How to display a date without hour, minutes, and seconds?
Steps to achieve your requirement:


Goto /admin/config/regional/date-time/formats/add link, and add Format string as explained in the PHP manual.


Now add Date type and select the format you created.


Finally, go to content type Manage Display settings and add your newly created date format.
At URL /admin/structure/types/manage/page/auto_label, add token of the DOB field with the format you created by Browsing Available Tokens.