12 – Maternal Recognition of Pregnancy

Question 1

What does CL in animals need to regress?

Answer 1

-PGF 2-alpha (2a) released from uterus=degenerates

Question 2

Domestic animals cycle:

Answer 2

-CL develops at ovulation and regenerates at next ovulation
>will be maintained if there is a baby or not
>only knows there is no baby if PGF-2a is released from uterus
*babies try and prevent the uterus from released PGF-2a

Question 3

What species use vaginal semen deposition?

Answer 3

-humans
-rapids
-rats
-cow
*cervix is open in dog and cat

Question 4

What species use uterine seme deposition?

Answer 4

-lammas
-camelids
-horses
-pigs
*AI

Question 5

Guinea pig, rats and mice copulatory plug:

Answer 5

-cervical cap

Question 6

Humans copulatory gel:

Answer 6

-coagulates into loose gel in minutes
-liquefies in half to one hour
*camelids also coagulates

Question 7

Dogs copulatory plug:

Answer 7

-use their penis

Question 8

What happens during bovine pregnancy?

Answer 8

-CL is need for the first half of pregnancy
-follicles continue to grow in waves
*at ~2weeks embryo tells mom via IFN-gamma to not release PGF-2a from uterus

Question 9

Maternal recognition of pregnancy involves:

Answer 9

-biochemical communication between the conceptus and its mother to provide UNINTERUPTED synthesis and release of progesterone
*different in each species

Question 10

Different species use different hormones to ‘signal’ to the CL:

Answer 10

-ruminants: IFN-gamma
-humans: hCG
-horses: eCG
-pigs: estrogen

Question 11

What happens if uterine horns are removed after ovulation?

Answer 11

-shows that there is something that comes from the ipsilateral uterine horn with the CL so that the uterus can talk to it
*cows, sheep, goats, pigs

Question 12

Vascular supply: carnivores

Answer 12

-2 blood vessels that supply the uterus
>ovarian artery (ovary and cranial uterus)
>vaginal artery (caudal uterus)
*anastomose with each other

Question 13

Vascular supply: cow, horse, pigs

Answer 13

-uterine artery=major blood supply to uterus

Question 14

Ovarian artery:

Answer 14

-off aorta
-ovarian and uterine branches

Question 15

Uterine artery:

Answer 15

-off internal iliac artery
*mare=external iliac artery

Question 16

Vaginal artery:

Answer 16

-off internal iliac artery (or internal pudendal artery)

Question 17

Why is the ovarian artery extremely coiled in the ruminants?

Answer 17

-counter-current exchange between uterine drainage (uterine vein) and ovarian supply
*so prostaglandin from uterus goes from uterine vein to the ovarian artery=go back to the ovaries instead of needing to go back through circulation
*LOCAL utero-ovarian pathway

Question 18

Lungs and prostaglandin:

Answer 18

-degrading system for prostaglandin=very little come back
*horses have a CL that is very sensitive to prostaglandin so will even recognize the small amounts that make it back
*SYSTEMIC pathway

Question 19

Pigs utero-ovarian vasculature:

Answer 19

-in between systemic and local route to transport prostaglandins

Question 20

Canine utero-ovarian vasculature:

Answer 20

-after ovulation they consider themselves pregnant=maintain CL for same length of what the pregnancy would be
*”pseudo” pregnant
-blood vessels don’t have as much anastomoses

Question 21

Embryonic development: strategies for MRP:

Answer 21

*first steps are similar among species
-growth after hatching is different
1. Cleavage
2. Hatching (day 6-7 zona pellucida hatches the embryo)
3. Growth

Question 22

Bovine embryo:

Answer 22

-uterine PGF-2a reaches ovary by ipsilateral transfer mechanism
-embryo elongates to fill uterine horn (ipsilateral to CL) to signal it’s presence

Question 23

Equine embryo strategy:

Answer 23

-uterine PGF-2a reaches the ovaries by a systemic route
-NO elongation, but uses mobility to signal its presence
-baby remains spherical
>the baby will go through uterine horn and make contact everywhere
*PG secretion

Question 24

Sows embryo:

Answer 24

-utero-ovarian relationship similar to sheep and cow
>MRP has local and systemic
-lengthening of baby to release chemical signal
-need at least 4 babies to declare she is pregnant
-will distribute babies to fill up both horns equally
*if embryo loss occurs after day 14=CL will NOT regress

Question 25

Camelids:

Answer 25

-induced ovulation
*need to send signal by 10 days (earlier than others)
-elongate baby early on
-becomes hard for embryo transfer