Querying for user's whose birthday is today plus other OR conditions
If you want to filter in your efq, you'll have to compare strings: 

   $today = new DateTime();
   $today = $today-&gt;format('Y-m-d\T00:00:00');


Then add in your query the condition

'field_date_of_birth_value', $today, '='


I can't tell more unless you show us your code.