Ex 3 - Assisted Reproductive Techniques

Question 1

What are some assisted repro techniques?

Answer 1

hormonal management 
collection and preservation of gametes 
AI, embryo transfer, IVF 
intracytoplasmic sperm infection 
cloning

Question 2

What is super ovulation?

Answer 2

development and ovulation of multiple follicles

Question 3

What can we administer for super ovulation?

Answer 3

FSH, eCG

Question 4

What spp is super ovulation used in most often?

Answer 4

primarily used in ruminants for embryo transfer (limited efficacy in mares)

• In cows, you may get unfertilized eggs passing into uterus and flushed out during super ovulation –> ~50% of the embryos will not suitable for embryo transfer
• In horses, this does not occur –> embryos must be able to secrete PGE2 in order to move through UTJ

Question 5

How is embryo collected for transfer?

Answer 5

• transcervical lavage
• fluid flushes out the embryo
• filtered out
• ID’d under dissection microscope

Question 6

How is the embryo stored for transfer?

Answer 6

cooled = 24 hr storage, slows metabolism

Froze = liquid nitrogen, ‘forever’ storage

Question 7

How can we transfer the embryo?

Answer 7

Non-surgical - preferred technique

Surgical - standing, flank incision

Question 8

Can we sex embryos?

Answer 8

Yes! a biopsy is used to determine sex

Clients want:
dairy cows –> females
cutting horses –> fillies

Question 9

In vitro fertilization

Answer 9

oocytes collected by transvaginal US and needle aspirate –> oocyte and capacitated sperm combined in dish

Once fertilized, inserted into mare

Question 10

What is gamete intrafallopian transfer?

Answer 10

oocyte collected from one female placed into the oviduct of a surrogate (recipient) female

Recipient is then inseminated

Question 11

What is Intracytoplasmic sperm injection (ICSI)

Answer 11

A single sperm is injected into the cytoplasm of an oocyte, using a micro manipulator –> bypasses true in vitro fertilization

If cleavage and embryonic development continues, the embryo is transferred

Transfer protocol –> transfer at late morula to blastocyst stage

Question 12

How is cloning performed?

Answer 12

Transplating the nucleus of one cell into an oocyte from which the nucleus has been removed

Currently, the equine breed assoc’s will NOT allow registration of cloned horses

Question 13

How can sperm be harvested from dead stallion?

Answer 13

Tail of epididymis –> dissected free from testis

• sperm are flushed from epididymis
• freezing extender added
• 20-100 straws are usually obtained (5-25 breeding doses per straw)

Question 14

How quickly must harvested sperm be processed?

Answer 14

12-24 hrs