Hello,

Sorry to come in late.

The short answer is we don't really know what levels are appropriate even in general for amphibians, never mind for a specific species under specific husbandry conditions. There is certainly mounting evidence that many amphibs (and reptiles at least, if not also birds) are not nearly as healthy in captivity as we like to think, and specifically that bone density is generally very poor (even in clinical healthy animals) compared to wild individuals. It is worth bearing in mind also that vitamin D deficiency also intimately affects the immune system.

Until we get many more studies done (and many more post-mortem exams of captive amphibs) we are unlikely to get a definitive scientific answer (although some work is being done), so it all relies largely on anecdotal evidence. Ideally, of course, you can get your frogs assessed (via radiographs and/or other diagnostics) at regular intervals to check bone density and blood mineral levels - ok, I know I'm really into fantasy land here....

Lynn makes many good points (and sounds very organised!) - they are certainly good general principles. In practice overdose is probably unlikely but you need to look at the whole picture (set-up, particularly with regards to provision of uv-B (how much is available, how much the animals actually get exposed to), diet etc) to assess "reasonable" levels. Dusting feeder rodents, for example, is completely different thing from dusting crickets - and even within the examples, rodent levels of nutrients can vary with age, whether starved before euthanasia, strain of rodent etc, whilst crickets will vary with the diet they're fed, what stage they are, whether just moulted...and you're presumably using some sort of multivitamin, so D3 levels may not be the only levels you have to consider.......you get some idea of the complexity...

Of course, the facetious answer to your question is yes, too much of anything is harmful .

Probably not much help I'm afraid, but (as with so much herp husbandry) we really don't have anything like good scientific evidence. The ideal is probably discussing your particular husbandry etc with an experienced vet/herpetologist, but otherwise all I can say is go with a moderate-sounding regime combined from several trusted sources. But try to make sure they apply to conditions as similar as possible to yours.

Bruce.