Impaction

[HadesDragons]

Originally Posted by PaleRider

HadesDragons:- Many thanks for your reply. I think that I would tend to agree that walnut shells are only suitable for chucking in the bin.

Do you have any personal connection to the case that you raised as an example? I ask because I have seen similar photographs illustrating the secondary effects of various cancers of the lower intestine/bowel where the impaction would not normally have occurred (from unseen mutations arising from the selective breeding of colour morphs in beardies. A very unwise practice which will come back to bite breeders in the future). I have also seen "experimental evidence" from studies conducted to quantify how much forced ingested matter will lead to impaction. An utterly contemptible process, but one which has been conducted nonetheless. In both circumstances, I have seen images misappropriated to support bogus claims of accidental impaction, so this is why I am suspicious of material posted on the interwebz. A surprising amount comes with an agenda.

I also asked for tales of personal experience.

I don't have any personal connection to that case - I just thought it was an interesting set of photos if you follow the dissection through.

I've never had a reptile die from impaction, although I have had a beardie who came close. He'd been kept on woodchip but seemed fine when I collected him - over the next week he started going off his food, becoming lethargic, and stopped pooing. I was possible to feel a hard lump just in front of his pelvis, so off he went to the vets. After a bit of treatment, some steroids to keep him going and lots of massages in warm baths, he eventually passed a large blood-soaked wood chip, accompanied by a minor prolapse. He was treated for that and monitored and eventually made a full recovery. Without veterinary intervention I doubt he would have made it - that's my personal opinion and that of the vet at the time. That was caused by a single woodchip which had presumably been accidentally ingested shortly before I took him home. From chatting to the person I bought him from, and from looking at their setups when I collected him, I'd have said he was being kept properly and it wasn't a husbandry issue which made him more vulnerable to impaction.

I've also had numerous people email me over the years for advice about unwell beardies, and a number of those seem to have been caused by impactions - usually wood chip or something similar, with a couple seemingly caused by sand. Of course, I'm just relying on what I'm being told by the people asking for advice, and I didn't actually see any of these with my own eyes, nor did I check the setups (especially in the sand impactions) to make sure that it wasn't sub-optimal husbandry which had made the beardie vulnerable to the impaction in the first place.


Going slightly off-topic to continue another point you raised, why would you say that cancers are caused by "unseen mutations arising from the selective breeding of colour morphs in beardies. A very unwise practice which will come back to bite breeders in the future", rather than by virtue of the fact that we are dealing with a relatively small captive gene pool, with no wild blood entering?

Surely as long as inbreeding is prevented (which most responsible breeders are careful of nowadays) then there's no more risk of hidden deleterious mutations accumulating in selectively-bred lines than there is of them accumulating in non-selectively bred lines? Being hidden, they won't be purged from either line until they start becoming apparent and affecting the beardies.

If anything, modern selectively bred colour lines may be more diverse, with beardies sourced from all over the world, whereas your average "non-colour" breeder will only source beardies from the local area, leading to a higher chance of them being related and sharing deleterious alleles? Selective breeding (at least of the higher-end colours) generally involves mixing genotypes from all over the world to get the best specimens - to my mind that's less likely to cause hidden cancer-causing mutations to pair up than breeding beardies which are all from the same local captive population?

I'd agree that if it's not done responsibly then you're opening yourself up to trouble, but I find it hard to believe that just a changed skin colour can lead to cancers (except the obvious UV-related skin cancers caused by reduced melanin)...? Slightly off-topic, but I think a worthwhile point to address?

[PaleRider]

To hades Dragons: again, thanks for your well considered response. This is exactly the type of information that I was asking for.

