1. Udder swelling: The udder, or milk-producing gland, will begin to swell as the cow approaches calving. This is due to the increased production of milk in preparation for the calf's birth.
2. Vulva swelling: The vulva, or external female reproductive organ, will also begin to swell and relax in preparation for the calf's passage.
3. Mucus discharge: A clear or slightly blood-tinged mucus discharge may be seen coming from the vulva. This is normal and is a sign that the cervix is beginning to dilate.
4. Restlessness: The cow may become restless and agitated as the time for calving approaches. She may paw at the ground, switch her tail, and frequently look back at her flank.
5. Lying down: The cow may lie down and get up frequently in the hours leading up to calving. This is normal behavior as the cow is trying to find a comfortable position for labor.
6. Labor: When the cow is ready to give birth, she will begin to strain and push. The calf's head and front feet will appear first, followed by the rest of the body. The entire birthing process can take anywhere from a few minutes to several hours.
It's important to note that every cow is different and may display different signs before calving. If you have any concerns about the health or well-being of your cow, it is always advisable to consult with a veterinarian.