Hemorrhage in the Broodmare

A mare is at the greatest risk of a deadly complication associated with foaling known as hemorrhage in the 24-48 hours after giving birth. However, it is important to note that hemorrhage can occur at any time during gestation, and that it should always be taken into consideration when a broodmare is exhibiting colic symptoms. It is speculated that with repeated pregnancies, the vasculature that supplies the uterus becomes sclerotic or less pliable with the enlarging and shrinking cycles. This is just a theory, however, because there has been very limited research into the problem of equine periparturient hermorrhage.

The site of hemorrhage can vary in the broodmare. The most catastrophic hemorrhage is when a uterine artery (which supplies the uterus) ruptures and the mare bleeds uncontrollably into the abdomen. Sometimes the artery will only leak into the broad ligament (which supports the uterus on either side). If this happens, it can lead to a large hematoma. The hematoma usually resolves itself, but in the acute phase of hemorrhage, it can begin bleeding into the abdomen. Other ways that a mare might hemorrhage are by a partial tear or full tear through the uterine wall or by disruption of vasculature traversing the uterine wall. If the disruption is not through the entire wall, the uterus can fill with blood.

If a foaling mare, or any pregnant mare, begins to show symptoms of colic, there are some subtle differences that can be picked up that might lead the owner to assume the colic is caused by hemorrhage rather than other causes, noted Barrie L. Britt, DVM, a registered pharmacist who practices with the Hagyard-Davidson-McGee veterinary firm in Lexington.

"She will be agitated and have a nervous look to her eye," noted Britt. "Depending on how long she has been hemorrhaging, she may have pale mucous membranes, and she may tend to paw and stomp at her abdomen with her hind legs. She will tend to be sweaty and clammy to the touch. Many times her rectal temperature will be sub-100° Fahrenheit, possibly even as low as 94-96 degrees."

The mare's heart rate might be normal, or it might be as high as 150 beats per minute. Therefore, a normal heart rate does not mean the mare isn't hemorrhaging, warned Britt.

Most hemorrhages in mares are post-foaling in older mares, said Britt, but "you do see hemorrhage in young mares who have not been carrying foals every year. It should always be something you rule out if the mare is colicky."

If the mare is showing any of these signs associated with a colic, Britt advised calling a veterinarian right away. "The quicker we find out what's going on, the better chance we have of saving the mare."

One of the precautionary measures Britt advises in post-foaling mare management is to have the veterinarian examine the mare when he or she arrives to check the newborn foal. The physical exam can reveal if the mare has symptoms suggestive of hemorrhage. He or she might even want to rectal the mare, if possible without a twitch, to check for a broad ligament hematoma.

If hemorrhage is a possibility, there are several steps that the owner can take. First, the veterinarian should be called immediately. After that, Britt advised that the mare be kept quiet, that she be blanketed to help her retain body heat, and that the foal should be protected.

Once the veterinarian arrives, he or she will do a general assessment of the mare, asking for detailed symptoms from the owner and performing a physical examination. The veterinarian might then decide to perform a trans-abdominal ultrasound examination to see if there is free fluid in the abdomen, and if none is seen, he or she might perform a rectal examination to see if the mare is hemorrhaging into the broad ligament.

In humans or small animals, if the patient is hemorrhaging the doctor would attempt to stabilize the patient, then do surgery to ligate or tie off the bleeding vessel. However, Britt noted that transporting, anesthetizing, and operating on a compromised, hemorrhaging broodmare has at this time not been successful.

If it is determined that the mare, indeed, is severely hemorrhaging, then she would first be given one to two liters of hypertonic saline. That would be followed by 12-18 liters of isotonic fluids interspersed with a colloid, such as plasma. This allows for rapid volume expansion in the vascular tree. Fresh, frozen plasma has clotting factors to help the mare try to repair the leak.

The mare also can be transfused with six to eight liters of fresh whole blood, preferably collected from a gelding donor from the farm or from donors which the veterinary clinic might maintain. The gelding can act as a donor as the mare is being treated with other fluids, and since he has not had foals, blood incompatibility is not as probable.

"There is a continual cycle of physical examination and assessment during this treatment period," said Britt. "The veterinarian might spend six or eight hours with the mare until she is stabilized. If they are stabilized, they usually are going to be okay."

During this treatment process the veterinarian also is doing blood tests. When the mare first hemorrhages, her true blood loss is not reflected in the hematocrit, but when she starts becoming rehydrated with the fluids, the red blood cells in her circulation become diluted. In a normal mare the hematocrit should test at 45-50. In hemorrhaging mares, the number often falls to 15-20.

If the mare is hemorrhaging and nothing is done for her, the cells of her body are not being nourished while the mare is trying to build a clot and stop the bleeding. The fluids and other therapy "keep the body alive while the mare attempts to compensate for the hemorrhage," said Britt.

The cost of the treatment was likened to the cost of a colic surgery once the veterinarian's time, fluids, and blood work are counted into the bill. "It's worthwhile to make a resuscitation effort with appropriate therapy because we feel that some of these mare will live," stressed Britt.

The foal can be kept near the mare by building a "hay cage" just outside the opened stall door. This protects the foal while the mare is getting up and down feeling colicky, and helps calm the mare. However, if the mare gets down and is being treated intensively, the foal probably should be removed and steps taken to obtain a nurse mare. Britt does encourage mare owners to try and get the colostrum from the mare and give it to the foal.

While Britt admitted that there is much veterinarians don't know about hemorrhage in the mare, there is ongoing work at her practice in conjunction with the University of Kentucky Diagnostic Laboratory. The lab is taking various tissue samples from mares which die from hemorrhage and trying to determine if there are common factors present.

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

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