A uterine prolapse in a cow that has calved is one of the true emergencies of food animal veterinary medicine.
This condition occurs at a relatively low frequency. Estimates would suggest that a maximum of two cows in every 1,000 calvings would have a uterine prolapse.
However, it is a serious life threatening condition for the animal, and prompt action needs to be taken.
The cow may push the uterus out through the birth canal, inside out, if it is straining badly after calving or if the uterus is extremely flaccid. This large solid mass of tissue will have five to eight centimetre long “buttons” on the surface where the membranes attach.
Any age of calving cow can be affected. Heifers that prolapse their uterus usually do so because of prolonged straining in a difficult calving. Older cows may also prolapse because of calving difficulties, but older cows may also prolapse because of low calcium levels, called milk fever.
Low levels of calcium have a detrimental effect on muscle tone and will cause the uterus to be flaccid and more likely to prolapse. Dairy cows are more prone to milk fever and therefore are more susceptible to uterine prolapses.
The uterus of a recently calved cow is a large muscular organ and so diagnosis of the problem is not difficult. However, prompt action needs to be taken to maximize the likelihood of the cow surviving.
Tissues will appear fairly normal when the uterus is first exposed. However, they will soon begin to swell and become dark red or purple. As fluid accumulates in the uterine tissues, they become much more fragile and easily damaged. The sooner the prolapse can be replaced, the less tissue damage will occur.
The first step in dealing with a uterine prolapse is to restrain the animal. In many cases, the cow is reluctant to stand and move anywhere because it is already in shock. Cows that are able to stand should be slowly and quietly restrained in as calm a manner as possible.
The uterine artery is a large blood vessel that is the blood supply’s main route to the uterus. The artery can be stretched and ruptured if a cow with a prolapse moves around excessively or runs. It will then bleed to death from internal blood loss.
Wherever possible, restrain the cow quietly without moving it. Remove other animals from the area so they don’t step on the uterus or damage it.
Cover the uterus with a clean moist towel to protect it if veterinary assistance is going to be delayed. As well, protect the tissues from freezing with an insulating blanket if it is cold out.
When putting this large muscular organ back into a cow’s body, the veterinarian will have to administer an epidural anesthetic to prevent the animal from pushing. The uterus will need to be carefully cleaned with warm soapy water, and all manure and bedding will have to be removed from the surface.
A placenta that is still attached can often be peeled off gently from the cotyledons, or “buttons,” at this time. Significant tears in the uterus will need to be repaired before it is returned. The veterinarian will then attempt to put the uterus back into the cow. This is not always easy.
The cow will still strain to some degree, despite the epidural, and it sometimes seems that this huge mass of tissue will never fit back in.
If the cow is lying down, the veterinarian may have the hind legs extended behind the cow in a “frog-legged” position to help with the positioning of the pelvis.
The veterinarian may need an assistant to help hold this large organ and to help keep it clean.
Everyone needs to be as clean as possible throughout this procedure to minimize contamination of the uterus.
It is important to ensure that the prolapse is completely returned to the normal position. The cow may re-prolapse if even a small portion of a uterine horn remains inverted. Many veterinarians will place sutures to help prevent the prolapse from re-occurring, although this may not always be necessary.
Cows are usually given oxytocin to cause the uterus to contract after it is replaced and often given antibiotics to prevent infection. Intravenous calcium should be administered if milk fever is also occurring.
The prognosis is usually good if the prolapse is returned quickly and the uterus has not been severely damaged or the uterine artery has not ruptured.
The fertility of cows that have suffered a uterine prolapse is reduced. They will not necessarily have a uterine prolapse in subsequent calvings and do not necessarily need to be culled.