Regarding my comments starting with "unseen mutations...", well... Where to begin? You are correct in saying that there is now a large global stock of the various morphs, and you are also correct in saying that responsible breeders take great care in their selection of the animals paired up for breeding. However (and this is a BIG however), the original stocks exported from Australia (mostly to Germany) were finite in number, and have not been [legally] supplemented since. The funky central coloured individuals were way over-exploited in the early breeding programmes, and significant inbreeding for multiple generations took place to try to isolate the brightest traits which did not rapidly vanish in the absence of full, natural sunlight. ALL global stock (in this case, I am specifically talking about the reds, although the same is true for all modern mutations) is derived from these initial few animals. It does not matter whether breeder "A" in London pairs his male with a female from breeder "B" in Buenos Aires (or wherever), there is a high (VERY high) likelihood that the animals are closely related.

I do not need to tell you of the risks of intensive inbreeding, and the time-bomb which that practice sets up, but maybe you are not aware of just how shallow the available gene pool is, not just for beardies in general, but especially for the "morphs" like the original reds and salmons.

Also, just what fraction of breeders are truly responsible do you think? 1%? 2%? It will not be much greater than that, and the remainder just carry on crossing generation after generation of siblings and offspring.

By the way, I was heavily involved in breeding programmes with some red beardies in the early 90's. I deliberately incubated for male from one colony and female from another, knowing that the offspring would be bred. While I could be certain that I was not supplying direct sibling pairs, the relationships a generation or two back were inevitably unclear or unavailable.

I am not aware of any legitimate injections of new stock into the global "herd", although I have been out of that game for quite some time now.

[Ssthisto]

Originally Posted by PaleRider

Finally, I am asking for reports of death by gut impaction, and not simply death with some sand and/or gravel in the digestive tract. It is particularly common for omnivorous/herbivorous herps to swallow small gravel to act as a sort of "crop" to aid with the break up of tough vegetable material, and the two things should not be confused.

I personally lost an adult female leopard gecko to gut impaction from playsand.

Surgery was performed by our vet because she'd had a prolapse; her gut was packed with sand and partly-digested black blood.

[Art_Gekko]

To PaleRider:

I had thoughts of posting something like this for a while now, but wan't sure whether it would just end in an argument as i'd probably have mis-phrased something.

My adult leo is on sand and when my two baby leo's get bigger they probably will be too so I have been interested in how many real/personal cases of impaction there have been.

Sympathies to anyone who has lost a pet to impaction.

[HadesDragons]

Originally Posted by PaleRider

To hades Dragons: again, thanks for your well considered response. This is exactly the type of information that I was asking for.

Regarding my comments starting with "unseen mutations...", well... Where to begin? You are correct in saying that there is now a large global stock of the various morphs, and you are also correct in saying that responsible breeders take great care in their selection of the animals paired up for breeding. However (and this is a BIG however), the original stocks exported from Australia (mostly to Germany) were finite in number, and have not been [legally] supplemented since. The funky central coloured individuals were way over-exploited in the early breeding programmes, and significant inbreeding for multiple generations took place to try to isolate the brightest traits which did not rapidly vanish in the absence of full, natural sunlight. ALL global stock (in this case, I am specifically talking about the reds, although the same is true for all modern mutations) is derived from these initial few animals. It does not matter whether breeder "A" in London pairs his male with a female from breeder "B" in Buenos Aires (or wherever), there is a high (VERY high) likelihood that the animals are closely related.

I do not need to tell you of the risks of intensive inbreeding, and the time-bomb which that practice sets up, but maybe you are not aware of just how shallow the available gene pool is, not just for beardies in general, but especially for the "morphs" like the original reds and salmons.

Also, just what fraction of breeders are truly responsible do you think? 1%? 2%? It will not be much greater than that, and the remainder just carry on crossing generation after generation of siblings and offspring.

By the way, I was heavily involved in breeding programmes with some red beardies in the early 90's. I deliberately incubated for male from one colony and female from another, knowing that the offspring would be bred. While I could be certain that I was not supplying direct sibling pairs, the relationships a generation or two back were inevitably unclear or unavailable.

I am not aware of any legitimate injections of new stock into the global "herd", although I have been out of that game for quite some time now.

