Termination of Pregnancy

Question 1

What are the three types of pregnancy termination

Answer 1

1) abortion
2) induction of parturition
3) twin reduction

Question 2

What are some indications for induction of abortion in cows?

Answer 2

• feedlot heifer
• incorrect sire
• heifers too young
• bull/colt/ram/buck got loose

Question 3

Approach to pregnancy determination depends on what

Answer 3

whether the animal is CL dependent for the entire pregnancy or not

Question 4

What animal species maintain the CL throughout gestation

Answer 4

cows
pigs
dogs
cats
goats

Question 5

what animal species do not have progesterone contribution from the placenta

Answer 5

dogs
cats
pigs
goats

Question 6

what is the contribution of the CL and placenta to progesterone production in sheep (ovine)

Answer 6

CL: <50-60d
Placenta: >50-60d

Question 7

what is the contribution of the CL and placenta to progesterone production in horses

Answer 7

CL (endometrial cups): 120-150d
Placenta: >70d

Question 8

when does the placenta start producing progesterone in cows

Answer 8

150-250d

Question 9

what plays an important role in initiation of parturition and what is a caveat

Answer 9

fetal glucocorticoids, only if the feto-placental unit is alive and functioning

Question 10

when can you induce abortion using PGF2a in cows

Answer 10

<150 d or >250d (when the placenta is not contributing to progesterone levels)

Question 11

when can you induce abortion using dexamethasone in cows? when is it 100% effective?

Answer 11

starts to work at 150d (low efficacy) and becomes 100% after 250d

Question 12

if you wanted to be 100% certain you can induce abortion in a cow and you don’t know what day of gestation, what can you use

Answer 12

both PGF2a (lyse the CL) and dexamethasone (stops placental secretion)

Question 13

T/F you only need 1 injection of PGF2a if inducing abortion in a cow <150 or >250d of gestation

Answer 13

F; give 2 to ensure you induce complete luteolysis

Question 14

what happens if you did not completely lyse the CL in a gestating cow using PGF2α

Answer 14

mummification

Question 15

in cases of fetal mummification or maceration in cows, how do you induce abortion

Answer 15

PGF2a -> luteolysis -> drop in progesterone

Question 16

what are indications for induction of abortion in horses?

Answer 16

1) wrong sire
2) unintentional breeding
3) twins
4) problem pregnancy (ex. hydrops, PPT rupture)

Question 17

In the horse, what is significant:
- in the first 35 days
- at day 35
- between 35-120 days
- after 120 days

Answer 17

• in the first 35 days: only CL
• at day 35: endometrial cups formed
• between 35-120 days: eCG from endometrial cups -> acts like LH -> secondary CL formed -> progesterone
• after 120 days: only placental source of progesterone

Question 18

how do we induce abortion in mares:
- <28 days of pregnancy:
- <35 days of pregnancy:
- 35-120 days of pregnancy:
- >120 days of pregnancy:

Answer 18

• <28 days: pinch one vesicle transrectally (in case of twins)
• <35 days: PGF2a
• 35-120 days: PGF2a twice daily for 3-5 days, may need manual extraction
• > 120 days: PGF2α twice daily for 3-5 days, oxytocin, assist and extract (usually need to euthanize fetus once born)

Question 19

How do we induce abortion in sheep vs goats

Answer 19

in goats, only the CL is the source of progesterone, so 2 PGF2a injections can be given at any stage of gestation

in sheep, <50-60 days you can give 2 shots of PGF2a since only the CL is present; after 50-60 days you can give multiple injections of corticosteroids and manually dilate/extract

Question 20

in pigs, how do we induce abortion

Answer 20

2 shots of PGF2a at any stage of gestation

Question 21

what are the concerns with twinning in mares

Answer 21

• leading cause of abortion before ultrasound
• rarely go to term due to placental insufficiency
• severe damage to the mare, and usually neither fetus survives

