Hi there!

Couple of weight / hibernation questions for you:

1. When should the weight be taken to decide if a tortoise is heavy enough to hibernate - before wind down or after it?  I've looked all over for an answer to this and not found one (maybe because we shouldn't wind down unless the weight is alright in which case it must be the pre-wind down weight??).  Obviously the tort looses quite a bit during wind down.

2. What do we do if the weight of the tortoise falls during hibernation such that the weight is now below the line?  Or using the calculation method rather than the graph, anything below 0.17?  Should such a tortoise be woken up, or if the weight loss has stopped, can hibernation continue for a few more weeks?

I measured the weight pre wind down and on that basis hibernated a tortoise whose weight is now below that considered suitable for hibernation, but she's been in the fridge for about 6 weeks.  She's still alive right now and I am planning on keeping going with this hibernation for another few weeks.

Thanks for your help. Jonathan

Hi Jonathan

This is an interesting question, I can tell you my views, other people may come in with their comments too.  I have always regarded the JR as a guide to be used prior to wind-down, as you say, we shouldnt wind them down for hibernation unless they are heavy enough in the first place.  Once I have started winddown, I dont refer to the graph again.  I check to make sure weight loss doesnt seem to have been excessive in the wind-down, then I use the weight they are when they go into the fridge as the starting hibernation weight, and work from there, looking at the percentage weight loss during actual hibernation.  So has your tortoise lost a lot of weight since going into the fridge?  If not, and if you were happy with her otherwise, I would do the same as you and continue with the hibernation.

One other thing that I do is keep records of weights year on year, so I can always refer to the previous years 'hibernation weight' and see how they compare.

I hope this helps,

best regards

Arlene

I do exactly the same with my Hermanns weights Arlene.  Obviously I can't use the JR with my Russians but I go on the pre windown weight just the same.

Helen

Thank you both for your comments.  I've been in a bit of a panic.  Someone I know lost a tortoise a couple of days ago in hibernation and has been trying to understand what hapenned.  In the process of that we've both found that none of the guides on the internet tell us when the weight should be taken.

Being a 'forum tart' I've been asking around and have received a number of answers.  Someone with huge experience and whose opinion I value highly felt that if a tortoise reaches a weight during hibernation that would be regarded as unsafe  to hibernate (if we were taking the weight before hibernation) then this tortoise should be got up.  I've now done that with one of mine though she lost most of the weight before she went down.  She has completed 7 weeks hibernation and I've just taken her out the fridge.

I have another one still in the fridge whose weight is at 0.1845 on the ratio which is halfway between normal and too light. I'm not sure what to do with that one.

These decisions are so difficult and I know its me that has to make them in the end.   

Hi Jonathan,

Times like these are truly terrible! I think that you've summed it all up in your last sentence -- the Jackson Ratio is just meant to be a guideline, and not a precise prescription, and you need to go with your gut instincts. But it is interesting that this has thrown up something that we've all seemed to ignore -- which is that there don't seem to be definite guidelines on how much weight a tortoise can safely lose during wind down. We all know about it being safe to lose up to 10% during hibernation itself, but no one that I can see addresses wind down.

I've been corresponding with your friend,and asking colleagues for advice, and Helen sent me the following quote from Stuart McArthur's book (it doesn't exactly address the problem, but it does imply that losing up to 5% a week for four weeks in hibernation is not desirable):
"Most hibernating species are best starved for a period of 3 - 4 weeks before entering hibernation, which in the UK, often commences at about the third week in October. However, by keeping animals at normal room temperature with normal activity during hibernation preparation where food is withheld, may result in animals losing up to 5% of their body weight per week (he quotes a personal communication with Meyer). Therefore, during this time temperature has to be gradually decreased. At the same time the animals should be bathed regularly in order to maximise hydration".

It's not much, but it's all I can find.

Nina

Thank you Nina, thats very helpful.  Andy H has commented that the temperature during wind down should be enough to encourage digestion and that has to be for a given number of days.  For some reason I cannot find the article that has the details. 

The tort I just got up lost 10% of her weight during wind down, and although she lost only a small amount after she went into the fridge, the combination of the two losses took her from being an ideal weight to being too light to hibernate. Especially with small ones there is very little space between safe and too light, and if I made a mistake of 2mm in the SLC measure it has a drastic effect on the numbers.

Frankly I'm totally stressed!  I'm going to leave my other juvenile in the fridge in case anything I do right now is a panic reaction.  Maybe tomorrow I'll be rational.

