's a very technical procedure and it's different in horses than in humans," said Regina Turner, associate professor of large animal reproduction at the New Bolton Center. "It takes a big financial investment and technical expertise."

"In horses, IVF -- mixing sperm and egg in a dish -- just doesn't work very well," she said. "There has been a lot of research with abysmal results."

Human and rat fertilization occurs easily in IVF, but horse sperm has to mature in a process known as capacitation.

"There is a whole different signaling mechanism in a stallion's sperm," Turner said.

My Special Girl's foal was conceived with a donor egg and the frozen sperm of a dead stallion, both from New Bolton Center. Her foal will be the first at Penn Vet.

Turner worked closely with Matthew "Tex" VerMilyea, director of the Assisted Reproductive Technology and Andrology Laboratory at Penn Fertility Care at the University of Pennsylvania.

"ICSI is very commonly used in the human field when we treat infertility cases when there are low sperm numbers of poor morphology or poor motility," said VerMilyea. "We use the procedure to bypass the natural binding of the sperm to the egg."

In conventional IVF, egg and sperm are placed in a Petri dish and fertilization takes place. But in ICSI, a needle pierces the egg, or zona pellucida, to deliver the sperm. But in some animal eggs, the needle can damage the shell.

"A horse egg is much more elastic than a human egg and you can't just shove in the needle, so I use a laser," he said. "It makes a couple of holes to give a head start for implantation to occur."

Typically, animal research, especially in the area of IVF, has helped advance human medicine, but here the tail is wagging the horse.

"A lot of things were done in rabbits and mice as well as monkeys and that has transitioned over to what we do on the human side of things," VerMilyea said. "But the horse is a different beast. Assisted reproduction is a bit more delicate and the massive size of the animal makes things all the more challenging."

ICSC can be used for race horses to continue the legacy of winning stallions or for mares that might have a blockage in the oviducts or a severe infection of the uterus or a tear in the cervix from a previous foal.

The sperm from a valuable stallion can be frozen and kept in storage tanks and, even years after its death, vets can retrieve a small amount to use for fertilization.

"There is a limited amount, and when you breed a mare the standard way you can use quite a bit each time," VerMilyea said. "With ICSI, you can shave off a tiny bit in a frozen dose, almost like a drop, and use a single sperm to inject into the egg. It extends the sperm."

My Special Girl was donated when she was 3 or 4 to the New Bolton Center, "probably because she was not very fast," and is part of its "teaching herd," said Turner.

She and 14 other mares are used for student vets who are learning to do physical exams.

"The mares are selected for their sweet temperaments and patience," she said. "You need a calm horse to put on the halter and handle them and walk them."

As the ICSI technology takes off, breeders could pay $6,000 to $8,000 for the procedure, according to Turner.

"Breeding is a big deal in horses," she said. "It's one of the few domestic species where babies are worth enough to justify a technique like this."