In late April, Colorado State University veterinarians witnessed the birth of healthy twin foals born four days apart. The births come nearly a year after their mother's death.
The foals' biological mother, Tuesday, was fatally injured in a tornado that ripped through Windsor, Colo., on May 22, 2008. Quick thinking and teamwork at the James L. Voss Veterinary Teaching Hospital and Equine Reproduction Laboratory allowed veterinarians to harvest Tuesday's ovaries before she had to be humanely euthanized. The products of state-of-the-art assisted reproduction technology, the two foals were born to two surrogate mothers at the ERL.
One surrogate mare, named Katie, gave birth to the first foal on April 25. Her foal is a buckskin colt that looks remarkably like his biological mother, Tuesday. The second mare to foal, named Friday in honor of Tuesday, gave birth on April 29 to a cremello-colored colt. Tuesday's family, the Mears, who own a small ranch in Lucerne, Colo., are enjoying Tuesday's legacy again through the twins, who arrived home at the ranch in early May.
Dr. Pat McCue from the CSU Equine Reproduction Laboratory tells the story of two foals born to surrogate mothers after their mother was a victim of last year's Windsor tornado. CBS Channel 4 reports »
"This clinical case demonstrates how equine reproduction research can be applied to help horse owners in critical situations," said Dr. Pat McCue, Director of the Equine Reproduction Laboratory in the College of Veterinary Medicine and Biomedical Sciences at Colorado State University.
At the ERL, a team of faculty members, staff and students collected 20 oocytes, or eggs, from Tuesday's two ovaries. The oocytes were incubated overnight and, the next day, 14 viable oocytes were fertilized through intracytoplasmic sperm injection (ICSI) using semen from a neighbor's cremello-colored American Quarter Horse stallion. Eight embryos developed from the injected oocytes and four were transferred into surrogate mares.
Fourteen days after transfer, ultrasounds revealed pregnancies in two of the recipient mares. The two surrogate mothers spent the majority of their pregnancy near Lucerne on the Mears' ranch. One mare, Katie, is owned by the Mears, while the other surrogate mare is owned by Colorado State and will be returned after her colt is weaned.
Although ICSI is the most advanced technology available in equine reproduction, it is rare to have two foals produced by the technique under such circumstances.
"There was a 25-to-30 percent chance that even one embryo would take, and it was something of a small miracle that two pregnancies survived in the surrogate mares," said Dr. McCue, who performed the work pro-bono after volunteering in Windsor with his family following the storm and seeing the devastation firsthand.
Before the death of her mare, Jennifer Mears trained Tuesday for only 30 days before her first show at the county fair, and Tuesday placed in all but one class. In her two years of showing, Tuesday earned multiple trophies and then was retired to ride just for pleasure. Mears has said that Tuesday was her best friend.