The fact my THH are all smaller and lighter than THB for their age just compounds the problems.  I've got a 4.5 year old tortoise that is 58mm and 36g.  Other people have hatchling Hermanns that are bigger than this!  Jonathan

I noticed that you posted about what a difference  a couple of mm error in an SCL can make to potential calculations of critical hibernation weight. I have found measuring SCL's of my little Horsfields a nightmare. They seem to grow and shrink depending on how much trouble I've had in measuring them. I am so worried about hibernation that I have resorted to using a pair of Verniers's calipers to measure the SCL's of my two to try to ensure the most accurate length. It has stopped me from fretting as much but then saying that my two don't go into the fridge until Friday.

Rachel

Hi Rachel,

What calculation are you using to determine hibernation weight with your horsfield? The McIntyre ratio is only a rough guide of average weights, based on a rather small sampling, and I'm sure you know that the Jackson Ratio can't be used for horsfields. The reason I'm asking is that if you have a formula, I'd love to have it, as it is always so frustrating with the various species that can't use the JR as a guide.

Nina

Hi, maybe I should look into the Vernier's calipers as I do worry my measuring isn't accurate enough.

The tort I got up yesterday seems to be doing well, loving some heat and has eaten twice.  She also had a very very long drink of water when in the bath - this tortoise rarely drinks and I think she must have been very thirsty indeed. Needless to say, I'm keeping a close eye on her!

Pleased to hear all is well.

Helen

Hi all,

It's me that lost the Hermann's in hibernation at the weekend and I just wanted to say a massive thanky ou to Nina and Ali for all their support and advice.

Thanks Dave, you are more than welcome and please dont forget you have my number so just call if you have any questions.

Ali (TPG)

Hi Dave, you should drop by here the odd time!  Nice bunch of torty types.

Hi Dave

Nina and Ali have kept us all at the TPG up to date with everything that you've been through too so a big thank you to them from the other TPG mods. 

Also just to let you know that I feel so much for you.  I also lost a little tortoise last week too (a leopard tortoise and not due to hibernation), but it is such a terrible feeling reflecting on what you might have done to give a different outcome; so I know exactly what you've been going through.

To be honest all we can do is do our best and more often than not we can't prevent the outcome despite our best efforts.  The experience you've been through and how you've been searching for an answer just goes to show to me what a caring owner you are. 

Warmest wishes 

Helen

Hi Nina

I know that a MacIntyre graph is only a guide but it does give me some idea of whether my little ones are in the right ball park or not and that makes me fret less which is a good thing.

I found a MacIntyre ratio for juveniles I will email it to you but I would imagine you already have it.

Rachel

Hi Rachel,

I know the McIntyre Ratio well, and it's a good guide, but it is based on a fairly small sample of tortoises (members of various forums sent in measurements of their tortoises), so you can't use it as gospel (but as you said, it gives you a ball park figure). There is another figure that was developed by Joe Heinen from the Russian Tortoise Group in the States: the length is measured in cm and the weight in gms, and the formula is height x width x length x .57 = the weight in grams. But I find it difficult to measure height, as I'm never sure if this is with the plastron touching the ground or not.

Nina

Hi Nina

Thankyou for the formula, it's a shame you don't know wether height is from the ground or not. I suppose it would make such a great difference as to be inaccurate if you measured height in the wrong way.

Rachel

Hi Rachel,

I've been meaning to do this for ages, and you've just prompted me {g} -- so I'll email Joe and find out about the height measurement. It does worry me though, as I have a tortoise with some pyramiding (she came to me that way), so her height might be falsely 'high' because of the 'bumps'. I'll ask him about that too.

Cheers,
Nina

Hi,

I have the full lab report on my tortoise. As promised here is the detail. (Apologies if it's a bit long and comlex). Any comment would be appreciated , my own view is that the hibernation process was not the cause but may have accelerated an existing clinical condition.

Dave.

Clinical Comments

Diagnosis – Hepatic Abscessation

Histopathology Report

Post Mortem tissues from a Hermann’s Tortoise, Testudo Hermanni Boettgeri

5 Samples received,   5 sections evaluated

Heart – No lesions are visible

Lung with attached skeletal muscle – No lesions are visible in the lung. The attached muscle shows wide separation and apparent compression of myocytes by clear space (possibly fixation artefact but probably oedema).

Oesophagus and Stomach - There are no significant findings in the oesophagus. The gastric lamina propria shows a light scattering of granulocytes.

Liver with Gall Bladder -  Multifocally and randomly, the hepatic parenchyma is replaced by zones of necrosis enclosed by epitelioid and multinucleate histiocytes and heterophils and a narrow rim of fibrosis (heterophilic  granulomas, “abscesses” ). There is moderate generalized congestion. The gall bladder is mildly dilated but within normal limits.

