Embryo Transfer Review
Mrs. Tarver
What is a major factor in embryo
transfer success?
• Successful control of estrus in donor and
recipient females
Why is embryo transfer done surgically
in pigs and sheep?
• It is difficult to pass an embryo collection
device through the cervix of the ewe or sow.
What is the transferred survival rate of
an embryo?
• 55% to 70%
What is an acceptable difference in
estrus between donor and recipient?
• Only up to one day difference in estrus cycles
is acceptable between donor and recipient
females.
What is the optimal placement for
implantation?
• The embryo is expelled into the uterine horn
that is on the same side as the ovulated ovary
to optimize the embryo implantation rate.
When and where was the first embryo
transfer performed?
• Using rabbits, a researcher at the University of
Cambridge in 1890 performed the first
embryo transfer.
What is superovulation?
• The release of many eggs (oocytes) during a
single estrus period
Embryos in early stages of development
should be deposited where?
• Oviduct
What is the most accurate predictor of
embryo transfer success rate?
• The stage of embryonic development
After superovulation when should the
female be bred?
• 12-24 hours after she comes into heat
What is in vitro fertilization?
• Laboratory technique for conception of an
embryo outside the mother’s body
What is a Foley catheter?
• A specially designed catheter used when
collecting embryos using non-surgical
methods.
How do conception rates compare for
surgically vs. non-surgically transferred
embryos?
• Conception rates are up to 5% greater with
surgical transfer
Why is synchronization of estrus
important for embryo transfer?
• It is important to establish a uniform uterine
environment for the embryo
Discuss embryo evaluation and the
grading scale.
• After collection, the embryos are evaluated
for quality using a stereoscopic microscope.
Shape, color, texture, and size are some
factors considered during the evaluation.
Embryos are graded on a scale from one
(excellent) to four (poor).