Equine pregnancy and parturition by Kavak Flashcards
(36 cards)
Stallion:
Sperm reaches the oviduct ca ? post breeding.
Most semen out of uterus ? post breeding.
Semen can be alive in the mare reproductive tract for ?
Sperm reaches the oviduct ca 5 minutes post breeding.
Most semen is out of the uterus 12 h post breeding.
Semen can be alive in the mare reproductive tract for 5-9 days.
Mare:
Ageing of the oocyte starts ? post ovulation.
Lifespan of the oocyte is ?
Fertilization occurs in the ?
Ageing of the oocyte starts 8 h post ovulation.
Lifespan of the oocyte 12 - 24 h.
Fertilization occurs in the ampulla.
When is it a Zygote?
When is it an Embryo?
When does it count as a Fetus?
Zygote:
From fertilization to attachment in the uterus 1 - 16 days.
Embryo:
Attachment to end of organogenesis timeframe 16 – 55 (60) day.
Fetus:
Organogenesis till parturition so from day 55 (60) to variable-day. In horses gestation is approx. 340 days.
When does a fetilized oocyte enter the uterus?
Only fertilized oocyte enters to uterus on D 5-6.
Unfertilized ovas stay in oviduct for couple of months
and degenerate.
Embryonic vesicle visible by ultrasound on what day?
Embryonic vesicle visible on day 9-10.
D 11-14 difference in uterine tone.
D 14 regression of CL if not fertilized.
Maternal recognition of
pregnancy factor in the mare?
And when does the mare’s conceptus produce this factor?
mares do not have a single specific pregnancy recognition hormone. Instead, the key factor is the mobility of the conceptus (early embryo) within the uterus.
The conceptus releases proteins, prostaglandins (notably PGE2), and estrogens, which help modulate uterine prostaglandin secretion and maintain the CL.
The equine conceptus produces its signaling factors starting around days 9–10 post-ovulation.
A horse embryo has highest mobility at what stage of gestation?
When does fixation occur?
When does amnion begin to develop?
Highest mobility D 9-16
Fixation D 16-18
Amnion starts to develop ca D 19
.
Fetal heart begins to beat at day
day 25
When does the allantois begin to develop?
When does eCG rise?
When do accessory CL develop?
D 28 allantois, (allanto-chorion), micro villae begin to develop
eCG rises on D 35-40 ( D 60 - Max PMSG (eCG) level)
D 50-55 accessory CL, microcotyledons (not in
endometrial cups)
Follicular development and formation of secondary CL up to D 140-160.
rise of estrogens in mare pregnancy on day?
total placental attachment on day?
development of fetal gonads on day?
D 90 rise of oestrogens (Estrone sulphate)
total placental attachment D 150
D 80-240 development of foetal gonads (ovaries, testicles) ja oestrogen production
Follicular development and formation of secondary CL up to D 140-160.
When do primary and
secondary CL disappear in mare pregnancy?
D 180 until parturition primary and
secondary CL disappear
Follicular development and formation of secondary CL up to D 140-160.
Sources of P4 in mare pregnancy.
Produced by CL and placenta.
Primary CL active up to D 25.
Highest at D 25, decreases from D 40-50.
New rise due to secondary CL at D 80-90.
Decrease at D 150.
Increase 1 months before parturition.
eCG (PMSG) is produced by
Produced by foetal trophoblasts which form
endometrial cups (EC).
- EC first seen D 36-40
Estrogens in mare pregnancy are produced by:
Highest level on D 35-60 (Ovarian activity).
D 60 onward production by foetus and placenta.
D 80-250 rise of oestrogens related to foetal gonads
activity.
Increase in last months of pregnancy.
Relaxin is produced by
placenta and foetus.
Secretion together with oestrogens.
Increase in concentration at D 75-80,
highest concentration D 180.
Function similar to progesterone.
No uterine contractions.
Some mares have heat during pregnancy. True or false.
Yes, supposedly some can display estrus behavior.
Ultrasound detection of mare pregnancy on day
D 14-16 post ovulation.
No foetus – new check 2-3 d later.
Last chance to induce abortion before endometrial cup formation in horses.
D 35 is the Last chance to induce abortion before EC formation.
Indicated if Multiple foetuses. Abort the smaller one with an Injection of PGF2alfa.
Ovaries on Rectal evaluation during mare pregnancy.
Day 0-40: Ovaries in normal place, freely movable
Day 41-150: Ovaries in normal place not so easily movable
Day 151-210: ovaries ventromedial, hard to palpate
Day 211 : ovaries close to midline out of manual reach
Palpable pregnancy on day ? in mares.
Day 18-25
Young mares embryonic vesicle palpable in junction
(caudal part of horns).
Uterine wall thin on emrbyonic vesicle place
Follicles in ovaries
Horns like tubes
Embryonic vesicle palpable 3-6 cm (golf ball), fluid filled
Round shape/oval thing in division of horns
Uterine wall thin on EV place
Follicles in ovaries
What days of gestation could the above be?
Days 25-35
Uterus in abdominal cavity from what days?
Day 42-55
Uterus in abdominal cavity
EV oval 8-9 cm (tennis ball) pregnant horn/uterine body
Fills uterine horn
Fetus palpable from day…
Days 55-65
Uterus in abdominal cavity
Pregnant horn filled
Foetus 10-15 cm (small football), oval, fills pregnant horn and body
Foetus palpable
Non-pregnant horn soft
Follicles in ovaries
eCG measurement 95% likely to be accurate at days
days 50-110
False negatives when Low PMSG so Too early >35d and too late <140p.
