No horse is identical to another, and no broodmare shows pregnancy signs in the same manner as another. Here, Dr. Khris Crowe outlines the warning signs owners should know to prevent a potential disaster.

No matter how prepared a horse owner is, as soon as the broodmare begins foaling, panic and doubt shadow every decision. While preparing for the foal is the best bet for a smooth birth, awareness of warning signs can often prevent disaster.

“First, I always ask when the mare is due,” says Khris Crowe, DVM, and attending veterinarian at the Red River Reproduction Center in Gainesville, Texas. “A lot of mares transfer around and the information is lost. Many clients can’t tell me the correct due date, and that is a problem. A mare will go between 330 and 350 days of gestation, but she is fair game to foal three weeks early or late. That is the most important thing for a broodmare owner to know.”

palomino mare and bay mare with foals
Photo by Kristin Pitzer

A reproductive specialist, Crowe has worked in Arizona, Georgia, Oklahoma and Texas, breeding and foaling out thousands of mares. Many performance-focused broodmares are bred to foal earlier, between January and March, while ranchers in colder climates time foaling for summer months. A problem can arise at any time during a mare’s pregnancy, but those in the last few months of gestation may be corrected and still allow birth of a healthy foal, says Crowe.

Here, Crowe shares more than 30 years of veterinary experience and insight on how to recognize a broodmare in trouble.

Normal vs. Abnormal

A mare begins to “bag up” when she is between three and five weeks of foaling. The mammary gland, or udder, will swell slightly, with the teats forming and beginning to fill. Yearly, Crowe receives calls on mares that begin to bag up three months or so in advance. This is the first sign of a number of potential complications.

After ruling out an incorrect due date, which Crow says is a frequent culprit, she focuses on two common diagnoses.


Once the foaling date is confirmed and deemed too far away for bagging up, Crowe says most veterinarians test for placentitis.

“Placentitis is an infection in part of the placenta,” she explains. “When this occurs, the mare is often preparing to abort the foal. First, check that the foal is alive and to see how advanced the infection is, then treat it. In the last seven or eight years, [vets] have gotten good at treating placentitis, whereas 30 years ago, when I graduated vet school, the mare always lost the foal.

“If a vet can get to the mare soon enough, we can treat the infection and monitor the mare’s hormones to work with her and get a live foal.”


While twins are met with joy in humans, two foals in one mare is no reason to rejoice. “Twinning” can endanger the mare and the foals growing within her.

“Twinning can cause a mare to bag up early,” Crowe says. “Now, we have a machine called an ultrasound, so twins can be prepared for. It is a tool used to monitor the foal in the mare’s belly. The mare usually aborts the [twin] babies, or has them incredibly premature. A veterinarian must be called to ensure the mare and foals’ safety if this [type of] pregnancy occurs.”

Warning Signs

A mare’s body changes subtly over the course of gestation, so abrupt changes are warning signs for horse owners. Familiarity with the mare’s physical appearance makes it easy to recognize changes worthy of concern.

Bell-Shaped Belly

“If the belly increases in size at an alarming rate, that is a potential problem,” she says.  “Instead of a normal pregnancy, the mare will look like she has multiple babies in there. Rather than a nice bell shape with a bulge to it, a belly that is too large too fast can drop down all the way to a mare’s hocks. When that happens we can have an abdominal hernia, where we have had a separation of the muscles of the abdomen, and some of the intestines are down in there.

“This can also happen with twinning and when there is an abnormality called hydrops, where there is an excessive amount of fetal fluid being produced. Another possibility is when there is a rupture in the pre-tubic tendon, which is a tendon in the pelvis that all the muscles hook to. This is rare, but it does happen on occasion. All of the muscles have no way of holding on to that pregnancy.”

Call a vet immediately when you notice an alarming change in the mare’s belly, says Crowe. While no horse owner wants to incur a veterinary bill, speed of treatment is key to correcting problems such as these, and increasing the chance for the mare to carry until her foaling date.

Dramatic Discharge

It is not unusual for a mare to have a small quantity of clear discharge during pregnancy, says Crowe. However, something may be going wrong if a lot of discharge begins to stream from the vulva.

“The discharge can be clear or bloody, and it shows that there may be an infected placenta,” she explains. “This may be an impending abortion. Call the veterinarian to rule out an infection or possible abortion.”

Small amounts of discharge can be explained, but a veterinarian should be called to investigate.

“What is happening as the belly gets bigger and heavier—and on older mares, lower—is that the vagina is no longer horizontal or tipped to the outside,” Crowe says. “It will tip back into the abdomen. The mare may begin to drip a little urine or have vaginitis. It all has to do with the weight of the baby and changing anatomy. Any notice of discharge should be investigated.”

palomino mare and foal
Photo by Darrell Dodds

Missing the Due Date

Much like a premature child, a premature foal brings a new set of challenges. If a broodmare that is not within three weeks of foaling shows signs of doing so, call a veterinarian immediately. However, healthy mares can foal prematurely, before 325 days of gestation.

Premature Delivery

“If the foal comes before 325 days, a vet needs to be there to help the foal survive,” Crowe says. “The foal may not be able to control its own temperature or breathe properly, and the mare may not have had enough time to produce colostrum. If the baby doesn’t get the first milk, it may be immune compromised.”


“The opposite happens all the time—a mare going way past her due date. Prolonged gestation is over 360 days,” Crowe says. “One cause of this is fescue toxicosis, which comes from fescue grasses. We don’t have fescue grass in Texas, but several states do.

“I would say that if your mare has reached 360 days and has no signs of an udder, it is a good idea to call the vet to do a rectal exam or ultrasound and make sure there is a live baby. There is a wonderful drug called domperidone that the vet can treat the mare with to take care of [the disease].”

Crowe also notes that older mares can hold their foals longer, and knowing a mare’s past foaling habits can keep owners from worrying needlessly.

The final reason a mare may be past her due date is one of Crowe’s least favorite diagnoses—she is not pregnant.

“Every year I have some mares who get to their due date and don’t foal. The owner calls and says the mare is big and fat, but doesn’t have an udder by her due date,” she explains. “Often, I do a rectal exam and there is no baby. It is sad to tell an owner who is looking forward to a baby that there is none. The owner has fed and fed this mare thinking she is pregnant, and she is fat from overfeeding and has no horse baby.”

1 Comment

  1. Valerie Glatthar Reply

    My question is related to lactation , my mare Foaled in April
    Of 2018 she lost her foal but still is dripping milk and has a small bag almost 2 years later . This seems abnormal but have had 3 vets check her and she is clean and normal otherwise I have been told . Is there something I can do or is this part of a bigger problem ? Thank you for any advice .

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