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Setting up for TDSD Study 1st question - Humidity

Discussion in 'Tortoise Breeding' started by Markw84, Dec 17, 2016.

  1. MichaelaW

    MichaelaW Well-Known Member

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    My brain is exploding.
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  2. zovick

    zovick Active Member

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    Hi Folks,

    I have never had good luck using water in ANY ratio with my vermiculite incubation medium (note that this statement applies only to tortoise eggs, not to turtle eggs). I use totally dry vermiculite and sprinkle my eggs very sparingly with water once or twice per week. I use Hovabators (still air, no fans). I keep a small crock of water in the Hovabator with the containers holding the eggs, but that is more to help the Hovabator maintain a more even temperature than to provide humidity to the eggs, since they are in containers with the tops in place and neither the tops nor the containers have holes anywhere in them. The only time the eggs are exposed to any outside air is when the tops are removed when I take them off to check the eggs a couple of times per week.

    This technique has worked for me with Indian Stars, Sri Lankan Stars, Burmese Stars, Radiated Tortoises, and Spider Tortoises of all 4 types.

    I have never attempted to measure humidity inside the egg containers or in the incubators, so cannot comment on its role, other than to say I don't personally consider it overly important. I can say that TSD was extremely successful in my Star Tortoises using the above method of incubation and no attempt to provide humidity to the eggs. Did not try TSD with Pyxis as the eggs were too few. I treated their eggs like gold and just tried to hatch them (this was nearly 20 years ago). TSD with Radiated Tortoises was less reliable, but did seem to work much of the time.

    Very few of my fertile eggs have failed to hatch since I began using the above technique in the early to mid-1990's. There seem to be a fair number of successful ways to incubate tortoise eggs.

    Bill Zovickian
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  3. zovick

    zovick Active Member

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    Here is an article I wrote for one of the first couple of Pyxis Studbooks (2003 or 2004?) which describes my incubation setup in more detail, plus has some other interesting facts regarding an extended cool down period of eggs and its effect on the eggs of several species and sub-species:


    Incubation Strategies for Pyxis Eggs.


    William H. Zovickian
    wzovickian@gmail.com


    Incubation techniques for many chelonian species are still evolving, and so it is with those for the Spider (Pyxis arachnoides) and the Flat-tailed (P. planicauda) tortoises of Madagascar. The author has experimented with varying techniques to break diapause and initiate development of Pyxis eggs for the past several years and has developed successful incubation methods for them. Incubation methods, however, will certainly evolve from those offered below, as these techniques are neither foolproof nor fully perfected. Nevertheless, the following technique has proven to be successful for incubating

    P.arachnoides eggs if they are fertile.


    Totally dry Vermiculite is used as an incubation substrate. Eggs are half buried in 1”-2” (25-50mm) of Vermiculite in small round (1.7 pint) Rubbermaid containers with the tops loosely positioned over them. Four of these containers fit in a Hovabator incubator (Hovabator Still Air Model #1602N, GQF Mfg. Savannah, GA 31498).


    The Rubbermaid containers with eggs are placed into the Hovabator and incubated at 87-89˚ F (30.5 – 31.6˚ C) for 5 weeks. At that time, the entire Tupperware container is removed from the incubator and placed in a cool location where the temperature will remain about 65-72˚ F (18.3 – 22.3˚ C) for 5 weeks. After the 5-week period, the container is returned to the incubator and incubation at 87-89˚ F is resumed. After 5 weeks, the eggs are candled. Those that still appear good, but show no signs of development, are cooled again for 5 weeks, then returned to the incubator. In some cases, eggs have been cooled three times before development occurred.


    Some additional points should be noted here: first, after the initial 5-week period in the incubator, the eggs are candled before being cooled. Any eggs that have begun to develop in the first 5 weeks are NOT removed from incubation, but left in the incubator to continue their development. Second, while the eggs are in the incubator, they are lightly sprinkled with water twice weekly. A small water bottle, fitted with an old-fashioned perforated sprinkle top, is kept in each incubator for this purpose. It is half filled, and laid on its side to fit in the incubator. Using isothermal water is best since it does not shock the eggs. A small open container of water is kept in the incubator during incubation to help maintain some humidity (though the exact relative humidity has not been recorded). Finally, if the embryos are dying in the eggs shortly before hatching, incubation temperature may be too high. Check frequently to see that the incubation temperature has not ventured above or below the recommended temperature. It is recommended that the temperature be carefully checked and lowered appropriately. It is suggested that a Raynger Non-contact Thermometer (Raynger ST, Model RAYST2PU, Raytek, Santa Cruz, CA) be kept near the incubators to check the actual temperatures of the eggs twice weekly when they are sprinkled.


