• Hello!

    Either you have not registered on this site yet, or you are registered but have not logged in. In either case, you will not be able to use the full functionality of this site until you have registered, and then logged in after your registration has been approved.

    Registration is FREE, so please register so you can participate instead of remaining a lurker....

    Please be certain that the location field is correctly filled out when you register. All registrations that appear to be bogus will be rejected. Which means that if your location field does NOT match the actual location of your registration IP address, then your registration will be rejected.

    Sorry about the strictness of this requirement, but it is necessary to block spammers and scammers at the door as much as possible.

Killing mice,CO2 and suffocation; what do you think?

breedingcolors

breedingcolors

Freaky!
Yesterday, I had to cull 4 adults mice but I didn't have my CO2 chamber yet and I was not able de kill them by throwing them on a wall :puke01:

So I put a mouse in a little container and I let the mouse died of suffocation. They did not seems to suffer and just fall asleep. Since we put CO2 in their container when we have a CO2 chamber, and since what they exhale is CO2, is it the same thing to kill mice like this?

I find it easy to do. They die in about 15 minutes like this (really small container).

Thanks!
 
I dint know the answer, but if someone else does it would be great because i was wondering the same thing as i am currently starting to breed mice and it would save alot of money in the long run if i dint need to buy, (co2, hose's, new tank for chamber, remote Coyle's and things!)
 
Ok, let me see if I can get this right...

Hypoxia (low O<sub>2</sub> level) is quite unpleasant, and what causes the "panic" response. (Like when someone is dunking you under water.)

A high CO<sub>2</sub> level is deadly, but not unpleasant.

So:

When you euthanize mice in a CO<sub>2</sub> chamber they are konked out in a matter of a few seconds, and don't experience hypoxia. This is humane.

When you enclose them in a sealed container, they slowly use up the oxygen, converting it to CO<sub>2</sub>, and slowly die (dunno whether it's of hypoxia or high CO<sub>2</sub> levels) which I think would be quite an unpleasant experience.

Feel free to correct me if I'm wrong on any of it. :)
 
Serp I think you hit the nail on the head (again), when any animal exhales the expelled breath is a mix of CO2 and Oxygen (among other gasses), thus taking a LOT longer to kill the mice as there is more available oxygen than a straight co2 chamber.

Traf, the "tank" for the kill chamber needs be nothing more than a tapperware type container with a tight fitting lid, costs less than a buck, just to clarify in case you were counting on an aquarium type "tank".

Using a CO2 tank, apart from being a quick and humane way of killing mice and rats, is also the first step to killing aerobic bacteria on these animals. The following freezing is an added safe guard to bacterial and other parasite infection.
 
breedingcolors said:
Thanks. This is answering my question. I will build my CO2 chamber for the next ones.
Click to expand...

That's a MUCH better option. The way you did it was actually very cruel. With a LARGE dose of CO2 so that almost all of the "air" is repased VERY quickly, the animal is actually "knocked out" before any jumping/thrashing/etc. occurs. Basically, it is "brain dead" in the sense that nothing is really getting registered BEFORE the painful looking stuff actually occurs. (That's what the past research has shown, anyway. SLOWLY increasing the CO2 level the way you just did it is similar to you breathing into a plastic bag for a long period (painful, and dangerous for you) - the gasping, breathing response, etc.

If you can't use CO2, use cervical seperation.

WARNING: CO2 doesn't work on pinks. They are pretty anaerobic, anyway. They have to be to live under a mom for so long! Universities can't legally CO2 pinks at all - they MUST use cervical separation (or another approved method). They do it by cutting the head off.

KJ
 
Serpwidgets said:
Hypoxia (low O<sub>2</sub> level) is quite unpleasant, and what causes the "panic" response. (Like when someone is dunking you under water.)

A high CO<sub>2</sub> level is deadly, but not unpleasant.

So:

When you euthanize mice in a CO<sub>2</sub> chamber they are konked out in a matter of a few seconds, and don't experience hypoxia. This is humane.

