Mares Every mare producing foals for the WSI must be inspected by our Mare Inspection Committee. If the mare meets our criteria for approval she becomes an Approved Mare and is entered into the Approved Book. When the Approved Mare produces her first foal for the WSI she is assigned a unique damline number. Every descendant of the mare, both male and female, is classified under this damline number; the damline number appears in the passport of each descendant. If the mare does not meet the criteria for approval the inspectors will explain the reasons why to the mare owner.