UVB not a necessity???

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nearpass

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I'm a newbie, I know, mostly a lurker and reader on many forums, but I have kept reptiles of quite a variety for almost 30 years. What I have summized, and this is strictly my opinion based on what I've experienced, is that UVB does effect behavior and health in some animals, most especially in the lizards that I've had, and I am quite sure that many of them (lizards) can do much better when it's provided in some form, as they are more difficult for us to 'get' into the sun. But, as has been stated here a few times, it is NOT sunshine and can not replace the sun for tortoises.

My main interest in this whole discussion is what I frequently read in my 'travels,' namely that turtles and tortoises with a variety of problems, from pyramiding to MBD (which in MY opinion) are not one and the same in many cases, to lack of appetite, and on and on in some discussions, can have their problems solved by the addition of UV/UVB. I feel this is very overly simplistic, and neglects many other aspects of their care which may be just as important. There is so much we just don't really know, I'm always concerned when there's "one solution" presented. On that, I guess I do have to agree with EJ.

Sorry if this is a bit disjointed, hope you understand what I'm getting at...I have a cold and my head is in a fog
 

-EJ

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My point was that the studies are species dependent.

Chameleons seem to be very sensitive to the need of UVB. Tortoises in general are obviously not.

Dr. Gehrmanns studies were first geared at the need and second, how effective each product was.

Those studies were also done long before the use of mercury vapor lamps.

I know someone has posted the link for the UK group that has been following the use of UVB in reptiles. I can't think of it off hand but it is probably the best resourse on the topic.

Madkins007 said:
Thanks, Nearpass, but that is one of the few I had already found of his stuff, actually on Melissa Kaplan's site.

For both you and EJ- I know a lot of his work deals with lizards, but the mechanics/physics of UV and the bulbs would be species-independent. That is, this bulb will work this way, no matter what is under it- and that is what I was looking for- how the bulbs actually worked.

EJ- I am not jumping on the 'You NEED TO OFFER UVB' bandwagon, but I did think that the study that shows that a lot of the lights used by those ON that bandwagon don' do much was really, really interesting!

By the way, I found a partial PDF from a Gehrmann article (don't ask me how that happened), but it shows the '% of product converted' by natural sunlight in Boston. Obviously, the numbers would be different closer to the equator, and they vary throughout the day and year, but...

At high noon, it is at about 0.2% in January (already more than the Reptisun 5.0 does) to about 1% in March, and almost 7% in July, then to almost 3% in September.

I'm going to try to make a coherent article out of this and post it soon. Rest assured, its focus will be for those that choose to use UV, not saying you MUST use UV.

 

Madkins007

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www.uvguide.uk.co is a great site, but I so far find no mention of the 295 nanometer/D3 conversion aspect of the issue there. They seem to treat all UVB about the same.

I would ASSUME (which I know is dangerous) that bulbs that produce D3 because of the temperature of the filaments, etc. would produce a more even gradient of wavelength outputs than fluorescent tubes, which are 'engineered' to emit specific wavelengths. I'm trying to figure out if this is true, and if there is a way to find out how much of their output is in the 295 nm zone, which might help us predict how much D3 conversion is going on.

I think it is kind of scary that none of the fluorescents tested converted even a full 1%. Sorta makes you wonder if they are worth it at all if you choose to use them.

For anyone interested, I just found an interesting article (through a link at the aforementioned ukguide.uk.co site) that is more recent (2004)- http://www.testudo.cc/

I have not read it in depth yet, but it looks interesting.
 

-EJ

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The wavelength is a given... the intensity/power of the wavelength...variable.

Bulbs don't produce D3. They provide the body to produce D3 from D2.

It is the gas in the bulb that allows the production of the light wavelength that allows the production of D3.

From what you wrote... how much UVB does a reptile actually need?



Madkins007 said:
www.uvguide.uk.co is a great site, but I so far find no mention of the 295 nanometer/D3 conversion aspect of the issue there. They seem to treat all UVB about the same.

I would ASSUME (which I know is dangerous) that bulbs that produce D3 because of the temperature of the filaments, etc. would produce a more even gradient of wavelength outputs than fluorescent tubes, which are 'engineered' to emit specific wavelengths. I'm trying to figure out if this is true, and if there is a way to find out how much of their output is in the 295 nm zone, which might help us predict how much D3 conversion is going on.

I think it is kind of scary that none of the fluorescents tested converted even a full 1%. Sorta makes you wonder if they are worth it at all if you choose to use them.

For anyone interested, I just found an interesting article (through a link at the aforementioned ukguide.uk.co site) that is more recent (2004)- http://www.testudo.cc/

I have not read it in depth yet, but it looks interesting.

 

Madkins007

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I know the bulb does not produce the D3, I meant that as a shorthand of saying 'the bulbs that produce the needed 295nm range of UVB to produce D3 in the skin'. And from what I can tell, the wavelength is not a given in fluorescents, which are tuned to produce their UVB on the 320nm zone more than the 295nm. After all, the visible range ends about 400nm, UVA is 400-320nm. I can call my bulb a UVB bulb if I design it to emit 319nm- but it will not really help convert proD3 to preD3. To get that conversion, you have to emit at closer to the UVC level (280-100nm).

Sorry- on the more important part of the comment... UVB needs.

As you know, there is not an accepted standard for vitamin D dosage, period, for reptiles, and almost by definition, no clinical standard for UVB needs. We can extrapolate guesses from climatic data, behaviors, diet, and skin structure- but that is just another name for 'guess'.

