Hier nog wat meer info over calcium:
De eierenschaal was ook al eerder op deze topic
http://www.barfplaats.nl/forum/index.ph ... #msg837392
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En ik had dit antwoord over Calcium citrate van Mary Straus gehad:
"Calcium citrate does not include any phosphorus. It (and other forms of plain calcium) is added to meals to balance out the phosphorus in meat and other foods, most of which have far more phosphorus than calcium.
Bone provides small amounts of some trace minerals in addition to calcium and phosphorus, but those can be supplied from other sources, including various foods and some whole food supplements, such as green blends.
Adult dogs do fine with plain calcium; puppies have a greater need for phosphorus and so ground bone or bone meal is preferred.
Mary Straus"
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Meer op
http://www.dogaware.com/wdjhomemade3.html :
3. Calcium: One of the most common mistakes that people make when feeding a home cooked diet is the failure to add calcium. You must add calcium when you feed a diet that does not include bones.
Adult dogs need around 800 to 1,000 mg of calcium per pound of food fed. They also require the calcium to be supplied in a proper proportion to phosphorus.
The ideal calcium:phosphorus ratio in the canine diet is between 1:1 and 2:1. Meat contains a lot of phosphorus, so the more meat a diet contains, the more calcium will be required to reach the correct calcium:phosphorus ratio. Adding 800 to 1,000 mg of calcium will provide the correct calcium:phosphorus ratio even for a high-meat diet, unless you use a calcium supplement that also contains phosphorus. In that case, moderately higher amounts of calcium may be needed to balance out the additional phosphorus contained in the supplement.
Ground eggshell can be used as a calcium supplement. Rinse eggshells and dry them on a counter overnight, or in the oven, then grind them in a clean coffee grinder. One large eggshell provides one teaspoon of ground eggshell, which contains 2,000 mg of calcium, so add ½ teaspoon ground eggshell per pound of food fed. Don’t use eggshells that haven’t been ground to powder, as they may not be absorbed as well.
You can use other types of calcium supplements (any form of calcium is fine). Calcium from seaweed, such as Animal Essentials’ Natural Calcium, also supplies other minerals (including magnesium, iodine, and selenium) that are beneficial. Bone meal is frequently used as a source of calcium in diets that don't include raw bone. However, bone meal contains calcium and phosphorus. Different brands of bone meal supplements contain different amounts of calcium and phosphorus, but the calcium:phosphorus ratio is always the same: 2:1. To balance a diet that contains lots of phosphorus, then, you will need to give an amount of bone meal that will provide 1,000 to 1,200 mg calcium per pound of food to keep the ideal calcium: phosphorus ratio in the diet correct.
Look for bone meal supplements that are guaranteed to be free of lead and other contaminants. You can also use a purified bone extract called Microcrystalline Hydroxyapatite (MCHA), but most of these supplements also contain vitamin D in high amounts, which would not be appropriate to use (see Supplements section further on in the text).