Veterinarians examined the process of cloned foal birth from embryo implantation to post natal life in a recent study, which was presented at the American Association of Equine Practitioners Convention, and found that although the risks during pregnancy are higher than average for cloned foals, these horses fare very well after they are born.

“These are high risk pregnancies for both mares and foals. The birthing process is more difficult, and foals suffer abnormalities common to cloned animals,” said Dr. Amie Johnson of Auburn Veterinary School, the lead researcher on the study—“Physical And Clinicopathologic Findings In Foals Produced By Somatic Cell Transfer.” 

The most common abnormalities include maladjustment, enlarged umbilical remnant and angular limb deformity of the front legs. “The majority of cloning data is in the bovine field. The results of horse cloning were relatively unknown. Similar problems were seen in horses as in cows, like the umbilical cord abnormalities, but there were differences. There were more leg abnormalities in foals, which is more common to the species,” reported Johnson.

The foals required significant help during birthing and in their first week of life according to Johnson. She recommended delivering cloned foals at a center equipped to handle critical care of neonates.

But foals fared much better than calves. The cloned foals experienced a lower mortality rate, and large offspring syndrome and gross placental abnormalities, as reported in cloned calves, weren’t found.

The study looked at 57 embryos that were implanted. Of that group, 31 resulted in pregnancy and 14 in a live birth. These numbers are considered very successful for nuclear transferred embryos. Two of the foals died after birth, resulting in a total of 12 foals that are currently alive and healthy.

“Once the foals reach a certain age, they seem to be as healthy as normal horses. There are five cloned horses currently living in Europe who seem to have no major problems and have blood work similar to a normal horse,” said Johnson. “This study is a definite success for cloning research.”