Test 1: 5 gestation Flashcards
Mare oocyte is in — at ovulation.
Metaphase II
when does ovulation occur
0-2 days before last day of estrus
Fertilization takes place in the — of the oviduct
ampullary portion
It is recommended that breeding takes place before
ovulation generally, during the
48 hour period before ovulation, although pregnancy may result if breeding occurs 12 to 18 hours after ovulation.
The fertilized ovum usually enters the uterus as a
— 6 days after ovulation.
late morula or an early blastocyst
The early embryo produces
— which allows transport through the oviduct.
PGE2
Once the embryo enters the uterus, it moves throughout the uterine lumen until — after ovulation
Day
16
If a mare is not pregnant, — is released from the endometrium on Day 14 and travels via the systemic circulation to the ovary to cause —.
PGF-2a
luteolysis
what is Uteroferrin
present in the uterine lumen from Day 8 until after Day 20. If the pregnancy is terminated, uteroferrin concentrations rapidly decrease.
- might cause maternal recognition of pregnancy in a mare
- estrogen, movement, PGF2⍺, uteroferrin
when can you see yolk sac on US
Day 9-21
when can you see embryo on US
day 21
when can you see heart beat and allontois
day 25
what day? . Allantois occupies approximately half of the vesicle. Size of regressing yolk sac is equal to the size of the developing allantois.
day 28-30
when?
Allantois occupies entire vesicle; yolk sac has regressed.
day 40-45
By 17 to 21 days, there is a tightening and lengthening of the cervix, giving it the
characteristic — shape of pregnancy. The — are no longer
palpable
“pencil”
endometrial folds
There are numerous follicles present on both ovaries from Day 10 to 210 of pregnancy. A primary corpus luteum forms from initial ovulation at the start of pregnancy and lasts until about — days of gestation.
150-180
Secondary corpora lutea form after Day 40 as a result of secondary ovulated follicles and — of unruptured follicles.
luteinization
why don’t mares need a corpus luteum to maintain the pregnancy after 75-100 days
Mares do not require a corpus luteum for maintenance of pregnancy after about 75 to 100 days of pregnancy. The fetal-placenta unit produces progestogens after 30 to 60 days of gestation.
Pregnenolone is derived
from the fetal adrenal and converted into progesterone in the placenta and then into — in the endometrium (first
detectable at day 30-60.).
5
α-pregnane, 3, 20 –dione
(DHP)
— is produced by placental trophoblast cells. Concentrations are high in late gestation and increase during parturition.
relaxins
May aid in relaxation of cervix and ligaments.
average gestation length for mare
342
(321-365)
characteristics of impending parturition in mare
- enlarged abdomen
- mammary development- 3-6 weeks prepartum, colostrum, “waxing”, increased calcium and magnesium content of milk
- relaxation of sacrosciatic ligament and vulva
- relaxation of cervix, 0-30 days prepartum
Stage 1 parturition in mare lasts —
1 or more hours
what happens during stage I parturition in mare
Duration + 1 hour.
Onset of uterine contractions.
Relaxation and dilation of cervix.
Restless. signs of abdominal pain, colic signs.
Sweat patches on flanks and behind elbows.
If disturbed, a mare can stop early stage of parturition.
The end of the first stage of parturition is marked by rupture of the cervical star of the allantochorionic membrane and escape of allantoic fluid. The foal rotates from a dorsopubic
or dorso-ilial position to a dorsosacral position just before delivery.
when does the stage I parturition end
- rupture of the cervical star of the allantochorionic membrane and escape of allantoic fluid
in stage 1 partuition the foal rotates from
dorsopubic or dorso-ilial position to a dorsosacral position just before delivery.
stage II parturition in mares lasts
less then 30 mins
what happens during stage II parturition in mare
- Duration < 30 minutes.
- Uterine contractions and abdominal contractions.
- Delivery of foal covered in its amnion.
- Normal presentation is anterior, longitudinal, dorsosacral, extended head, neck and front legs.
normal presentation of foal in stage II parturition in mare
Normal presentation is anterior, longitudinal, dorsosacral, extended head, neck and front legs.
stage 3 parturition lasts how long in mare
less then 3 hours
what happens during stage 3 parturition in mares
- Duration ≤3 hours.
- Expulsion of the placental membranes.
- The placenta should always be examined for completeness paying particular attention to the presence of the tip of each uterine horn.
- Average weight of a placenta is approximately (11% of weight of conceptus) 13 pounds.
- The chorion has a velvety red surface.
- The allantois has a smooth whitish surface.
The — has a velvety red surface.
