Assisted repro tech - embryo transfer

Question 1

What is superovulation?

Answer 1

stimulation or more dominant follicles than would occur naturally

Question 2

What is ovum pick-up (OPU)?

Answer 2

collection of oocytes from multiple follicles in vitro

Question 3

What is in vitro fertilisation (IVF)?

Answer 3

fertilisation of the oocyte with sperm in a petri dish

Question 4

What is embryo transfer (ET)?

Answer 4

transfer of an embryo, derived from the mating of 2 valuable parents, into a fertile by less valuable host female who carries the pregnancy to term and offspring to weaning

Question 5

What are the advantages of embryo transfer?

Answer 5

max repro effeciency of high quality animals
speeds up herd genetic improvement
Avoids female infertility due to uterine/ tract abnormality
Enables breeding from injured/old females
Enables athletic females to remain ‘working’
Lowers risk of disease spread
Conservation of endangred species

Question 6

What are the disadvantages of embryo transfer?

Answer 6

Expensive
potential narrowing of gene pool
enhancement of genetically linked undersirable traits by mistake
breed society permission needed
requires skill

Question 7

Describe the process of embryo transfer and OPU+IVF

Answer 7

Question 8

How is superovulation stimulated?

Answer 8

Repeated gonadotrophin treatment (e.g., eCG or FSH) to allow more follicles to ovulate

Question 9

How are embryos collected from the uterus?

Answer 9

trans-cervical flush of uterus via catheter

Question 10

Explain the process of embryo searching

Answer 10

Embryos collected from uterus are located and graded under dissecting microscope

Question 11

Describe the process of transferring an embryo into a recipient

Answer 11

Transferred into uterine horn
Surgically or non-surgical (via cervix using fine pipette or catheter
Oestrus cycle of recipient is behind doner to allow embryo to ‘catch up’ in development

Question 12

Describe the process of ovum-pick up and in vitro production of embryo

Answer 12

1. ovarian stimulation - low dose FSH => medium follicles
2. oocyte collection (in vivo) - transvaginal aspiration of medium follicles via specialised ultrasound probe - needle inserted into follicle, fluid collected under vacuum
3. in vitro production of embryo - oocytes matured and fertilised in lab => ET