Management of the Pregnant and Foaling Mare

Question 1

What do the endometrial cups produce?

Answer 1

eCG (equine chorionic gonadotropin)
PMSG (pregnant mare serum gonadotropin)

Question 2

What is the purpose of endometrial cups?

Answer 2

Prevents rebreed of mare until about 4 months from initial conception if pregnancy is lost after cup formation

Question 3

What is the function of secondary CLs?

Answer 3

Increase progesterone

Question 4

Identify the structre

Answer 4

Secondary CL

Question 5

Identify the structure

Answer 5

Ovaries during pregnancy
Luteal structures which eventually regress

Question 6

Identify the structure

Answer 6

Ovaries during pregnancy
Luteal structures which eventually regress

Question 7

How is eCG used for pregnancy diagnosis?

Answer 7

Positive = tests are present
False negative = time of sample collection
False positive = fetal death after cup formation (rare)

Question 8

At what point of pregnancy do placental progestins maintain pregnancy?

Answer 8

~120 days

Question 9

When can fetal sex be determined?

Answer 9

After 60d genital tubercle identified
After 90d mammary glands, prepuce identified

Question 10

How does the bladder look as compared to the pregnant uterus?

Answer 10

Urine in bladder is grey
Allantoic fluid is anechoic

Question 11

What are the strategies for twin reduction?

Answer 11

Natural reduction before 16d
Manual reduction at 12-15d
Abortion before 35d

Question 12

When can twins be diagnosed early?

Answer 12

12-14d

Question 13

What happens if pregnancy is ended after 35d?

Answer 13

Will not return to estrus after cups form until regression

Question 14

What hormone maintains pregnancy after the CL?

Answer 14

Progesterone

Question 15

Identify the structure

Answer 15

Primary CL

Question 16

Identify the structure

Answer 16

Secondary CL

Question 17

Identify the structure

Answer 17

Secondary Cl

Question 18

What is the benefit of Altrenogest (synthetic progestin)?

Answer 18

Can still determine endogenous progesterone

Question 19

How is pregnancy loss diagnosed?

Answer 19

Return to estrus (may retain CL, formation of endometrial cups)
Palpation or ultrasound (developmental failure, no heartbeat, disrupted membranes, changes in echogenicity)

Question 20

What is the significance of trophoblastic vesicles?

Answer 20

Development of trophoblast but not inner cell mass
Embryo insult
Retained CL
Can maintain for 20-40d
Probably no cup formation

Question 21

Identify the structure

Answer 21

Trophoblastic vesicles

Question 22

What is the normal length of gestation? What is considered premature?

Answer 22

Normal: 340d
(Range 320-360d)
Premature: < 320d

Question 23

What are the signs of foaling?

Answer 23

Mammary gland development (2-6w)
Ventral edema
Dropped abdomen (2-3w)
Perineal relaxation (1-3w)
Teat engorgement (7-10d)
Mammary electrolytes
Waxing (48-72h)
Elongation of vulva (0-24h)

Question 24

Pregnancy Stage I

Answer 24

Uterine contractions (restless, lying down, pawing, sweating)
Foal repositioning (1-4h)
Rupture of chorioallantoic membrane

Question 25

Pregnancy Stage II

Answer 25

Active straining Appearance of amnion Birth of foal Duration of 10-60 minutes

Question 26

What is the correct way for a foal to be born?

Answer 26

Front legs Nose Shoulders

Question 27

Pregnancy Stage III

Answer 27

Expel placenta Mild colic signs Pass placenta (15m-3h)

Question 28

After how long is the placenta considered retained?

Answer 28

3 hours

Question 29

What is the significance of premature separation of the placenta?

Answer 29

Chorioallantoic membrane fails to rupture and placenta separate from the endometrium *Loss of blood supply to fetus = emergency*

Question 30

What is the treatment for retained placenta?

Answer 30

Oxytocin Uterine lavage Infusion of fluid into allantoic space Antibiotics, NSAIDs

Question 31

When is best to breed the postpartum mare?

Answer 31

Assure at least 9 days to ovulation after foaling if want to breed in "foal heat" *If needed, allow to ovulate and then short cycle*