Sex and development in bovine in-vitro fertilized embryos.
In vitro fertilized bovine embryos were karyotyped at Day 7 and Day 8 post insemination. The results showed that the percentage of males (sex ratio) was dependent on the developmental stage. Among expanded blastocysts (the most advanced embryos), the sex ratio was 100%, followed by 89% for expanding blastocysts, 75% for blastocysts, and 40% for young blastocysts, all analyzed at Day 7. For embryos karyotyped at Day 8, the sex ratio was 20%. The average mitotic index for all in vitro fertilized embryos was 3.5%. These results suggest that the apparent relationship between sex and developmental rate could be used as a method for noninvasive sexing of in vitro fertilized embryos.
Avery
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B
Department of Reproduction, Royal Veterinary and Agricultural University, 13 Bülowsvej, DK-1870 Frederiksberg C, Denmark.
Madison
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V
Greve
T
T