Cows give birth any age, since a cow is a female bovine that has already had a calf or two. Heifers, on the other hand, give birth when they're ~24 months of age. Since the gestation period is around...
If the calf is alive and healthy, then just leave momma and her baby be for a few hours to let the cow mother-up to her calf. If the calf doesn't appear to have gotten up and suckled from Mom yet,...