    Eggs from all three subspecies of P. arachnoides have been hatched using the above technique. The incubation techniques for P. planicauda are decidedly more problematic, as the technique used for P. arachnoides has not proven successful. Recently, however, a revolutionary new technique has been discovered, which has proven successful for this species and which has produced offspring in the shortest incubation times the author has experienced for tortoises.


    Because the author was moving from Connecticut to Georgia and concerned that the movement of incubating eggs would be lethal for those embryos, it was decided to withhold incubation temperatures until after relocation. The move was planned for the last few days of July 2002 and the decision was made not to begin incubation of any Pyxis eggs that were laid after December 2001, nor any other tortoise eggs laid after February 2002. Necessity is the mother of invention, as they say.


    Eight assorted (different species and races) Pyxis eggs laid during the months of January through March, as well as three clutches of Burmese Star Tortoise (Geochelone platynota) eggs laid in May and June, were the subjects of the following experimentation. All of these eggs were kept at 65-72˚ F until the author’s move to Georgia. To transport the eggs, they were kept in their Tupperware containers with wadded paper towels placed over them. These tightly sealed containers were then buried in picnic coolers filled with Aspen shavings. The picnic coolers were placed in the author’s car and driven to Georgia, a trip of about 16 hours.


    Upon arrival, the incubators were set up and recalibrated. The various eggs described above were placed in the Hovabators. The eggs were candled 3 weeks later to check for any signs of development. To the author’s great surprise, the eggs were observed to be developing much faster than he previously experienced. The eggs were filled with blood vessels and small embryos that were readily visible, and were at the stage of development normally seen at 60-75 days.


    Two P. planicauda hatched at 75 and 82 days after incubation was initiated. The only previous Flat-tailed Tortoise hatched by the author (1978) required 295 days of incubation. That egg was incubated from the time it was laid until it hatched without cooling. The six Spider Tortoise eggs also hatched very quickly, ranging from 80-115 days. The fertile eggs from all three clutches of Burmese Star Tortoise eggs (9) hatched in 76-86 days, compared with a typical incubation time of 90-130 days.


    In over thirty years of breeding tortoises of various species, and before the above reported success, the author has had only two eggs hatch in less than 90 days. That number represents perhaps 1% of all tortoises hatched by the author. Twelve of the tortoises in the aforementioned group of eggs, or 70%, hatched in less than 90 days, while the others took far less time than earlier incubation methods. From these experiences it appears that an extended cooling period before initiation of incubation dramatically improves the hatching rate of Pyxis eggs, and parenthetically that for G.platynota, and accelerates development time. The author invites feedback from those who try the above techniques as well as those who have experienced good hatching success using other methodologies. Working together, we can develop a reliable formula for hatching these enigmatic Pyxis tortoises.


    Post Script: Though the author has not attempted this technique, he is aware of others who have successfully incubated Pyxis eggs in open containers that are floated in water in picnic coolers and kept at 84-86˚ F (28.9 – 30.0˚ C).
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  4. Tom

    Tom The Dog Trainer 5 Year Member

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    Your post demonstrates that we all have much to learn.

    Thank you very much for contributing here!
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  5. Neal

    Neal Well-Known Member 5 Year Member

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    Thank you Bill, this is a very interesting post.

    When I first started incubating tortoise eggs I had a lot of help from Egyptiandan here on the forum. He suggested using completely dry medium, and I didn't take his advice until this year. I've always done a 1/.8 ratio of medium/water by weight and it's worked out OK, but I've had a lot of fertile eggs that never hatched. This year I have several egg trays at different ratios and a couple with no water. It's too early to tell if it will make a difference, but your post gives me a lot more optimism.
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  6. Markw84

    Markw84 Well-Known Member 5 Year Member

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    Bill

    Thank you so much for your contribution. What a valuable resource you are to our community. I will be doing another separate post on diapause and look forward to a dialogue there. Your thoughts on humidity are helpful as although you state you believe it not too important, I believe your methods tend towards the "less than 100% RH" position.
  7. Markw84

    Markw84 Well-Known Member 5 Year Member

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    Thank you!! More food for thought on less humidity. Please keep us posted on your results.
  8. G-stars

    G-stars Well-Known Member

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    Hey Mark, don't really have as much experience in hatching babies as some of the other members here. Also I never really pay to much attention to the humidity. But I did keep the medium dry and keep a container of water in there to help with the humidity.

