rowsep

row separators (horizontal ruling). Specifies the presence or absence of row separator rules. Provides the default value for all descendant elements. 
If rowsep is non-zero, display the internal row rules below each entry; if zero, do not display the rules. Ignored for the last row of the table (i.e., the last row of the last tgroup in this table), where the frame value applies. 
Default: IMPLIED (implies value from stylesheet if available, otherwise inherited value (inheritance path = table, tgroup, colspec, row, entry), if not, implies "1").