Instructions
Consider animal flesh; it's one of the best sources of phosphorus for your cat. If your vet instructs you to add phosphorus to your cat's diet, try chicken, which contains approximately 46 mg phosphorus per ounce or ground beef, which contains approximately 40 mg per ounce.
Be prepared to add some calcium along with the chicken or beef if your vet recommends it. The calcium to phosphorus ratio for a healthy cat with high functioning kidneys is approximately 1.5:1, but be sure to listen to your vet's recommendation to accommodate your cat's individual needs.
If you don't have a powerful enough grinder to grind up actual bone, you can use bone meal. Several brands of bone meal are available, but you'll need to read the nutrient content and be sure to supplement your cat's diet accordingly.
Try ground eggshells for calcium. Once you know the required calcium levels for your cat, you can add eggshells to balance the recommended phosphorus. A small amount of ground eggshells goes a long way--1/4 tsp. provides 400 mg of elemental calcium.
Do your homework and be prepared to do a lot of measuring. If researched and done correctly, creating a balance of nutrients, vitamins and minerals by feeding your cat a homemade diet is a wise choice, but not one to be taken lightly.
How do I Add Phosphorus to a Cat Diet?
Phosphorus is essential to a cat's physical development, particularly to bone and teeth strength as well as cellular integrity, primarily because of its interaction with calcium absorption. The ratio of calcium and phosphorus necessary for your individual cat's needs varies according to health and age, so it's important to have your cat examined by a veterinarian to determine the required calcium to phosphorus ratio for optimum health.