Repro Flashcards
Which individual triggers the onset of parturition, Fetus or Mother?
fetus
Maturation of the HPA axis of the fetus needs to occur first to trigger parturition. This entails the hypothalamus secreting ___________, which goes to the anterior pituitary and stimulates _________ to be released. This hormones stimulates the adrenal cortex to produce __________. All of which allows the fetus to become “stressed.”
corticotropin releasing hormone (CRH) adrenocorticotropic hormone (ACTH) this hormone cortisol
The fetus must reach “capacity” to trigger parturition. What does this mean?
As the fetus grows, space within the uterus becomes limited. This is a stimulus for ACTH secretion by the fetal pituitary, and subsequent cortisol secretion.
the cumulation of HPA axis maturation and _____________ = FETAL STRESS
fetus reaching mature size
the fetal pituitary stimulates secretion of adrenal ________.
cortisol
Fetal cortisol causes a decrease in ________ and an increase in estrogen.
Estrogen causes increased secretions by repro tract, increased myometrial contractions, increased pressure, increased cervical stimulation, increased oxytocin.
progesterone
T/F: enzymes that convert cholesterol to progesterone are upregulated before parturition and enzymes that convert progesterone to estrogen are down regulated
FALSE – down regulated chol –> prog, upregulate prog –> estrogen
overall outcome = decrease prog, increase E2
T/F: in most species, testing progesterone is not very useful because it does not “drop” until right before parturition will occur.
true
what is the purpose of progesterone decreasing during initiation of parturition?
removes the block on uterine contractions
remember, progesterone prevents contractions so that the fetus stays within the uterus during gestation.
What is the purpose of increased estrogen during initiation of parturition?
uterus will become responsive to induction of contractions
oxytocin receptors will be induced
pelvic ligaments will relax
vulva swells/softens
Cortisol increases production of ________, which is important for lung maturation. This is critical for when the fetus takes its first breath in preventing the lungs from collapsing.
surfactant
Expansion of the birth canal is mediated by what 2 hormones?
estrogen and relaxin
maternal behavior is mediated by what hormone?
oxytocin
synthesis and ejection of milk is mediated by what 2 hormones?
prolactin (synthesis)
oxytocin (ejection/let down)
initiation of uterine contractions is mediated by what 2 hormones?
PGF and oxytocin
termination of pregnancy is ultimately determined by what hormone?
PGF
Mammary enlargement, colostrum production, enlargement + elongation of vulva, pelvic ligament relaxation and softening of perineum, as well as isolation and decreased appetite are all signs of …
impending parturition
these would be signs during stage I of parturition when estrogen is taking effect
Gestation of camelids and mares…
11-12 months
gestation for cattle
9 months
gestation for sheep and goats
5 months (150-152 days)
gestation for pigs
3 months, 3 weeks, and 3 days (114 days total)
What stage of parturition is described as:
1. relaxation/dilation of cervix
2. uterine contractions commence (oxytocin, PGF, E2)
3. fetus adopts birthing position
4. chorioallantois enters the vagina
first stage
What signs can be observed from the dam during the first stage of parturition?
- isolation
- decreased/non-existent appetite
- signs of colic (treading, looking at flank, restless, pawing ground)
- tail flagging/raising
- vaginal discharge
- milk/colostrum production
What is the term for when oxytocin is released from the pituitary and causes uterine contractions that lead to the fetus positioning itself within the birth canal and in doing so, the pressure triggers nerves that carry signals to the brain (PVN) to continue producing oxytocin. (positive feedback)
Ferguson reflex
What could occur if the Ferguson reflex fails and the fetus does not position itself correctly?
failure of cervical dilation and dystocia
What stage of parturition is described as:
1. cervix is completely dilated
2. uterine contractions continue
3. abdominal contractions begin
4. fetus enters birth canal which causes rupture of chorioallantois membrane
5. fetus is expelled
second stage of parturition
What is physically observed during the second stage of parturition?
- water breaks
- active abdominal contractions (she may frequently lie down)
- delivery of fetus
What stage of parturition is described as:
1. placental circulation is lost
2. placental separation begins
3. uterine and abdominal contractions continue
4. placenta is expelled
third stage of parturition
T/F: the time for the placenta to be expelled varies between species
true
which stage of parturition is the longest? which is the shortest?
longest = stage 1
shortest = stage 2 and 3
T/F: expectancy dates are precise based on age of individual and species and by just watching the signs of parturition
false – they are more precise when assistance was provided during the breeding (prog/ovulation timing, timed AI, early preg detection, fetal aging, marking by male, etc.)
What are the 2 most effective ways to predict parturition in dogs?
- twice daily rectal temperatures to see the transient drop (97.5-98)
- ultrasound for fetal gut motility and renal T pelvis
In mares, you can measure milk Ca and pH to predict parturition. What would the values be if she were going to foal within the next 24-72 hr?
milk Ca = > 200 ppm
decrease in milk pH (acidic, 6.5-6.8)
What are the 2 most reliable ways to predict parturition in ruminants?
