Lecture 14: Equine Pregnancy & Parturition (Macpherson) Flashcards Preview

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Flashcards in Lecture 14: Equine Pregnancy & Parturition (Macpherson) Deck (37)
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0
Q

function of the ampulla?

A

allows sperm passage

1
Q

what is the function of the infundibulum in the mare?

A

its “the baseball mitt” used to catch the ovum.
important –> it covers the ovulation fossa in the mare

it then moves the ovum to the oviduct

2
Q

what is the site of fertilization in the mare?

A

the ampullary isthmic junction

3
Q

what is the oviductal papilla?

A

it is the opening of an oviduct to the mare. it protects the oviduct from infection during mating.

4
Q

when is the embryo transported to the uterus?

A

day 5.5 to 6

5
Q

what hormone is released while the embryo is in the oviduct?

A

prostaglandin E it stimulates muscle contraction to help transport the embryo out of the oviduct to the uterine horn.

6
Q

what covers the compact morula?

A

the zona pellucida

7
Q

what is unique about the blastocyst in the mare?

A

it has a capsule to keep the conceptus cervical

8
Q

what 3 structures are in the blastocyst that were discussed in class?

A
  • capsule (unique to the mare!)
  • blastoceoele cavity
  • inner cell mass
9
Q

what 2 things were mentioned in class about the expanded blastocyst?

A
  1. it still contains an inner cell mass

2. it is what is most often seen in a uterine flush

10
Q

what is a UFO? and what is it an indication of?

A

an unfertilized oocyte!

  • it stays dormant in the oviduct
  • usually an indication that there is also an embryo!
11
Q

when is early detection of pregnancy in a mare?

A

day 13 - 15 post-ovulation

12
Q

what is the state of the uterus and ovary during early detection of pregnancy? what should you see?

A
  • uterus should be very toned (because it is under the influence of progesterone)
  • a CL should be present on the ovary
13
Q

Can mare double ovulate? what is important about this?

A

Yes - make sure you don’t get twins!

14
Q

when should you check for twins?

A

2 weeks after ovulation

15
Q

how does the embryo receive early nutrition? (2 ways)

A
  1. supported initially by the yolk sac

2. uterine glands produce histiotroph - nutrients that are secreted by the endometrium and absorbed by the early embryo.

16
Q

what are endometrial cups? and what hormone do they secrete?

A
  • structures produced by cells of trophoblastic embryo that migrate from embryo to endometrium.
  • they form molar like structures (unique to the mare!) and secrete a hormone called equine gonadacotropin (ECG).
17
Q

what does equine gonadacotropin (ECG) do? how long is it secreted for?

A
  • it promotes growth of secondary CL which must be maintained to 200 days of pregnancy
  • ECG is produced until 200 days of gestation
18
Q

why is ECG produced only until the 200th day of gestation?

A

because the fetal placental unit “takes over” for the last 1/3 of gestation.

19
Q

what is the mare placentation?

A
  • diffuse
  • epitheliochorial
  • non-deciduate
  • microplacentomes - that interdigitate with the endometrium
20
Q

when do twins usually die?

A

at about 2/3 through gestation

21
Q

are twins ever appropriate in the mare?

A

NEVER! NEEEEEVERRRRR!

22
Q

what are the 2 things that threaten pregnancy the most?

A
  • twins

- placental infection

23
Q

what is the length of gestation?

A

320 to 360 days (highly variable; large range - unique to the mare)

24
Q

what is unique about gestation length in horses?

A
  • gestational length is repeatable in the individual.
  • meaning if Lucy has a foal at day 342 then she will have future foals around that time too. If she doesn’t, that is considered abnormal and is cause for concern.
25
Q

what things will vary the length of gestation?

A
  • day length
  • age
  • number of pregnancies
26
Q

what factors are important for parturition (4 things)?

A
  • length of gestation
  • fetal maturation
  • colostrum production
  • cervical dilation
27
Q

name 2 important things about fetal maturation talked about during class.

A
  1. fetal maturation occurs in the last week of gestation.
  2. occurs in response to rising levels of cortisol released by the adrenal gland.
    - if fetus is born without being exposed to cortisol, it will not have necessary functions for survival
28
Q

when will mare start producing colostrum?

A

about 2 weeks before delivery

29
Q

how can you measure electrolytes in colostrum production to predict fetal delivery?

A
  • Na and K should invert: K production should increase and Na production should decrease.
  • Ca should be > 40mg/dl
30
Q

when does the cervix dilate? what is the significance of cervical dilation?

A
  • it dilates prior to parturition

- this allows for faster delivery and improved neonatal adaptability

31
Q

how should fetus be positioned for delivery?

A

in the anterior longitudinal position (like they are getting ready to DIVE into life!)

32
Q

how long is the mare in stage I for?

A

1-4 hours

33
Q

how long is the mare in stage II for?

A

30 to 60 minutes

34
Q

how long is the mare in stage 3 for?

A

< 3 hours

35
Q

what happens if the mare has not expelled fetal membranes after 3 hours?

A

it’s considered an emergency!

36
Q

possible complication of parturition is what is called “red bag dystocia” what does this mean?

A

a portion of the placenta has detached from the uterine wall prematurely, reducing/eliminating exchange of nutrients (ie oxygen) to the fetus. you will literally see “the red bag” hanging out of the vulva before you see the fetus. This is considered a true emergency!

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