Cow number 3456 is due to calve in about a month’s time. What should you look for as she get’s closer to her due date?
Use these hints developed by the University of Wisconsin extension, with input from private veterinarians, Iowa State University extension specialists and University of Wisconsin veterinarians.
Watch body shape. If you stand behind the cow, her abdomen, or belly, will have a barrel shape about four weeks before calving. About a week before calving, that shape changes to look like a pear. The day of calving, the cow’s belly seems to almost disappear, as the calf moves into the birth canal.
Look for discharge. As the cow gets closer to calving, you’ll notice a difference in the discharge coming from her vulva — the external genital organs. The consistency of the discharge changes, going from rather thick and sticky to clear and free-flowing. Just before calving, the lips of the vulva become larger and softer and lose their wrinkles.
Watch for udder fill. The cow’s udder begins to fill with colostrum. This happens from front to back, meaning that the front quarters fill first, then the rear quarters. The teats fill last. Heifers will begin to show this edema, or swelling, during the fourth month of pregnancy. In older cows, udder enlargement may not show until two or three weeks before calving. Just before calving — with a day or two — the liquid in the udder changes from a sticky rather clear serum-like liquid to thick, yellowish colostrum.
Pelvis relaxes. As all of these other changes take place, the ligaments that connect the various bones of the pelvis begin to relax. You’ll notice that the cow may walk a little unsteadily because of this. The relaxation is caused by a hormone called Relaxin.As this process takes place, the ligaments around the tailhead get loose, the ligaments around the pin bones become loose and the tail becomes more flexible so that the calf can be born. The nearer to calving, the looser these areas become. After the pelvis completely relaxes, it is generally followed by delivery within about 12 to 16 hours.