Embryo Transfer - Anatomy & Physiology
Introduction
Multiple ovulation and embryo transfer has been commercially available since the 1970s, but not widely used because it requires a highly skilled team.
Synchronization of Recipients with the Donor
- GOAL: To synchronize the donor and recipient to be in the same stage of the oestrous cycle.
- REASON: To prepare the uterus of the recipient to support preattachment embryogenesis.
- HOW: Treat recipient with a hormonal regime that induces oestrus to occur at the same time as the donor.
Superovulation of the Donor
Inseminating the Donor
- GOAL: Inseminate donor with semen from genetically superior bulls. To generate the best fertilisation rates and genetic combinations possible.
- REASON: Enhance rate of genetic progress.
- HOW: Use highly fertile semen and well-trained, experienced inseminators.
Recovery and Identification of Viable Embryos
- GOAL: To nonsurgically collect (flush) embryos from the donor to transfer.
- REASON: To recover viable embryos.
- HOW:
- Before the procedure is started, a local anaesthetic is injected to cause relaxation of the rectum.
- At day 6-8 a specialized catheter has a small balloon that can be inflated to prevent retrogade flow of the flushing medium.
- A flushing medium is then introduced into the uterus, lavaged and returned through the catheter to a collection vessel.
Transfer of Viable Embryos into Synchronised Recipients
- GOAL: To deposit a potentially viable embryo into the uterine horn of each recipient.
- REASON: To achieve pregnancy in each recipient.
- HOW:
- Both donor and recipient have a corpus luteum at similar stages of leutinization.
- Uterine environment in the donor and recipient are quite similar.
- A single embryo is placed into the uterine horn using a transfer pipette.