Difference between revisions of "Normal Parturition - Anatomy & Physiology"

Latest revision as of 18:27, 3 July 2012

Stages of Parturition

Stage 1: this is the preparatory stage, starting at the onset of regular uterine contractions followed by cervical dilatation and the foetus assuming the correct disposition for passage through the birth canal.
Stage 2: the expulsive stage, characterised by the onset of abdominal contractions which together with uterine contractions lead to foetal expulsion
Stage 3: separation and expulsion of the foetal membranes. In polycotous species second and third stages are often inter-mixed.

The following table summarises the normal time taken to progress through the stages of parturition in different species.

Species	Mare	Cow	Ewe	Sow	Bitch
Stage 1: Contractions and Cervical Dilation	1-4 hours	2-6 hours	2-6 hours	2-12 hours	6-12 hours
Stage 2: Foetal Expulsion	12-30 minutes	30 minutes - 4 hours	30-120 minutes	150-180 minutes	6 hours (up to 24 hours with large litters)
Stage 3: Placental Expulsion	1 hour	6-12 hours	5-8 hours	1-4 hours	Placenta Exits with Foetus

The step in the reproductive process that immediately precedes lactation, uterine involution and return to cyclicity. It is initiated by the foetus and involves a complex cascade of endocrine events. Parturition is the process by which the conceptus (foetus, placenta and placental membranes) is expelled from the uterus; this requires cervical softening,coordinated myometrial contractions and contraction of abdominal muscles to occur

Placental Changes

During the last 5 days of gestation, there are changes in the placenta.

Collaginisation of the placentome.
Flattening of maternal crypt epithelium.
Leucocyte migration and increased activity.
Reduction of binucleate cells in the trophectoderm.
Weakening of the acellular protein layer between cotyledonary and caruncular epithelium.

Contractions

Open endometrial crypts
Foetal villi have shrunk due to the escape of blood from the foetal side of the placenta when the umbillical cord ruptures.
Myometrial contractions aid exsanguination of the placenta.
Separation of foetal membranes.
Apex of the allantochorionic sac becomes inverted.
As the sac is 'rolled' down the uterine horns, foetal villi are drawn out of the crypts.
When a large portion becomes detached and inverted, it forms a mass in the maternal pelvis.
- Stimulates reflex contractions of abdominal muscles.
- Completes expulsion of the allantochorionic sac.
In polytocious species, dehisence and expulsion of foetal membranes are interspersed with births of the young.
- Only expulsion of the last afterbirth stimulates abdominal contractions.
The final stage of allantochorionic expulsion lasts 1 hour (mare) - 6 hours (cow).
Domestic animals normally eat the afterbirth.
- Not the mare or camelids.

Placental Expulsion

In most species, expulsion of foetal membranes quickly follows expulsion of the foetus.

After the birth of the young, regular abdominal contractions largely cease.
Myometrial contractions persist.
- Decreased amplitude, but become more frequent and less regular.
- Important for dehiscence and expulsion of foetal membranes.
Waves of contractions from uterus to the cervix persist.
- Act in a peristaltic fashion in the cow and sow in the reverse direction.

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Difference between revisions of "Normal Parturition - Anatomy & Physiology"

