Some Vet Tips and Observations.

If you're fine with using cheats, I would recommend enabling testingcheats, then Shift-click on the mess the pets have made and chose Destroy Object. Otherwise it's pretty hard to keep up with the cleaning. Something else which helped me receive higher ratings was to put knight's armors in every room, because they boost the environment immensely. They don't really fit into the style of my vet clinic, though, therefore I downsize them and place them inside a counter or somewhere they can't be seen.