Instructions
Look at the udders underneath the cow. The udder will begin to swell or fill out, forming a bag shape two or more weeks before the actual labor. If this is the cow's first calf, the udders can begin to swell as much as three months before delivery.
Check the vulva from behind the heifer and notice whether or not it's springing, or has become swollen. An enlarged, swollen vulva is a sign that the calf is coming within a few weeks.
Identify the loss of the cervical plug two weeks prior to delivery. The cervical plug will ooze out of the vulva and appear like a thick mucus. If evident, it will pool behind the cow.
Insert one hand into the rectum and place the other hand on the exterior ligament along the rim of the rectum. Notice the amount of centimeters or inches the ligament is displaced when your hand is inserted into the rectum. A displacement amount of two inches or more indicates that calving will occur in 24 hours.
Look for the cow's teats to begin to leak milk, also called strutting. This is often a sign that the cow will give birth in 12 to 24 hours, but this sign is not reliable in a poor milking cow which might not strut at all.
Watch the cow to spot any changes in her behavior. A cow near delivery will often separate from the herd so she can birth alone. She also might repeatedly lie down on the ground and display signs of discomfort. This could indicate that she is in the first stage of labor.
How to Determine the Time for a Calf to be Born
Cows have a gestation period of 279 to 287 days. If you know when the cow was inseminated, calculate 279 days out from that day to find the expected date of delivery. If you are unsure of the date the cow was inseminated, there are other signs you can look for. Once you notice that your cow will give birth, prepare a clean area for her to give birth to her calf. Cows typically don't require assistance, but you will want to stand by just in case there is a problem.