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Successful reduction of a monozygotic equine twin pregnancy via transabdominal ultrasound-guided cardiac puncture


  • Present addresses: D.G. Orellana, Urbanizacion Colinas De Santa Rosa, Carrera 11a con 13a, 11a-25, Barquisimeto-Venezuela; C.K. Ast, 527, Copperline Drive, Garner, North Carolina, 27529, USA.



In horses, twin pregnancy is pathological and represents a potentially life-threatening condition to the mare and foal. Twinning occurs in approximately 2% of pregnancies. Of these, the majority of cases are dizygotic twins, resulting from 2 ovulations and monozygotic twins are rare. A 12-year-old Quarter Horse mare was presented for breeding management with shipped cooled semen and embryo transfer. Seven days post ovulation, a single late morula/early blastocyst was recovered and transferred immediately to a recipient mare. Thirty-six days after transfer, transrectal ultrasound examination revealed the presence of 2 embryos. A transcutaneous reduction of one of the fetuses was performed successfully at 128 days of gestation. This report is the first to describe a successful reduction of monozygotic twins by transcutaneous ultrasound-guided cardiac puncture.