Embryo Transferin Beef Cattle

Ms. BailesAGSC 336 – Advanced Animal Science

Objectives

• Define embryo transfer

• Explain the steps of embryo transfer

• List the advantages of embryo transfer

• List the disadvantages of embryo transfer

What is Embryo Transfer?

Collecting embryos from asuperovulated donor cow...

…and transferring the embryos to synchronized recipients to complete the gestation period.

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.

Superovulation of DonorDay 0 to Day 4

• Follicle Stimulating Hormones (Known as FSH)

• Injections 2x daily, 4 days

(Day 0 starts 8-14 days following estrus cycle.)

Result: Multiple Folicles

Superovulation--Day 3

• Prostaglandin injection causing Corpus Luteum regression to bring on estrus.

Result: Multiple Folicles

Superovulation--Day 5

• Onset of estrus

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.

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.

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.

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.

The Recipient

• Reproductively sound, good mothering ability.

• Good overall health, nutrition.

• Must be synchronized to receive the embryo.

Synchronization Protocol--Day 0

• Insert intravaginal CIDR.

• Administer 2 cc combo Estradiol Benzoate and Progesterone.

Day 7

• Remove CIDR

• Administer 5cc Prostaglandin

Day 8

• Final Injection:

1 cc Estradiol Benzoate

Day 8 through Day 10

• Day 8 pm through Day 10am:

Observe for onset of estrus.

Day 16--Transfer Embryo

• Transfer Embryo into synchronized recipient who has come into estrus.

• Procedure is simple,

much like A.I.

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.

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.

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.

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.