It's a valid point, but I would still stand by the suggestion that breeding non-morph dragons sourced from the local area presents the same kind of risks of them sharing the same deleterious alleles. I've no idea what the percentage would be, but I would suggest that a lot of non-morph beardies are the result of keepers keeping a male and female together (often purchased at the same time, and often siblings), resulting in babies. Most of these will then go to a pet shop, to be bought in pairs etc etc... There are issues with inbreeding with any isolated population from a small founder stock, but I suspect that inbreeding is as serious a problem in non-morph lines as it is in morph lines.

I've no doubt that many breeders are less than responsible when it comes to inbreeding - as with everything, sandly the mighty dollar often trumps ethics...


Out of interest, did you have any success "incubating for"? The newest evidence suggests that beardies actually use the ZZ/ZW sex determination method, and that the sexes are "fixed" before the eggs are laid. The only way to alter this is to use a temperature high enough to disrupt the enzyme which causes an embryo to follow the "male" developmental pathway, to get genetic males developing as female beardies - I've attempted to summarise it here:

Temperature-Dependent Sex Reversals in Bearded Dragon Incubation - Hades Dragons UK

Sorry for taking the thread so far off topic by the way - if you want to keep this as a thread dedicated to impaction then I'm happy to move the genetics posts into their own thread - let me know!

[PaleRider]

@Hades: now that's interesting! I never retained any of the young which I produced (and I stopped breeding them 12 years ago now) but it does seem that my best attempts at controlling my output were flawed.

Clearly sometimes, good intentions are simply not enough. I will have to dig my data down from the loft, but I can say with some certainty that I was not ever incubating at or above 34C, so I was probably not having the influence that I thought I was. Back in those days though, we were largely making it up as we went along, keeping notes and to be honest, publishing very little of the information.

I think that we will have to agree to disagree on the scale of inbreeding with specific colours as I have no vested interest in proving or disproving this. I would venture though, in the light of the GSD information (news to me, as I completely turned my back on herpetoculture ten years ago), that things may be even worse for the coloureds that I thought they were.

Thanks for the continuing interesting input though.

[Rukmini]

I must say this is an amazingly interesting thread. I am very interested in all the science behind breeding and genetics.

I understand both sides of the inbreeding argument and must say that I think I would lean to the fact that the colours have less of a gene pool. (I have no actual idea if this is correct but in my head-) Out of the whole population (brought into captivity) Lets say 10,000 individuals only a percentage of them would have the trate that breaders are interested in. Even if that percentage is 50% then that has halfed your gene pool. And with no input and individuals dieing without passing on their genes (often people have pets that they don't breed) the gene pool is only getting smaller.

Sorry if that made no sense at all.

[HadesDragons]

Originally Posted by Rukmini

I must say this is an amazingly interesting thread. I am very interested in all the science behind breeding and genetics.

I understand both sides of the inbreeding argument and must say that I think I would lean to the fact that the colours have less of a gene pool. (I have no actual idea if this is correct but in my head-) Out of the whole population (brought into captivity) Lets say 10,000 individuals only a percentage of them would have the trate that breaders are interested in. Even if that percentage is 50% then that has halfed your gene pool. And with no input and individuals dieing without passing on their genes (often people have pets that they don't breed) the gene pool is only getting smaller.

Sorry if that made no sense at all.

Absolutely - the point I'm trying to get across is that although the coloured gene pool is small, it's probably no smaller than, say, the Southampton gene pool (taking that as an example as that's where it says you're from). Whilst myself and other colour morph breeders are likely to get coloured beardies from all over the world (to get as diverse a selection as we can from the already-limited coloured pool), your average Joe Bloggs will probably just pop down to his local store to buy a regular one. He might then buy another in order to breed them (maybe from the same store, if not then probably from the same area), so the effective size of his gene pool is small - it doesn't matter that normal morph beardies in the US are much more distantly related to his than UK ones are, because he's not breeding his normals to US normals, so the US genes never get a chance to get into "his" local genepool. Most of the people in that area will be buying and breeding locally-bought beardies, then selling them locally, so the line for that particular area can be thought of as being "cycled" around that local area.

