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Birth of a calf
(with
photos)Introduction
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.
Predict time of calving
A farmer can accurately predict the time of calving by keeping good records. Relevant reproduction records include:
• 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 birth process
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 the udder).
• Pelvic ligaments relax.
• Vulva swells (up to six times its normal size) and becomes flabby. White, stringy mucous is secreted from the vagina.
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 completely.
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.
Presentation, position and posture
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 the mother.
Observation and examination
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 be made.
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.
These pictures are from the Dutch movie "Iris" (1987) with Monique van de Ven
Our practice did the veterinary advise during the shooting of this movie.
