Euthanasia by ethyl alcohol

[Mark]

I recently had the sad task of euthanizing a couple of sick newts. I opted for a homemade alcohol solution (5% ethyl alcohol) as I had access to the ingredients. The process is pretty simple; bathe the animal in a 5% solution until it’s anesthetised and then place it in a much higher concentrated solution to ensure the job is complete. One thing I wasn’t sure about was how long this procedure was going to take and as it's quite a distressing task to perform I was hoping it would be quick – it wasn’t. Each newt took on average 20 minutes to become anesthetised (perhaps even dead rather than knocked out). These were medium sized aquatic newts, around 12-13cm in length.

I would like to update the caudate culture euthanizing article with some estimates of timings for this procedure – just so people know what too expect. Jen has euthanized small larvae and suggests it takes around 5 mins for them to become sedated. A medium sized newt appears to take around 20 mins based on my example. Does anyone have experience with this method for larger caudates, for example a large 30cm axolotl? Does it vary depending on whether the animal is terrestrial or aquatic? Please post your timings and experiences below. It would also be interesting to understand timings for other humane methods as mentioned in the cc article.

 

[Azhael]

I´ve only have to do it once with a newt of a similar size as yours and it took about the same time, perhaps even a bit longer. It wasn´t nice....

 

[Molch]

I'm very glad you posted this; when I euthanized some spinner larvae last spring, I used the same method and I too thought it looked like a drawn-out death, and not an easy one. I'd say it took about 5 minutes for them to get knocked out, but I thought 5 minutes of writhing agony was too long.

When I had another two spinners later, I euthanized those by throwing them in boiling hot water. While that has a cruel ring to it, the fact is that they died instantly, within one second. It certainly looked like a better death than the one in alcohol. Obviously, this would only work for tiny larvae, never for bigger newts. These were tiny enough that the hot water killed them instantly. Still, I don't recommend that method either, although I don't know if there's a faster method. There's a potential for too much suffering if the newts is too large.

How about putting them in the fridge and then the freezer? I dunno, but at least it's a somewhat "natural" way to go, since some newts undoubtedly suffer freezing deaths in nature.

Then, there's the option of feeding small larvae to bigger newts, but you have to immobilize them somehow, which would involve injuring them in some way..

bottom line is, it may be impossible to die without suffering a bit; all I know is I won't use the alcohol method again, it was just too messy.

 

[eljorgo]

As a Chemist I think you guys are doing it wrong. I've advise Chloroform above any other substance. If takes just a few minutes/seconds for them to reach heaven. I've had a friend euthanizing adult Bufo and Pleurodeles in no time. Way more efficient and less suffering (for humans) because there is no suffering at all for them.
Cheers,

 

[Molch]

As a Chemist I think you guys are doing it wrong. I've advise Chloroform above any other substance. If takes just a few minutes/seconds for them to reach heaven. I've had a friend euthanizing adult Bufo and Pleurodeles in no time. Way more efficient and less suffering (for humans) because there is no suffering at all for them.
Cheers,

this is interesting, but is chloroform something that's available to ordinary folks?

 

[monique]

I used a solution with alcohol and it was not a quick death. 15 minuten at least....

 

[liam]

Dear all,

I have just read through the various posts under this thread and felt that I should respond in some way.

I have read into the subjects of euthanasia and anaesthesia of amphibians in as much depth as I can, and as a Veterinary Surgeon I also have real life experience of euthanasia in a variety of exotic species. I’ve read the caudata culture article that was mentioned, and I must admit to having a few concerns.

Firstly, the use of ethyl alcohol: I have never read about its use in any peer reviewed articles on the subject, and I feel that I am relatively well versed on the matter. I’ve read about MS-222, clove oil, propofol, pentobarbitone, benzocaine, isoflurane, medetomidine and ketamine, but the ONLY reference that I can find to the use of ethyl alcohol is in Krieger Publishing’s “Amphibian Medicine and Captive Husbandry”. It is worth noting that this book does NOT provide a single reference for this. The authors also mention the fact that ethyl alcohol has been used in the past in order to provide better, more realistic preservation of specimens for museum use, etc. compared to formalin. This part is true. You get much more colour bleaching etc. with formalin as opposed to ethanol. The main reason for the widespread use of formalin is that it is far cheaper. In the past many amphibians were killed for educational and scientific use using ethanol. Historically, welfare was not a major concern when obtaining specimens. Now however, it obviously is!

