Pregnant Mares

Early lactation can be a sign that your mare is getting ready to abort her pregnancy. Should you believe that this is the case and are concerned about the health of your mare please make an appointment with your veterinarian.

Mares can become aggressive during pregnancy because they are uncomfortable or because of the hormonal changes that are taking place. If your mare’s aggression mimics that of a stallion, then it is possible that your mare is suffering from granulosa theca cell tumors (GTC). These tumors produces steroids and in most cases male testosterone. Testosterone is the male sex hormone and will cause your mare to act like a stallion.

These tumors are located by performing an ultrasound scan and then blood work will be done to confirm the presence of testosterone.

The short answer is yes. There are some things to consider though. Your mare can be turned out with other mares as long as they get along. A pregnant mare should not be turned out with a stallion or even geldings.

Geldings, while they no longer have the sex drive of a stallion, can still get an erection. Should a gelding mount and then penetrate the cervix of your mare, the pregnancy will likely be aborted.

With a healthy pregnancy, you should be able to ride your pregnant mare until she is at 200 days of gestation.

The gestation period for a pregnant mare is typically 338-343 days. Some mares can foal as early as 320 days or go out as long as 380 days. If you mare’s pregnancy goes much past 340 days you may want to consider having your veterinarian perform an exam to ensure your mare is healthy and all is well

The danger isn’t in eating the fescue itself. The danger is in eating endophytic fungus infected fescue. If your mare does eat endophytic fungus infected fescue she may contract fescue toxicosis. If your mare does become exposed the following pregnancy complications may occur:

• The mare’s pregnancy may be prolonged, causing her to deliver a larger than normal foal increasing the risk of problems during birth.
• Milk production can be effected to the point the mare produces little or no milk.
• The placenta may become thick or tough causing the mare to have problems expelling the placenta.
• A foal that does not develop properly in utero, resulting in conformation or functional abnormalities.
• The death of the mare and/or foal during birth.