Physical and clinicopathologic findings in foals derived by use of somatic cell nuclear transfer: 14 cases (2004-2008).

This study examines the health of foals (baby horses) produced through somatic cell nuclear transfer (NT), a type of cloning. The researchers found that while some of the cloned foals required intensive medical care, many were healthy and all of the surviving foals stayed healthy after birth.

Introduction and Methodology

• The study is a retrospective case series analyzing the health outcomes of 14 foals born through somatic cell nuclear transfer (SCNT), a cloning technique, at a university laboratory between 2004 and 2008.
• Medical records were evaluated to identify all the pregnancies that resulted in live-born foals through SCNT. They collected data on gestation length, birth weight, complications during birth, abnormalities of the fetal membranes and umbilicus, the mentality of the foal, limb deformities, and any other observed abnormalities during the neonatal period.
• The clinicopathologic data were also examined if available, including records of 4 recipient mares (female parents) during gestation.

Results of the Study

• The results showed that six out of the fourteen foals were clinically normal for all evaluated variables.
• The remaining eight foals experienced a range of abnormalities including maladjustment (difficulties in adapting to their environment), enlarged umbilical remnants, and angular deformities of the forelimbs (abnormal positioning of the limbs).
• The two foals that succumbed to these conditions died within a week of birth, while the remaining foals had their conditions resolved with medical or surgical management.
• No cases of Large Offspring Syndrome, a condition common in cloned farm animals characterized by excessive growth and other abnormalities, or major abnormalities of the fetal membranes, were detected in this study.
• The surviving foals remained healthy after they were given medical or surgical treatment for their conditions.

Conclusion and Recommendations

• Comparing the outcome of this study with reports from cloned calves, the researchers conclude that while the perinatal mortality rate was lower for cloned foals, some of them still needed intensive medical care.
• They recommend that the birth of foals from nuclear transfer should be conducted in centers that are fully equipped to provide critical care for neonates.