Large Animal Obstetrics Flashcards
what is stage I of labor?
presentation of fetus to cervix
what is stage II of labor?
delivery of fetus/fetuses
what is stage III of labor?
delivery of placental membranes
increasing ______________________ lead to uterine contractions which push the fetus towards the cervix
estrogen and prostaglandin
what initiates stage I of labor?
fetus applies pressure to cervix
leads to release of oxytocin from hypothalamus
what is the ferguson reflex?
self sustaining cycle of uterine contractions initiated by pressure on cervix: oxytocin release from posterior pituitary, which leads to uterine contractions, which further increases pressure on cervix, which stimulates more oxytocin release
the fetus must ____________ the cervix for the cervix to dilate
engage
what is the normal presentation for parturition?
animal faces caudally, thoracic limbs are extended with head resting on limbs
also: posterior position with pelvic limbs extended can work
how long does stage I of labor last in the cow?
2-12 hours
how long does stage I of labor last in the mare?
1-4 hours
what is dystocia?
1st or 2nd stage of labor is prolonged and assistance is required for delivery
difficult birth
what are the main categories of causes of dystocia?
uterine inertia
fetal malposition
fetopelvic disproportion
twinning (species dependent)
what is primary uterine inertia?
lack of normal uterine contractions
fail to progress to stage II
break down of normal hormonal cascade for myometrial contraction
what is secondary uterine inertia?
exhaustion of uterine muscle
loss of contractions during stage II of labor
how can you treat uterine inertia?
manual extraction
oxytocin- only if cervix dilated
calcium
what are bandl’s rings?
strong sustained tetanic contractions caused by exhaustion spasms of uterine muscle
uterine contracts in tight ring around fetus or cranial to cervix
who can prepubic tendon rupture occur in?
more common draft mare
rarely cow or ewe
how can fetus presentation be described?
cranial/anterior or caudal/posterior longitudinal
ventral or dorsal transverse
what is the fetus’ position?
relationship of dorsum of fetus to dam’s pelvis
what is the posture of the fetus?
relationship of extremities to fetal body
what are the options for position of the fetus (not all normal)?
dorso-sacral: normal
dorso-pubic
dorso-ilial (left)
dorso-ilial (right)
if a calf is emphysematous and dead when it is delivered, how long ago did it die?
48+ hours
what are the options for correcting malposition?
repulsion
rotation
version
adjustment
controlled vaginal delivery
what does it mean to correct malposition through version?
turn from transverse to longitudinal
what can you give to aid in uterine relaxation?
epinephrine
clenbuterol: equine
what should you do if the fetus is in a dog-sitting posture?
repel anterior half of fetus and extract by hindlimbs
if extract by front end, risk ventral uterine rupture
what are the options for fetopelvic disproportion?
forced extraction
cesarean sectiomn
fetotomy
how can you extract to keep the fetal arc?
once chest is delivered, direct pull downs towards udder
do not continue to pull straight out
where should you incise if you are performing an episiotomy?
11:00 or 1:00
what does meconium staining indicate?
intrauterine hypoxia
what might a partial fetotomy be helpful for?
deviated head
retained hind limb
breech
hip lock
when do PGF2alpha and oxytocin become activated during labor?
stage I: presentation of fetus to cervix
does delivery of placental membranes require contractions?
yes
what leads to rupture of the fetal membranes?
fetal head and feet apply pressure to fetal membranes
in which animals does the fetus need to alter its position so that the head and feet are positioned to the posterior of the dam?
mare
cow
ewe
if a fetus is positioned in a posterior position with thee pelvic limbs extended, can it often be delivered?
yes
how long does stage I of labor las in the doe and ewe?
doe: 1-10 hours
ewe: 2-6 hours
how long does stage II of labor last in the ewe and doe?
ewe: 30min-2hr
doe: 1-3hr
how long does stage II of labor in the cow last?
2-4+ hours
in horses, every 10 minute increase over 30 minutes in stage II of labor equals a _______ increase in foal mortality
10%
16% increase in death before discharge
how long does stage II of labor last in camelids?
30min-1.5hours
what are the miscellaneous causes of dystocia (not main)?
abnormal pelvic inlet
vulval or cervical stenosis
uterine torsion
fetal congenital abnormalities
fetal death
who is primary uterine inertia common in?
bitch
sometimes old dairy cows and sows
what are the risk factors for primary uterine inertia?
lack of exercise
obesity
overstretching of uterus: hydrops, large litters
debilitating disease, cachexia
hypocalcemia
what is at increased risk with uterine inertia?
retained placenta
metritis
why is a prepubic tendon rupture a problem?
dam cannot abdominal press
prognosis poor
how many major joints are distal to the elbow and hock?
elbow: two, bend in same direction
hock: one, bends in opposite direction to hock
which peripheral reflexes can you test to see if the calf is alive or dead?
pedal
ocular
anal
what is hyperreflexia a sign of?
hypoxia
what indicates a fetus has been dead for 6-12 hours?
corneas are cloudy
if hair slips easily on a dead fetus, how long has it been dead?
24 hours
also corneas cloudy
what is rotation vs version?
rotation: turn fetus on long axis
version: turn from transverse to longitudinal
in which animal should you anesthetize and elevate the hind legs to make space for a controlled vaginal delivery?
only equines
what can you use for an epidural?
lidocaine 1ml/200lb
what is clenbuterol recommended for?
equine
tocolytic to achieve more space for manipulations
beta2 adrenergic agonist
which lubricant can you use if a C-section is likely?
carboxymethylcellulose: ok if enters abdomen
no J-lube: severe inflammatory response in abdomen
what is a worry if a fetus is in breech?
pressure on umbilicus
if horse: almost always C section
what would indicate there might not be enough space/fetopelvic disproportion to deliver by traction?
head not through cervix before traction applied
feet crossed over one another and pointing out: pressure being applied to shoulders
if both: guarded for delivery by traction
where should you place chains for forced extraction in a bovine?
around pastern and right above fetlock, traction to dorsal aspect limb
what are the six classic cuts for fetotomy?
remove head
remove arms by cutting between scapulas and thorax
cut through rib cage to remove thorax
cut right before pelvis
cut through pelvis longitudinally
make sure dead before fetotomy: occlude cord with hand
what might a partial fetotomy be useful for?
deviated head
breech
retained hindlimb
hip lock
what is a long difficult delivery associated with?
decreased mothering
can affect colostrum intake
