Parturition and dystocia Flashcards

1
Q

Describe the stage of preparation in parturition

A

production of relaxin (polypeptide hormone) from placenta (CL in sow)
Causes relaxation of pubic symphysis, vulval and perineal tissues

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2
Q

Describe the first stage of parturition - onset of uterine contractions

A

Fetus produces cortisol:
- cortisol enzymes convert progesteone to oestradiol
- progesterone decline removes myometrial contraction block
- increased basal uterine contractions
- elevated oestrogen increases reproductive tract secretions -> lubrication

Cortisol => increased uterine prostaglandin:
- lysis of CL
- uterine contraction due to increased PGF2a and oestrogen
- relaxin production causes degradation and remodelling of cervical matrix and cervical os opens

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3
Q

How do uterine contractions cause haemorrhage in species with deciduate placentas?

A

Placental attachments to endometrium become less intimate
Superficial cells undergo fatty degeneration
Separation of margins begins => haemorrhage

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4
Q

What are the signs of the first stage of parturition?

A
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5
Q

Describe the 2nd stage of parturition - expulsion of the fetus

A

Fergusons reflex
Allantochorion ruptures as it moves towards cervix - allantoic fluid escapes from vulva
Contractions continue, amnion appears at vulva (water bag)
Fetal limbs appear in amnion
Fetus becomes hypoxic as it enters birth canal - promotes foetal movement which stimulates myometrial contractions
Foetal head reaches vulva - climax of uterine and abdominal muscle effort
Foetus expelled

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6
Q

Describe the Fergusons reflex in the second stage of parturition

A

Fergusons reflex:
- abdominal and uterine contractions
- force fetus against cervix
- neuro-hormonal reflex
- brain release of oxytocin
- myometrial contractions

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7
Q

What stimulates the foetus to breath after parturition?

A

air hitting nostrils

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8
Q

What happens to the umbilical cord after parturition?

A

The cord ruptures after some time
Then the umbilical arteries and urachus retract into the abdomen to prevent haemorrhage

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9
Q

What is the risk of premature rupture of the umbilical cord?

A

deprive newborn of large volume of blood which would normally pass from the placenta

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10
Q

What happens to the amnion after/during birth?

A

May rupture during birth
Fetus may be delivered within the amnion and movement ruptures it

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11
Q

Describe the 3rd stage of parturition - expulsion of placenta

A

Regular abdominal contractions cease
Myometrial contractions decrease in amplitude, become less regular but become more frequent
Lack of foetus results in vasoconstriction of arteries supplying chorionic villi - villi decrease in size and release from crypts
Uterine contractions cause:
- opening of endometrial cups
- exsanguination/loss of blood from placenta
- separation of the foetal membrane
When inverted membranes form a mass in pelvis => reflex abdominal contractions
Allantochorion/placenta is expulsed

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12
Q

What is the puerperium

A

the period after expulsion of the placenta where the repro tract reduces in size to that before pregnancy
~2-8weeks

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13
Q

What is this foetal presentation?

A

Cranial longitudinal presentation
dorsal position
extended posture

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14
Q

What is this foetal position?

A

Caudal longitudinal presentation
dorsal position
extended posture

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15
Q

What is dystocia?

A

difficult birth

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16
Q

What are the common causes of dystocia?

A

foetus too big
dam too small
abnormal foetal position
multiple foetuses
poor or absent uterine contractions (primary or secondary intertia)

17
Q

What is the most common reason for dystocia in cows?

A

big calf
abnormal dispositionq

18
Q

What are the possible foetal presentations and positions?

A

Presentation:
- cranial longitudinal
- caudal longitudinal
- dorsal transverse
- ventral transverse

Position:
- dorsal
- ventral
- left lateral
- right lateral

19
Q

Why is dystocia an emergency in mares?

A

2nd stage of parturition is very short (~30 mins)

20
Q

What are the ways to manage dystocia?

A

Drug therapy:
- oxytocin => contractions
- clenbuterol (tocolytic) => stops contractions
Surgical treatment:
- epidural anaesthesia => stop contractions
- episiotomy - enlarge birth canal
- fetotomy
- caesarean
Euthanasia
Manipulation of foetus - MUTATION

21
Q

What is traction used for in managing parturition?

A

provided at the time of contractions to aid expulsion
also helps allow foetal breathing

22
Q

What methods are there for providing traction to live and dead foetuses?

A

Live:
- calving jack
- head/neck snare
- vectis forceps

Dead:
- chains
- eye hooks
- self closing hooks

23
Q

What should you do after delivery in a dystocia?

A

check there are no other foetuses
Check for lacerations and perforations
ensure no defects such as pelvic fractures
Consider analgesia, antimicrobial therapy

24
Q

What is primary and secondary inertis?

A

Primary uterine inertia is the failure to initiate contractions at parturition. Secondary uterine inertia is the failure to progress once contractions are initiated (uterine fatigue)

25
Q

What are the husbandry consideration in sow parturition?

A
26
Q

What are the signs of a ewe entering parturition?

A
27
Q

What are the signs of a sow entering parturition?

A
28
Q

What are the signs of a queen in parturition?

A
29
Q

What are the signs on a bitch in parturition?

A
30
Q

What are the signs of a cow entering parturition?

A

Decreased lying time
restlessness
decreased rumination
tail rising
swollen and red vulva
water bag appears at vulva

31
Q

What are the signs that a mare is foaling?

A

Restlesness
Pacing
Looking at flank
Sweating
Frequent urinating
raising/swishing tail
lying down and getting up
nesting behaviour
vulva elongation
vaginal discharge
uterine contractions
rolling

32
Q

What is the difference between foetal and maternal dystocia?

A

Foetal - caused by the foetus e.g., large foetus, disposition
Maternal - caused by dam e.g., too small, uterine inertia