Review: Parturition Flashcards
What are the 3 Ps of fetal presentation?
Presentation, Position, Posture
Describe “presentation” of the fetus:
Longitudinal axis of the fetus in relation to the birth canal
Anterior vs. Posterior
Describe “position” of the fetus:
Relationship of the DORSUM of the fetus to the quadrants of the maternal pelvis
Dorso-sacral vs. Dorsopubic
Describe “posture” of the fetus:
Position of the extremities, head, and neck of the fetus
Examples: head back, wry neck, leg back,
What is the “normal” presentation of a fetus?
Anterior presentation
Dorsal-sacral position
Front limbs and head extended
Stage 1 of parturition:
Overall restlessness
+/- Anorexia
Separation from herd/flock
Ends with rupture of chorioallantoic membrane
Stage 2 of Parturition:
Active contractions with pushing
Ends with passage of the fetus
Should be rapid!
Stage 3 of Parturition:
Expulsion of fetal tissue (placenta)
In litter bearing species, cycle between stage 2 and 3 until all fetuses delivered
Stage 1 of Bovine parturition is typically longer in:
Heifers
How long does Stage 1 typically last in Bovine species?
Average 6 hours, up to 24 hours
Stage 2 in Bovine species typically lasts:
2-4 hours on average
Calf can survive up to 8 hours if umbilicus is intact
How long on average should we see the placenta pass in bovine species?
8 hours on average
Describe Stage 1 specifically for Equine species:
Most mares foal at night, 12a-6a
1-4 hours on average
Can delay if interrupted (need quiet/cameras in foaling barn)
Describe Stage 2 in Equine species:
Frequent urination/defecation
Pushing & delivery
11-20 min on average (forceful/fast)
Describe Stage 3 in Equine:
Pass placenta in whole by 3 hours (need to layout and check)
“1, 2, 3 Rule”
-Foal standing within 1 hour
-Foal standing and nursing within 2 hours
-Placenta passes entirely in 3 hours
Typical time for Stage 1 of Small Ruminants?
Primiparous: 2-12 hours
Pluriparous: 1-2 hours
Typical time for Stage 2 for Small Ruminants?
1-3 hours on average, depends on number of fetuses
Timeline for Stage 3 for Small Ruminants?
Pass placenta in whole by 1 hour, considered retained at 12 hours
Average time for Stage 1 for Small Animals?
16-18 hours on average
Average time for Stage 2 for Small Animals?
4-12 hours on average
Average time for Stage 3 for Small Animals?
No set time, cycling between stage 2 and 3 until all fetuses are passed
Retained placentas are RARE
In pigs, when do the females start nesting?
At least 24 hours before Stage 1
Stage 1 in pigs typically lasts:
2-12 hours
Piglets expelled every _____ and duration can be _____ for the whole litter
15 min; 2-4 hours
For pigs, fetal membranes are expelled _______ and retained placentas are ____
Between each piglet; rare
Camelids Stage 1 lasts:
Average 4 hours
Often very stoic, no outward signs
Stage 2 for camelids typically lasts:
30-45 min average
If longer, examination warranted
Stage 3 for camelids typically lasts:
Pass placenta in whole by 6 hours
What triggers the onset of parturition?
Fetal stress
How does fetal stress initiate parturition?
Maturation of the fetal HPA axis
Small space leads to fetal stress, increasing cortisol levels, leading to a chain of events
How do progesterone levels affect the onset of parturition?
Decreased progesterone removed the “block” on uterine contractions
How do estrogen levels affect the onset of parturition?
Increased estrogen causes induction of oxytocin receptors, pelvic ligament relaxation, vulvar swelling, and uterus becomes responsive to induction of contractions
Which hormones cause the pelvic ligaments to relax & what other clinical signs would be noticeable?
Relaxin, Estrogen
Gluteal muscles sink, tailhead becomes more prominent, sacrosciatic ligament softens
Cortisol levels in the fetus also enhances:
surfactant production (leads to lung maturation)
Yay Lungs!
Expansion of the birth canal is caused by:
Relaxin, estrogens
Maternal behavior prior to parturition is controlled by:
Oxytocin
Which two hormones control milk production in the dam?
Prolactin (synthesis) and oxytocin (letdown/ejection)
Initiation of uterine contractions is caused by:
PGF, oxytocin
Which hormone is responsible for the termination of pregnancy?
PGF
Signs of impending parturition:
Mammary enlargement and colostrum production, Enlargement/elongation and laxity of vulva
Pelvic (sacrosciatic) ligament relaxation and softening of the perineum area, isolation, decrease in appetite (off feed)
Gestation lengths of large animals:
Camelids/mares: 11-12 months
Cattle: 283 days (~9.5 months)
Sheep: 152 days (~5 months)
Goats: 150 days (~5 months)
Pigs: 114 days (3 mo, 3 weeks, 3 days)
First stage of parturition is initiated by:
The fetus