Instructions
Look at the cow's udder and vulva. The udder should fill out (called "bagging"), the vulva should relax and enlarge (called "springing") and the cervical plug, a mucous material, should be excreted from the vulva. This usually happens two or more weeks before calving.
Look at the cow's pelvic ligaments. They should relax 12 to 24 hours before calving.
Pay attention to change in the cow's behavior. The cow may try to isolate herself, become reluctant to eat, lick her side and stomp her feet. These changes occur within four to 24 hours of the calving and mean it is imminent.
How to Know When a Cow Is Getting Close to Having a Calf
There are a number of ways to determine when a cow is close to calving, though they appear at different times in individual cows, depending on their breed and age, for example. The signs may also occur earlier in cows that are calving for the first time. Cows usually carry their calves for a period of 280 to 290 days, and these signs will become evident within weeks of the calving.