University of wisconsin-madison

Signs of Parturition - Physical and Behavior

During the last few weeks of parturition there is an increased release of the hormone relaxin. This hormone will cause relaxation of cervix and eventually cervical dilate during parturition. In addition, it relaxes the uterus to prevent premature contractions and also relaxes the sacrosiatic ligaments. In the mare this can be observed as a softening of the tial head and croup. To detect this change, press on the area to the side of the tail head with your hand as shown in the image. Comparisons with a non-pregnant mare will allow you to detect this difference on late term mares. Palpation of the ligaments is essential as visual observation alone detects the changes in only 50% of mares.

In addition to the effects of relaxin, a drop in progesterone and increasing estrogen leads to contractions in the myometrium or muscles of the uterus. These contractions can be sometimes seen as the mare will stop breathing briefly or even look back or bite her side. Note that these are prefoaling contractions and not part of labor. Similar contractins in humans are often called false labor.

In a herd situation, the mare will separate from the herd to foal by herself. This is not observed under most management situations since mares are usually stalled for foaling. Foaling occurs predominately at night, with 70% foaling between 10 PM and 2 AM. It has also been reported that some mares will have a decrease in PM temperature on the day of foaling.

This demonstrates the technique for examining the softening of the pelvic ligaments in a mare.

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