What's a backdrop? LOL! JK
Seriously though I never thought of doing that.
I'm lucky to get a pic of my cat when she goes whizzing by so I don't worry about backdrops. And my poor old doggie is usually lying down somewhere so I just take her pic on whatever she happens to be lying on.
Yup I have one extreme (kitten) to the other (13 yr old dog).
Are you talking about taking "professional" pics of your animals?