Reptile Forum, Reptile Classifieds - CaptiveBred

[mafia_69]

did the animal had any complications at all? is it healthy?

i never tought this was possible

[crocdoc]

Against all better judgement to continue with this thread, I feel compelled to comment on the comparison between a mammal's nutritional contribution to its offspring and a monitor's.

At the risk of stating the obvious, a mammal (with the notable exception of the three species of monotreme - ie the platypus and two echidnas) contributes to the nutrition of the foetus throughout its development. A monitor's contribution is the one-off 'gift' of a yolk sac before the egg is shelled. For the rest of the x months (up to 12 or more, in some instances) of incubation, the foetus is on its own. Any effect the female's nutrition would have had on it would have affected it long before then.

Let's say there is some nutritional factor involved, though, and examine this idea (again).

1. What an amazing thing for each and every egg to have exactly the right amount of what it needs to last it all of the way through incubation, only to run short at the very last instant, when it pips. Coincidentally replicating the exact symptoms of an egg that was incubated too wet!

2. Continuing on with the nutritional factor theme, how is it that some monitors only run out of factor 'x' after a few clutches, whereas some other monitors are already out of it when they lay their first clutch? The fact that the dead-in-egg syndrome has been observed in a few species of unrelated monitors with their first clutches has been covered in an early post in this thread

3. If a female monitor is unable to bounce back nutrionally after three months (I believe someone mentioned a three month gap between clutches), then (and no offence to anyone here, as this is just theoretical) there must be some incredibly serious husbandry issues, since others are able to get viable clutches laid a month or so apart, time after time, and have them all hatch.

4. As has been mentioned earlier, females lacking nutrition lay fewer eggs (not infertile, as you suggested, as the female's nutrition does not affect the male's virility). The eggs may be weaker, but they'll be more likely to die at various points during incubation, rather than consistently at the very last day, just as they pip.

Now let's examine the possibility of being able to incubate successive clutches exactly the same, since this has been used as an argument against the idea of it being an incubation issue. Personally, I couldn't possibly replicate the incubation conditions of each and ever clutch, but maybe others can overcome these obstacles:

1. The quality of perlite one buys is not scientifically exact when it comes to quality. It's purchased (in Australia, anyway) from places that sell nursery products, as it is normally used for soil enhancement. Consequently the grain and existing moisture level vary from batch to batch, affecting the resulting water potential of the mixed incubation substrate.

2. The quality within a bag of perlite varies. Suppose one were to buy a bag, carry it home and put it on the floor. In the process, the contents settle a bit and we can all remember those experiments with sand and mud in school in which the fine grains go to the bottom, leaving the coarse grains at the top. We tip out some of the (coarser) perlite and use it for the first clutch. When the second clutch comes, we tip out a bit more, but it is now finer - which means greater surface area and altered water potential. The next clutch, even more so.

Note: This is an imaginary scenario and I am merely playing devil's advocate (not suggesting this is what's killing eggs), but showing you how subtle little things make it impossible to replicate conditions.

3. The clutches change. Perhaps the female lays fewer eggs with successive clutches, or smaller eggs. These eggs absorb less water as they develop than previous clutches, affecting the remaining moisture levels in the egg box (ie the water potential of the incubating medium)

4. As humans, there is inbuilt error into our handling of everything, so how we handle each clutch differs. We open the door of the incubator daily with the first clutch because we are excited with our new eggs, but open the incubator and look at the eggs less and less frequently with successive clutches (I'm guilty of this, so my hand is up). Maybe we treat the first clutch like the eggs are incredibly delicate and leave them alone, other than to stare at them, but start to 'fiddle' a bit more with successive clutches. Touching them, weighing them or doing something we wouldn't have dared done with the first clutch (my hand is up again).

As I said, these are just a few small examples of how incubation is never exactly the same from clutch to clutch.

Finally, let's look at what is going on with an egg at the time that most of these eggs seem to be dying: at or before pipping.

Like mammals, reptiles have to make the switch from obtaining oxygen via umbilical blood vessels to taking their first breathe with their lungs. At that point where they are about to take their first breath, living in a fluid filled egg and breathing the outside air, what is most likely to affect this process: Fluid levels (and pressure) in the egg or some nutritional factor? Humidity levels in the surrounding air or some nutritional factor?

[crocdoc]

Oh my, I have just noticed this. It's FRs response to your querie:
http://www.varanus.net/forums/read.php?2,526,542#msg-542

[Magpye]

Comparative physiology is not unheard of. Fruit fly's have similar physiological processes to mammals and so it is not without reason to consider reptiles may have similar physiological process also. To clarify a few issues you raised (without the sarcasm lol):

1. "Bouncing back" - I was prescribing to the idea that the diet lacked an essential something. Try not to take the following example out of context, it is just that - an example - cats require an amino acid, taurine, that other mammals do not. I was proposing that whilst we may feed the odatria an adequate diet to sustain their own health, it is possible we may not be providing them with the necessary nutrient to produce successive clutches.

