Parturition Flashcards
Covers: Initiation of Parturition 1/2; Stages of Parturition
What fetal endocrine axis is required for triggering the onset of parturition?
(The fetal hypothalamic-pituitary-adrenal/HPA axis)
What does space limitation stimulate in the fetus that eventually induces parturition?
(ACTH secretion by the fetal pituitary)
What triggers the fetal pituitary to start producing ACTH which then triggers parturition?
(Space limitation, triggers parturition through the cortisol released from the adrenals in response to the ACTH)
What effect does fetal cortisol have on the progesterone and estrogen levels in the mother?
(Induces the enzymes that form progesterone to instead start making estrogen so progesterone levels fall while estrogen levels rise; also triggers the release of PGF to lyse any luteal structures to further reduce progesterone)
Decreasing what hormone removes the block it has on uterine contractions and is a necessary step for the initiation of parturition?
(Progesterone)
The rising levels of estrogen close to parturition induce an increase in receptors to what hormone in the reproductive tract?
(Oxytocin receptors)
What hormones are important for pelvic ligament relaxation (presents as gluteal muscles sinking, tailhead becoming more prominent, and sacrosciatic ligament softening) and expansion of the birth canal? Two answers.
(Relaxin and estrogen)
Fetal cortisol is not only important for triggering parturition, it also is important for final maturations of what structure in the fetus?
(The lungs, specifically cortisol enhances surfactant production which is important for the babies first breath)
What hormone is important for synthesis versus ejection of milk from the dam?
(Prolactin is important for synthesis and oxytocin is important for letdown)
What is the location of the chorioallantoic membrane in the first stage of parturition?
(It is entering the vagina at this time)
What occurs to the chorioallantoic membrane in the second stage of parturition?
(It ruptures after the fetus enters the birth canal)
What is the purpose of the uterine contractions in the first stage of parturition (which are mediated by oxytocin, PGF, and estrogen)?
(Aids the fetus in adopting the birthing posture)
A failure of what reflex related to parturition can result in dystocia?
(Ferguson reflex → failure of the cervix to dilate may result from malpositioning of the fetus or conditions that prevent stimulation of the ferguson reflex)
What is the status of the cervix during the second stage of parturition?
(Cervix will be completely dilated)
What other contractions join the uterine contractions in the second stage of parturition?
(Abdominal contractions)
Which stage of parturition does placental dehiscence, separation, and expulsion occur within?
(The third stage of parturition)
Which of the stages of parturition is the longest?
(The first stage)
Change in temperature as a way to predict parturition is most commonly used in what species?
(Dogs, will see a drop to 98-9.5 degrees F)
In what time frame will foaling occur if the mare’s milk has transitioned from mildly basic to mildly acidic?
(Foaling will occur within 24 hours)
What is the issue with using the appearance of the mammary glands to predict parturition in swine?
(Typically mammary glands become enlarged 1-2 days prior to farrowing in swine but this time frame can be different in sows versus gilts)
What disease of the placenta leads to overstretching of the endometrium which can predispose a mom for dystocia?
(Hydrops allantois)
If the cervix is closed in a case of uterine torsion, what is the best treatment?
(Perform a c-section as it is rare the cervix will dilate if there is uterine torsion)
After what day of gestation can you induce parturition in a cow?
(270 days and beyond)
When should a cow calve after the administration of dexamethasone when inducing parturition? Answer is a range.
(24-72 hours later, average is 48 hours)
What should be administered with dexamethasone in cattle if you want to shorten the time to calving?
(Prostaglandins, can expect calving within 24-48 hours, average is 36 hours, as opposed to 24-72 with dexamethasone alone)
What is a common sequela of induction of parturition in cattle?
(Retained placenta)
After what day of gestation can you induce parturition in a ewe?
(137 days and beyond)
Why do you only need to use prostaglandins to induce parturition in a doe?
(Does are dependent on their CL for progesterone so once you lyse the CL with PGF, their progesterone falls enough for parturition)
After what day of gestation can you induce parturition in a doe?
(144 days and beyond)
After what day of gestation can you induce parturition in a sow?
(112 days and beyond)
What drug is used for induction of parturition in mares?
(Oxytocin)
What are the three Ps in relation to parturition?
(Presentation, position, and posture)
What event does stage one of parturition end with?
(The rupture of the chorioallantoic membrane)
What event does stage two of parturition end with?
(Passage of the fetus)
When should a cow pass the placenta in whole after successful parturition?
(On average, 8 hours)
What time of day is preferred by mares for parturition?
(Night, 12-6am specifically)
What should occur 1, 2, and 3 hours postpartum for a foal and mare?
(1 hour - foal should be standing; 2 hours - foal should be standing and nursing; 3 hours - placenta should be passed entirely)
When should a mare pass the placenta in whole after successful parturition?
(Within 3 hours)
When is the placenta considered retained in a small ruminant?
(If it has not passed by 12 hours postpartum)
When should a camelid pass the placenta in whole after successful parturition?
(6 hours)
Stage II of parturition in camelids can be what duration before you should intervene?
(30-45 minutes)
Retained placentas are common or rare in dogs?
(Rare)
Retained placentas are common or rare in pigs?
(Rare)
What is the position of a fetus if someone tells you they are dorsosacral?
(The fetuses dorsum/spine is towards the dam’s sacrum)
What is the position of a fetus if someone tells you they are dorsopubic?
(The fetsuses dorsum/spine is towards the dam’s pubis, tummy is towards the dam’s sacrum)
What is the normal presentation of a fetus upon parturition?
(Anterior presentation)
What is the normal position of a fetus upon parturition?
(Dorsosacral position)
