title: Viability of frozen-thawed bovine embryos bisected in sucrose: A preliminary report.
abstract: A method for producing identical twin calves is described in which Day 7 frozen-thawed bovine embryos in 12.5% sucrose solution were bisected using a fine microsurgical blade. The resulting bisected embryos were transferred nonsurgically to the uterine horn ipsilateral to the corpus luteum of synchronous recipients (+/-1 d), two bisected embryos per recipient. The pregnancy rate when both halves remained in the same zona pellucida was 50% (5 10 ); the pregnancy rate was 1 5 for morulae and 4 5 for blastocysts. The pregnancy rate for unfrozen morulae bisected in PBS and transferred without zona pellucida was 27% (4 15 ). The in vitro survival rate of embryos bisected in 12.5% sucrose when both halves remained in the original zona pellucida was 82% (18 22 ), which was higher than when embryos were bisected in PBS (53%, 9 17 ).
authors.affiliation: Fukushima National Livestock Breeding Station Ministry of Agriculture, Forestry and Fisheries Nishishirakawa-gun, Fukushima 961, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: I
authors.initials: I
authors.lastname: Shimohira