:I have always learned and been told that a heifer is a female cow that has not given birth.  A lot of people will refer to a cow that has had only one calf as a first-calf heifer.  However, this is an oxymoron but is generally considered acceptable language since no terminology exists to define a cow that has had only one calf.  I have never heard the term second-calf heifer used;  after their second calf they are referred to as cows only.