I have been unable to find ANY references in the literature to the use of ethanol as an immersive anaesthetic. There are a number of mentions of its use as an intravenous or oral agent in other species, but I have concerns about its efficacy via immersion, and its use in amphibians at all. Whilst I must admit to a certain naivety where the use of ethanol as an anaesthetic is concerned (I think that it is archaic?), I suspect that the osmotic gradient alone could cause severe electrolyte imbalances and damage (pain) to the animal in question, giving a fairly unpleasant death. How do we know that it isn’t just weakening and then killing these animals? As no studies seem to have been performed, I do not think that I could happily advocate this method of euthanasia as being humane, and with other much better alternatives in existence, I don’t think that anybody should be routinely practicing its use.

I have euthanased several amphibians (though admittedly most have been anurans). I have always found that an intracoelomic or intrahepatic injection of pentobarbitone has resulted in minimal stress or struggling and has provided a very efficient and fast death, usually taking less than 20 seconds (compared to the 30 minutes quoted by Wright and Whittaker). Death has been confirmed via use of a doppler ultrasound probe to ensure that the heart had actually stopped beating.

Now, I obviously don’t know each of your circumstances but as far as I am concerned if a person is to take on an animal (especially a vertebrate) it is paramount to ensure that they have the necessary funds to facilitate it’s medical treatment, should it become necessary, and also its euthanasia (when the time comes). This holds true for ALL pets and I don’t see why it should be optional for amphibians. Most vets are not unreasonable and I’d be surprised if this was to cost more than £10-20 (in some cases likely even less).

If people are looking for alternative methods for anaesthetising small larvae etc. there HAS been experimental work done on the use of clove oil in Urodelans (Mitchell et al, 2009). In this study involving 12 Tiger Salamanders, Clove Oil produced a surgical plane of anaesthesia in 8/12 animals tested. It is worth noting that the Tiger Salamanders were only exposed to immersion for 10 minutes. In the same experiment, 12/12 Leopard Frogs achieved a surgical plane of anaesthesia, but they were exposed for 15 minutes. Perhaps longer would have achieved a more ubiquitous result? Once anaesthetised, a suitable method of dispatch could be performed.

I have to express concern at some of the methods mentioned in other posts above. Immersion in boiling water whilst conscious is NEVER an acceptable method of euthanasia. Placement in the fridge and then freezer is also certainly unacceptable. Crystallisation of water molecules as temperatures drop below freezing can cause lysis of cells and pain. I think that the option of death by ingestion is, again, unacceptable as a method of humane euthanasia.

I hope that my post has not come across as hostile, it was not meant as such – only to give my perspective and experiences with this issue.

Best regards,

Liam Reid BVMS MRCVS

 

[Kaysie]

Liam, your post does not come across as hostile at all.

I think you provide a valuable insight here, and it should be something that we reflect in our resources as well. I speak for all of us when I say that we want to provide the most accurate information we can to those who keep caudates, both as pets and for research or breeding.

 

[Jake]

Here is my suggestion: forget using chemicals and making the matter that much more complicated, go to the back yard, grab a nice brick or a hammer and smash the animal. The death will not take longer than the blink of an eye, so neither the animal nor keeper will suffer. If it's a larger animal that will splatter, simply place it in a plastic bag to contain the organs and bodily fluids that would normally end up all over you and anyone else in the area.

Note: if you have terrible aim and can't hit a small target with a brick, try a cynder block....or have a friend do it.

Just a thought.

 

[Molch]

many thanks Liam for the view from a professional. I wonder if we could still find an acceptable humane home euthanasia method. Having a newt euthanized by a vet isn't always a practical option. Most vets wouldn't know anything about amphibians. I don't even have a vet in my town; the nearest one is 500 miles away and I doubt he's has ever seen a newt in his life, or would even know what a newt is.

I agree boiling water is no good. I did it one time only with two tiny deformed larvae that hadn't even reached the 4-legged stage. I did it mainly because I certainly didn't want to try the ethanol method again, which seemed cruel to me. All I know is they died instantly. Is there another, humane, method that can provide an instant death?

