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In‐vivo fertilisation and initial embryogenesis in the mare
Author(s) -
GRØNDAHL C.,
NIELSEN C. GRØNDAHL,
ERIKSEN T.,
GREVE T.,
HYTTEL P.
Publication year - 1993
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1993.tb04833.x
Subject(s) - pronucleus , ovulation , blastomere , andrology , embryo , apposition , embryogenesis , human fertilization , zygote , biology , chemistry , anatomy , endocrinology , medicine , microbiology and biotechnology , hormone
Summary Eleven mares were induced to ovulate by treatment with 3,000 iu hCG and subsequently inseminated with frozen‐thawed semen. The time of ovulation was determined by transrectal ultrasonography of the ovaries performed every 4 h. At different times after ovulation ova were collected from oviducts removed by surgery through a flank incision under general anaesthesia. The presumed fertilised ova were cultured for 20 min in a medium containing [ 3 H]uridine, fixed, embedded in Epon, semithin‐sectioned and processed for autoradiography. Selected semithin sections were re‐embedded and processed for transmission electron microscopy. Spherical, paternal and maternal pronuclei were observed within 12 h after ovulation, and by 19 h the pronuclei had migrated to close apposition. The 2‐cell stage was seen within 34 h and a major activation of RNA synthesis was detected at 64 h after ovulation in 4 blastomeres of a 6‐cell embryo, suggesting maternal‐embryonic transition apparently occurs at the 4th cell cycle.