parturition Flashcards
what animal was an artificial womb used for
premature lamb
why is creating an artificial womb for humans harder than lambs
discoid placenta is harder to mimic
what initiates parturition
fetal release of CRH and adrenal corticosteroids
what causes uterine contractions during parturition
PGF2a
what causes dilation of the cervix
relaxin
what end hormone is progesterone converted to
estradiol
what enzyme converts progesterone to 17a-hydroxyprogesterone
17a-hydroxylase
what enzyme converts 17a-hydroxyprogesterone to androstenedione
17-20 desmolase
what enzyme converts androstenedione to estradiol
aromatase
signs of impending parturition
-udder development/milk letdown
-hollowing and relaxing
-nesting
-isolation
-refusal of feed
-colicky/discomfort
stage 1 of parturition(preparation) Characteristics
-contractions become regular
-rotation of the fetus
-dilation of the cervix
-relaxation of pubic symphysis
what is the pubic symphysis
pelvic muscle attached to the broad ligament
stage 2 of parturition(fetal expulsion) characteristics
-chorioallantois rupture
-fetus forced through birth canal
-rupture of amnion
-delivery of fetus
-umbilical cord severed
purpose of chorionallantois rupture
lubrication
what is PGF2a released by
the uterus
stage 3 of parturition(delivery of membranes) characteristics
-chorionic villi loosen/detach
-afterbirth is shed
-placental delivery
causes of retained placenta
-early delivery
-disease/vitamin imbalance
-twins/triplets
consequences of retained placenta
bacteria can migrate up placenta and cause a uterine infection
what phaser of parturition is the shortest
stage 2
causes of dystocia
-small dam
-large fetus
-malpresentation
types of malpresentation
-breech(backwards)
-one leg back
-hind legs only
-head back
-both forelegs back
-elbow lock
-twin: one front one back
-twin: 4 legs 1 head
sow induction of parturition
PGF(only after day 112 or will abort)
ewe induction of parturition
glucocorticoids
cow induction of parturition
glucocorticoids within 2 weeks of term
what is likely for cow induced parturition
retained placenta
mare induction of parturition
no good method
-oxytocin and PGF, repeat oxytocin until stage 2 starts
why are there no good methods to induce parturition
parturition is induced by fetal hormones, all methods act on the maternal side