The clove oil thing sounds fishy. If it takes 10 to 15 minutes for them to get knocked out - again, that's far too long. That sounds no better than the ethanol method. Do we know they don't suffer during those 15 minutes?

I do think ingestion is an acceptable method. No doubt there'll be some brief suffering (is it possible to die with no suffering at all?) ; but we feed live foods to our caudates all the time, and most of us have no moral objections to chopping up an earthworm or feeding a cricket to a newt. Young larvae grow up in their parents' tank and some get eaten by siblings or adults. Larvae get eaten in ponds and creeks by adults and other predators. So if a larva must die, why not go Mama Nature's way and let it be a snack to one of the adults? Obviously not if it was diseased in some way.

anyways, interesting discussion. I hope the end result will be that we can come up with a humane, quick, home euthanasia method that is acceptable to everybody

 

[newtboyuk]

I must say I’ve been following this thread with interest (and some concerns) but Liam has beaten to me to all the salient points! With the utmost respect to everyone that has posted, there are a few that I think are worth mentioning again.

Ethyl alcohol has traditionally been used as a method to preserve amphibians better for post mortem or specimen preservation. I can’t see that it would have any significant anaesthetic or analgesic (pain relief) properties. It probably just kills them slowly. As Liam has mentioned, all of the places that mention this method have based it all on the same reference which is outdated and should probably not be perpetuated. (Perhaps time to update the CC article?)

Putting an animal in the fridge neither sedates it, provides anaesthesia or provides analgesia. It has been well established that freezing is a slow and likely painful method of euthanasia due to formation of ice crystals within the body. I do not recommend this at all. Just because something may happen in nature does not necessarily make it acceptable for a captive animal that is dependant on a carer. The only time freezing is considered acceptable is following anaesthesia and then using immersion in liquid nitrogen which is pretty much instantaneous.

With regard to hitting the animal with a brick/hammer; In theory if the brain and brainstem were destroyed in a single blow, then this would be an acceptable method of euthanasia, however any one who has any experience of severely injured amphibians (eg. squashed by cars) will know that they can take quite a long time do die even with massive injuries that would have killed a mammal instantly. For these reasons, I would not recommend this as a method of euthanasia and do not think that we should be advocating it.

Although topical benzocaine and clove oil immersion are far superior to any of the above methods, my experience working as a vet is that injectable pentobarbitone results in a rapid death through anaesthetic overdose in seconds.

My apologies if I have come across as inflammatory – it was not my intention at all. Issues of quality of life and euthanasia are ones that I have to deal with every day in work and they are unfortunately some of the most difficult but important aspects of keeping any animal.

May I ask a different question and take this thread mildly off topic? The question is essentially: Why not take it a vet?


Mark Naguib BVMS(Hons) MRCVS

 

[newtboyuk]

Hi Molch,

I can understand that a 1000 mile round trip would be pretty impractical for you but I'd suspect for the vast majority of people there would be a closer vet. I don't think that the vet necessarily needs to have any amphibian experience if the purpose of the visit is to carry out euthanasia - any vet should be able to do this.

The difference between clove oil and alcohol is that clove oil is both an analgesic and an anaesthetic which has been used for a long time, particularly in fish but also in amphibia. We do in fact know that pain sensation is vastly reduced - therefore the time is far less relevant here as (to the best of our knowledge) the animal is not suffering but rather going to sleep slowly. Clove oil is still used as a dental analgesic even today.

You do raise some interesting points regarding small larvae and ingestion. As you say, with diseased animals this would be definitely unwise. I'd also be cautious about feeding seemingly healthy animals of one species to another where they come from different geographical areas for this reason too.

Mark

 

[Otterwoman]

I, for one (and I know I'm not alone) REALLY appreciate the experts weighing in. That's one of the GREAT things about having people of all backgrounds contributing to the forum.

Can I ask a really stupid question?
Is freezing different for herps than for mammals? I know that I once had hypothermia and it was actually not unpleasant at all. I could easily have fallen asleep (I was, in fact, almost asleep) and died and I don't think I would have experienced any pain. Am I missing something?

