Pregnancy & MRP

Question 1

What would you get back from a uterus flush?

Answer 1

Morula
Early blastocyst
Hatching blastocyst
Hatched blastocyst

Question 2

• Tight junctions form between the outer cells of the morula; gap junctions form between the inners
• Na+ is pumped out by the outer cells and water begins to accumulate to form the blastocoele cavity
• As fluid accumulates, the outer cells become flattened around the embryo to form the trophoblast and the inner cells polarize to a pole to form the inner cell mass (ICM)

Answer 2

Transition of a morula into an early blastocyst

Question 3

Fill in the blanks:
Pregnancy in the Bitch
- LH surge when P4 is around __ ng/ml (Day 0)
- Ovulation 2 days later when P4 is around __ ng/ml
- Oocytes are ovulated as Primary Oocytes (immature)
- Oocytes take __ days to complete maturation after OV
- Oocytes remain viable for __days in the oviduct

Answer 3

• 2
• 5
• 2
• 2

Question 4

(T/F) Diestrous length is the same for Pregnant vs. Not pregnant

Answer 4

True

Question 5

When is the best time to do an Ultrasonography on a Bitch?

Answer 5

30 days after LH surge

Question 6

Pregnancy in the Bitch, P4 peaks around ____________________

Answer 6

mid-gestation (25-50 ng/ml)

Question 7

What is “Day 0” in a mare?

Answer 7

the day of ovulation

Question 8

Pregnancy Diagnosis of Mare:
- Ultrasound can detect pregnancy at ______________
- Heartbeat can be detected at ____________

Answer 8

• 14 days (or earlier)
• 25 days

Question 9

What forms around Day 35 in a pregnant mare?

Answer 9

Endometrial Cups

Question 10

Pregnancy in the Mare:
What do Endometrial Cups secrete?

Answer 10

eCG (equine Chorionic Gonadotropin)

Question 11

Pregnancy in the Mare:
Where are the Endometrial Cups derived from?

Answer 11

Cells from Chorionic Girdle

Question 12

Pregnancy in the Mare:
Endometrial Cups degenerate around ___________ days of gestation

Answer 12

100

Question 13

The embryo must provide a timely biochemical signal to the mother to avoid luteolysis. This is known as:

Answer 13

Maternal recognition of pregnancy

Question 14

When must maternal recognition of pregnancy occur?

Answer 14

Before PGF2alpha is produced or secreted by the endometrium

Question 15

What is the mechanism of maternal recognition in the cow?

Answer 15

Interferon-Tau secreted by the embryo inhibits synthesis of endometrial oxytocin receptors.

(It binds to the endometrium and inhibits the synthesis of endometrial oxytocin receptors further results in the inhibition of PGF2alpha synthesis)

Question 16

What does the sow need to stay pregnant?

Answer 16

Needs at least 4 embryos (two in each horn)

Question 17

The embryo must produce signals that prevent _____________ and maintain elevated progesterone concentrations

Answer 17

luteolysis

Question 18

(T/F) Maternal recognition of pregnancy must occur after the natural time of luteolysis

Answer 18

False, must occur BEFORE

Question 19

What is the mechanism of maternal recognition in the mare?

Answer 19

Unknown, but the embryo must migrate throughout the uterus before natural PGF2-alpha release

Question 20

What is the mechanism of maternal recognition in the sow?

Answer 20

Estradiol from the embryo changes direction of PGF2-alpha release from endocrine to exocrine

Question 21

Fill in the blank: Following administration of prostaglandin F2α into a female during diestrus, you would expect the serum concentration of progesterone to ___________. This results from a direct action of prostaglandin F2α on the _______________.

Answer 21

Decrease –corpus luteum