Pregnancy and Foaling Flashcards
What is formed on the embryo on day 6?
Glycoprotein capsule- moves into the uterus and makes the embryo strong and recognizable
What is happening from days 8-16?
The embryo has trans uterine movement- making continues contact with all parts of the uterus
What is formed in the embryo on day 14?
The yolk sac
What is happening on days 16-17?
Fixation and amnion- embryo is stuck at the base of one of the horns
What is happening on day 25?
Chorionic girdle developing- heartbeat is now detectable
What is happening on day 35?
Endometrial cups form girdle- cups secrete equine chorionic gonadotrophin
Name classification before day 58
Embryo
Name classification after day 58
Fetus
What can happen at day 60?
Transrectal fetal sexing
What is the earliest day embryo flushing should start at
Day 6 1/2 - 7
Where is equine chorionic gonadotrophin produced at
The endometrial cups
What is the function of eCG
Acts on the LH receptor, supports the CL, causes secondary Cl formation
What does eCG do in other species
Acts on FSH receptors in other species and causes super ovulation
When is the first luteal response
Normal ovulation to CL
When is the second luteal response
when ECG begins to be produced and stimulates the first Cl to continue producing progesterone (rescuing primary CL day 35
When is the third luteal response
Formation of secondary Cl due to ECG
What does the fetoplacental unit do
From day 120 on it maintains the pregnancy by estrogens and 5 alpha pregnanes
When should you use supplemental progesterone
During the first 100-120 days
Characteristic of a diffused placenta and epitheliochorial
The attachment is all over, no blood to blood transfusion and the transfer of nutrients is less efficient
What is NI
Antibodies in the colostrum
What happens on day 240 that reduces dystocia
Foal’s back legs get tucked into a uterine horn
One horse breeding advantage over cattle
No need for a small stallion on maiden mares- fetus will grow as much as the uterus allows
Why causes early embryonic death
No recognition of pregnancy, no EC formed- day 60 of pregnancy check is advised after cups have formed
Two reasons why twins are undesirable
Cannot get enough nutrients for both placentas and the type of uterus cannot handle twin size
Most common twin management
Pinching on day 15-16 before fixation, 90% success rate
General process of pinching
each embryo is moved into a horn and one is squished against the side of the uterus
Alternative twin management methods
Moniter for double ovulation, aspiration (30%), intracardiac injection (penicillin 40%)
Three ultrasound exams that are recommended
12-15 days (twin monitor), day 25 (heartbeat), and 60 (ensure mare is pregnant after endometrial cups have formed)
Artifact
White spots on the top and bottom of the embryo
Uterus tone
Should increase to uterus and cervix days 15-16 (due to progesterone)
Size of uterus at day 25
golf ball sized
Other methods of pregnancy diagnosis
Teasing, blood tests, hormone level tests
Early embryonic death
Affects 2.5-25% of pregnancies, common in 18+ mares
What does the herpes virus do
Causes abortions, attacks blood supply to the placenta
Herpes virus type
EHV-1 subtype V
When should herpes vaccination be given
At months 5,7, and 9 (60 days)
How should body condition scores be managed
Checked every month, should be 6-6+, critical time is last 2-3 months (lactation)
How is toxicosis identified
Leaves form a collar at the bases of the stems- hardy plant
What does fescue produce and what does it do
produces ergot alkaloid - ergovaline, blocks dopamine receptors
What is impacted by fescue toxicosis
Inhibits prolactin, vasoconstriction, lowers fetal cortisol (longer gestation)
How to prevent fescue toxicosis
Dry lot the mare from days 30-90
What is the normal gestation period
320-360 days (340 average)
Domperidone
Helps countereffect the ergot alkaloid (give two weeks before birth if there is no dry lot system)
Prefoaling vaccines
An annual booster given thirty days prior to foaling so that the mare has a peak of antibodies in the bloodstream (will be in foal colostrum)
When should late gestation mares be moved
Arrive at new facility thirty days prior to foaling- will adjust to new microbes
What are caslicks
A seal the vulva makes to keep out bacteria- have to cut open
Start of fetal viability
Day 320
Primiparous mare
Maiden mare- don’t show a predictable trend for getting ready to foal
Multiparous mare
tend to show development steady over time
Udder filling
Begins 2-6 weeks before foaling, teats fill with milk in last week, waxing in final days, dripping/ streaming in final hours before birth
Muscle relaxation
vulva relaxes in the final days, cervix dilates but cannot be monitored (too invasive)
electrolytes in mammary secretions
sodium decreases while potassium increases, milk calcium increases 24 hours before foaling
Ph levels
Drop before foaling
Complications of colic while foaling
uterine torsion
What is premature udder a sign of
A mare is going to abort quickly
Vulva discharge with color is a sign of what
Infection of the placenta in gestation
Why are abnormally large abdomens difficult
Can rupture tendons holding the uterus- prepubic tendon rupture
Why is there an association between laminitis and late gestation
Pregnancy hormones can cause laminitis- pregnancy induced laminitis
Why do we foal in straw?