The — has a smooth whitish surface.
chorion
allantois
During the last 2-3 days of gestation, fetal ACTH —, 17 α-hydroxylase (adrenal enzyme) converts progesterone to — which is required for fetal maturation
increases
cortisol
PGE2 causes cervical —.
relaxation
when to induce parturition in mares
The mare should be over 330 days pregnant and have developed mammary glands that contain colostrum.
what meds to induce parturition in mare
oxytocin and dexamethasone
uterine involution occurs — in mares
quickly- 6-10 days
* Little tissue is lost at parturition due to the epitheliochorial placental attachment, therefore vaginal discharge is scant.
what is a foal heat
ovulation 7-9 days after foaling, may not maintain pregnancy
what to do for retained placenta
If placenta remains in the uterus after 3 hours, therapy should be started.
* Early treatment (3-8 hours) - 10-20 IU oxytocin IV or IM every 15 minutes.
* If retention is prolonged (> 8 hours) or other complications are present such as dystocia, fetotomy, cesarean section, more aggressive therapy is promptly required. Laminitis is a frequent sequela to prolonged untreated retained placenta. - oxytocin, NSAID, broad spectrum system antibiotics, exercise, sucking by foal, Ca gluconate, fluids
the early mare embryo is surrounded by — that helps with movement
glycoprotein capsule
the mare has what type of placenta
- Diffuse, nondeciduate. endometrium not sloughed, can ovulate in 7 days
- Epitheliochorial 6 layers- no antibody exchange, need colostrum (uterine epithelium is in contact with the outer layer of the chorion.
- Microcotyledonary. (fuzzy) Attachment does not occur until as late as 38 to 39 days. It is not complete until Day 150.
We are looking at the chorionic surface of a mare’s fetal membranes. The top bar of the F is the gravid horn, the lower bar of the F is the nongravid horn. The cervical star (located at the base of the F) is the area that ruptures to allow the foal to be delivered.
layers of epitheliochorial placenta
6 layers
FETAL BLOOD
- Endothelium of fetal blood vessel
- Fetal mesenchyme
- Trophoblast cell (chorionic epithelium)
- Endometrial epithelium
- Uterine stroma
- Endothelium of uterine blood vessel
MATERNAL BLOOD
cells from the chorionic girdle will do what?
burrow into endometrium
* form endometrial cups, which produce equine chorionic gonadotropin (ECG) → ↑FSH and ↑ LH which leads to additional follicels and grow and leutrinze (secondary corpora lutea) →↑ progesterone
why do endometrial cups only present 40-120 days
have stallion DNA, female uterus will attack and destroy the cups
endometrial cups make EGC which leads to secondary corpora lutea
how to diagnose pregnancy in mare
- Palpation per rectum > 28 days
- Transrectal ultrasonography 14 days
- transabdominal US: 80 days
- estrone sulfate: 150 days
- ECG assay: 40-120 days- when there are endometrial cups
gestation length of mare
342
321-365
late gestation- laying on its back
Progesterone and 5 α-DHP — during the last 2-3 weeks of pregnancy.
increase
During the last 2-3 days of gestation, fetal ACTH increases, 17 α-hydroxylase (adrenal
enzyme) converts progesterone to — which is required for fetal maturation
cortisol
During Stage I of labor the fetus rotates from a — position to a — position.
dorsopubic
dorsosacral
Mare at the end of Stage I of labor as evidenced by the —
expulsion of allantoic fluid when the chorioallantois ruptures.
foals do not have a — like a ruminant therefore they can be born encased in their —
mesovarium
amnion
The — has a velvety red surface. The — has a smooth whitish surface.
chorion
allantois
why would you induce a mare
- ventral hernia
- ruptured prepubic tendon
- prolonged gestation
- medical problem
- mares requiring assistance
- nurse mare prep
— can be given to induce birth in a mare in 7 days
dexamethasone
- may help develop fetal lungs
— can be given to induce a mare to give birth in 1 hr
oxytocin
what happens during uterine involution
- passage of placenta
- removal of uterine fluids
- decrease in uterine size
- repair of endometrium
how long is uterine involution in a mare
6-10 days
very fast because of epitheliochorial placental attachment- little tissue is lost during parturition
If placenta remains in the uterus after —, therapy should be started.
3 hours
what happens with retained fetal membrane in mare
- metritis
- endotoxemia
- laminitis
- death
how to treat retained placenta 3-8 hrs
give oxytocin
treatment for retained placenta > 8 hrs
oxytocin
antibiotics- penicillin and gentamicin
NSAID- flunixin meglumine
lavage uterus
umbilical vessel infusion
how does umbilical vessel infusion work
way to remove retained pacenta
* all water into the umbilical vessels, will distend the allantoic vessels and should release
uterine artery rupture can cause
- bleeding into broad ligament, abdomen and/or uterus
- can become colicy, shocky and die
two most common non-infectious causes of abortion in mares
twins
umbilical cord torsion
3 top viral causes of abortion in mares
EHV-1- vaccinate 5,7,9 months of gestation
equine viral arteritis ∓vaccinate
equine infectious anemia-coggins test- cull +
