8- Pharmacological control of reproduction in the female

Question 1

How to stimulate early onset of cyclicity in sheep

Answer 1

melatonin
progestogen sponges in combination with eCG/GnRH
Ram effect

Question 2

Name 3 ways to control oestrus/ ovulation

Answer 2

Influence photoperiod
Mimick release of gonadotropins
Lengthen the luteal phase
Block progesterone
Shortening the luteal phase

Question 3

Name one protocol of controlling oestrus in cattle

Answer 3

P4 plus PGF
Ovsynch (With or without p4)
Two doses of PGF

Question 4

What is Ovsynch?

Answer 4

GnRH was administered to cause ovulation of the dominant follicle

CL = P4 (7 days)
PGF2 given to remove luteal structure - Follicular phase with a dominant follicle

GnRH given 2 days later = ovulation of dominant follicle

16-20hrs later = Ai

Question 5

What hormone can be given to suppress oestrus?

Answer 5

Progestogen
GnRH agonist

Question 6

What hormone can you give to induce oestrus in a dog?

Answer 6

Prolactin inhibitors
hCG to induce ovulaation

Question 7

What is anovulatory anoestrus?

Answer 7

Ovaries & HPG axis has shut down

Question 8

What are the 2 most common targets of immunocenception (vaccine for female contraception)?

Answer 8

Zona pellucida vaccines
Anti-GnRH vaccines

Question 9

Describe the main principles of the treatment of pseudopregnancy/ termination of pregnancy

Answer 9

Block action of progesterone
Terminate luteal function- PGF2a or Prolactin
Mimic fetal signal
combination may be required

Question 10

How to treat persistent CL

Answer 10

Prostaglandin F2a