Shavings stick to everything
When do most horses foal
8pm-6am
Methods of foal watch
Check in morning, night watch, video monitoring, automated devices
Kinds of automatic devices
Surcingle transmitter, halter transmitter, vulva magnets
Hormone cascade of partruition
Fetal adrenal cortisol (fetal stress) causes placental PGF2A to release (uterine contractions) increasing oxytocin receptors
What happens when oxytocin receptors increase
Milk let down, surge with Ferguson reflux, uterine contractions
Is induction common
No, if needed give oxytocin never corticosteroids
What is the water breaking
Allantochorion breaks
What happens in a red bag delivery
Allantochorion does not break, (1.5-2% of foaling’s)
What should happen during the first stage of parturition
Initial uterine contractions position foal, cervix dilates, ends with the rupture of the allantochorion
Urine vs amnionic fluid
smells different, horse should immediate become uncomfortable after water breaking, amnionic fluid is brown
Signs of stage one
Lip curling, biting at sides, sweating (from oxytocin and prostaglandins)
Righting reflex
Foal starts to turn at the end of stage one and the beginning of stage two
Red flag in stage one
Placenta previa-
Premature placental separation
Unattached from the uterus early- foals oxygen is now limited
Second stage of parturition
Water breaking to foal being born
Foal presentation
anterior longitudinal (foals head toward mare’s vulva)
Foal position
dorso -sacral (foal’s back to mare’s spine for proper position)
Foal posture
head, neck, and forelimbs extended (location of extremities)
Red flags at stage two of parturition
foal not in correct orientation or taking too long to be born
Ferguson reflex
stretching of the birth canal causes a surge of the hormones that help deliver the foal (mainly oxytocin)
Delayed progress of birthing
At 20 minutes assistance should be given, at partial delivery, the foal cannot get enough oxygen when the placenta detaches
How much time before an exponential of foal loss
40 minutes
How long do we want stage two to last
Less than 30 minutes
Dystocia occurs in
10% of deliveries- thoroughbreds, drafts and minis
Malposture
misplacement of limbs or head (61% of dystocia’s)
Malpresentation
turned around (foal hind is facing vulva) Breach
Malposition
upside down
Other causes of dystocia
Large fetus, weak maternal contractions, exhausted mare
Assisted vaginal delivery
elevate hind end and push foal in to manipulate position
Cesarean section
80-85% mare survival
Fetotomy
foal is taken out in pieces, saw through leg joints
How do we prepare the mare for foaling
Wash udder, put a leather halter on, braid and wrap tail
How do we prepare the stalls for foaling
Put straw in stall, extra water buckets for mare, lead rope on both sides of the stall
Consequences of NIs
Foal becomes lethargic and mucus turns yellow
When does placentation start
Day 40- 95
Cervico cranial dislocation procedure
Break fetus neck through flank incision- low success rate