Kidney, Ovary and Oviduct – Renal parenchymal elements are mildly separated by clear space (artefact or oedema). Renal tubular epithelial cells frequently contain droplets of proteinaceous material (interpreted as within normal limits). The ovary shows moderate numbers of small follicles. The oviduct appears normal.

Morphological Diagnosis:

1.        Liver – Multifocal, random heterophilic granulomas (“abscesses”)

2.        Stomach – Minimal granulocytic gastritis

3.        Skeletal muscle and kidney – Equivocal oedema

4.        Ovary – Normal inactive ovary

5.        Heart, Lung and Oesophagus – No significant findings

Comment:

This female Hermann’s tortoise died with multiple hepatic heterophilic  granulomas (“Abscesses”). Tortoises form granulomas in response to a wide variety of insults. In this case, the random distribution of the lesions is suggestive of a haematogenous infection, which is likely to have contributed to illness and death.

The initial sections, no causative agent is visible. I have ordered several special stains to search more thoroughly for conventional bacteria, acid-fast bacteria and fungi, and will issue a final report as soon as these stains have been received.

The remaining lesions are of uncertain importance. The gastric inflammation is very mild and could represent a response to parasites, foreign bodies or other antigens. It is unlikely to have much clinical impact.

There is uncertain oedema in the muscle and kidney. A cause is not visible. One possibility would be underlying hypoproteinaemia of any cause. Systemic infection with altered vascular permeability could also be considered. The hepatic lesions do not appear widespread enough to have caused liver failure, so these are an unlikely cause. Finally it is difficult to distinguish mild oedema from artefact; if no oedema was recognised at gross post mortem examination, then this finding should be interpreted cautiously.  

Hi Dave,

Thanks so much for posting that. It is very interesting (even if I am struggling to make sense of it). Am I right in interpreting the vet as saying that your tortoise probably died an underlying liver infection which resulted in multiple abscesses in the liver? And that there was also some swelling due to excess fluid (oedema) in the muscle and kidney, which could have been caused by hyproteinaemia (which I found defined as: A condition in which total serum protein level is below the normal range. Hypoproteinemia can be caused by protein malabsorption in the gastrointestinal tract)? But that this low protein level was probably not the sole cause of death?

It certainly looks as if you did nothing wrong, either in your wind down or in the hibernation, that could have caused the death of Dozer, and although that won't diminish the sadness I know you feel, it must be a relief to know that you had no part in causing his death.

Nina

Hi Nina,

The cause of death was stated as Hepatic Abscessation (as you say liver abscesses) and that the lesions are suggestive of a haematogenous infection (which was interpreted by my vet as septicaemia, blood poisoning). So the abscesses caused blood poisoning.  The cause of the abscesses remain unknown, further tests are being taken to try and "grow" the cause bacterium, fungi etc.

The Oedema (fluid retention of the organs and muscle tissue) was also inconclusive as a contributory factor. As per the comments, no Oedema was found (or perhaps mentioned) in the initial post mortem.

So I do feel a little better, the wind down process may have accelerated an existing disease but the tortoise was in fine visible condition and weight prior to the hibernation wind down. It would seem this process left the tortoise open to an accelerated advancement of the ailment.

Hi Dave

That is interesting and hopefully there might be a suggestion of what caused the septicaemia. 

Fingers crossed that something will be evident in the histological samples.

Helen

Thanks Helen,

There is a possibility of the septicemia being a result of the failure of the liver, one of the main roles of the liver being detoxfication. The liver fails to function, the system becomes toxic. So either the liver failed to combat the poisoning or the abcesses contributed to it.

However, there is a comment in the report that says:

"The hepatic lesions do not appear widespread enough to have caused liver failure, so these are an unlikely cause."

"The hepatic lesions do not appear widespread enough to have caused liver failure, so these are an unlikely cause."

I'm thinking that the absesses contributed to what was already going on with this poor tortoise.  Fatty atrophy of the liver can be due to a number of causes (I think I read fat deposits were found?).

How are you feeling in yourself now you have this report hopefully a bit better? 

Helen

I feel a bit better knowing that there appears to have been an existing illness. Still beating myself up that I confused what I took to be normal "wind down" weight loss and behaviour with what it's now apparant was a real health issue. Big lesson learned is to go with my insincts rather than charts and guides.  Still hasn't put me off hibernating my tortoises though. :)

Thanks again for everyones help and support, if any more information is forthcoming I'll be sure to let you know.

Well you are right in that a guide is not instructions set in tablets of stone.  A guide is just that, a set of guidleines to help point you in the right direction.  Nothing can beat gut instinct and you are right in that sometimes it is better to follow that.  It usually works well for me where reanimals are concerned but not too good for other things.  For example, I keep having a gut feeling that I am about to win the lottery but so far that one has failed

Helen