When you enclose them in a sealed container, they slowly use up the oxygen, converting it to CO<sub>2</sub>, and slowly die (dunno whether it's of hypoxia or high CO<sub>2</sub> levels) which I think would be quite an unpleasant experience.
Click to expand...

I can't agree with you.
When you are drowning you are experiencing HUGE and FAST O<sub>2</sub>
deficit, you can't breathe so you are panicking.

It can be compared to using CO<sub>2</sub> chamber with valve 100% opened. CO<sub>2</sub> displaces oxygen really rapidly, just like water in the example above. Mouse is trying to breathe, it's lungs are working, chest too, but nothing happens.
Slow raising CO<sub>2</sub>level is another story. Mouse can't notice it, it feels only sleepy, more and more sleepy. When it falls asleep then it is the time to open valve to finish work.

On the other hand I'm not supporting the idea of leaving mice in jar and wait till oxygen rans out. Are you sure that those mice were really dead, not just deeply stunned? I prefer to keep everything under control and this method leaves far too many things uncertain.
 
@sojkas:

Here's what the NYU school of medicine says:

Guidelines for Performing Euthanasia via C02
For rodent species, CO2 is an acceptable form of euthanasia when used under the following guidelines:

We do not recommend prefilling (precharging) the euthanasia chamber with CO2, since high concentrations (>70%) can cause nasal irritation and excitability. Rather, the animals should first be placed into the chamber, followed by the addition of CO2 at a low flow rate (20% of the chamber volume per minute) to complete the process. Rapid gas flows should be avoided since excessive noises ("winds") can develop and induce excitement/distress in the animals.

Place the animals into the chamber and turn the red lever until you hear gas flowing at a low rate.

Gas flow should be maintained for at least 1 minute after apparent clinical death (approximately 5 minutes total). A timer should be used to ensure adequate length of exposure.

It is important to confirm that an animal is dead after removing it from the chamber. This may be accomplished by assuring lack of heartbeat or by performing cervical dislocation following CO2 narcosis or creation of a pneumothorax following CO2 narcosis.

According to the 2000 Report of the AVMA Panel on Euthanasia, "Compressed CO2 gas in cylinders is the only recommended source of carbon dioxide because the inflow to the chamber can be regulated precisely. CO2 generated by other methods such as from dry ice, fire extinguishers, or chemical means (e.g. antacids) is unacceptable."

Only one species at a time should be placed into a chamber, and the chambers must not be overcrowded. Animals must meet the minimum space requirements listed in the "GUIDE" up until the time of euthanasia. When placed into the chamber, all animals must have floor space.

Euthanasia should always be done in cohorts (live animals should not be placed in the chamber with dead animals).

Chambers should be kept clean to minimize odors that might distress animals prior to euthanasia.

Animals must not be euthanized in animal housing rooms, except under special circumstances such as during quarantine for infectious disease agents.

Neonates: Since the time period for euthanasia is substantially prolonged in neonatal rodents (rodents 13-16 days) inherent resistance to hypoxia, CO2 narcosis must be followed by decapitation after the animals lose consciousness.
Click to expand...
Sounds like they agree with your idea of not blasting it right away. :)

I thought this was rather interesting too:
Animals must not be euthanized in animal housing rooms, except under special circumstances such as during quarantine for infectious disease agents.
Click to expand...
Mice are smart enough to learn by watching other mice. For example, when other mice see one of their buddies step onto a mousetrap and he is killed, the observers will show mortal fear of mousetraps from that time forward. They might learn that "the CO2 chamber is a death trap" by observing, too.

IMO the most important thing, if you're goal is to be humane, is making sure that the way you do it does not cause them to panic at any point. The guidelines quoted seem to reflect this, too. :)
 
When you are drowning you are experiencing HUGE and FAST O2
deficit, you can't breathe so you are panicking.

It can be compared to using CO2 chamber with valve 100% opened. CO2 displaces oxygen really rapidly, just like water in the example above.
Click to expand...

