Parturition is the physiologic process by which the
pregnant uterus delivers the foetus and placenta
from the maternal animal.
Parturition comes from the Latin word parturire, "to
be ready to bear young one" and is related
to partus, the past participle of parere, "to
Changes not visible externally.
Preparation of birth canal and foetus for expulsion.
Signs of discomfort, mild colic, restlessness with
elevated pulse and respiratory rate, body temperature
Structure of cervix changes.
Onset of myometrial contractions.
Foetus assumes the disposition for expulsion.
Loosening of the ground substance due to changes in
the composition of collagen components.
Increased incorporation of water which permits collagen
fibres to separate under extension forces.
(Fitzpatrick and Dobson,1979)
Cervix dilates: external os opening before internal os
and becomes cone shaped due to wide dilation of
external os. (Abusineina,1963)
Simultaneous shortening and internal os dilation.
Vagina and uterus form continuous canal that becomes
tightly engaged by the distended allantochorion.
Presence of cervicotubular and tubular-cervical
contractions. Gillette and Holm (1963); Taverne et al. (1979)
Cervicotubular contractions prevent the premature
displacement of foetuses, thus ensuring orderly
expulsion from the horns. (Taverne et al., 1979)
Isolated ,uncoordinated waves changes to regular and
coordinated peristaltic type.
Frequency increases from 12-24 per hour in last 2 hours
to 48 per hour just before expulsion (30 per hour in
ewe). (Gillette and Holm 1963)
Placental attachment becomes less intimate.
Superficial cells undergo fatty degeneration.
Separation of margins with haemorrhage in deciduate
Becomes more active and disposes itself.
Progressive rotation from ventral to dorsal position and
fore limbs, head and neck extended in foal and puppy.
In calf and lamb extension only.
Flexed knees of calf first occupy dilating cervix; 30
minutes later digits are in cervix and it extends carpal
joints in its efforts to ‘stand up in utero’. Abusineina (1963)
Refers to expulsion of foetus.
In polytocous species stage cannot be separated from
Sign: Apperance of abdominal contractions,
superimposed upon onset of each myometrial
contractions. (Gillette and Holm,1963; Zerobin and Spörri, 1972)
Disappearance of cervicotubular contractions.
(Zerobin and Spörri, 1972)
Allantochorionic sac ruptures and gush of urine like fluid
escapes from vulva.
Amnion traverses vagina and appears at vulva as
‘water-bag’ with foetal limbs.
Foetal head next occupies vulva,contractions of uterine
and abdominal muscles reach climax of expulsive effort,
maximum effort coinciding with the birth of the foetal
Further straining causes foetal thorax to pass through
Usually, birth of hips quickly follows and hind limbs may
Foetus is born in amnion and quick movement causes its
rupture; respirations, then begin.
In mare, cow and ewe (when monotocous) foetus is
usually delivered in anterior presentation, dorsal position
and extended posture.
In polytocous bitch and sow up to 40–45% of foetuses
may be normally delivered in posterior presentation.
Animal 2nd Stage
Cow, Buffalo 70 min
Mare 17 min
Ewe 1 hr
Sow 4 hrs
Camel 30 min
Bitch 6-12 hrs
After 2nd stage, regular abdominal contractions largely
cease. (Gillette and Holm, 1963)
Myometrial contractions persist; decrease in amplitude.
These contractions are important for dehiscence and
expulsion of fetal membranes.
Waves of contractions passing from uterine tube to
cervix persist, but in cow and sow reappearance of
contractions in reverse direction.
(Zerobin and Spörri, 1972; Ngiam, 1977)
Weakening of acellular layer of adhesive protein, ‘glue
line’ between cotyledonary and caruncular epithelium, is
probably important in ensuring placental separation.
(Bjorkmann and Sollen, 1960)
In last 5 days of gestation collagenisation of placentome
and flattening of maternal crypt epithelium in cow.
Foetal villi have shrunk, owing mainly to sudden loss of
turgidity related to escape of blood from foetal side of
placenta when umbilical cord ruptures.
Early degenerative or maturational changes which are
seen in caruncles of ewe and cow, cause separation of
Apex of allantochorionic sac becomes inverted and as
sac is ‘rolled’ down cornua the fetal villi are drawn out of
This forms a mass within maternal pelvis which
stimulates reflex contractions of abdominal muscles
leads to expulsion of fetal membranes.
Domestic animals normally eat afterbirth except Mare.
Eating of foetal membranes Foetal membranes along with placentomes
In polytocous species,dehiscence and expulsion of fetal
membranes are interspersed with fetal births.
Stimulus of suckling causes release of oxytocin, which
promotes ‘letdown’ of milk and augmentation of
Suckling resulted in greater synchrony of contractions
and increase in number of tubocervical contractions.
Suckling exerts a favourable influence on expulsion of
Animal 3rd Stage
Cow, Buffalo 6-12 hrs
Ewe 2-3 hrs
Sow 4 hrs
Camel 1 hr
Bitch Along with fetus or
Immediate approach of labour has been recognised by
slackening of pelvic ligaments and change of the
mammary secretion from a relatively transparent, honey-
like secretion to an opaque cellular secretion –
colostrum. Parkinson,T. J. (1993)
Occasional straining may occur during 1st stage.
Food is only picked; rumination is irregular; there may be
kicking at belly.
Line of demarcation between first and second stages is
not clear-cut, as in mare.
Umbilical cord is shorter in calf and its rupture generally
occurs as calf falls from vulva.
Imminence of labour can be recognised by degree of
mammary hypertrophy, waxing of teats and possibly
escape of milk from glands.
Best indication: onset of patchy sweating behind elbows
and about flanks 4 hrs before birth of foal.
Tail is frequently raised or held to one side or slapping of
it against the anus and kicking at abdomen.
Onset of 2nd stage occurs abruptly characterised by
appearance of amnion or commencement of forcible
straining. Pycock,J.F (1977)
During its delivery, head is generally in oblique position;
it may even be transverse – cheek lying on the limbs.
Separation of placenta tends to proceed rapidly once
second stage begins. Pycock,J.F (1977)
Straining is not a feature of third stage.
Imminence of parturition indicated by preparing bed.
Transient drop in body temperature, 1.2°C within 24
hours before of parturition.
40% of puppies born in posterior presentation.
Umbilical cord intact at birth quickly torn by mother.
Uterine discharge dark green in colour, due to
breakdown of marginal haematoma (‘green
border’).(Queen: brown coloration)
Stage of expulsion of foetuses most irregular, tendency
for puppies to be expelled from alternate horns.
(Van der Weyden et al., 1989).
60 to 75% of sows farrow at night. (Bichard et al., 1976;
Kovenic and Avakumovic, 1978)
No separate 2nd and 3rd stage of labour.
Several alternating periods of rest and bed-making and
in the hour preceding birth of first piglet, sow settles
quietly into lateral recumbency.
Jones(1966) and by Randall (1972)
Offspring delivered randomly from both uterine horns.
Taverne et al.(1977)
55.4% anterior and 44.6% posterior presentations.
Mean interval between consecutive births is 16 minutes.
Fetal membranes tend to be expelled as 2 or 3 masses of
joined allantochorions with placental stalks of umbilical
Sow usually stands up and micturates profusely after
Early-born piglets are more likely to survive than either
middle-born ones or late-born ones from tips of the
uterine horns.(Dzuik and Harmon, 1969; Sprecher et
al., 1974; Leman et al., 1979).