Latest revision as of 18:27, 3 July 2012

Contents

Stages of Parturition

Placental Changes

Contractions

Placental Expulsion

Parturition Behaviour

Mare

Cow

Ewe

Sow

Bitch

Cat

Navigation menu

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@@ Line 1: / Line 1: @@
-<big><center>[[Reproductive System|'''BACK TO REPRODUCTIVE SYSTEM''']]</center></big>
+{{OpenPagesTop}}
+==Stages of Parturition==
-<big><center>[[Reproductive_System#Parturition|'''BACK TO PARTURITION''']]</center></big>
+*Stage 1: this is the preparatory stage, starting at the onset of regular uterine contractions followed by cervical dilatation and the foetus assuming the correct disposition for passage through the birth canal.
+*Stage 2: the expulsive stage, characterised by the onset of abdominal contractions which together with uterine contractions lead to foetal expulsion
+*Stage 3: separation and expulsion of the foetal membranes. In polycotous species second and third stages are often inter-mixed.
+The following table summarises the normal time taken to progress through the stages of parturition in different species.
 {| style="width:75%; height:200px" border="1"
@@ Line 22: / Line 25: @@
 | '''Stage 2: Foetal Expulsion'''
 | 12-30 minutes
-| 30-60 minutes
+| 30 minutes - 4 hours
 | 30-120 minutes
 | 150-180 minutes
@@ Line 38: / Line 41: @@
+The step in the reproductive process that immediately precedes lactation, uterine involution and return to cyclicity.  It is initiated by the foetus and involves a complex cascade of endocrine events. Parturition is the process by which the conceptus (foetus, placenta and placental membranes) is expelled from the [[Uterus - Anatomy & Physiology|uterus]]; this requires [[Cervical Softening - Anatomy & Physiology|cervical softening]],[[Uterine Contraction - Anatomy & Physiology|coordinated myometrial contractions]] and contraction of abdominal muscles
-Parturition is the Process by which the conceptus (foetus, placenta and placental membranes) are expelled from the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|Uterus]] requires:
+to occur
-* [[Parturition - Cervical Softening - Anatomy & Physiology|Cervical Softening]]
-* [[Parturition - Coordinated Myometrial Contraction - Anatomy & Physiology|Coordinated Myometrial Contraction]]
-* Voluntary contraction of abdominal muscles
-= Stage 3: Placental Expulsion =
-In most species, expulsion of foetal membranes quickly follows expulsion of the foetus.
-* After the birth of the young, regular abdominal contractions largely cease.
-* Myometrial contractions persist.
-** Decreased amplitude, but become more frequent and less regular.
-** Important for dehiscence and expulsion of foetal membranes.
-* Waves of contractions from uterus to the cervix persist.
-** Act in a peristaltic fashion in the cow and sow in the reverse direction.
 == Placental Changes ==
@@ Line 70: / Line 58: @@
 * Open endometrial crypts
 * Foetal villi have shrunk due to the escape of blood from the foetal side of the placenta when the umbillical cord ruptures.
-* Myometrial contractions aid exsanguination of the placenta.
+* [[Uterine Contraction - Anatomy & Physiology|Myometrial contractions]] aid exsanguination of the placenta.
 * Separation of foetal membranes.
 * Apex of the allantochorionic sac becomes inverted.
@@ Line 83: / Line 71: @@
 ** Not the mare or camelids.
-= Parturition Behaviour =
+== Placental Expulsion ==
-== Mare ==
+In most species, expulsion of foetal membranes quickly follows expulsion of the foetus.
-=== Stage 1 ===
+* After the birth of the young, regular abdominal contractions largely cease.
+* Myometrial contractions persist.
-* Mammary hypertrophy, waxing of the teats and possible escape of milk from the glands.
+** Decreased amplitude, but become more frequent and less regular.
-* Patchy sweating behind the elbows and around the flanks.
+** Important for dehiscence and expulsion of foetal membranes.
-** Commences ~4 hours before the birth of the foal and increases as the stage progresses.
+* Waves of contractions from uterus to the cervix persist.
-* Yawns
+** Act in a peristaltic fashion in the cow and sow in the reverse direction.
-* No indication of pain.
-* Food is taken readily
-* Respirations are normal
-* Pulse is ~60
-* Body temperature may become slightly subnormal (36.5-37◦C).
-* Restlessness, wanders aimlessly.
-* Tail is frequently raised or held to one side.
-* May swish the tail or slap it against the anus.
-* Kicking of the abdomen
-* Towards the end of this stage:
-** Crouching
-** Straddling of hindlimbs
-** Going down on knees or sternum and rising again
-** Glancing at flank
-* This stage terminates with the rupture of the allantochorionic membrane and the escape of allantoic fluid from the vulva.
-** No visible straining during this period.
-=== Stage 2 ===
-* Abrupt onset, lasts~17 minutes
-* Appearance of the amnion or commencement of forceful straining
-** Not much delay between them, often coincide.
-* Soon after straining begins, the mare goes down.
-* Lies on her side with the limbs extended
-** Generally remains in this position until the foal is born.
-* Transperent blue/white 'water bag' (amnion) visible at the vulva
-* Quickly followed by the appearance in it of a digit.
-* Straining at regular intervals.
-** Each comprises 3/4 powerful expulsive efforts followed by a period of rest.
-** Generally 3 minutes long
-* One forelimb procedes the other by 7-8cm
-** One elbow passes through the pelvic inlet before the other preventing minimal obstruction.
-* Head is usually in the oblique position, but may be transverse with the cheek lying on the limbs.
-* Greates and longest effort is with birth of the head.
-* After expulsion of the foal, the mare may remain on her side exhausted for up to 30 minutes.
-* Umbillical cord is intact when the foal is born.
-** Subsequently ruptures 5-8cm below the belly due to movement of the mare or foal.
-* Foal is usually born within the amnion, which is ruptured by movements of the forelegs.
