When should cows pass their pregnancy membranes?

Inside the womb of the cow there a number of membranes which help to keep the calf alive and healthy. Once the calf has been delivered, these membranes must be expelled from the body.

During calving two 'water bags' are expelled. Once the calf is out, 2-12 hours later (normally) the placenta is passed. This looks like a small puddle of bloody, white membraned fluids which are held together in a single bag. The membranes have visible 'button-like' projections called caruncles (these are the blood artery junctions which supplied the calf during gestation).

The placenta is usually passed fairly soon, but other membranes sometimes remain inside the womb - often bits that have become separated from the main expulsion matter. Retention of membranes can become a serious issue if not monitored properly.

Up to 10 days after calving the cow may be seen with bits of 'cleansing' hanging out of her. This is fairly normal and most cows will take this 10 day period to properly cleanse their womb and on the 10th day whatever is left inside is almost certainly pushed out. Accompanying this will be a foul smell; this is often a good way to tell if a cow is still cleansing!

However, although this 10 day retention is common, it should still be treated as abnormal. Check the cows temperature if you have not seen any membranes being passed after 24 hours since calving.

When you see these membranes hanging out the back end of a cow, do not be tempted to pull them out. By manually removing the membranes you disrupt the body's natural process and risk breaking off a small piece and leaving it deep within the womb. 

Leaving membranes inside the womb can lead to metritis (womb infection), peritonitis (infection of the lower abdomen) and infertility. If a cow is taking a long time to pass her membranes, she has a temperature or you are worried about infection, there are tablet capsules that can be placed in the womb which release antibiotics directly into the area of concern - the womb. 

Summary


1) Cow calves
2) ~12 hours later she should pass the main part of the placenta
3) ~24 hours the rest of the placenta should be passed. If it is not, then monitor the cow's temperature.
4) ~10 days all parts of the placenta will be passed, accompanied by a putrid smell. 
5) 10th day check for infection. Often a pus-filled uterus will be palpable.