Best way to pre-kill?

[Badgemash]

death by CO2 has nothing to do with death by loss of oxygen.

its true, mammals cannot detect a drop in blood oxygen levels or atmospheric oxygen levels, mammals dont really know whats going on and then they pass out.

BUT MAMMALS ARE AWARE OF BLOOD CO2 LEVELS AND FREAK OUT COMPLETELY WHEN A RISE IN BLOOD CO2 IS DETECTED.

thats like suffocating in a room without fresh air. its also half of the reason why drowning is so terrible. you do feel that the air is getting bad, unbreathable, you get terrified, and suffocate in agony. that is all the response to blood CO2 level increase. its sneaky and undetectible only when you have a drop in blood oxygen levels WITHOUT corresponding CO2 buildup, like when a pressurized cabin leaks or on mount everest.

with CO2, its not like getting drowsy at low pressure or high altitude. you can have that for your rhodents if you use a noble gas or nitrogen. you cannot have that when CO2 is used. if you want to grant mammals a peaceful death by an undetectible drop in oxygen so that they peaceful pass out, you can use basically anything other than CO2 to displace the oxygen. hydrogen, nitrogen, helium, argon, whatever.

just inhale some CO2 already and tell me it feels just like one of these military pressure drop experiments, i dare you. the fact is it doesnt. you get that light-headedness drowsyness without fear and panic if you overdo it with breathing helium for funny voices. CO2 is totally different and just dreadful.

I do understand what you are saying, and agree to some extent with one key point. What you are talking about is acute hypercapnia, which you would induce by precharging the chamber with CO2 or pouring water on dry ice. I agree, that would be painful and inhumane. I am talking about inducing hypoxia through oxygen displacement and and slowly increasing blood CO2. You are correct that you could also induce hypoxia with other gases, and if you chose to use and have access other gases that have backing from the veterinary community I fully support your decision to do so.

[Mike41793]

I'm going to skip over all the debate and add in a minor detail that I think may be relevant as far as CO2 goes. As military aircrew you have to do altitude chamber training regularly, most depressurization events are slow leaks (the kind you see in the movies is super rare) so it is essential to know (and be reminded at regular intervals) what hypoxia actually feels like so you can recognize it and respond appropriately. I'm assuming not many people have here have first-hand knowledge of what it feels like to actually be hypoxic.

Losing oxygen fast (we did practice that too) is pretty scary, you can feel your lungs straining and it is alarming. Slow leaks however are kind of fun. Everything in your brain slows down, things seem amusing for no reason. Your reactions slow dramatically, but it isn't alarming, more of an intriguing event that you somehow can't process. Eventually the fog gets thicker and thicker and you black out (or put your ox mask on and suddenly realize you were seeing in black and white only and didn't even notice).

I have no reason to think that rodents experience hypoxia any differently than humans, we're mammals with very similar biological processes. Thus I believe that CO2 is a humane method as long as it is done gradually. Just control the flow, however you chose to do it.

I'm giving you a gold star for sharing this. I find this very interesting.

See, pythonfriend, i TRUST something like this. "Experiencing hypoxia due to military training" and "ive tried huffing gases at home so i know what i'm talking about" are QUITE different.

[Badgemash]

Quite interesting! Thanks for sharing. Although I think we need to see this video to fully appreciate the effects of hypoxia...

I was told it was deleted, but I doubt it really was. I'll ask her when she gets into work if she still has it.

[Badgemash]

I'm giving you a gold star for sharing this. I find this very interesting.

See, pythonfriend, i TRUST something like this. "Experiencing hypoxia due to military training" and "ive tried huffing gases at home so i know what i'm talking about" are QUITE different.

Thanks, it was actually pretty funny. I had to take my mask off and do some really basic puzzles with crayons, like "color this box purple." But since the cones in the eye are very sensitive to oxygen deprivation, I was only seeing in black and white after a few minutes (I didn't realize it though) and was basically scribbling green allover the page like a two year old and giggling to myself.

[Pythonfriend]

i can be stubborn

and i will be, unless you have some studies that show that a rise of blood CO2 levels does not feel terrible for humans. yes i want studies on human subjects that, unlike rats, can be asked about what feels how.

as a fine example of a mammal i say from personal experience CO2 is dreadful, and studies done only on rhodents wont convince me otherwise. thats the problem, you think i can be convinced that CO2 is not terrible based merely on carefully observing rhodents die from it.

think of it this way: someone got sentenced to death, in the gas chamber, and oddly enough is allowed to choose the gas. and asks for advice on what gas to choose. i would advise something that does not cause a feeling of being suffocated, let alone that amplifies it. that removes HCN and CO2 from the list.

