Got Babies?Embryo Transfer in

LivestockCLF3256

Kati Chamberlin - AgEd 410, Spring 2013

Introduction

What is embryo transfer?Removing fertilized eggs from a donor and placing

them in a recipient female

Most common in beef and dairy cattle

Also known as “ova” transplantation

How does it work?



http://www.oces.okstate.edu/extension-fact-sheets-2/mobile-fact-sheets/ansi-3158/ANSI-3994%20Figure%201.jpg/image_preview

What’s the process?

1. SuperovulationDonor female is stimulated to ovulate more

than one egg/cycle

Hormones are injected to cause superovulation

2. InseminationThe donor cow (the cow superovulated) is

bred

Common hormones used for superovulation

PMSG (pregnant mare’s serum gonadotropin)

FSH (follicle stimulating hormone)eCG (equine chorionic gonadotrophin)Prostaglandin F2 alpha

LH (luteinizing hormone)

http://www.nzdl.org/gsdl/collect/fnl2.2/archives/HASH42a2.dir/p16.gif

What’s the process?3. Ova Collection (Flushing)

Nonsurgical: rubber catheter inserted through cervix saline solution flushed into and out of uterusharvests the embryos 7-8 days after estrus30 minute or less procedurestandard method

http://www.fao.org/docrep/004/T0117E/T0117E10.jpg

Flushing process

Click HERE if video does not play

What’s the process?

4. Evaluation of the EmbryosRegularity of shape of the embryoCompactness of the blastomeres Variation in cell sizeColor and texture of the cytoplasm

What’s the process?

4. Evaluation of Embyo’s cont.Overall diameter of the embryoPresence of extruded cells and vesiclesRegularity of the zona pellucida

Embryo Classification

Grades: Grade 1: Excellent or Good Grade 2: Fair Grade 3: Poor Grade 4: Dead or degenerating

Embryo ClassificationStage of Development:

Stage 1: Unfertilized Stage 2: 2 to 12 cellStage 3: Early morulaStage 4: MorulaStage 5: Early BlastocystStage 6: BlastocystStage 7: Expanded BlastocystStage 8: Hatched BlastocystStage 9: Expanding Hatched Blastocyst

http://www.oces.okstate.edu/extension-fact-sheets-2/mobile-fact-sheets/ansi-3158

What’s the process?

5. ImplantationRecipient cows must be at right stage in estrous

cycle to receive embryo

Recipient cows are synchronized with donor

The eggs are transferred to the recipient cows

Quick! What are the

five processes of Embryo Transfer?

Benefits of Embryo Transfer

A dozen calves might be obtained from a valuable cow in one year

The rate of genetic improvement would quicken

Progeny testing of heifers can be done quicker

Genetically inferior animals could be made more productive by using them as recipient animals

Benefits of Embryo Transfer

Large numbers of fertilized eggs can be transferred from young heifers

Large amount of fertilized eggs can be transferred into mature recipients

Valuable cows that fail to conceive due to hormonal defects would not need to be culled

Limitations

Expensive

The technique for harvesting the ova is complicated

Donors used repeatedly may become incapable of carrying to full term

FFA/SAE and Career opportunities

Bred replacement heifer for the fair

Embryologist

Internship with veterinarian

Veterinarian tech/ Veterinarian

In-vitro fertilization at a Dairy

Embryo transfer technician

What do you think has better pregnancy rates, embryos

transferred that were frozen or fresh?

Are there any limitations to using frozen embryos?