For this reason I use it sparingly, carefully and wash it often. Some people suggest having a person in the picture to show scale, but I do not agree with this. I want the photo to show as much as possible of the animal. You can put weight and height in the information text. An alternative to a completely neutral background shows the place, for example inside a cage.
Some people like to photograph animals behind bars to elicit more sympathy.
There is a place for such photographs, but for this work I want to see the individual. I want someone to adopt him because they fall in love with him, not because they feel sorry for him. There are occasions, like moms and pups inside a shelter on a cold winter day, when they just can t be photographed anywhere else but in the cage. Ideally you can find a couple of places, one in sunlight and one in shade. You might choose to shoot the black dog in the shade and the shiny red dog in the sunlight.