Equine pregnancy and parturition by Kavak Flashcards
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.
Horse gestation in months and in days.
When can a foal be born alive within this frame?
11 months and 5 days
335 – 342 days
Can be born alive from day 305- day 400. (Can go over that much and still be okayish.)
Foals before 300 d not viable.
Thoroughbred (325-340) vs draught breeds (330-340) vs hybrids
(350-370).
When do foals count as premature?
Parturition before d 320 - premature.
Affect of age on pregnancy in mares?
Affect of food?
Older mares have longer gestations than younger.
Important from age 8-12 Y and forward.
Good food makes gestation shorter.
What stimulates the placenta to produce PGF2α?
Fetal cortisol stimulate placenta to produce PGF2α.
Parturition: Phase I
Initially uterine contractions and opening of
cervix.
Myometrial contractions increase ca 5 days
before parturition.
Duration of phase I, ca 1 hour (30 min-6 hours).
Mare can sorta „control“ I phase duration.
Mare will be restless, slight colic signs, appetiteless.
I phase ends with:
rupture of chorioallantois (water bag)
(then comes Beginning of delivery of fetus)
Parturition Phase II:
15 to 30 minutes from rupture of
chorioallantois (water bag)
Foal enters vagina and initiates abdominal
pressure and uterine contractions (ferguson
reflex).
Amnion from vulva
Contractions occur in groups of 3-4 followed
by a rest period of 3 to 5 minutes).
Ends with delivery of fetus.
Stage III of parturition.
Passage of the fetal membranes.
Expel placenta 1- 3 hrs post-foaling. Make knots in the placenta if it drags on the floor or is indanger of being stepped on by the mare.
Placental removal thanks to uterine contractions.
Uterine involution in ca ? days.
9 days
Most fluids out from uterus within 12-24 h.
You should try not to disturb mare during parturition but in the these cases, intervene: (7)
- Red velvet mass between vulvar lips – detachment of placenta.
- Strong abdominal pressure but no legs within 5 min.
- Strong abdominal pressure, legs seen but no forward movement of fetus for 10 min.
- 1 leg missing from presentation
- Nothing happening within 15 minutes after braking of fetal membranes.
- Delivery in standing position.
- Rectovaginal perforation
Describe uterine involution in days.
3-5 d post partum horns are freely palpable
rectally
6-8 d post partum new endometrial epithelia
15 d post partum could be very small amount of
fluid in uterus
30 d post partum uterus should have normal size
Foal should do the following how soon after birth?:
Stand
Suckle
Drink enough colostrum within
Meconium in
Urinate in
Walk around within
Foal should:
Stand – 15-60 min (30 min)
Suckling 45-135 min
Drink enough colostrum within 60 min
Meconium in 2 hours
Urinate in 8 hours
Walk around within 2 hours
Keep an eye on the foal’s reflexes – suckling, vision, attention, thermoregulation, ears.
