Pregnancy Maintenance And Diagnosis

Question 1

Duration of pregnancy in:
Cow
Small ruminants
Mare
Sow
Cat/bitch
Woman

Answer 1

1. 275-285d (9month)
   2.145-150d (5m)
   3.315-388d (11m)
   4.114d (3m, 3w, 3d)
   5.65d 65d
   6.268d (9m)

Question 2

functions of the placenta

Answer 2

-supports foetal growth with nutrient
-Ensure adequate oxygen transfer
-C02/waste brought back from foetal circulation to be disposed of

Question 3

What do the Endocrinological functions of the placenta ensure? What is the functioN?

Answer 3

ensure conceptus growth and maternal adaptations
-production of different hormones such as progesterone

Question 4

At what stage (day) of pregnancy does placenta take over in progesterone production from CL in each species?

Answer 4

On anki

Question 5

The source of progesterone during gestation (CL or placenta) has significance for…

Answer 5

Indicating at what stage of pregnancy the animal is at and whether a pregnancy needs to be terminated or not

Question 6

What is the source of progesterone in ruminant placenta?

Answer 6

uninuclear and the differentiating binuclear (giant) trophoblast cells (outermost. Cells of placenta)

Question 7

Where are binucleated giant cells located histologically In placenta and at what stage of pregnancy?

Answer 7

within the trophoblast cell layer of chorionic villi, and early in pregnancy form a maternal-fetal syncytium

(Histological Diagram on anki)

Question 8

Placenta has important nutritional function and secretes what in ruminants, rodents and the woman

Answer 8

Placental lactogens hormone

Question 9

What 2 types of activity do placental lactogens have?

Answer 9

Lactotrope- prolactin type activities
Somatotrope- growth hormone type activities

Question 10

Functions of the placental lactogens

Answer 10

important for conceptus growth and maternal adaptations:
➢‘Uterine milk’ production from endometrial glands
➢Placental and fetal growth
➢Maternal glucose metabolism
➢Mammogenesis synthesis also in giant cells

Question 11

Special feature in mare;
After maternal recognition of pregnancy in the mare, what is formed?

Answer 11

Chorionic girdle

Question 12

Chorionic girdle
-where does this form
-what are these for?

Answer 12

-periphery of yolk ac
-endometrial cups development which secrete eCG (equine chorionic gonadotrophin)

Question 13

Endometrium cups are responsible for what?

Answer 13

Secretion of equine chorionic gonadotrophin (eCG)

Question 14

Describe what is occurring at each stage of equine embryonic development shown here, and what day each stage is at

Answer 14

On anki

Question 15

In the mare eCG is secreted from what day to what day of gestation?

Answer 15

Day 35 to day 20 of gestation

Question 16

What does secretion of eCG lead to?

Answer 16

accessory Corpora Lutea and increased progesterone concentrations

Question 17

What is the immunological function of the placenta?

Answer 17

protects the conceptus which is antigenically different (‘fetal allograft’)

Question 18

What is Foetal/localised invasiveness at the level of chorion?

Answer 18

refers to the ability of the developing embryo/fetus to invade and establish contact with the maternal tissues through the chorion, which is the outermost membrane surrounding the developing embryo/fetus in mammals

Question 19

What does foetal/local invasiveness at the level Of the chorion lead to?

Answer 19

Localised maternal immune response

Question 20

What is maternal Rejection of the fetal Cells

Answer 20

cells from the developing fetus enter the maternal bloodstream during pregnancy, and can potentially trigger an immune response in the mother. This occurs because sometimes the maternal body does not recognise the fetal cells (usually should) so will trigger an immune response against them.

Question 21

What are the 2 examples of maternal rejection of fetal cells in the mare

Answer 21

Localised maternal immune reaction below the endometrial cups

Maternal rejection of fetal red blood cells (RBCs)

Question 22

What does localised maternal immune reaction below endometrial cups do?

Answer 22

-ensures no generalised placenta rejection occurs and the conceptus survives
-will cause cup rejection and loss of function with subsequent sloughing off

Question 23

What occurs with maternal rejection of fetal RBC’s

-what can this cause?

Answer 23

If mother exposed to fetal RBC’s, she will mount an immune response; Produces haemolytic maternal antibodies against fetal red blood cells; antibodies bind to antigens on surface of RBC’s which destroys them.

If these antibodies are produced, they will end up in the colostrum and foal ingesting it can develop anaemia 2-3 days later-this is called isohaemolytic anaemia

Question 24

How can ingestion of haemolytic maternal antibodies by the foal be prevented?

Answer 24

Foal must be fed a different colostrum for the first 24 hours & prevented from suckling its dam for this time period

Question 25

Pregnenolone is used as what in foetal circulation?

Answer 25

Precursor for androgen (transferred from maternal circulation to foetal circulation through placenta)

Question 26

Oestrogen production by the placenta is important for what?

Answer 26

placental growth and function, blood flow and thus fetal growth

Question 27

What are the 3 major forms of oestrogen?

Answer 27

Oestrone
Oestradiol
Oestriol

Question 28

Androgen precursors can be produced by dam or fetus?

Answer 28

Both!

Question 29

Describe the process of production or the different types of oestrogen by the placenta

(With diagram on anki)

Answer 29

-Cholesterol forms pregnenolone
-pregnenolone is passed from maternal circulation to foetal circulation through placenta
-pregnenolone becomes precursor for androgen factor. DHEA-S (androgen factors can also be produced in maternal circulation)
-androgen factor forms into androstenedione & testosterone which are precursors for the 2 oestrogen type; oestrone & Oestradiol in the maternal circulation
-to produce oestriol, dam must have a healthy liver; DHEA-S is not able to be converted to 16aOH-DHEA-S which is now a precursor for oestriol

Question 30

What day does oestrone levels rise in bovine during pregnancy?

Answer 30

Day 50-60

Question 31

What do placental hormones do in maternal metabolism?

Answer 31

Support foetal development particularly during term of maximal growth & ensure maximal foetal support for parturition and lactation

Question 32

Placenta produces __________, ___________, _________ _______ which has what effect on these body tissue types?

Answer 32

On anki

Question 33

Which hormone can we use to diagnose a pregnancy in dog?
-how long after pregnancy is a rise in this hormone detectable?

Answer 33

Relaxin- produced by placenta & only produced during pregnancy therefore differentiates from pseudo pregnancy bitches
-3 weeks after pregnancy

Question 34

From which day is relaxin detectable in PREGNANCY in a cat?

Answer 34

From day 25

Question 35

What technique can be used to detect relaxin?

Answer 35

ELISA

Question 36

What is another physical way we can detect pregnancy in small animals?

Answer 36

Physical examination; abdominal palpating when embryonic vesicles have distinct gestational sacs lined up along the uterine horns- feel like walnuts

Question 37

Advantages of abdominal palpating for pregnancy

Answer 37

-can differentiate pregnancy from pseudopregnancy
-possible to do early on in pregnancy

Question 38

What is anotherr 2 ways of detecting pregnancy l

Answer 38

1. Using heat detection;

-No return to oestrous at around day 21

2. Using progesterone ELISA;

-use a milk or blood sample to measure progesterone from the normal time of luteolysis, but one ‘high’ result is not definitive
-If luteolysis is prevented by the embryo (bTP) then progesterone secretion is maintained beyond the normal luteal phase, so beyond Day 18 of the cycle
-This maintained high progesterone can be detected by ELISA (in milk or blood) Day 18, Day 21 and Day 24 after breeding (so frequent sampling is best!)