12% UVB = no calcium with D3?

[Goose502]

Honestly, who knows exactly what the fluorescent fixtures are actually putting out? We know specific levels of UVB/UVI and maybe UVC. The sun is true “full spectrum” lighting. A man-made glass tube full of different gasses and electricity will never replicate our sun. I can’t recommend natural sun enough whenever possible. As for indoor lighting, I feel like we are still guessing. I’ve personally used 6% t5 HO bulbs from Arcadia for years, and have never run into any problems, but I also provide natural sun as often as possible living in NorCal.

 

[DeremensisBlue]

We run into problems when we try and simplify something as complex as UVB needs into a simple “get this bulb or get that bulb”. What is important is that UV Index that is measured at the chameleon’s basking perch. This varies greatly with how far the perch is from the bulb, what angle the perch is from the bulb, whether the bulb is in a single bulb reflector or a quad bulb reflector, and what kind of screen it goes through. And then we get married to our favorite piece of advice and it somehow morphs from “this has worked” to “this is the only thing that will work”. The fact is that veiled chameleons have been raised on T8 5.0s all the way up to T5 12% with varying levels of Vitamin D3 supplemented. To my knowledge no one has actually tested how much D3 is too much. There has just been some anecdotal armchair veterinary work done over pictures on the internet to put together an idea.


Here is an experiment I did and you can draw whatever conclusions you would like from it. I raised up two brothers and two sisters (brothers and sisters unrelated to each other). One pair has a UVI of 3 (roughly equivalent to T5 6% levels) and one pair UVI of 6 (roughly equivalent to T5 12% levels). Neither pair were exposed to any other source of UVB and there was no D3 supplemented between 1.5 months of age and 8 months of age – their major growth period. I ended the study when the females mated and laid a fully calcified clutch of eggs. There was no difference in growth rate or end size. All members of the study showed no signs of MBD and were healthy.

What this tells me is that they can get all their D3 from the lighting technology we have available to us. This does not mean that I wouldn’t “top off” their D3 with occasional supplements in standard husbandry advice, but it does mean that the real life requirements are a bit looser than our black and white advice. I think the 12% in a quad fixture going through screen to a perch six to nine inches below the bulb combined with a substantial heat lamp is a good template. And it is important to include heat in the equation because they naturally are limiting their basking by heat. UVI 6 without heat is not natural. Making a chameleon huddle to the top of the screen to absorb warmth from a T5 bulb is asking for some of that UVB related trouble.

I also have a friend who uses Repashy Calcium plus with T8 5.0 bulbs for panther chameleons. He changed to T5s as an experiment and continued with Repashy Calcium plus which has been accused of causing MBD from over supplementing Vitamin D3. And there was no issues even with the increased UVB exposure. Once again, this is not to say vitamin D3 overdose is not an issue. It is just to say that the fear level may be exaggerated. It really takes more people willing to do controlled studies and share results.


So, more work definitely needs to be done. Take these data tidbits for what they are worth.