The amount of calcium is not or should not be given based on the weight of the dog or cat. Instead, the calcium must counter balance the phosphorus entering the body.
Therefore, the amount of calcium you give must be enough to counter balance the phosphorus in the meat you are feeding.
A lack of calcium will lead to health problems like kidney stones and even renal failure ? but it's not just a lack of calcium, one must also consider the ability or should I say, the inability for the body to absorb the calcium it is getting ? commercial pet foods and cooked meat diets cause to produce less acid in the stomach which ultimately causes calcium absorption problem. Only a raw meat diet produces enough acid in the stomach to allow the body to properly assimilate and utilize the calcium in the food being fed.
So the calcium given should help the body have almost twice as much calcium as phosphorus. Some will say that dogs and cats only need a 1:1 ratio of calcium to phosphorus. Others will give different ratios but people like Dr. Pitcairn, DVM and others say 2:1 ? that is, 2 parts calcium for 1 part phosphorus. Personally, I go with the 2:1 ratio. It's arguably better to have more calcium than to have too little calcium. Since calcium is needed in such high amounts, it is far easier to give too little than too much ? and too little calcium is something we definitely want to avoid.
Dogs and cats need essentially the same amounts of calcium. People can argue or debate over the exact amounts, but the reality is that you will never obtain a perfect 100% balance because we don't know exactly how much phosphorus there in the food we are feeding. We can only guess based on average nutritional values of the meats we are feeding.
Based on the average phosphorus content of meat, adding 1 teaspoon (2.5 mL) of ground egg shells helps to provide the body with enough calcium to create the ideal 2:1 ratio of calcium to phosphorus.
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