 

[eljorgo]

Hey, well Im against vet treatment at all whe it comes to were I live. At least from all the vets I've meet, I'd put them in tears in no time in matter of caudate knowledge. I have myself a cousin, and she doesn't know practically nothing about caudates as most of her colleges. This been said, if you have a mouse, a cat, a dog, a sheep or a rabbit, yes go to the vet. If you have a urodela, yes go to vet waste your money and get nothing done. This is a very valid and truthful condition within my country. I cant speak for others. Thus in many places, such as ones I've lived before don't have a regular vet within 100km. And an exotic one within 1300km.
I have euthanized 3 ways. Jake's type of method. In this case a very fast decapitation not even a second, worked well since was a tiny morph. I've thrown one small animal into a cup of boiling water. In no time was 'boiled'. And I've tried chloroform. By far the best and cheapest thing I've ever come with. No need for ignorants, expensive procedures, doctors or a mix of them.
You do all by yourself with no time and with 100% efficiency.
Anyway it's only my point of view.
Cheers,
Jorge

 

[Molch]

May I ask a different question and take this thread mildly off topic? The question is essentially: Why not take it a vet?
Mark Naguib BVMS(Hons) MRCVS

thanks so much for weighing in.
As for the above question - trust me, if there was such a person within reach, that is the definite thing I would do.

Then again, Alaska bush vets are used to sled dogs and big animals and don't have very tender sensibilities. I bet you anything, even if we had a vet here, if I showed up with a 1-inch newt larva for euthanasia, he'd laugh and say something like "Why not just hit it with a brick?"

 

[JacksonR]

"Why not just hit it with a brick?"[/QUOTE]


I always thought newt euthanasia was odd myself. As long as the death is quick I guess.

I've had to do worse things. To make my snake eat, a petstore employee told me to chop off the baby mouse's head. I was like 9 so I did...that was not a very good experience.It didn't work either.

 

[Jake]

With regard to hitting the animal with a brick/hammer; In theory if the brain and brainstem were destroyed in a single blow, then this would be an acceptable method of euthanasia, however any one who has any experience of severely injured amphibians (eg. squashed by cars) will know that they can take quite a long time do die even with massive injuries that would have killed a mammal instantly. For these reasons, I would not recommend this as a method of euthanasia and do not think that we should be advocating it.

Well, I think it would be a miracle if a 3 inch newt survived being smashed flat by a brick with all of it's organs ruined. You may not know this (don't worry, it's not your fault) but I live in the country and I do in fact have plenty of first hand experience with severely injured amphibians on the road. When it rains here the streets become littered with smashed frogs, toads and salamanders. When their bodies are smeared into the pavement they certainly don't survive. Though I've never held a stethoscope to the jelly-like goo on the road right after one was hit to check to see if it's ruptured heart was still beating.

 

[Greatwtehunter]

I just use Orajel and I'm pretty pleased with it.

 

[Azhael]

I definitely wouldn´t recommend alcohol, it clearly causes distress.
Urethane was mentioned as an anaesthetic for amphibians in one of my courses, and benzocaine as one of the standard chemicals used for euthanasia. What do you think of urethane? would it be acceptable to use it in conjuction with a traumatic method of euthanasia (with a fully anaesthetized animal, of course)? And is benzocaine available to the public?

Nobody is saying a caudate would survive being squashed with a rock. The point is that even very traumatic deaths are not instantaneous for some reptiles and amphibians, which opens the possibility of the animal suffering. I´ve seen toads convulsion and gape after being half driven over, snakes continue to move after being beheaded, etc. I think that´s essentially the problem.

I´m personally not totally against a "natural death" in the sense of for example, like Molch says, allowing deformed larvae to be predated. I can´t find a reason that invalidates it as inmoral. However, i fully agree that when it comes to artifitially ending an animal´s life we should strive to use the fastest most painless method available to us, and i don´t think alcohol qualifies, so thank you very much for offering a professional perspective, Liam and Newtboyuk, i too apreciate your contribution very much.

 

[Greatwtehunter]

Benzocaine is readily available to the general public. It's the active ingredient in many over the counter topical anesthetic ointments i.e Orajel, Anbesol, Anacaine, even Vagisil Feminine Cream.