Question 22

T/F twinning in the mare can be unilateral or bilateral

Answer 22

T

Question 23

how can you tell whether twins in a mare ovulated at the same time or not

Answer 23

if they are the same size or different sizes on ultrasound

Question 24

when and how is manual twin reduction performed in the name

Answer 24

best at 14-17 days (before fixation) but can be done up to day 28; manually crush per rectum by massaging up the horn and popping

Question 25

what is the difference in management of twin pregnancy if unilateral vs bilateral pregnancy in the mare

Answer 25

if unilateral: >85% chance that natural reduction will occur and the twins will reduce to a singleton or no pregnancy if bilateral: very likely to continue as twins until abortion in late gestation

Question 26

how can we reduce twins in the mare: - between days 28-55 - between days 70-120 - between days 90-180

Answer 26

days 28-55: ultrasound monitored disruption days 70-120: craniocervical dislocation (rectally, by colpotomy or by flank incision) days 90-180: transabdominal ultrasound guided injection of procaine penicillin

Question 27

is the twinning rate in cows going up or down and why

Answer 27

up; selection for higher production, more double ovulations, synchronization programs

Question 28

what are the 3 main issues with twinning in cows

Answer 28

- freemartins - higher embryo/pregnancy loss - associated with dystocia and postpartum disease

Question 29

how can we reduce twins in cows

Answer 29

manual rupture between days 35-40

Question 30

what are some indications for initiation of parturition

Answer 30

1) disease in dam 2) ensuring assistance at delivery 3) high risk pregnancy 4) owner convenience?

Question 31

the physiology of parturition is characterized by declining ______________ and rising _________________

Answer 31

progesterone; estrogen

Question 32

what is the most common combination used to initiate parturition in cows? when can this be done? how soon after do they calve? what is an issue?

Answer 32

dexamethasone and PGF2α; last 2 weeks of pregnancy; 36h; retained placenta

Question 33

the earlier that calving is initiated: - what effect of mortality? - what effect on value? - what effect on sales?

Answer 33

- higher mortality - less value - fewer sales

Question 34

how do we induce parturition in: - ovine - caprine - porcine

Answer 34

- ovine: corticosteroid (PGF2a not effective) - caprine: PGF2a (>140d) - porcine: PGF2a (>111d) and oxytocin 24h later

Question 35

how soon after initiating parturition will the following species give birth: - ovine - caprine - porcine

Answer 35

- ovine: 42h - caprine: 30-50h - porcine: 6h

Question 36

what concerns are unique about initiating parturition in mares?

Answer 36

the fetus matures in the last 2 days of gestation, and horses have a wide range of normal gestation lengths

Question 37

what are the guidelines for safe induction of parturition in mares? (4)

Answer 37

1) minimum 330 days 2) udder development and colostrum present 3) relaxation of sacrosciatic ligaments and vulva 4) analysis of colostrum indicates fetal maturity

Question 38

what are the electrolytes changes we want to observe in a mare before initiating parturition

Answer 38

1) increase in calcium to >400ppm or >200ppm for 2 consecutive days 2) potassium greater than sodium (sodium <35 mmol/ml, potassium >80 mmol/ml)

Question 39

T/F the pH of the mares milk determines fetal readiness for birth

Answer 39

T

Question 40

when the mares milk pH drops below _____, you can expect them to foal within the next _____

Answer 40

6.4; 24h

Question 41

what is the fastest and best way to induce parturition in the mare? a) PGF2a b) oxytocin c) corticosteroids

Answer 41

b) oxytocin

Question 42

how do you induce parturition with oxytocin

Answer 42

IV injection (10-15 IU) every 15-20 minutes; usually foal within 60min

Question 43

can corticosteroids be used to initiate parturition in the mare? what is a problem with this method?

Answer 43

yes, but will foal in 8 DAYS, no colostrum, risk of laminitis, can lead to dystocia and fetal death

Question 44

T/F mares are incredibly sensitive to oxytocin in late pregnancy and will foal even if fetus is not mature

Answer 44

T