This document discusses the process of embryo transfer in beef cattle. It involves collecting embryos from a superovulated donor cow through artificial insemination and flushing, and then transferring the embryos to synchronized recipient cows to complete gestation. The key steps are superovulating the donor cow, artificially inseminating her, flushing her uterus 7 days later to collect embryos, processing and evaluating the embryos, and then transferring high quality embryos into synchronized recipient cows 16 days after their estrus cycles have been aligned through hormone treatments.

1. Embryo Transfer
in Beef Cattle
Ms. Bailes
AGSC 336 – Advanced Animal Science

3. Objectives
• Define embryo transfer
• Explain the steps of embryo transfer
• List the advantages of embryo transfer
• List the disadvantages of embryo transfer

4. What is Embryo
Transfer?
Collecting embryos from a
superovulated donor cow...
…and transferring the embryos
to synchronized recipients to
complete the gestation period.

5. The Donor Cow
• Top quality female, free of
reproductive abnormalities
or genetic defects, proven
maternal qualities.
• Personal goals/preferences
play large part in donor
selection.
• Marketability of the donors
calves.

6. Superovulation of Donor
Day 0 to Day 4
• Follicle Stimulating Hormones
(Known as FSH)
• Injections 2x daily, 4 days
(Day 0 starts 8-14 days following estrus cycle.)

7. Superovulation--Day 3
Result: Multiple Folicles
• Prostaglandin injection
causing Corpus Luteum
regression to bring on
estrus.
Result: Multiple Folicles

8. Superovulation--Day 5
• Onset of estrus

9. A.I. of Superovulated Donor
• Artificially Inseminate when in
standing estrus, usually 5 days
after superovulation.
• Usually multiple inseminations at
12, 24, 36 hrs. after onset of
estrus.
• Preferably, more than one straw
of high quality semen.

10. Embryo Recovery from Donor
• Approximately 7 days after
breeding.
• Easy, takes less than 30
minutes.
• Insert foley catheter with
inflatable balloon into
donor’s uterus.
• Flushing solution (saline)
is introduced into each
uterine horn.

11. Recovery of Embryos
• Solution filled
uterine horn is
gently massaged.
• Fluid containing
the embryos is
drawn back out
and collected
though a filter into
a holding cylinder.

12. Embryo Processing
• After 20-30 minutes embryos
located with stereoscopic
microscope.
• Embryos are washed and
transferred to holding medium.
(Procedure generally repeated 3 times.)
• Embryos are evaluated for state
of development and quality.
• Initially classified: “good” or
“bad.” “Good” embryos are
further classified.

13. The Recipient
• Reproductively sound, good mothering ability.
• Good overall health, nutrition.
• Must be synchronized to receive the embryo.

14. Synchronization Protocol--Day 0
• Insert
intravaginal
CIDR.
• Administer 2 cc
combo Estradiol
Benzoate and
Progesterone.

15. Day 7
• Remove CIDR
• Administer 5cc
Prostaglandin

16. Day 8
• Final Injection:
1 cc Estradiol Benzoate

17. Day 8 through Day 10
• Day 8 pm
through Day
10am:
Observe for
onset of estrus.

18. Day 16--Transfer Embryo
• Transfer Embryo into
synchronized recipient
who has come into
estrus.
• Procedure is simple,
much like A.I.

19. Activity
• Each card has a step in the embryo transfer
process.
• Put yourselves in the proper order of
embryo transfer and then explain the
process.

20. Advantages of E.T.
• Increased number of calves of genetically
superior cows.
• Increased marketing opportunities--
offspring AND embryos.
• Ease of Import/Export.
• Embyros can be stored indefinitely.

21. Disadvantages of E.T.
• Increased expenses and higher break-even costs for
calves.
• Estrus detection required.
• Synchronization of recipient with donor.
• Specialized equipment and trained personnel.
• More expensive and time consuming than
traditional reproductive methods.

22. In Summary…
• E.T. is not for every herd.
• Each female born has thousands of potential
eggs.
• Complete the crossword puzzle which is a
summary/review of what we learned today.