The reasons that cause dogs to have white feces are as follows:

1. When there is a parasite infection in the dog's body, it may cause white feces. Common parasites include roundworms, hookworms, tapeworms, etc. These parasites can affect the dog’s digestion and absorption function, causing abnormal color of feces.

2. If the dog's food is nutritionally deficient, especially if it lacks nutrients such as protein and fat, The stool may also be whitish. This is usually related to the dog’s unreasonable diet or poor food quality.