Bovine - Pregnancy and Parturition

Question 1

How long does standing estrus last?

Answer 1

12-18 hours

Question 2

When does ovulation occur in relation to standing estrus?

Answer 2

10-16 hours after the end of standing estrus

Question 3

How long does it take from the start of estrus to ovulation?

Answer 3

30 hours

Question 4

When does insemination occur in relation to estrus/ovulation?

Answer 4

it occurs during estrus so that semen is present at the time of ovulation for fertilization (ampulla)

Question 5

What is the viability of fresh semen?

Answer 5

36-48 hours

Question 6

What is the viability of frozen semen?

Answer 6

12-24 hours (conventional) or 8 hours (sexed)

Question 7

What is a sperm reservoir in a cow?

Answer 7

Sperm attaches to the wall of the oviduct, slows down their metabolic activity until there is a chemical response that reactivates them, then they unattach and move to the ampulla

Question 8

What occurs here (1)?

Answer 8

retrograde loss, phagocytosis, entrance into cervix/uterus

Question 9

What occurs here (2)?

Answer 9

privelaged pathways’, removal of non-motile sperm, removal of some abnormalities

Question 10

What occurs here (3)?

Answer 10

capacitation initiated, phagocytosis

Question 11

What occurs here (4)?

Answer 11

capacitation completed, hyperactive motility

Question 12

What occurs here (5)?

Answer 12

acrosome reaction, spermatozoon penetrates oocyte, male and female pronuclei form

Question 13

When must maternal recognition occur?

Answer 13

prior to luteolysis

Question 14

What is needed to allow changes in the endometrium to support pregnancy?

Answer 14

progesterone

Question 15

What is Interferon-T?

Answer 15

a signaling molecule

Question 16

What is interferon-T produced by?

Answer 16

trophoblastic cells from the embryo

Question 17

What does interferon-T do?

Answer 17

it blocks the release of prostaglandin from the endometrium - blocks oxytocin receptor

Question 18

What cellular layer makes the placenta?

Answer 18

the trophoblasts cellular layer

Question 19

When, during pregnancy, does attachment of the embryo begin and when is it completed?

Answer 19

it starts at day 20 and is completed by day 40

Question 20

What type of placenta do cattle have?

Answer 20

cotyledonary

Question 21

How many layers are in between the fetus and the dam in cattle?

Answer 21

6 layers - syndesmochorial

Question 22

What are the parts of the placenta?

Answer 22

amnion, allantois, and chorion

Question 23

How is pregnancy diagnosed in cattle?

Answer 23

rectal palpation, ultrasound, and blood tests (expensive)

Question 24

What are the cardinal signs via rectal palpation of pregnancy?

Answer 24

fetus, amniotic vesicle, membrane slip, and placentomes

Question 25

What are the advantages to doing ultrasound for pregancy testing?

Answer 25

fetal viability, fetal sexing, better twin diagnosis, and pathology

Question 26

What hormone is needed throughout pregnancy?

Answer 26

progesterone

Question 27

What provides the primary source of progesterone for the first 5 months of pregnancy?

Answer 27

the corpus luteum

Question 28

What provides progesterone from 6-8 months?

Answer 28

the placenta

Question 29

What provides progesterone in the last month of pregnancy?

Answer 29

the corpus luteum

Question 30

A.

Answer 30

fetal cortisol

Question 31

B.

Answer 31

placental P4

Question 32

C.

Answer 32

E2

Question 33

D.

Answer 33

increased secretion by reproductive tract

Question 34

E.

Answer 34

lubrication

Question 35

F.

Answer 35

increase in myometrial contractions

Question 36

G.

Answer 36

increase in pressure

Question 37

H.

Answer 37

increase in cervical stimulation

Question 38

I.

Answer 38

Increase in oxytocin

Question 39

J.

Answer 39

Maximum pressure

Question 40

K.

Answer 40

PGF2-alpha

Question 41

L.

Answer 41

Luteolysis

Question 42

M.

Answer 42

Relaxin

Question 43

N.

Answer 43

Pelvic ligament stretching

Question 44

What is the function of progesterone during pregnancy?

Answer 44

to inhibit or block myometrial activity (uterine quiescence)

Question 45

What causes the initiation of myometrial contractions?

Answer 45

removal of progesterone block by conversion of progesterone to estrogen by fetal cortisol - also allows PGF to be releaseed to aid in parturition

Question 46

What initiates stage 1 of parturition?

Answer 46

the fetus

Question 47

What occurs during stage 1 of parturition?

Answer 47

myometrial contractions and cerviccal dilation - prepares the fetus for delivery

Question 48

How long does stage 1 of parturition typically take?

Answer 48

2-6 hours

Question 49

What are the typical signs associated with stage 1 parturition?

Answer 49

separating from the herd (prey animals), mild contractions and moving around (up and down), and pelvic ligaments relax (relaxin)

Question 50

What occurs during stage 2 of parturition?

Answer 50

fetal expulsion - straining and strong contractions (ferguson reflex), breaking allantois, and breaking amnion

Question 51

How long does fetal expulsion typically take in cows? Heifers?

Answer 51

cows - 30-60 minutes, heifers - 2 hours

Question 52

What occurs during stage 3 of parturition?

Answer 52

fetal membrane expulsion

Question 53

How long does fetal membrane expulson typically take?

Answer 53

6-12 hours

Question 54

When should you consider that there is a retained fetal membrane?

Answer 54

after 12 hours

Question 55

What must happen in order for the fetal membrane to be dislodged?

Answer 55

chorionic villi must dislodge from crypts on the endometrium (caruncles)

Question 56

When would you want to induce parturition?

Answer 56

mismating or to induce it prior to the due date

Question 57

What can you give prior to 150 days of pregnancy to induce parturition?

Answer 57

PGF

Question 58

What can you give after 150 days of pregnancy to induce parturition?

Answer 58

dexamethasone and PGF

Question 59

When trying to induce a viable calf early, what exogenous drugs can be used?

Answer 59

PGF, dexamethasone, or PGF and dexamethasone

Question 60

What role does dexamethasone play when inducing parturition?

Answer 60

mimic fetal cortisol