title: The sex ratios of bovine embryos produced in vivo and in vitro.
abstract: The male:female ratio of developing bovine embryos produced and allowed to develop in vitro and in vivo was determined retrospectively from the cytogenetic analysis of 804 embyos. The overall male:female ratio of the 307 (38%) embryos that could be sexed was 162 (52.8%):145 (47.2%) and did not differ (P>0.05) from the expected 1:1 ratio. Among premorula stage embryos produced in vivo (n = 66) and in vitro (n = 30), the ratios were 1.2:1 and 0.76:1, respectively. Among morulae and blastocysts produced in vivo (n = 74), produced and cultured in vitro (n = 106, and produced in vitro and cultured in vivo (n = 31), the ratios were 1.11:1, 1.3:1 and 0.94:1, respectively, none of which differed significantly from 1:1. There was no difference (P>0.05) in the number of cells or mitotic index between male and female morulae and blastocyst, respectively.
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
authors.forename: W A
authors.initials: WA
authors.lastname: King
authors.forename: B R
authors.initials: BR
authors.lastname: Yadav
authors.forename: K P
authors.initials: KP
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Picard
authors.forename: M A
authors.initials: MA
authors.lastname: Sirard
authors.forename: A
authors.initials: A
authors.lastname: Verini Supplizi
authors.forename: K J
authors.initials: KJ
authors.lastname: Betteridge