Stage One: Dilation of Cervix
To understand how a cow's udder changes during its pregnancy you must understand the changes that occur during the birth. Milk is not taken from cows until after the weaning of the babies. Cows are also not milked during pregnancy, nor do they produce the milk. During pregnancy the udders should look as they normally do with slight swelling, but if a severe swelling or discoloration appears it's best to have an expert check for any infections. The udders do begin to change once the birthing begins, which starts with the dilation of the cow's cervix. This can begin up to 24 hours before the actual birth begins and a noticeable growth or swelling in the udders is common. The cow's uterine muscular activity is very quiet during this stage and the dilation can go unnoticed. However, other signs to look for are any behavioral differences or appearance of discomfort with the cow.
Stage Two: Delivery
During the second stage of birth the udder may begin to moisten or slightly drip. This is a normal sign of a healthy birth and is a common experience as the baby is delivered. If pregnancy does not occur at the expected time or lactation appears to be occurring in the udder early, the best option is to induce labor for the cow. This is necessary to prevent excessive udder edema from occurring after the birth and also to ensure that the udder supports do not become damaged. Udder edema is a metabolic problem where the udders produce an excess fluid. However, udder edema is common in a cows during pregnancy and sometimes after birthing, but it's not harmful to the cow. However, it can cause problems later if the cow is intended for dairy purposes since damage to the udders could occur. The best solutions to prevent this is to induce labor or to exercise out the excess liquid out frequently, which will strengthen the udders.
Stage Three: Shedding of the Placenta
During the final stage of pregnancy and after the babies have been delivered the udders can appear swollen for up to 24 hours. After the placenta and fetal membranes have shed, the babies will begin feeding. The swollen udder will stay slightly enlarged but go back to looking normal. The babies feeding helps to strengthen the udder and the entire process is vital for dairy cows until the weaning process begins.
