A couple of times a week, we sprinkle some calcium powder on our RF's food. Is this a good thing or a bad thing? If its good, how often should we do it?
GBtortoises said:Calcium is definitely an important mineral for tortoises, especially developing young and egg laying females. Many green foods contain calcium naturally. In captivity most people do supplement their tortoises diet with calcium carbonate either in powder form, cuttlebone or both. I prefer to make it available to my tortoises at all times seperately in a shallow dish rather than coating their food with it. By offering it seperately they can control the amount and frequency that they need it rather than it being force fed to them. I have seen my tortoises of all ages and several different species consume the calcium on their own at very different intervals and amounts.
Madkins007 said:Remember- animals CANNOT metabolize calcium without adequate doses of vitamin D to 'unlock' the cells so you need to make sure you are offering the right amounts of that as well. There is a guideline for dosages, etc. at http://www.tortoiselibrary.nutguide.com that shows you the min. and max. dosages based on the animal's weight.
Excess calcium will be secreted in the feces, etc. as long as the animal is properly hydrated, but can cause problems otherwise. There is not much reason to offer more calcium than they can use.
The best calcium is very fine particles, such as those found in foods. The larger the particle, the harder it is to absorb. Fine calcium citrate dust is probably the best option, but it contains a lower percentage of calcium per dose than the more common calcium carbonate. A decent 'pinch' of calcium powder is about a week's dosage for a small tortoise.
You can test your calcium options for bio-availability by dissolving a little in some vinegar. The more completely it dissolves, the better. A lot of commonly recommended tortoise calcium options do not dissolve completely. That does not mean they are bad, just not offering as much dosing as we might want. Cuttlebone, for example, does not dissolve well. It is offering a nice amount of useful grit and crunch, but not as much calcium as some people think.
As for the vitamin D- if the torts are outside in sunlight strong enough to cause you to tan, and that does not pass through most kinds of glass or plastics, for about an hour a week over several sessions, then no additional vitamin D is needed.
If you are using a vitamin d supplement, like in most calcium powders or vitamins, or UVB bulbs, you probably want to provide supplemental D at the low dosage levels. If the tortoise gets no regular UVB or vitamin D in the diet, you probably want to aim for the middle to upper range of UVB.
Our goal is to offer a BALANCED amount of the key nutrients. While there is usually a wide 'safe zone', there are problems with too much or too little of most vitamins, minerals, and other nutrients.