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Birth of a calf
Most cows can calve and produce a healthy calf
without assistance from the owner or herdsman. Cows
should calve in a clean, well grassed, sheltered paddock
near the house or dairy where she can be observed in case
calving difficulties develop. This area should not be
overstocked and paddocks should be rotated and spelled to
reduce disease build up. Prior to calving the cow
must be adequately fed to meet her needs and those of her
developing foetus, to reduce risks of metabolic diseases –
milk fever or ketosis and difficulties at calving.
time of calving
A farmer can accurately predict the time of calving by
keeping good records. Relevant reproduction records
• date a cow previously calved
• date(s) she was serviced
• Sire used and method (AI or bull)
• expected calving date.
Average gestation for a cow is 283 days but ranges from 273
to 291 days. Her expected calving date (ECD) can be
calculated by adding 7 days and subtracting 3 months from
the most recent mating date. Thus a cow mated on 1st
July 2003 will be due to calve about 8th April 2004.
The signs of parturition (birth process) are:
• The udder of the cow enlarges 1 to 2 weeks before
calving. This is not a reliable sign in heifers as
their udders begin to develop half way through pregnancy.
• Colostrum is produced (a creamy or pink secretion from
• Pelvic ligaments relax.
• Vulva swells (up to six times its normal size) and
becomes flabby. White, stringy mucous is secreted from the
The birth process can be
divided into three stages.
1. The muscles of the
wall of the uterus begin to contract. These
contractions occur about every 15 minutes and last from 15
to 30 seconds. This stage may last 3 to 4
hours. The cow will become restless, stand alone, and
occasionally strain weakly. The foetal membranes
enter the vagina and pass on to the vulva where they appear
as the ‘waterbag’. This waterbag soon ruptures.
By this time, the head and forelimbs of the calf enter the
cervix, dilating it so that the cavity of the uterus
becomes continuous with the vagina.
2. During this second
stage, the calf enters the vagina causing stronger
contractions from the diaphragm, abdominal muscles and
uterus. The cow may stand or lie down and strain for
10 to 15 seconds every 2 minutes. When the calf’s
feet reach the vulva, a second membrane ruptures which
lubricates the passage for the head and body. As the
forelimbs appear the cow may rest before expelling the calf
3. This final stage
begins immediately after the calf has been expelled.
The uterus contracts rapidly which causes the afterbirth to
separate from the uterus. The contractions force the
membranes through the cervix into the vagina and eventually
through the vulva. The afterbirth (placental
membranes) is usually expelled shortly after the calf is
borne but can take several days. Cows with retained
placenta may require follow up veterinary attention.
Most calves at birth are in anterior presentation, dorsal
position and normal posture that is, the forefeet first,
one foot just preceding the other, the head is lying on the
knees, and the backbone is lying against the backbone of
Provided the cow behaves normally there is no need for
concern if she is a week (or even longer) overdue.
Once parturition has begun, observe closely at a
distance. If this stage continues for longer than 24
hours the cow should be examined.
Once the cow enters the second stage of labour,
abnormalities can be recognized. Be aware that
heifers often take longer to calve so delay
examinations. If cows have been straining (in labour)
for 4 hours without making progress, investigation should
The longer the cow is in labour, the less likely she is
able to produce a live calf. Once the hind or
forelimbs of the calf reach the vulva the umbilical cord is
probably pressed between the calf and cow’s pelvis or even
ruptured. When this occurs the calf begins
breathing. If the calf is normally presented and the
muzzle is close to the vulva, the calf should be able to
breathe. If it is in the posterior presentation it will
soon die. If the operator is inexperienced and the
calf is not presented and positioned normally, a veterinary
surgeon should be contacted.