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Post by bitbyter on Sept 28, 2014 18:19:49 GMT -5
This is a common design for a rodent euthanasia chamber using baking soda and vinegar to generate the required CO2. It is important to know the exact volume of the two chambers (mixing chamber and killing chamber) as you will need to generate enough CO2 from the chemical reaction to displace all of the air from these two chambers. If you don't you may not end up with dead rodents or it may cause undo suffering and we want this to be as humane as possible.
I have someone figuring out the math involved in determining the amount of CO2 required for my setup (5 gallons of volume). I have actually asked for the amounts to generate 5.5 to 6 gallons just to be extra sure all the air is displaced. Once the math is figured out and I understand how the formula works I will post it here as well.
Anyhow, here are the two videos I have recorded on how to build a vinegar and baking soda Euthanasia Chamber:
NOTE: I have decided NOT to use this style of chamber because the results are to unpredictable even if you do the math correctly. This is because Baking Soda can go stale and not produce enough CO2 during the chemical reaction. See later posts for how to build a CO2 chamber using a paintball canister.
Part 1
Part 2
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Post by bitbyter on Sept 28, 2014 18:23:32 GMT -5
Here are some links to articles showing that killing the rodents via CO2 is actually an anaesthetic process vs. suffocation. They fall asleep before the lack of oxygen kills them, so it makes for a very humane method of euthanasia. This is an article regarding using CO2 in slaughterhouses but the info is relevant. This is an article about rat euthanasia using CO2.
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Post by bitbyter on Dec 19, 2014 17:15:11 GMT -5
Ok, I have revised my plans and have decided to go with a CO2 chamber with the CO2 provided by a paintball canister. After more research and discussions with other feeder breeders I decided that the baking soda method was to inaccurate. If your baking soda isn't fresh, the reaction will not be efficient and might not produce enough CO2. Here is the parts list for the system I have built: 1 Paintball CO2 Canister: ~ $20 or so 1 CO2 Fill Adapter Remote On/Off 3000psi Gauge: ~ $10 on ebay <- Direct link to product Also, a word of warning, the valve above with the gauge is kind of counter intuitive. The wheel on the top needs to be totally UP before you attach the valve to the tank. Screwed UP is OFF for this valve, screwed down is ON. I learned that the hard way. 1 Watts Compression Needle Valve 1/4 in OD x 1/8 in MIP 2 Watts Hose Barb 1/8" x 1/4" 10' 1/8" Clear Tubing Small Plastic Tub Window / Door Rubber Weather Stripping (optional) Silicone Teflon Plumbers Tape (for the threads of the various components) All these parts can be found at Home Depot except for the paintball CO2 canister & the valve / gauge. Below is a short video on how it all goes together.
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Post by bitbyter on Dec 19, 2014 20:13:30 GMT -5
You will also need an adjustable wrench to tighten all the components to the valve. Once everything is together, put in a bathtub full of water and turn it on slightly to check for leaks.
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Post by msav on Dec 19, 2014 21:44:24 GMT -5
I would watch the rats closely when you do this. I read that the rate that you apply the Co2 has to be correct. if you put it in the chamber too fast the rats panic and suffocate. they say you have to add it slowly so the rats fall asleep then pass away.
After reading this I decided to go the cervical dislocation route. I have gotten quite good at it. I use a sharpening steel behind the neck, then push down while simultaneously pulling on the base of the tail.
They are out immediately. It freaks me out when they twitch afterwards though.
I saw a video where someone did the Co2 incorrectly and it looked really cruel.
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Post by bitbyter on Dec 19, 2014 22:03:38 GMT -5
That's why I have the needle valve on there. It allows more precise control than the main valve on the top.
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Post by msav on Dec 20, 2014 14:37:09 GMT -5
I did not dig into it as deep as you. but do you have a way of knowing the concentration of Co2 in the chamber. also is there documentation as to what concentration is needed to do a humane euthanasiation?
Once you get yours set up and fined tuned I would love to see it in action and your notes on how your dialed in the Co2 concentration.
The vids I watched made me not want to try it. I don't want them to suffer.
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Post by bitbyter on Dec 28, 2014 20:58:54 GMT -5
All I can do it try it and see how it goes. I figure if you go slow enough with the CO2 at the beginning they should fall unconscious. Then increase the concentration until all air is out of the chamber. Most ones I've seen online don't use the needle valve as part of the design. I followed an old design I found on a snake forum that is no longer active.
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Post by bitbyter on Dec 31, 2014 20:09:55 GMT -5
The girls are nomming the first of my home raised mice. One of my males was getting really violent with the rest of the males. He was not just nipping but biting and holding on. I was starting to see wounds on the other males. Since I had two grey males and couldn't tell them apart, they both ended up as tonight's dinner.
The CO2 chamber worked really well. The needle valve was instrumental in being able to easy control the flow of CO2. Slow at first to knock them out and then turned up to finish the job. There was no pee or poop to indicate fear. The just lay down and that was it. Their lungs were working hard but that is a natural reaction because of the limited oxygen. All in all, I was very happy with how humane the process was. I'll be euthanizing the rest of my male mice tomorrow and will film the process.
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Post by bitbyter on Jan 1, 2015 14:09:46 GMT -5
Well today was culling day. The males have been fighting really badly the last few days and actually injuring each other.
It went pretty well. Not as fast as my first two that I tested with yesterday but I went a little slower with the CO2 this time. The needle valve on my canister really allows for precise control or the CO2 flow.
A bit of explanation on how CO2 actually kills. CO2 is a natural by-product of respiration. This is what you exhale when you breath. The brain detects the CO2 concentration in your body and triggers the diaphragm to exhale. When using a CO2 chamber you are replacing the Oxygen in the chamber with CO2 (CO2 is heavier than Oxygen and forces it out of the chamber through the vent tube). Since the mice's brains detect the increased CO2 levels in their bodies it causes hyperventilation (which just speeds up unconsciousness because the Oxygen in the chamber is being replaced with CO2). Though this looks bad, more often than not they are usually unconscious by this point. CO2 binds to the hemoglobin in their blood and causes unconsciousness very quickly.
All in all this is probably the most humane way to euthanize rodents besides cervical dislocation. The problem with CD is that it can go badly if the rodent squirms at the last second (I've experienced this and it wasn't pleasant).
IF I HAVE ANY ERRORS IN THE CO2 EXPLANATION WRONG, PLEASE LET ME KNOW AND I WILL CORRECT THEM.
WARNING: GRAPHIC VIDEO BELOW - EUTHANASIA OF RODENTS
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Post by Sherry on Jan 1, 2015 17:16:52 GMT -5
That was faster than I had expected.
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Post by bitbyter on Jan 1, 2015 17:45:24 GMT -5
I actually went slower than I did with the test two yesterday. I could have gone a little faster I think without causing them undue stress.
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Post by Deleted on Jan 1, 2015 17:48:33 GMT -5
oooh, that fast breathing--would have to have a black box. If you can handle it good for you.
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Post by bitbyter on Jan 1, 2015 18:05:52 GMT -5
Keep in mind that they are unconscious by that point. There is a little hyperventilation while they are conscious but that just speeds up the process.
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Post by Sherry on Jan 1, 2015 19:13:34 GMT -5
I guess because I sat with so many people who have passed(long term care), I am accustomed to that happening after unconsciousness.
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