Maternal recognition of pregnancy

Question 1

What are the 2 methods of maternal recognition of pregnancy?

Answer 1

1. inhibition of active luteolysis
2. enhancement of luteotrophic stimuli

Question 2

which species display inhibition of active luteolysis?

Answer 2

sow and ruminants

Question 3

which species display enhancement of luteotrophic stimuli?

Answer 3

bitch

Question 4

Describe inhibition of luteolysis in ruminants

Answer 4

1. trophoblast cells of the expanding blastocyst produce trophoblast protein a couple of days before luteolysis should occur
2. trophoblast protein binds to oxytocin receptors on maternal endometrium and stops PGF-2a production
3. the more progesterone produced by mother, the more trophoblast protein produced

Question 5

Describe inhibition of active luteolysis in the sow

Answer 5

1. oestradiol redirects PGF-2a release from cells into the uterine lumen where it is metabolised
2. single embryo can’t produce enough oestradiol to inhibit this, need at least 3-4 conceptuses

Question 6

Describe enhancement of luteotrophic stimuli in the bitch

Answer 6

• LH and prolactin are upregulated
• CL is sustained for the whole of the pregnancy
• no factor is produced from embryo