This I can't agree with. CO2 does not displace oxygen, they are independent of each other. CO2 is dissolved in the blood, buffered by conversion to and from bicarbonate, and crosses into the alveolus 100 times more easily than Oxygen. Oxygen is barely dissolved in the blood, being mainly carried by hemoglobin. It can be displaced by Carbon Monoxide CO, but not CO2. It doesn't bond hemoglobin.

Panic due to suffocation / drowning is caused by hypoxia (too low of oxygen), regardless of what the CO2 levels are doing. Gradually raising CO2 in the face of plenty of oxygen at first causes an increased heart rate and respiratory rate in response to metabolic acidosis, then a threshhold is reached and the heart and respiratory centers are suppressed.
 
Hurley said:
This I can't agree with. CO2 does not displace oxygen, they are independent of each other. CO2 is dissolved in the blood, buffered by conversion to and from bicarbonate, and crosses into the alveolus 100 times more easily than Oxygen. Oxygen is barely dissolved in the blood, being mainly carried by hemoglobin. It can be displaced by Carbon Monoxide CO, but not CO2. It doesn't bond hemoglobin.
Click to expand...
I was effering about CO<sub>2</Sub>displacing air in tank, not in blood.
Hurley said:
Panic due to suffocation / drowning is caused by hypoxia (too low of oxygen), regardless of what the CO2 levels are doing. Gradually raising CO2 in the face of plenty of oxygen at first causes an increased heart rate and respiratory rate in response to metabolic acidosis, then a threshhold is reached and the heart and respiratory centers are suppressed.
Click to expand...
Well, I can say only what I've observed. When CO<sub>2</Sub>is being added slowly mice just fall asleep. I know that this is the way mice are treated in Unversity I was studying as I was curious and I asked about it.
 
Allow me to disagree with the NYU guidelines in favor of the AVMA guidelines, which in 2000 basically said that the only problem with euthanasia by exposure to a high concentration of CO2 was that it could cause deep unconsciousness rather than death (so apparently-dead animals have to be kept in the chamber for several minutes until they are actually dead, or another method of killing used after they're unconscious), and that it does cause distress in some species (animals that are capable of surviving without oxygen for a long time).

From personal experience, in a very well-charged chamber full of CO2, mice will be unconscious before I have even set them on the floor of the chamber, and rats have just enough time to stand before slumping forward, unconscious. I've never seen any struggle, attempt escape, or fear-defecate, so short of postmortem serum cortisol level testing, I can't get any more evidence to suggest that it's a very humane method for in-home use. Also, for what it's worth, I would euthanize my pet rodents this way if my access to vet care were restricted for some reason; this isn't just something I would do to feeder rodents.
 
I think I posted this in another thread, just can't remember where. A colleague of mine got the brilliant idea while we were running hot water on dry ice in the sink to take a good whiff of it. He stuck his head in the vapor and took one decent breath and nearly went down. He said he just saw stars and black, no pain, no sensation at all, really, just felt like he was going to pass out.

As for my personal observations of mice in CO2 vapor from dry ice, they are unconscious almost immediately. You do have to wait for enough CO2 to build up in the system to cause respiratory arrest leading to death by hypoxia once they stop breathing. <i>(That's the point where you see the "agonal" gasping breathing which is a reflex of the diaphragm in response to low oxygen levels. The mice aren't conscious at that point. Agonal gasping is a life-saving mechanism that the body uses to sustaining itself in the case of some event causing temporary respiratory arrest. It tries to keep some oxygen coming in while waiting for the respiratory center to kick back in.)</i> I leave them in the chamber for a couple minutes after they stop breathing to ensure they don't recover, then place them immediately in the freezer.

Like Rhinecat, I follow the AVMA guidelines, and I wouldn't hesitate to put down a pet rodent the same way.
 
OK I have a question. Would there be a problem if the feeders were put in a container then placed in a deep freezer instead of using the CO2 first? because when things die by freezing to death there is no pain and the victim will fall asleep long before death occurs right? Or is this just unethical to do? :shrugs:
 
You must log in or register to reply here.
Back
Top