Termination of Pregnancy and Induction of Parturition

Question 1

what does approach to termination depend on

Answer 1

-Some species are CL‐dependent for the whole pregnancy, meaning NO contribution from the placenta

Question 2

How well does PGF2a work to induce abortion in Cows?

Answer 2

highly effective until 150d, and then again after 250d into gestation

Question 3

Efficiency of pregnancy termination using cortisol ‐ cow

Answer 3

doesn’t work before 150d, works well after 250d

Question 4

what is dexamethasone

Answer 4

cortisol

Question 5

Efficiency of pregnancy termination – Combination ‐ cow

Answer 5

when you give dexamethasone and PGF2a together, its fully effective throughout the entire gestation

Question 6

causes for abortion in mares

Answer 6

-Wrong sire
-Unintentional breeding
-Twins
-Problem pregnancy (Hydrops, Prepubic tendon rupture)

Question 7

how to induce abortion in mare <28d

Answer 7

Pinch one vesicle transrectally (twins)

Question 8

how to induce abortion in mare <35d

Answer 8

PGF2α

before cups form and produce eCG

Question 9

how to induce abortion in mare 35 – 120 days

Answer 9

PGF2α – twice daily for 3‐5 days +/‐ manual extraction

(when cups are present)

Question 10

how to induce abortion in mare > 120 days

Answer 10

-PGF2α – twice daily for 3‐5 days, then oxytocin to expel fetus +/‐ assist and extract
-Fetus usually born alive

Question 11

how to induce abortion in sheep before 50-60d

Answer 11

In sheep, one injection of PGF2a is 90% effective in inducing abortion before 50‐60 days; two injections 48 hours apart ‐ is 100% effective

Question 12

how to induce abortion in sheep after 50-60d

Answer 12

After 50‐60 days corticosteroid is somewhat effective – may require
multiple injections and manual dilation/extraction

Question 13

induction of abortion in goats

Answer 13

PGF2a is effective at any stage of pregnancy

Question 14

induction of abortion in pigs

Answer 14

PGF2a is effective at any stage of pregnancy

Question 15

how many PGF2a injections are recommended for induction of abortion and why

Answer 15

-2 PGF2a injections is recommended to ensure complete luteolysis
-Reduced risk of fetal mummification
-Increases success rate

Question 16

what was the leading cause of abortion in mares before U/S

Answer 16

twinning

Question 17

what is twinning usually due to

Answer 17

Usually due to double ovulation

Question 18

how do you prevent twinning going to term

Answer 18

-Routine early diagnosis by ultrasound at

Question 19

when is it best to pinch a twin?

Answer 19

-Best performed at 14‐17 days (before fixation)
-Can still be done up to approx. day 28
-Manual crushing per‐rectum

Question 20

Management of Twin Pregnancy in
Mares (unilateral vs bilateral)

Answer 20

-Depends on whether the embryonic vesicles are in the same horn (unilateral) or separate horns (bilateral)
-If unilateral, >85% chance that by day 60 the pregnancy will reduce to a singleton or no pregnancy, on its own (natural reduction)
-If bilateral, highly likely to continue as twins until abortion in late gestation

Question 21

twin reduction in the mare; Day 28 – 55

Answer 21

-Ultrasound monitored disruption
-good for bilateral cases

Question 22

twin reduction in the mare; Day 70 – 120

Answer 22

Craniocervical dislocation
-Rectally
-Colpotomy (vaginal incision)
-Flank incision

Question 23

twin reduction in the mare; Day 90 – 180

Answer 23

Transabdominal ultrasound‐guided
puncture
-Intra‐fetal injection of procaine penicillin
-The later performed, the greater the risk of placental insufficiency and abortion of pregnancy

Question 24

twin pregnancies in cows; why its selected for, what its associated with

Answer 24

-Selection for increased milk production = more double ovulations; also higher use of synchronization programs

-Associated with higher embryo/pregnancy losses
-92% of cows dx with singleton will calve vs. 76% of cows dx with twins (as low as 54% in some studies)
-Higher rates of dystocia and postpartum disease
-Risk of Freemartin Syndrome in calves

-Manual rupture of one sac at

Question 25

reasons for induction of parturition (4)

Answer 25

-Illness in the dam -Ensuring assistance at delivery -High risk pregnancies -Owner convenience

Question 26

Physiology of parturition in cows (hormones)

Answer 26

-Declining progesterone -Increasing estrogen

Question 27

what is a high risk when you induce parturition

Answer 27

-Very high incidence of retained placenta

Question 28

what drugs can you give to induce parturition in cows

Answer 28

-Dexamethasone and Prostaglandin combination. Most predictable -Within 2 weeks of calving -Calving about 36 hours after administration -With Dex only = about 43‐52 hrs -With PGF only = 45‐72 hrs

Question 29

Induction of parturition in ovine

Answer 29

-Corticosteroid – 80% lamb in 42 hrs (avg) -PGF not effective

Question 30

Induction of parturition in caprine

Answer 30

-PGF2α >140 days – kidding in 30‐50 hrs

Question 31

Induction of parturition in porcine

Answer 31

-PGF2α day 111 + oxytocin 24 hrs later; farrow in ~ 6 hrs

Question 32

Guidelines for Safe Induction in mares (4)

Answer 32

1. Min 330 days gestation 2. Udder development + colostrum 3. Relaxation of sacrosciatic ligaments and vulva 4. Electrolyte analysis of colostrum indicates fetal maturity

Question 33

when does fetal maturation happen in horses

Answer 33

last 2 days of gestation

Question 34

how do Electrolyte changes in milk indicate fetal maturity

Answer 34

-Increase in Calcium (Ca2+) to >400 ppm, or >200 ppm (10 mmol/ml) on two consecutive days, indicates fetal maturity -Potassium should be greater than Sodium -Decrease in Sodium to <35 mmol/ml -Increase in Potassium to > 80 mmol/ml

Question 35

pH of Mare’s Milk Determines Fetal Readiness for Birth

Answer 35

-Using standard pH strips, milk can be tested to determine fetal readiness -When pH drops below 6.4 = foaling within 24 hours

Question 36

what should you always avoid when inducing parturition in mares

Answer 36

PGF2α -NOT reliable (remember, no CL’s are present after 120 days in mares) -NOT recommended

Question 37

what can you use to induce parturition in a mare

Answer 37

Oxytocin -10‐15 IU, IV, repeat every 15‐20 min -Usually foal within 60 min (after 2nd or 3rd injection)

Question 38

what is another option for inducing parturition last case scenario?

Answer 38

Corticosteroids -Only cross equine placenta if very high doses given repeatedly -Foal approximately 8 days later -Appears safe between 315 and 325 days gestation to induce fetal maturation

Question 39

risks of using corticosteroids to induce parturition in mares

Answer 39

-Risk of laminitis -No colostrum -If used close to term leads to dystocia and fetal death in high %

Question 40

what are mares incredibly sensitive to in late pregnancy

Answer 40

-Mares are exquisitely sensitive to oxytocin in late pregnancy even if fetus is not mature -Potential to induce too early and have a dead foal!!

Question 41

time to baby if you give PGF2α + Dex in cows

Answer 41

36h

Question 42

time to baby if you give Dex in ewes

Answer 42

42h

Question 43

time to baby if you give PGF2α in does

Answer 43

30-50h

Question 44

time to baby if you give PGF2α + Oxytocin ( in 24hrs) in pigs

Answer 44

6h

Question 45

time to baby if you give Low dose Oxytocin in horses

Answer 45

<1h