title: Quick-splitting of bovine embryos.
abstract: Described is a simplified method of bovine embryo bisection amenable to on-farm embryo transfer. Using a microblade operated by a hand-held micromanipulator, Day 7 bovine embryos were bisected while in the zona pellucida. With a vertical motion, the embryo was pinned between the blade and the bottom of a plastic petri dish and bisected. Demi-embryos were transferred nonsurgically (without zonae pellucidae) into synchronized recipients. Pregnancy rates were normal with 5 13 (38%) and 9 20 (45%) of recipients confirmed pregnant 70 to 80 d after receiving either twin or single half embryos, respectively. This compared to 12 28 (43%) of recipients becoming pregnant from transfer of whole embryos. These data confirm that bovine demi-embryos do not need zonae pellucidae on Day 7 and that simplified field methods of bisection give normal pregnancy results.
authors.affiliation: CSIRO, Division of Tropical Animal Science Tropical Cattle Research Centre Box 5545, Rockhampton Mail Centre Queensland 4702, Australia.
authors.forename: T J
authors.initials: TJ
authors.lastname: Williams
authors.forename: L
authors.initials: L
authors.lastname: Moore