The date is a number already. Just format A1 as General and you'll see the date serial number.
What do you want to achieve? If you need the date number without the year:
=A1-DATE(YEAR(A1),1,1)+1, Format as General or number (Excel will format it automatically as date, which is not what you need)
If you just want to show the date without a year, format it Custom as mm dd or something similar
Microsoft MVP - Excel