What kind of ammo fits the cz 75 bd 9mm ?

9x19
9mm Luger
9mm Parabellum
 
Any of those will work.

I use .44 mag. in mine and it works great. If it is a squirrel or rabbit I use something
smaller like a .22 mag.

The name kinda gives it away ... 9MM.

If you have to ask, you need to attend a class. Every firearm has the caliber stamped or roll marked on the barrel. Simply buy ammo that matches the roll mark on the barrel, i.e. 9mm, .45ACP, .357 Magnum. Its not hard. Every box of ammo has the caliber clearly printed on the end flap of the box.

Rather than beat you up for your question, I'd rather answer it,  and insist you take a basic firearms class. You should know your firearm inside and out.

9mm Luger/9x19mm Parabellum - the same thing just a different name depending on country it is made in or whether military vs sporting designation.  Been around for almost 120 years and still probably the most popular handgun cartridge  in the world.
https://en.wikipedia.org/wiki/9%C3%9719mm_Parabellum

9.3x 74R or 9.3x62

.44 mags shoot awesome out of those cz 75 bd 9mms 

I would go with 9mm Luger.

It takes normal 9x19 mm Luger Parabellum ammo, not 9x17, 9x18, 9x21, or 9x23.

9mm luger, 9mm ball ammo or 9mm hallow point.