Healthy amount of UVB?

[T Smart]

Obviously heating, humidity, diet, husbandry, and UVB are all are essential, but I'm curious how much UVB tortoises really need? Does time spent outside cover for time spent inside?

I have no problems providing UVB. I provide rays every day, either inside with a "Repti Sun UVB Tube", or outside weather permitting. I've seen this topic pop up time to time, especially with tortoises being housed outdoors for most of the year. I realize that UVB isn't harmful, but is there a point were providing it is pointless.

 

[Tom]

Its a good question. No one knows the answer. What we have is anecdotal information gleaned from individual keepers over many years. 100 different people do it 100 different ways, and all are successful. This leads me to believe that minimal amounts of UV exposure will "get the job done". More UV exposure for longer durations doesn't seem to do any harm, within reason.

In my experience, an hour or two of access to direct sunshine a week will result in the complete prevention of MBD indefinitely. They only time I've ever seen MBD in a tortoise is when they are kept exclusively indoors with no UV source and fed poorly for a year or more. I don't use any UV in most of my indoor enclosures, but my tortoises go outside several times a week all year long.

I'm also reminded of one of our former moderators, Kristina, who lived in Cadillac Michigan. Her tortoises enjoyed sunshine all summer long in outdoor enclosures, but they spent all winter indoors with no UV source what so ever, and they all did well. You can imagine how long the winters in MI must be. This demonstrated that tortoises of a variety of sizes, ages and species, did quite well with no UV for 7-8 months of every year, as long as they were able to get good UV the rest of the year.

Another factor is that indoor UV bulbs make nice, balanced, bright light, and there are psychological benefits in addition to any UV benefits they offer. When housing a tortoise indoors, it still needs to look like it is daytime, and UV lights help to accomplish this. Forrest tortoises that might live under a dense canopy excepted of course.

 

[Sterant]

One suggestion would be to follow the Ferguson Zone method. That's what I do and I've never had any issues. You will need a UVB meter, like a Solarmeter 6.5. Then set your lamps to the reading suggested by the Ferguson Zone chart. As for the daily exposure (how long the lights are on), I leave mine on 12 hours a day.

 

[T Smart]

Obviously heating, humidity, diet, husbandry, and UVB are all are essential, but I'm curious how much UVB tortoises really need? Does time spent outside cover for time spent inside?

I have no problems providing UVB. I provide rays every day, either inside with a "Repti Sun UVB Tube", or outside weather permitting. I've seen this topic pop up time to time, especially with tortoises being housed outdoors for most of the year. I realize that UVB isn't harmful, but is there a point were providing it is pointless.

Wow, I really botched that first post.

Revision:

I've seen this topic come up in multiple threads over the years, but the opinions seemed mixed.

I understand heating, humidity, diet, husbandry, and UVB are all are essential, but I'm curious how much UVB tortoises really need? Does time outside compensate for time inside? If so, how much time would this be?

My little guy is provided rays both inside with a "Repti Sun UVB Tube", or outside weather permitting, so he's not lacking. I'm just curious if there a point were it becomes futile?

 

[Tom]

I'm just curious if there a point were it becomes futile?

I don't believe so. If you live in a warmer climate and your tortoise gets UV all year long from the sun, we could argue that indoor UV is not "necessary". But I don't think anyone would argue that the correct levels of UV from an indoor bulb is either futile or detrimental in any way. In Chicago, I think most experienced tortoise keepers would argue that indoor UV would be both beneficial and necessary.

 

[Sterant]

I don't believe so. If you live in a warmer climate and your tortoise gets UV all year long from the sun, we could argue that indoor UV is not "necessary". But I don't think anyone would argue that the correct levels of UV from an indoor bulb is either futile or detrimental in any way. In Chicago, I think most experienced tortoise keepers would argue that indoor UV would be both beneficial and necessary.

Not to mention that plenty of keepers live in areas where their tortoises are outside year-round. They are getting exposed to a lot of UVB, with what I would say are fantastic results.

 

[wellington]

Not to mention that plenty of keepers live in areas where their tortoises are outside year-round. They are getting exposed to a lot of UVB, with what I would say are fantastic results.

A lot of those results are only if they are raising the tort humid. I have seen lots of torts both from very dry, yet sunny AZ, to very humid and sunny Florida and they don't look any better then torts raised in CA or IL.

 

[Sterant]

A lot of those results are only if they are raising the tort humid. I have seen lots of torts both from very dry, yet sunny AZ, to very humid and sunny Florida and they don't look any better then torts raised in CA or IL.

Agree totally. i should not have phrased that last post the way I did. That's what I get for posting while I'm at work ;-) What I should have said is that animals living outdoors exclusively are exposed to a lot of UVB with no negative effects.

 

[wellington]

Agree totally. i should not have phrased that last post the way I did. That's what I get for posting while I'm at work ;-) What I should have said is that animals living outdoors exclusively are exposed to a lot of UVB with no negative effects.

Lol, it's fine. Just like it to be clear that not all in the warmer states do better then us in the colder states, just because of location.

 

[Brian Perry]

Obviously heating, humidity, diet, husbandry, and UVB are all are essential, but I'm curious how much UVB tortoises really need? Does time spent outside cover for time spent inside?

I have no problems providing UVB. I provide rays every day, either inside with a "Repti Sun UVB Tube", or outside weather permitting. I've seen this topic pop up time to time, especially with tortoises being housed outdoors for most of the year. I realize that UVB isn't harmful, but is there a point were providing it is pointless.

Proving UVB is essentially “pointless” if you are providing dietary calcium + D3.

 

[Tom]

Proving UVB is essentially “pointless” if you are providing dietary calcium + D3.

Have you tested this theory over many years with many species? Please share what you've learned.

 

[Brian Perry]

Have you tested this theory over many years with many species? Please share what you've learned.

Hey, Tom. There is an abundance of literature on line which makes it quite clear that the sole function of UVB is to produce D3. You know that D3 is required for calcium absorption...right? It seems pointless to consider performing research, that I am ill-equipped to conduct, when others have already done it. Approx. five years ago, I met with a herp veterinarian and we discussed this topic extensively. Sometimes, you can find a herp class at a local community college.

 

[Yvonne G]

I'm not sure, but @Will may talk a little about UVB, diet, etc. at the conference in Arizona. I know that Will depends upon the Vitamin D in the foods he feeds his tortoises. Not sure if he uses UVB lights or not. I don't want to put words in his mouth, so I hope he sees the alert and comes here to respond.

 

[Tom]

Hey, Tom. There is an abundance of literature on line which makes it quite clear that the sole function of UVB is to produce D3. You know that D3 is required for calcium absorption...right? It seems pointless to consider performing research, that I am ill-equipped to conduct, when others have already done it. Approx. five years ago, I met with a herp veterinarian and we discussed this topic extensively. Sometimes, you can find a herp class at a local community college.

That's the thing Brian. I don't think others have done this research. Assumptions are made and conclusions are jumped to, but I've yet to come across anyone who keeps a tortoise solely indoors, with no UV, and relies only on D3 dietary supplements. Have you? What exactly did you discuss with this her vet? I have discussions with herp vets several times a month and none of the ones I know have any definitive info on this subject.

@Will has just about got me convinced that tortoise can utilize dietary D3 based on some research he has shown me, but still, to this day, no one has done a study that clearly demonstrates this. I want to see a study with some simple before and after blood draws to check D3 levels over time.