2. I mention nothing of interbreeding which your point 2 appears to suggest.

What it appears that you are saying, from another perspective, is that the breeder is capable without much effort of producing a successful first clutch, however thereafter he/she becomes incapable at repeating the same level of success because of their inability to reproduce the same incubation conditions - ie water potentials,

Whilst the water potential/pressure theory appears more than plausible, and is a credible scientific answer (for individual cases), it does not adequately ascribe to the basics of repetition. Whilst every individual factor cannot be replicated, it seems that the breeder (according to what is being argued here) is uniquely capable of achieving the correct balance of variables for the first clutch only. This is the reason several breeders are doubting the plausibility of the water potential argument. It seems a faultless argument if you look at an individual clutch, but if you look at the bigger picture, which from what I have read appears global, then it seems a little less credible.

The randomness as you prescribe it relating to incubation conditions does not reasonably correlate with the sequential 100%, 70%, 40%, etc.. success rates that breeders have been experiencing.

If you feel it is against your better judgment to have a theoretical discussion whereby the logic you are advocating is being critiqued then I am happy to drop the subject. People have opinions and experiences. At the moment I lack experience and I'm open to suggestion. I do agree that water potentials and pressure differentials have a significant effect on the success of a clutch, however I do not see this as an explanation for the pattern of events that have been described by numerous breeders. As a one-off maybe, but to be able to reproduce this failure successfully and attribute it to the randomness of incubation variables is a bit on the extreme for me.

[crocdoc]

You are nothing short of exasperating.

[Mwoxy]

Hi all, new to this thread(and very late).

Hope this hasn't been thrashed out too much. It's a real long thread to read all of it!.... Crocdoc has mentioned the quality of perlite several times, FR states dry perlite. I think the importance of this is being diminished.

For fun, well based on all I had read(mainly FR), I dried a bag of perlite in the oven, before I prepared my egg boxes. The perlite was already way above 1:1 from the bag(purchased UK, usually stored outside, bags have vent holes!!!).

If you now mix a 1:1(by weight) from the bag, the perlite is far too wet. Probably 1:3+

FR always goes on about incubating eggs, not water. I know he rubs many, including me, up the wrong way, but this is the crux. You need to monitor(no pun intended) your eggs. Crocdoc has covered this many times, but( hope I haven't missed a critical post), the starting point is very often overlooked. Judging moisture content by hand of perlite is really difficult, compared to vermiculite. You can't just squeeze it, you really need to weigh it.

Again I hope I haven't trod on any toes, or re-invented the wheel, just my observation/experience.

As a footnote I have only noticed reduction in hatchling viability with bad nesting.

Cheers

Mark

[Sam Sweet]

Apparently, Magpye, you are being advised that opening egg boxes can create a pressure difference that will cause eggs to burst. Anyone who has had cause to cut open a lizard or snake egg will wonder about this, since those shells are both tough and elastic, yes? There would have to be a heckuva pressure differential built up between the egg box and the air outside (which would be at atmospheric pressure). The air pressure inside the egg box would somehow have to get up to several atm and stay there w/o popping the lid off, yes? I don't suppose that'd be bad for the eggs, in fact it must be good if the advice is to not open the box so the eggs won't burst.

Not to burst anyone's bubble, what is inside the eggs is fluid pressure (no air in them), and this is the result of water uptake. As long as the water potential within the egg is greater (= more negative, in terms of kPa) than that of the substrate (and the shell allows it), water will move into the egg. Since fluids are incompressible, this stretches the shell and at some point the slightest jostle can in fact burst an egg which has been incubated too wet. And with that little phrase ('incubated too wet'), we are jolly well back where we started.

[kev]

so the moral of the story so far is :

1. feed them adequately
2. hope the nesting is good
3. dry your perlite and mix the right amounts of water to start
4. don't float ya eggs
5 read the eggs carefully and correct if necessary, but don't fiddle to much and be mindful of adding too much water especially late in incubation.
6 keep your fingers crossed

[crocdoc]

There, we have our recipe!

[Magpye]

I'm not disagreeing with what you are saying about water potentials, what I am disagreeing with is that this is being used to explain the pattern of success that is being displayed. As crocdoc would say:

"You, however, have a knack for taking things entirely out of context and not picking up on a single point I make. "

I would illustrate the point I am trying to make with a diagram but I feel it would make little difference as it was just completely ignored in the last post. I will explain as best I can as this will be quicker.

If human error during incubation is accountable for eggs failing (ie water potentials/wet eggs, then we would see a pattern of egg success in the form of a squiggly line with success rates varying with each individual clutch from good to bad to good to bad, etc.

What is being reported is a curve, or a straight line, from the peak of 100% success, gradually declining to 0% success. No flux, no randomness. This suggests something was present at the start that gradually diminished with each successive breeding.

I am not looking for something/someone to blame. Its blatantly obvious breeders are at fault for failling eggs because as several of you have pointed out - eggs are designed to hatch.

IF YOU TAKE THE TIME AND EFFORT to read what I have written in THIS and the PREVIOUS posts you will see that I ACCEPT water potentials to be a factor in egg success. What I do not accept is that the only factor in the pattern of failure that has been described.

There are no need for the immature or sarcastic comments that you continue to make crocdoc, whilst FR may rant - as Sam stated in an earlier post - as an academic yourself I expected better.