Effect of time of artificial insemination on embryo sex ratio in dairy cattle

J.B. Roelofs, E.B. Bouwman, H.G. Pedersen, Z. Riestra Rasmussen, N.M. Soede, P.D. Thomsen, B. Kemp

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11 Citations (Scopus)


The objective of the present study was to examine whether different intervals between insemination and ovulation have an influence on the sex of seven-day-old embryos in dairy cattle. Cows were inseminated once with semen of one of two bulls of proven fertility between 36 h before ovulation and 12 h after ovulation. Time of ovulation was assessed by ultrasound at 4-h intervals. In total, 64 embryos were determined to be male or female. Of these 64 embryos, 51.6% were female. The sex ratio in the various insemination¿ovulation intervals (early: between 36 and 20 h before ovulation; intermediate: between 20 and 8 h before ovulation; late: between 8 h before and 12 h after ovulation) did not significantly differ from the expected 1:1 sex ratio (50, 50 and 55% females, respectively). Bull (Bull A and B) and Parity (primiparous and multiparous) had no influence on the expected 1:1 sex ratio either. The number of cell cycles was similar for male and female (P = 0.23) embryos when quality of the embryo (P <0.0001) was included in the model
Original languageEnglish
Pages (from-to)366-371
JournalAnimal Reproduction Science
Issue number3-4
Publication statusPublished - 2006


  • gender ratio
  • ovulation
  • spermatozoa
  • cows

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