How to Make Your Own Ground Eggshell Calcium Supplement for Dogs and Cats

Most of the body's calcium is found in bones. It forms a base for your pets' bone structure, and works with phosphorous, boron, vitamin D and other nutrients to support muscle and nerve function, balance hormone levels and keep blood healthy. Eggshells pack a calcium punch, as they are about 94 to 97 percent calcium. This calcium is highly absorbable due to its natural form, and because other trace minerals present within the shell increase absorption.

Calcium requirements are based on body weight. Per kilogram of body weight, adult dogs need about 120 mg, and pups 320. Cats need about 128 mg per kilogram, and kittens 400. To find your pet's weight in kilograms, divide his weight in pounds by 2.2. For example, a 10-pound dog weighs 4.5 kilograms and he'd need 540 mg of calcium daily (120 mg per kilogram x 4.5 kilograms = 540 mg). Your pet's needs may vary, so run your estimate past your vet.

One average-size eggshell has 750 to 800 mg of calcium, along with trace elements like boron, copper, iron, magnesium, manganese, zinc and more. Eggshells have a total of 27 trace elements and a composition similar to bones and teeth. They're porous, so they are vulnerable to contaminants, chemicals and bacteria in their environment. Therefore, buy organic when possible. Cooking eggshells will help destroy bacteria, but it won't remove chemicals.

Remove egg from shell. Keep the thin membrane, as it contains nutrients. Drop shells in boiling water for a minute or two to kill bacteria. Dry, then place in a coffee grinder. Grinding protects your pet's mouth, as shells are sharp otherwise. If you don't have a grinder, place them in a plastic bag and roll them with a rolling pin until well crushed. Last resort is to use your hands to crush them. When they no longer hurt your hand, they're probably safe for your pet's mouth.