[Mike41793]

i can be stubborn

and i will be, unless you have some studies that show that a rise of blood CO2 levels does not feel terrible for humans. yes i want studies on human subjects that, unlike rats, can be asked about what feels how.

as a fine example of a mammal i say from personal experience CO2 is dreadful, and studies done only on rhodents wont convince me otherwise. thats the problem, you think i can be convinced that CO2 is not terrible based merely on carefully observing rhodents die from it.

think of it this way: someone got sentenced to death, in the gas chamber, and oddly enough is allowed to choose the gas. and asks for advice on what gas to choose. i would advise something that does not cause a feeling of being suffocated, let alone that amplifies it. that removes HCN and CO2 from the list.

Dude are you honestly illiterate? Badgesmash just posted about his MILITARY TRAINING EXPERIENCE with CO2 exposure.

You're not being stubborn, you're being utterly brainless.

[Cipher]

I'm sorry to have caused an argument.


I tried cervical dislocation for my feedings yesterday, and I think it went ok. I'm pretty sure they died instantly. I used the method in the posted Youtube video (pressing its neck down with feeding tongs and pulling by the tail) because I thought it would be easier/better than doing it with my hands. It didn't require as much force as I thought it would, but that may have been because it was only a rat pup. I don't think it will be easy once I'm doing something bigger, though, but I guess I'll learn as I go. Might even figure out an alternate arrangement before then.

Thanks everyone for your help!

[sorraia]

I'm sorry to have caused an argument.


I tried cervical dislocation for my feedings yesterday, and I think it went ok. I'm pretty sure they died instantly. I used the method in the posted Youtube video (pressing its neck down with feeding tongs and pulling by the tail) because I thought it would be easier/better than doing it with my hands. It didn't require as much force as I thought it would, but that may have been because it was only a rat pup. I don't think it will be easy once I'm doing something bigger, though, but I guess I'll learn as I go. Might even figure out an alternate arrangement before then.

Thanks everyone for your help!

If you are going to use cervical dislocation on small rats or larger, you'll need to hold both the tail and hind legs. If you hold only the tail, there's a chance it could deglove, meaning the skin is pulled off. This won't kill the rat (or at least not immediately), but would be extremely painful. Using the hind legs to help "support" the tail (for lack of better words) decreases the chance of a degloving.

Personally... I use CO2. For me, it's more foolproof (and thus more humane) than pure cervical dislocation. In my observations it does NOT induce panic and terror when done properly. In my observations, "properly" has been to slowly introduce the gas to the rats. They basically just fall asleep. If gas is introduced first or built up too quickly, there IS a panic reaction, with the animals showing absolute terror and clawing at the chamber to get out. (I found this out accidentally when doing batches of rats. Didn't realize there was still gas in the chamber when I introduced the next batch, and that's what happened. Never again will I do that.) With slow introduction, the rats fall asleep peacefully while sniffing around the chamber and exploring. A quick introduction of gas after that causes their final death.

[Borgy76]

Seems like cervical dislocation is probably the easiest method if you are going to do it one at a time for feeding, CO2 seems like it would be more appropriate if you were breeding feeder rats/mice or buying bulk live. Both methods seem to be pretty painless and easy, CO2 maybe a little more because you have to build a proper chamber, but not impossible. Seems like some members like to argue just for the sake of arguing. Reminds me of another member that is on time-out right now.

[Raven01]

if you use gas, i would advise against the use of CO2.

its rather quick, but when mammals detect a CO2 increase in the blood stream they react with panic and a feeling of asphyxiation before they die.

i think its more humane to use a gas that prevent such a CO2 buildup.

nitrogen or helium is much slower, but since there is no CO2 buildup they fall asleep peacefully.

optimal would be nitrous oxide / laughing gas. super fast and super painless, it knocks them out within a few seconds and they feel euphoria. you can cheaply buy single-use cartridges that are usually used in whipped cream dispensers. its legal to own as long as you dont use it as a drug.

edit @ tribal: i think its the mass murderer clown from the Rob Zombie movie "house of 1000 corpses"

No they don't. CO2 was the standard accepted practice to euthanize rats when I was in university. We had no "kill chambers" just our rats in clear plastic bags and CO2 cylinders. The rats did not become agitated at all, they got dopey, went to sleep and then ceased breathing. Low doses are known to cause agitated/fearful behaviour but the high concentrations showed none of this despite what some people "think" with never having had experience using it.
If carbon monoxide were more stable it would likely replace CO2 very quickly though.

EDIT: OH crap I hadn't noticed there were 4 pages of this.