Estimated Foaling Dates
This is the estimated date of parturition/birth. Unless otherwise changed, it is calculated at 340 days. This is, however, only an estimate -- and by no means should it be used to determine when your Mare is going to foal. There are many external indications and tests to provide you with an accurate idea of when to expect parturition/birthing.
Several commercial kits to estimate foaling time have recently come onto the market. These test kits are based on the fact that in most mares, calcium and magnesium concentrations in prepartum mammary secretion rise progressively during the latter portion of gestation to the time of foaling. However, we have found the kits to sometimes be unreliable and recommend monitoring of the mare continue. A majority of mares will show a significant rise in calcium and magnesium concentration just prior to parturition.