- breeding dates and physical changes
- size of fetus (US, palpation) – less accurate for multiple fetuses
what are signs of impending parturition in pigs?
- enlarged mammary glands 1-2d before
- restless, nesting 12-24 hr before
- frequent urination/defecation, increased RR within final few hours
- lie in lateral recumbency in last 15-60 min
Myometrial defects, biochemical deficiencies (milk fever, ketosis), and environmental disturbances (temp stress) can cause primary uterine inertia which leads to what?
failure of expulsive forces and subsequent dystocia
Secondary uterine inertia leading to dystocia can be caused by …
exhaustion as a consequence of another cause of dystocia
T/F: uterine damage/rupture can lead to failure of expulsive forces and dystocia
true
A older cow presents to you for dystocia. You believe the source is abdominally-related. What could be the issue?
- inability to strain
- prepubic tendon rupture
- abdominal herniation
When a farmer wants to breed his new cows, you want to do a pelvic exam first in order to check for 2 things to ensure her birth canal is not obstructed and the risk for dystocia is as low as possible?
- minimum area (LxW) is at least 150 cm2
- bony pelvis does not have any fractures, neoplasia, disease, or spurs.
What are the 4 soft tissues that can obstruct the birth canal and lead to dystocia?
- vulva (congenitally too small, fibrosis, immature)
- vagina (congenital, fibrosis, prolapse, neoplasia, perivaginal abscess, hymen)
- cervix (congenital, fibrosis, failure to dilate)
- uterus (torsion, deviation, herniation, adhesions, stenosis)
What is the required treatment for true ringwomb in sheep (idiopathic failure of cervix to dilate)?
c-section and cull ewe
If dystocia is due to lack of cervical dilation as a result of lack of stimulation (fetus malpositioned, fetus too large, does not engage properly in birth canal, vaginal prolapse, uterine torsion), what can your plan for treatment be?
stimulate manually
if the cervix has adhesions or fibrosis, what is your concern with regard to the parturition process?
it will not be able to dilate due to previous trauma and c-section will be necessary. You will cull this female
T/F: if uterine torsion is present, the cervix will dilate but the fetus will be unable to be expelled
FALSE - cervix will not dilate because it is closed from the torsion. c-section will be the best option
if the cervix is closed due to uterine torsion in a cow, what can you as the veterinarian do that is non-invasive?
roll/plank the cow
if the cervix is open with uterine torsion, what are your options for treatment?
detorsion rod – twists the baby and the uterus
c-section if you cannot fix the torsion
deficiency of ________ can cause fetal-induced dystocia due to failure to initiate parturition.
ACTH and/or cortisol
What is the term that describes the baby being too big thus causing dystocia?
fetomaternal disproportion
What is the term for when the fetus comes out in an incorrect position and causes dystocia?
fetal maldisposition
T/F: if the fetus is dead, it will still deliver normally
false – dystocia will occur because the fetus is responsible for initiating parturition
Black vulvar discharge is a sign of…
death of the fetus
Red bag in mares is indicative of…
premature placental separation.
the baby would be suffocating. You need to break the placenta and deliver.
prolonged gestation, mismating, edema of mammary glands, medical concerns (preg toxemia, hydrops), or high likelihood of needing intervention are all indications for __________.
parturition induction
T/F: induction of parturition can alter timing and increase occurrence of other post-partum conditions
true
You are called to medically induce parturition in a cow. What drug(s) will you use and how many hours after which she will be expected to calf
- dexamethasone if beyond 270d –> calf in 24-72hr
- prostaglanding + dex –> calf in 24-48 hr
T/F: retained placenta is common sequela of parturition induction in cattle
true
Survival rate of the calf is good if you induce parturition within _____ of their normal calving date
1-2 weeks
describe medical induction of parturition in sheep and how long post-administration it will take her to lamb
- dexamethasone if beyond 137d
- prostaglandin (lutalyse) + dex
lambs within 36-48 hours
Survival of lambs is good if you induce parturition within ______ of their normal lambing date
1 week
You are called to medically induce parturition in a goat that is 144d gestation. What drug(s) will you use and how long will it take her to kid post-administration?
GOATS ARE CL DEPENDENT
prostaglandin (lutalyse or cloprostenol)
she will kid within 30-36 hours
Survival of kids is good if you induce parturition within ______ of their normal kidding date
1 week
if you have concerns about prematurity when inducing parturition in goats, what can you add to the prostaglandin?
dexamethasone 6-12 hrs before induction
If you are called to medically induce parturition of a pig, What drug(s) would you use and how long will it take post-administration for her to farrow?