What I find most ironic about this discovery is that all these people yelling about NEEDING UVB may not be offering anything the reptile can use for D3 production in their bulbs.

My main interest here is to help those who choose to offer UVB select something that works for their animals.
 

fifthdawn

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Just curious, there are obviously cases where tortoises get MBD and those that don't. Lets assume the UVB bulbs really isn't providing more than 1% conversion.

What do you think is the difference between those with MBD and those without? Diet? Being kept outdoors? Or maybe 1% is enough?
 

-ryan-

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The bottom line is that you have to ask yourself a couple basic questions. Would a tortoise deprived of calcium grow quickly and smoothly, without deformity or softness of the shell? Would a tortoise deprived of calcium continue to live a strong and active life after the main growth period? Would a tortoise deprived of calcium reproduce and lay dozens of eggs year after year?

Those are the questions that I ask myself. My russians have done all of those things (and my red foot, to a lesser extent though because I don't breed him and he has only grown 2" since I've had him since he was already 9" when I got him). I don't use UVB producing bulbs with any of those animals. Not even the hatchlings just out of the egg. They grow and grow, and my adults make more babies (now that I figured out how to incubate the eggs effectively). I unfortunately cannot keep them outdoors where I live (but for a few short times in the summer), and I wish I could, but not for the UVB. For the space, free heating, and free food.

I think we all need to make our own decisions about how we would like to care for our animals. I respect that some people wish to buy expensive light bulbs for their animals in hope that it will help them. I personally have spent my time trying to better understand the big three (heat, hydration, and diet) with a lot of success.

Here's a three year old russian, hatched from an egg just over three years ago. She has never had a UVB producing bulb, and she has not yet been outside in the natural sunlight. She does, however, have access to a toasty hot spot, dirt to burrow in, and a pretty basic diet that I feel hits the important points. I did make a lot of mistakes with this one, but I think she turned out just fine :)

 

Madkins007

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Sudhira said:
Now I am really confused.

The problem is that this issue is not black and white and there is a lot we don't know for sure.

There is little proof they need UVB, and lots of evidence that tortoises raised with no intentional UVB seem to do just fine.

That said, there are a lot of benefits to reasonable levels of UVB- ideally from natural, unfiltered sunlight. Besides helping with vitamin D3 production in the skin, it also helps control germ growth, enhance natural colors, and may play a helpful role in many aspects of breeding.

My personal opinion would be to offer access to natural sunlight whenever possible. When it is not, I would suggest that using a decent amount of UVB light would probably help your tortoise, but if you cannot, it does not seem to really hurt it... as long as other elements are in good shape- temps, hydration, diet, etc.
 

DeanS

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I'm only going to say...as long as torts receive 5-7 hours of quality sunlight...that's all they need. Me? I leave them outside from 8-5 (living in the high desert, I can do that). However, at night, EVERYONE (big and small) comes in. I have a Zoo Med Tortoise House for the little ones (with chopped up timothy in the den) and the larger boys go into EXTRA LARGE VariKennels full of timothy with a hole cut in the top to allow for night lamps. BTW, Mortimer and Aladar's crates are in the laundry room where the humidity is a constant 15% and minimum 65 degrees (during winter and early spring) and as high as 80 during the late spring, summer and fall. It's only during the winter and early spring that I use UVB at all.
 

Kristina

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Does anyone have a test meter? I would love to see what the typical "grocery store" brands of MV bulbs produce, compared to a "reptile" MVB.
 

moswen

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sorry guys i didn't read the whole thread, but a vet that i took tula to 2 years ago told me that uv light really isn't necessary in the winter time as long as tula gets sun in the summer. i thought about this and the tortoises that hibernate don't get uv obviously under ground, but those species are obviously designed to not need it... however, tula is a big girl so i'm not sure what she would have said about growing babies.

also, something i just thought of that may sound stupid in a little while if someone disproves my thoughts is that tortoises that don't hibernate live in hot climates, and only come out in the morning and evening so they only get those weakest hours of actual sunlight per day anyways, so they may actually be fine without it...?

but just for the record, i use uv in the winter when they're not outside daily!
 

fifthdawn

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moswen said:
sorry guys i didn't read the whole thread, but a vet that i took tula to 2 years ago told me that uv light really isn't necessary in the winter time as long as tula gets sun in the summer. i thought about this and the tortoises that hibernate don't get uv obviously under ground, but those species are obviously designed to not need it... however, tula is a big girl so i'm not sure what she would have said about growing babies.

also, something i just thought of that may sound stupid in a little while if someone disproves my thoughts is that tortoises that don't hibernate live in hot climates, and only come out in the morning and evening so they only get those weakest hours of actual sunlight per day anyways, so they may actually be fine without it...?

but just for the record, i use uv in the winter when they're not outside daily!

No species are "designed to" not need UVB during certain seasons. When you get down to the molecular level in all biological species, they're almost exactly the same.

First, you need to understand the scientific reasoning for UVB. UVB help create vitamin D3 which is necessary for calcium metabolism. If theres no calcium, theres no need for vitamin d3 (there are other uses but the problem in reptiles concerning vit D has always been calcium related). A tortoise who hibernates over the winter would not be eatting, thus no need for UVB.

As to your second question, tortoises will synthesize enough vitamin D3 in about 1-2 hour of uvb exposure. Majority of basking is not to make vitamin D3, but simply regulate body temperature for digestion. The vitamin D3 pathway stops working once their body gets enough D3. In order words, reptiles will always make EXACTLY enough D3 and the D3 pathway will stop.
 
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