Nulliparous
A nulliparous, or gilt, is the sow that has never farrowed. The sows are nulliparous from the moment in which they enter the farm until the moment of their first farrowing. On many occasions we use the term "primiparous sow" to define the sows that are in this period of their lives. Nevertheless, it is more accurate to say that the sows are primiparous after their first farrowing and until their second farrowing.