Normal Parturition (Calving)
By Sheila Lindsay
The average beef cow is pregnant for 280 days. Signs of approaching parturition can be seen during the last month of gestation. Growth of the mammary glands becomes very apparent. A sinking around the tailhead due to relaxation of pelvic ligaments will make the tailhead appear more prominent. The vulva with soften and become more swollen. Mucus may be seen stringing from the vulva. The combination of these signs are often termed “springing”.
Most cows will try to leave the herd and seek a place of seclusion for the birth. At the beginning of the birthing process a small bubble (the allanto-chorion) is seen protruding from the lips of the vulva. The “water bag” has a similar appearance to a water balloon. This should not be confused with a vaginal prolapse which is much thicker and has an appearance of swollen tissues. Once the water bag appears there should be a steady increase in contraction strength along with a decrease in contraction intervals. Depending on how far you are from a veterinarian or other person capable of dealing with birthing problems, or dystocia, will dictate how long to let the birthing process continue without intervention. Once the bubble is seen, the calf should be out within 2 hours.
If the birthing process does not progress, help should be summoned within 2 hours. If only a tail is presented to the vulva, a breech should be suspected and the cow will also need assistance. Once the torso of the calf has cleared the pelvis the amniotic sac must break to allow the calf to breathe. Occasionally this must be done manually. Usually the amniotic sac breaks as the calf and/or the cow move. As the hind legs are expelled the umbilical chord breaks and the calf is free from the cow.
Weather permitting, the cow and calf should not be disturbed at this time so they may bond. The cows licking will dry the calf and stimulate the baby to its feet. Ideally the calf should be up and nursing within a couple hours. At this time we usually treat the navel with iodine and weigh and measure the calf.