PIGS ARE CL DEPENDENT
1. prostaglandin at least 112-113d of gestation –> farrow in 18-36 hours
2. prostaglandin + low dose oxytocin (20hr after) –> farrow in subseq 6 hr
describe induction of parturition in mares
make sure cervix is dilated at least 2 cm before starting
give oxytocin IV or IM (10 IU)
describe induction of parturition in bitches/queens
bitches - algepristone
none for queens
what are 3 indications for equine castration?
- behavior
- unsuitable genetics
- disease (orchitis, neoplasia, trauma, torsion, hernia)
What pre-operative considerations should be taken into account prior to equine castration?
- physical exam – reschedule if not healthy
- inspect the scrotum – are both testes descended, are both the scrotum and testes normal (no inguinal hernia, hydrocele, or testicular abnormalities)
- give NSAIDs prior to sx and tetanus toxoid
What 5 decisions about the procedure do you need to make when preparing for equine castration?
- standing vs recumbent
- approach – 2 parallel incisions vs scrotal raphe
- method of removal – open, closed, mod closed
- which instrument to use and if ligatures will be placed
- will there be closure?
If your equine patient is tall, docile, and has well developed testes, what approach will you take to their castration?
standing with sedation and a local lidocaine block
(Standing/or/Recumbent) castration requires general anesthesia and a local lidocaine block.
recumbent
T/F: in the scrotal raphe castration approach, you are actually removing some of the skin tissue.
true
______ method of castration is described as incising through the skin, SQ, and parietal tunic of testes
open
________ method of castration is described as making the initial incision through the skin and SQ, then making an additional small incision in the parietal tunic allowing access to the vasculature.
modified closed
If a horse is in left lateral recumbency, which incision should you make first when doing castration?
LEFT testicle
whichever testicle is DOWN, you should incise first because blood will obscure the surgical field
What is the purpose and mechanism of the emasculator used in LA castration?
the emasculator crushes the tissue causing hemostasis and then cuts the testicle off after.
In what instance would ligatures be used in addition to the emasculator and where would they be placed? what are risks of this?
if the animal is larger and has more tissue to be crushed. the ligature ensures better hemostasis.
place proximal to emasculator. The risk is that the suture material serves as a foreign body.
Describe the difference between Serra and Reimer emasculators?
serra – squeeze and cuts at the same time
reimer – crush and cut at different times and has ratchet to lock into place once you’ve crushed
This castration tool uses high speed torsion of the spermatic cord as a means to do coagulation/hemostasis and remove the testis all at one fast pace.
henderson
what is the advantage to doing open castration and using the emasculator on the vasculature?
better hemostasis because there is less tissue
What are the 2 most common complications of LA castration?
edema**
hemorrhage
If cord remnants are left behind during LA castration, what type of infection can occur?
Champignon – streptococcus
Scirrhous cord – staphylococcus
Note – these infections will not resolve with antibiotics alone, they require you to go back in a remove the remnants.
What are 3 pre-operative things you should do prior to equine castration?
- tetanus prophylaxis
- palpate scrotum
- give NSAIDs (+/-)
is general anesthesia required in young farm animal castrations? old?
young – no
old - no unless dont have proper restraint
What type of analgesia is used for farm animal castration?
- NSAIDs (flunixin)
- lidocaine – local into spermatic cord (careful of hematoma)
- intratesticular lidocaine
- sedation (if not GA is used)
what are the 3 approaches to farm animal castration?
- scalpel blade (tent and cut distal scrotum)
- scalpel blade (2 parallel incisions)
- newberry knife
What 3 techniques can you use to actually remove the testicle after you’ve cut in farm animals?
- pull
- ligate and transect
- emasculate and transect
what is the bloodless technique for farm animal castration?
elastic banding around the scrotum, which causes loss of blood supply and subsequent necrosis until the scrotum just falls off.
young animals – elastrator (green ring)
old animals – calicrate bander/EZE bander
If you want to castrate a piglet, what is your approach? How would that differ if it were a pet pot belly?
piglet – anesthesia, restrain them by holding their hind limbs, scrotal or prescrotal incision, pull, and leave open to drain
pot belly – GA in dorsal recumbency
what are the 3 P’s for fetal presentation
- Presentation – longitudinal axis of fetus in relation to dams birth canal (Anterior vs Posterior vs Transverse)
- Position – relationship of the dorsum of fetus to the quadrants of the dam pelvis (Dorso-sarcal = fetus spine is toward dams sacrum; Dorsopubic = fetus belly toward dam sacrum)
- Posture – position of extremities, head, and neck; (head back, wry neck, leg back)
What is the normal presentation of the fetus during parturition?
anterior position
dorsal-sacral position
front limb and head extension
How would you describe “true breech” with the 3 P’s?
position = posterior dorsopubic/dorsosacral
posture = bilateral hindlimb flexion
What is the best recommendation if you have a transverse presentation?
c-section