-* Lower portions of the hindlimbs often remain within the vagina for minutes after the rest of the foal is born.
-=== Stage 3 ===
-* Membranes expelled quickly after the birth of the foal.
-* Usually within 3 hours.
-* Duration of stage 3 is ~30 minutes.
-* Afterbirth is expelled by myometrial contractions with no straining.
-== Cow ==
-=== Stage 1 ===
-* Lasts ~6 hours
-* Relaxing of pelvic ligaments.
-* Mammary secretions change from transparent,honey-like to opaque, cellular colostrum.
-* Body temperature subnormal by ~0.6◦C.
-* Parturition will begin 12 hours after complete relaxation of the posterior borders of the sacrosciatic ligaments.
-* Heifers may show signs of abdominal pain for up to 24 hours before the cervix is fully dilated.
-* Occasional straining may occur.
-* Picks at feed, irregular rumination
-* 'Lowing'
-* Kicking of the abdomen
-* Restless, may stand with her back arched and tail raised.
-** May go down and rise again frequently
-* Pulse rate often increased to 80-90.
-=== Stage 2 ===
-* Lasts 30 minutes - 4 hours
-** Longer in heifers than in cows
-** Male calves take longer to be born
-* Onset marked by the appearance of the amnoin ('water bag') at the vulva.
-* Less frequent straining
-* Remains standing at first
-* During passage of the head through the vulva, the cow normally goes down and remains recumbent until the calf is born.
-* May lie on her side or in sternal recumbency.
-* Placental separation occurs more slowly than in the mare.
-* Umbillical cord of the calf is shorter than in the foal and generally ruptures as the calf falls from the vulva.
-=== Stage 3 ===
-* Expulsion of the foetal membranes usually occurs ~6 hours after the birth of the calf.
-** After 24 hours consider a pathological cause for retained placenta.
-* Cow will eat the foetal membranes.
-== Ewe ==
-Similar to the cow, except incidence of twinning and triplets is high.
-=== Stage 2 ===
-* Completed within 1 hour usually.
-* Lambs nrmally in enterior presentation.
-* In twin births where one foetus occupies each horn, one horn develops contractions before the other.
-** Hence distocia due to simultaneous presentation is more common when both foetuses occupy the same horn.
-=== Stage 3 ===
-* Placenta usually expelled within 2-3 hours after birth of the lamb.
-== Sow ==
-=== Stage 1 ===
-=== Stage 2 ===
-=== Stage 3 ===
-== Bitch ==
-=== Stage 1 ===
-* Lasts ~ 12 hours
-* Prepares the bed
-* If carrying one pup, the onset of lactation coincides with parturition.
-* If carrying multiple pups, milk may be expressed from the teats several days prior to the onset of parturition.
-* Body temperature subnormal by at least 1.2◦C within 24 hours before the onset of labour.
-* Restless
-* Indifferent to food
-* Panting
-=== Stage 2 ===
-* Depends upon the number of foetuses, but usually lasts ~6 hours.
-* Straining indicates the onset of the second stage.
-* Bitch remains in her bed in sternal recumbency
-* 'Water bag' of the first foetus appears at the vulva, and attains the size of a golf ball.
-* Bitch licks the vulva vigorously and usually ruptures the 'water bag'.
-* Delivery of the head requires the greates effort, once this is bord the rest of the foetus follows easily.
-* Expulsion of the first foetus may take up to 1 hour.
-* Umbillical cord is intact at birth, the mother will soon bite it away.
-* Bitch rests for a time after the birth of the first puppy.
-** Lies licking the puppy, which soon begins to suckle.
-** Pays frequent attention to the vulva and licks any discharge.
-* Foetal membranes generally voided in 10-15 minutes and eaten by the bitch.
-* Straining recommences after a delay of 30 minutes - 2 hours.
-* Effort and time required for subsequent deliveries is usually less than the first.
-* May rest in between subsequent deliveries, but may not.  The period of rest is also very variable.
-* Puppies tend to be expelled from alternate horns (unlike the sow).
-* Expulsion of foetal membranes is also irregular, they may come out individually, or the next puppy may be born with the membranes of its predeccessor around its neck.
-=== Stage 3 ===
-* Membranes of the last foetus are expelled with it or shortly afterwards.
-* Discharge is dark green in colour.
-** Due to breakdown of the marginal haematoma, blood pigment biliverdin escapes.
-== Cat ==
-During the last week of pregnancy, the queen seeks a nesting area.  This is usually a quiet, undisturbed spot but some house cats will demand more human contact.Mammary development becomes noticable in the last week of pregnancy, especially in maiden cats. Rectal temperature may fall a few days before parturition, but this is not a reliable indicator.
-=== Stage 1 ===
-* Restless
-* Frequently visits the site for kittening
-* Occasionally lies down and will strain unproductively.
-=== Stage 2 ===
+== Parturition Behaviour ==
-* Straining in lateral recumbency.
+=== [[Parturition Behaviour - Mare|Mare]] ===
-* Rapid expulsion of kittens with a short interval between each birth.
-* Parturition usually complete within a few hours.
-* If the queen is alarmed, this may disrupt the pattern and she may move the kittens to a new area before parturition resumes.
-* Soon after birth the kittens begin to suckle.
-=== Stage 3 ===
+===[[Parturition Behaviour - Cow| Cow]] ===
-* Placentae usually expelled still attached to the foetus or shortly afterwards.
+===[[Parturition Behaviour - Ewe| Ewe]] ===
-* Consumed by the queen.
-* Breakdown of marginal haematoma releases biliverdin, giving the discharge a brownish colour.
+===[[Parturition Behaviour - Sow| Sow]] ===
+===[[Parturition Behaviour - Bitch| Bitch]] ===
+===[[Parturition Behaviour - Cat| Cat]] ===
-<big><center>[[Reproductive System|'''BACK TO REPRODUCTIVE SYSTEM''']]</center></big>
-<big><center>[[Reproductive_System#Parturition|'''BACK TO PARTURITION''']]</center></big>
+{{OpenPages}}
+[[Category:Parturition]]
+[[Category:Bullet Points]]