Furthermore, I doubt that people import or export normal beardies to or from the UK any more, so - for normal morphs - the UK could be thought of as something of a genetic island. Rather than having the large worldwide "normal" gene pool, we only really have the UK (if there's no flow of genes in normal lines into the UK then the rest of the world's captive population may as well not exist). That already restricts the size of the gene pool down to what's in the UK, before you even consider the possible effects that localisation could have. Few people are going to travel long distances for a normal beardie, so the genes with normals aren't shuffled around the country as much as they might be with more high-end colours.

I don't know what percentage of the world's normal morph beardies are in the UK, but it is certainly a restricted gene pool when you compare it to the size of the worldwide gene pool.

I honestly don't know how much a problem it will turn out to be in the grand scheme of things, or how "fixable" a problem it will be. However I suspect that when (and with no new blood entering captivity and casual inbreeding all-too-common it will be a "when" not an "if") we start to see serious weaknesses appearing with captive beardie lines that normal lines ("localities" within the UK, if you will) may be affected just as much, and be just as prone to problems as higher-end coloured ones.

[marcgroovyge]

Originally Posted by marcgroovyge

At the end of the day people try to keep their reps as far away from harm as possible. So if there is the most smallest chance that a animal can have health issues from digestion people choose to stay away from it. Personally lino is the best substrate. You can hoover the poo out and then wipe over the sufaces with the cleaning spray and kitchen roll, done.

BUT it really it personal preference as to what each individual uses as a substrate and no one else should go out of their way to critise that. I have kept leos on sand before and there was no problems at all. Also I have bought a leo that was kept on bark, which didnt not eat for near 2 weeks until he pooped out 3 bark chips. Reps can and will eat anything, its like leaving a toddler to their own devises. I have seen a leo go to eat a locust, which has been grabbing the corner of kitchen roll and the leo ended up muching the kitchen roll aswell until i had to intervene.

There are many dos and donts but you cant wrap them up in cotton wool. As I have said before it is personal preference and nearly every substrate has health risks.

As shown in http://www.reptileforums.co.uk/lizar...te-debate.html

[PaleRider]

Sorry. I said that I would have to agree to disagree, but I have just spent an evening ironing shirts (Shanghai beckons!) and am a little bored, so I might just add a couple more lines since this is an interesting topic.

The issue with the hi-colours is that the originating stock for these animals may be as few as 50 individuals which were bred, re-bred, cross-bred, re-cross-bred and so on ad nauseam. A surprising amount of the US stock of these early specialities (reds and salmons) is derived from a surprisingly small number of animals and it is not a lot better in Europe. The exponential growth of the number of these specialised beardies, and their distribution around the globe, with some costly international pairings yielding apparently diverse bloodlines, only serves to disguise the fact that the entire global stock is derived from so few original animals that the early iterations of parent/sibling pairing were far greater in number than for the less desirable "normals". In the extreme, if you start with just two animals, no matter how geographically separated subsequent pairings may be, the relationship is there and has been for each and every step in between. Even twenty or thirty years later.

Of course, the hi-colours may represent genetically superior strains which will withstand the rigours of such a regime far better than the mean, but this will be purely a matter of luck and if the opposite were true, then the prognosis would be poor. Very poor indeed.

By the way, I located some of my old notes on incubation temps and no, I never scratched 34C, so while well meaning, I was clearly wasting my time there. Rather entertainingly, I also dug out a set of notes from a notable US breeder from those days (for which I paid almost 100 Dollars at the time) giving apparently verified stats for temperature vs. sex ratio in hundreds and hundreds of clutches. Looking back, maybe the almost idealised correlations are too tidy. Who knows. In any case, my original acceptance of this data now only goes to reinforce my cynicism towards "conventional wisdom", given what I have learned today.