Embryo transfer involves collecting embryos from a donor cow and transferring them to recipient cows. The donor cow is given follicle stimulating hormones to cause it to superovulate and produce multiple embryos. The embryos are then collected from the donor cow approximately 7 days after artificial insemination. The embryos are evaluated and the highest quality embryos are transferred into recipient cows that have been synchronized to the same stage of estrus as the donor cow through the use of hormones. Embryo transfer allows for the propagation of genetics from superior cows and makes it possible to export or store embryos indefinitely.

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 Prostaglandin injection causing Corpus Luteum regression to bring on estrus. Result: Multiple Folicles 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.