You can register a sow/gilt through the following path: 

Management> Breeding Herd> Data entry>  Females> Purchase  > Add

There are three categories of female purchase:

  1. Gilts

Click on the "Add Gilt Purchase" icon And the following screen will open

Click on this icon for an open sow, and this icon  for a pregnant sow purchase.

After filling all data, just click on "save and close (if there is no other entry to add) or save and continue (to add another entry).