    I've been planning on doing an experiment for a while now. The idea is to see what temperatures are achieved in an outdoor and indoor nest site. The lows, the highs, average, and median. It interests me to see just how much the temps fluctuate underground. I may also incorporate humidity as well.
  9. Markw84

    Markw84 Well-Known Member 5 Year Member

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    Sounds interesting, Gus. You might be interested - - I use sensors that are quite accurate and they keep a log of readings taken every 60 seconds of the temp and humidity to the nearest 0.1f and 0.1%RH. They will store up to 20 days info if you have not been in range in a while. They auto download data to your mobile phone via Bluetooth when you are in range. That way you have an exact record of the temperature and humidity history, not just what you saw and recorded when you check. If you're interested, I can give you the info.
  10. KevinGG

    KevinGG Active Member

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    Wow that's a great setup. I'd be interested in buying something that logs data straight to your phone. What are you using?
  11. G-stars

    G-stars Well-Known Member

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    Yes I am. I'm sure others would be interested as well.
  12. Will

    Will Well-Known Member

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    In looking for the paper that indicates "when" that pivot in incubation occurs, I re-found these two. If you have a specific question I'd he happy to try and re-state what the authors have said in more lay terms.

    I really miss 'seminar' classes in school, where about a dozen or so people would recommend a paper on a topic, everyone would read those paper(s), and in a discussion we would try to figure what the hell the author was getting at. Unless you are an author in the field (a very narrow part of the field even) it takes a few reads and talking it out to determine what is being communicated.

    So if you want to try it out here and the OP does not mind...

    Attached Files:

  13. Will

    Will Well-Known Member

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    This one has experimental DESIGN in the title, maybe it will be more helpful, I did not read it yet.

    Attached Files:

  14. Will

    Will Well-Known Member

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  15. Markw84

    Markw84 Well-Known Member 5 Year Member

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    @Will To whom are you addressing this? I am the OP, so I am confused?? I'm not sure what you are referring to with the "when" of the pivot. The Pivot point refers to the exact temperature at which you would expect the exact 50/50 male to female ratio produced. The "when" in incubation is the "temperature sensitive period", and actually better defined for me in later papers and is a window of time period not a point.

    I appreciate you input greatly, and actually am familiar with all these papers you have referenced. Unfortunately they are very old studies, (17 years, 26 years, 36 years, etc) and tend to focus on results from Red-Ears or Snappers, as far as establishing a pivotal temperature, as it is know quite well for these species. Lots of good info though, but nothing touching on humidity. I plan on doing more separate threads on a few of the issues these papers address, as I find it quite interesting. I hope you will participate. My main interests now are in getting the incubator set up as much as possible to eliminate as many variables as possible. My main focus will be that pivot point for platynota. What effects breaking diapause has on that and possible effects that may have on the temperature sensitive period. As well as the question, can we better manage scute deformity manipulating temperatures lower at Stage 12 - 17 and then raising Temperatures at Stage 17 to the higher "female" levels?

    Do you have thoughts about the humidity best for egg development? My experiments with techniques commonly suggested produce 100% RH at the egg. I would conjecture that RH inside the egg chamber with damp soil and the wet mud plug that seals the chamber would probably also be about 100%. Yet we are all concerned about suffocating the embryo. Will you share your thoughts???
  16. Markw84

    Markw84 Well-Known Member 5 Year Member

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  17. Anyfoot

    Anyfoot Well-Known Member

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    Does higher himidity levels reduce oxygen levels. I assumed it did. If that's the case when an embryo develops to the stage of an actual heart beat you would think the himidity level needs to be lower.
    Can someone explain what chalking is, I don't mean it's when the egg shell goes the color of chalk. What is actually happening, because I'm of the opinion it's making the eggshell more porous, allowing more oxygen to pass through and Probably extracting calcium too.
  18. Will

    Will Well-Known Member

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    I no longer have any subscriptions, but have found many ways around just buying the paper, give me a title and I'll full around with it.
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  19. Will

    Will Well-Known Member

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    Page 162 has some discussion on 'when' sex is determined. The "I wonder" problem I see with this is that higher temps also influence a shorter incubation period than lower temps, so 'when' that critical time is also seems like it will shift with temps. I've never had the moment needed with the right person to tease this out.

    I stopped buying book at some point as the pounds of pulp got to much to manage. There is a book that reviews and compiles a good lot of these papers. Kuckling's book of the reproductive biology of the chelonia may have something, and I do have that book. I'll look if I don't forget. It seems like I have forgotten to look stuff up before when I said I would. Call me on if I forget.

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  20. Markw84

    Markw84 Well-Known Member 5 Year Member

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    @Will if you can find those publications = that would be much appreciated.

    Still would like to hear your take on humidity. Some readings speculate that humidity may also affect hatch time. I personally have noticed in looking back some of the clutches I've had that tended to dry out a little more, did hatch sooner.

    Do you believe 100% RH is the way to go? Most any closed container even with holes towards the top edges, and a moist substrate will produce 100%. It also seems reasonable the egg chamber of a wild tortoise, in moist earth and with a mud plug seal, will also produce 100%. Yet my inclination is still more towards 80-90%. Please comment...
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