Measurement of early pregnancy factor activity for monitoring the viability of the equine embryo

• Published in: Theriogenology Vol. 50; no. 2; pp. 255 - 262
• Main Authors: Takagi, M, Nishimura, K, Oguri, N, Ohnuma, K, Ito, K, Takahashi, J, Yasuda, Y, Miyazawa, K, Sato, K
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.07.1998
• Subjects: Animals; BLOOD SERUM; CABALLOS; Chaperonin 10; CHEVAL; DIAGNOSIS DE LA GESTACION; DIAGNOSTIC DE GESTATION; early embryonic death; early pregnancy factor; EMBRYO MORTALITY; EMBRYO TRANSFER; Embryo Transfer - veterinary; equine embryo; Female; Fetal Death - diagnosis; Fetal Death - veterinary; GLICOPROTEINAS; GLYCOPROTEINE; GLYCOPROTEINS; Horse Diseases - diagnosis; HORSES; Horses - embryology; IMMUNOLOGICAL TECHNIQUES; Immunosuppressive Agents - analysis; MORTALIDAD; MORTALITE; MORTALITY; OVULACION; OVULATION; Peptides - analysis; Pregnancy; PREGNANCY DIAGNOSIS; Pregnancy Proteins; Pregnancy Tests - veterinary; Pregnancy, Animal - physiology; ROSETTE INHIBITION TEST; SERUM SANGUIN; SUERO SANGUINEO; Suppressor Factors, Immunologic; TECHNIQUE IMMUNOLOGIQUE; TECNICAS INMUNOLOGICAS; TRANSFERENCIA DE EMBRIONES; TRANSFERT EMBRYONNAIRE; VIABILIDAD; VIABILITE; VIABILITY; equine embryo; early embryonic death; early pregnancy factor
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/S0093-691X(98)00133-2

The viability of embryos before flushing from donor mares (n=5) and after transfer to recipient mares (n=7) was monitored in mare serum by detecting early pregnancy factor (EPF) using the rosette inhibition test (RIT). The EPF activity was measured in donor mares before and after natural mating at natural estrus; after ovulation on Days 2, 5 and 8; and after embryo flushing (Day 8) on Days 8, 9, 10 and 13 after ovulation. The collected embryos were transferred immediately after flushing. The EPF activity in recipient mares were measured on the day of transfer and after embryo transfer on Days 1, 2, 3 and 5. Pregnancy was confirmed on Day 12 to 14 after embryo transfer. The mean EPF activity of donor mares was increased to the pregnant level (> an RI titer score of 10) on Day 2 after ovulation. Two days after flushing the embryos, the EPF activity of donor mares had decreased to the nonpregnant level. Among the 7 recipient mares, 3 mares were diagnosed pregnant on Day 12 after embryo transfer with ultrasound. The EPF activity of the pregnant recipient mares was increased above the minimum level observed in pregnant mares on Days 2 to 3 after transfer. However, among the nonpregnant recipient mares after embryo transfer, the EPF activity of 3 mares remained at the pregnant level only 2 to 3 d and then declined to the nonpregnant level . In one recipient mare, EPF activity did not reach the pregnant level throughout the sample collection. The results of this study indicated that equine EPF can be detected in serum of pregnant mares as early as Day 2 after ovulation. From our observation, we conclude that the measurement of EPF activity is useful for monitoring the in vivo viability of equine embryos and early detection of embryonic death.