The process of a cow giving birth to a baby is calving. On a dairy farm, calving season generally happens in the spring.
This noun refers to the birth of any calf, a word that describes the young of many mammals in addition to cattle. Elephants, whales, and bison are among the animals that go through calving, resulting in their own little calves. Since the 19th century, the word has also been used to describe what happens when huge ice chunks break off from a glacier: "During ice calving, there's often an unbelievably loud cracking sound."