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may be exacerbated by pregnancy. Another common problem is a mare that’s older and looks like she may be developing metabolic problems or is borderline for Cushing’s syn- drome. Those mares will be at high risk for carrying a foal successfully,” explains Tibary.
“During breeding season, the mares that are hard to get pregnant would also be flagged as high risk, not so much because of their health, but for the risk of losing the pregnancy. Some of them tend to have early pregnancy loss,” he says.
“Most veterinarians recommend doing early pregnancy/fetal evaluation after the mare is bred. We do the first ultrasound examina- tion of the mare for pregnancy diagnosis at 14 days after breeding. The second check would be somewhere between 25 and 30 days. That’s when we determine whether the pregnancy
is healthy or not. As we do the pregnancy diagnosis, we may flag some mares for another check just to make sure things are going all right,” he says.
“No mare should go into the winter without verification, to know if she is still pregnant.
My recommendation is for all mares to have another evaluation in the fall. Then, we can detect the mares whose pregnancies don’t look that great and may require further monitoring. These series of examinations are one reason why veterinarians were able to pick up on the problem with MRLS (Mare Reproductive Loss Syndrome) in Kentucky a few years back; dur- ing pregnancy monitoring they discovered that the mares were showing abnormalities of the placenta or fetal fluid,” he says.
As mares are monitored through pregnancy, many will be considered normal, some will
be dropped from the high-risk category, and others will be flagged as requiring further examination. “The latter category will include the mares that are maintained on progesterone, such as Regumate.” These mares require con- tinual monitoring to make sure the pregnancy is continuing on course.
“The reason we do the series of evaluations is that we don’t want to be surprised later and find that the mare has lost the pregnancy. Most of the losses occur before 50 days. Chances are, the non-professional breeders will not be aware of that loss. We won’t know it occurred unless we are checking the mare,” says Tibary.
“Complications due to pregnancy that might have serious consequences for the mare’s health generally do not happen until about the 5th month of pregnancy. That’s when we start seeing problems if the mare loses the pregnancy. By then, the fetus is large enough that it can damage the cervix if the mare aborts. There might also be a resulting uterine infection, which could
An exam should be performed on a pregnant mare suffering from colic to determine if it is of gastrointestinal origin or of uterine origin.
produce endotoxins that would be serious for the mare,” he explains.
Once a mare is declared pregnant, anything that happens to her in terms of diseases would also flag her as high risk for carrying that foal
to term. “Any pregnant mare that is hospitalized for a serious health problem (such as fever, colic, septic wounds, or any type of lameness) becomes a high risk pregnancy because we need to moni- tor that fetus,” he says. Stress on the mare from a major health problem can impact the pregnancy.
“When a mare is several months into pregnancy, any surgery (particularly abdominal surgery) or disease that has systemic conse- quences may affect the fetus,” says Tibary. The high-risk pregnancy can be broken down into three categories - high risk for the mare, high risk for the fetus, or high risk for both.
“One of the most common presentations we see here in the clinic includes pregnant mares that come in for colic surgery. Any time we have a mare that colics and she’s mid to late term gestation, we must determine whether colic is of gastrointestinal origin or of uterine origin. Uterine torsion can be a serious problem in a pregnant mare,” he explains.
“If a mare is hospitalized for colic, fever,
or any infectious disease, we consider her a high risk pregnancy and engage a series of fetal and placental monitoring. While she is being treated, we are dealing with two patients and we try to make sure the fetus is still doing okay.
The good thing is that, during the past dozen years, there’s been substantial advancement in how we monitor these pregnancies, particularly with ultrasonography to monitor the fetus and placenta,” he says.
“To some extent, we can also monitor the important hormones, particularly progester- one and estrogens (estrone sulfate). This has become quite valuable in determining what’s going on with the pregnancy. This monitoring requires a series of what we call biophysical profiling of the fetus. We can also evaluate and measure certain parameters, such as fetal heart rate and fetal activity, density of fetal fluid, depth of fetal fluid, etc., as well as the thick- ness of the utero-placental units,” he says.
There are many reproductive disorders that may put the mare at high risk. “She may not show any signs of illness, but any mare that starts bagging up or has an abnormal vaginal discharge (bloody or mucopurrulent) becomes high risk. The primary reason for discharge and early bagging up is placentitis. With the new information available, we can manage placentitis with certain treatments - particu- larly if it’s an ascending placentitis (infection that invades through the cervix from the vagina),” he says.
The treatment usually includes antibiotics, and is generally based on how severe the infec- tion is and how the fetus is responding. “The main treatment for this, and for managing a
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equine health