Article

Bisection of equine embryos

Animal Reproduction Laboratory, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
Equine Veterinary Journal (Impact Factor: 2.37). 06/2010; 21(S8):129 - 133. DOI: 10.1111/j.2042-3306.1989.tb04697.x

ABSTRACT Three experiments were designed to evaluate methods of bisecting equine embryos. Viability of demi-embryos was compared to whole embryos in vitro and in vivo. In Experiment 1, Day 6 embryos were bisected either using a standard micromanipulation technique or a manual split of embryos that were adhered to a petri dish. Viability was assessed by culture in vitro. Bisected embryos in both groups increased in size during culture and developed normally. In general, manual bisection was accomplished with less difficulty and time than the micromanipulation method. Eleven additional embryos were bisected manually and both halves transferred surgically into the same recipient (Experiment 2). More pregnancies were obtained from transfer of twin whole embryos (16/22) compared to bisected, demi-embryos (5/22). In Experiment 3, 30 embryos were bisected manually; 15 were encapsulated in agar chip. Both halves were transferred non-surgically to each recipient. Fifteen whole embryos were transferred non-surgically to recipients as controls. The number of vesicles per original embryo was greater for whole embryos than for demi-embryos in agar chips.

0 Bookmarks
 · 
141 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper reviews current equine assisted reproduction techniques. Embryo transfer is the most common equine ART, but is still limited by the inability to superovulate mares effectively. Immature oocytes may be recovered by transvaginal ultrasound-guided aspiration of immature follicles, or from ovaries postmortem, and can be effectively matured in vitro. Notably, the in vivo-matured oocyte may be easily recovered from the stimulated preovulatory follicle. Standard IVF is still not repeatable in the horse; however, embryos and foals can be produced by surgical transfer of mature oocytes to the oviducts of inseminated recipient mares or via intracytoplasmic sperm injection (ICSI). Currently, ICSI and in vitro embryo culture are routinely performed by only a few laboratories, but reported blastocyst development rates approach those found after bovine IVF (i.e. 25%-35%). Nuclear transfer can be relatively efficient (up to 26% live foal rate per transferred embryo), but few laboratories are working in this area. Equine blastocysts may be biopsied via micromanipulation, with normal pregnancy rates after biopsy, and accurate genetic analysis. Equine expanded blastocysts may be vitrified after collapsing them via micromanipulation, with normal pregnancy rates after warming and transfer. Many of these recently developed techniques are now in clinical use.
    Reproduction Fertility and Development 12/2012; 25(1):80-93. DOI:10.1071/RD12263 · 2.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The development of methods to produce embryos in vitro in the horse has been delayed compared with other domestic species. Oocytes can be collected from excised ovaries or from the small or preovulatory follicles of live mares. Intracytoplasmic sperm injection is the only reliable method to fertilize equine oocytes in vitro. Intracytoplasmic sperm injection-produced embryos can be transferred into the oviducts of recipient mares or cultured to the morula or blastocyst stage of development for nonsurgical embryo transfers into recipients' uteri. Embryos cultured in vitro have some morphological differences compared with embryos collected from the mares' uteri. Most notably, the embryonic capsule does not form in culture, and the zona pellucida fails to expand completely. However, embryo produced in vitro can result in viable pregnancies and healthy offspring.
    Journal of Equine Veterinary Science 07/2012; 32(7):367-371. DOI:10.1016/j.jevs.2012.05.054 · 0.89 Impact Factor
  • Source