Mare Pregnancy Diagnosis & Twin Pregnancy

Question 1

Endometrial cups in mares produce:

Answer 1

equine chorionic gonadotropin (eCG)

These cups start to produce eCG between days 35 and 42

Question 2

If you have an EED past day 38 in the mare, when would you expect her to come back into heat?

Answer 2

100-120 days

If the conceptus dies, the endometrial cups usually maintain their production of eCG until 120 to 150 days of gestation.

Question 3

Fetal sexing in the mare involves finding the location of the _________

Answer 3

genital tubercle

The genital tubercle is the precursor to the penis in the male and precursor to the clitoris in the female. To determine the sex of the fetus, you find this structure and determine its location relative to other fetal structures. This can be done between ~55-90 days of gestation

Question 4

In the mare, implantation and endometrial cup formation occurs ~_____ days post-ovulation

Answer 4

35-40 days

Question 5

T/F: Twins generally occur due to double ovulations

Answer 5

True

Question 6

Roughly ___% of twin pregnancies reach term in mares

Answer 6

9%

Question 7

Pregnancy diagnosis can be done as early as ____ days but in general it’s more reliable between ____ and ____ days post-ovulation.

Answer 7

The diagnosis can be done as early as 10 days but in general it’s more reliable between 14 and 16 days post-ovulation.

Question 8

The reason for the low survival rate of twins is due to:

Answer 8

competition for placental space

Question 9

In the mare, endometrial cup regression occurs ~_____ days post-ovulation

Answer 9

100-120 days

Question 10

Survival rate after twin reduction in mares is over 90% if it’s done before ____ days

Answer 10

16-20 days

often mares that have had a twin reduction procedure will be given progesterone and flunixin

Question 11

Is this 16 D vesicle normal?

Answer 11

Yes.

Question 12

The equine conceptus is mobile within the uterus until fixation occurs ____ days post-ovulation

Answer 12

16 days

Question 13

What is the method of choice for pregnancy diagnosis in the mare?

Answer 13

ultrasound

Question 14

In the mare, the fetal heartbeat becomes detectable ~_____ days post-ovulation

Answer 14

25 days

Question 15

In the mare, the embryo will enter the uterus ~ _____ days post-ovulation

Answer 15

5-6 days

Question 16

Maintenance of the pregnancy in the mare after 120 days is primarily the responsibility of the:

Answer 16

Fetal chorioallantois

Question 17

Pregnancy diagnosis in the mare can be done earlier than in other species because of the presence of the __________

Answer 17

embryonic capsule​

• Pregnancy diagnosis in the mare can be done earlier than in other species because of the presence of the embryonic capsule that maintains the embryo in a round shape for the first 20 days.*
• The diagnosis can be done as early as 10 days but in general it’s more reliable between 14 and 16 days post ovulation.*

Question 18

What is the 2^nd most common non-infectious cause of abortion in the mare?

Answer 18

Twinning

1^st is fetal maldisposition

Question 19

In the mare, the pregnancy is no longer dependent on the CL ~_____ days post-ovulation

Answer 19

90-100 days

Question 20

What day do you want to detect TWINS in a mare?

Answer 20

12-14

Because this is before they attach/fixate. If you need to crush one you need to do it before day 16