Initiation and Induction of Parturition

Question 1

what 2 things need to happen for the fetus to trigger the onset of parturition?

Answer 1

1. Maturation of HPA Axis
2. Fetus Reaches Capacity: space limitation appears to be the stimulus for ACTH secretion by the fetal pituitary

Question 2

the culmination of HPA axis maturation and fetus reaching mature size =

Answer 2

fetal size

Question 3

the fetal pituitary stimulates secretion of adrenal corticoids =

Answer 3

cortisol

Question 4

at intiation of parturition decreased ___ removes the block on uterine contractions

Answer 4

decreased

Question 5

increased __ causes the uterus to be responsive to induction of contractions, induction of oxytocin receptors, pelvic ligaments relax and the vulva swells

Answer 5

estrogen

Question 6

expansion of the birth canal is controlled by what hormone?

Answer 6

relaxin, estrogens

Question 7

maternal behavior is controlled by what hormones?

Answer 7

oxygen

Question 8

milk synthesis is caused by __ while ejection is caused by __

Answer 8

prolactin, oxytocin

Question 9

__ and __ initiate uterine contractions

Answer 9

PGF, oxytocin

Question 10

what are signs of impending parturition?

Answer 10

• mammary enlargement and colostrum production
• enlargement and elongation/laxity of vulva
• pelvic ligament relaxation and softening of the perineum area
• isolation and decrease in appetite

Question 11

longer gestation has a __ standard deviation

Answer 11

longer

Question 12

describe the first stage of parturition

Answer 12

initiated by the fetus

• relaxation/dilation of the cervix
• uterine contraction commence by oxytocin, PGF2alpha, and E2
• fetus adopts birth posture
• chorioallantois enters vagina

Question 13

describe the behaviors of the first stage of parturition

Answer 13

females will isolate themselves, stop eating, show signs of colic, tail flagging, vaginal discharge, milk production

Question 14

ferguson reflex

Answer 14

as the fetus moves through the birth canal, elevated pressure on the cervix stimulates sensory neurons. A neural pathway terminates in the paraventricular nucleus and causes oxytocin to be secreted from the posterior pituitary lobe. Oxytocin stimulates contractions of the myometrium

Question 15

describe the second stage of parturition

Answer 15

• cervix has completely dilated
• uterine contractions continue
• abdominal contractions commence
• fetus enters birth canal, causing rupture of chorioallantoic membrane
• fetus expelled

Question 16

what is observed in the second stage of parturition?

Answer 16

• water breaks bc of chorioallantois rupture
• active abdominal contractions
• delivery of fetus

Question 17

what happens in the third stage of parturition?

Answer 17

• placental circulation is lost
• placental dehiscence and separation occurs
• uterine and abdominal contractions continue
• placenta expulsion

Question 18

when is the second stage of parturition completed?

Answer 18

when the calf is delivered

Question 19

when is the third stage of parturition completed?

Answer 19

upon placental expulsion

Question 20

predict dog parturition with twice daily rectal temps to see __ , __ for fetal gut motility and renal “T”, and __ levels may be performed

Answer 20

transient drop, ultrasonography, P4

Question 21

to predict mare parturition, watch the milk __ levels to be >200 ppm with foaling expected to be within __ hours. Alternatively a decrease in milk pH from alkaline to acidic means foaling within __ hours

Answer 21

calcium, 25-72 hours, 24 hours

Question 22

`ruminants most rely on __ and __ for predicting parturition. A drop in rectal temperatures by __ happens 24 hours before parturition

Answer 22

breeding dates, physical changes, 0.5F

Question 23

pigs mostly rely on __ and __ for predicting parturition. They will have enlarged mammary glands __ before farrowing with restless/nesting behaviors __ hours prior and laying in lateral recumbency in the last __

Answer 23

breeding dates, physical changes, 1-2 days, 12-24 hours, hour

Question 24

dystocia: primary uterine inertia is caused by __, __ and __ while secondary uterine intertia is caused by consequences of __

Answer 24

myometrial defects, biochemical deficiencies, environmental disturbance, another cause (exhaustion)

Question 25

dystocia from failure of expulsive forces

Answer 25

inability to strain: age, pain, pre-pubic tendon rupture, abdominal herniation

Question 26

dystocia from obstruction of the birth canal

Answer 26

bony pelvis: fracture, breed, diet, immaturity, neoplasia, disease soft tissue: vulva, vagina, cervix, uterus

Question 27

what may cause lack of cervical dilation?

Answer 27

1. ringwomb in sheep: failure of the cervix to dilate -> c section and cull 2. lack of stimulation 3. adhesions/fibrosis: cervix will not dilate due to previous trauma -> c section and cull

Question 28

in the case of uterine torsion if the cervix is **closed** its rare it will __ and __ is the best option. alternatively, you can try __ or __

Answer 28

dilate, c-section, rolling or planking

Question 29

in cases of uterine torsion if the cervix is open, you can use a __ but if you can't fix it then go to __

Answer 29

detorsion rod, c-section

Question 30

what are some fetal causes of dystocia

Answer 30

- hormone deficiency (ACTH/cortisol) - fetomaternal disproportion - fetal maldisposition - fetal death

Question 31

a __ fetus cannot initiate parturition

Answer 31

dead

Question 32

black vulvar discharge in the bitch

Answer 32

death of a puppy

Question 33

red bag abortion

Answer 33

in the mare, may result in the premature placental separation

Question 34

reasons for parturition induction

Answer 34

- mismating (do it EARLY) - prolonged gestation (100% sure) - edema of the mammary gland - medical necessity (preg toxemia, hydrops) - convenience

Question 35

induction in cattle

Answer 35

dexmethasone if beyond 270 days should make them calve within 24-72 hours and the interval can be tightened with prostaglandin co-admin. The calves often survive if induced within 1-2 wks of calving date and a retained placenta is a common sequela.

Question 36

induction in sheep

Answer 36

dexmethasone +/- prostaglandin if beyond 137 days will make them lamb within 36-48 hours. Lambs have a good survival rate within 1 wks of their normal lambing date.

Question 37

induction in goats

Answer 37

give prostaglandin at least 144 days gestation and will kid within 30-36 hours. The survival of the kid is good if within 1 week of their normal lambing date

Question 38

induction in pigs

Answer 38

PGF2 alpha at lwast 112-113. days in gestation will make them farrow within 18-36 hours. IU oxytocin can be given to increase % of sows to farrow in subsequent 6 hours but higher doses may fatigue them sooner

Question 39

__ and __ are CL dependent for induction

Answer 39

goats and pigs

Question 40

induction in mares is a __ idea and __ is most commonly used

Answer 40

bad, oxytocin

Question 41

induction in bitches/queens

Answer 41

can be difficult and fetal death can result prior to parturition