Reptile & Amphibian Forums

This interesting topic came up on another forum and I thought I'd bring it up here....

see: http://www.b2g2.com/boards/board.cgi?action=read&id=1125439062&user=kyherpsoc

What do you think?
Is freezing painful?

I have often wondered if over the counter barbituates (given in human dosages)...like sleep-aid, etc. would be more humane in just causing sleep and the heart to stop.

Thoughts?

I think, because of the difficulty in any kind of hypothesis being proven beyond any doubt, that I would prefer to use a method of either tranquilizing the nervous system with drugs or using blunt force that would insure a really quick death. I think that would be a more assured and humane approach. I would personally feel that there would be less suffering than by freezing. I don't think there would be any way to be positive about a lack of suffering without going through the process of freezing, subjectively, as a reptile.

Wow Dean interesting topic.

Without having read the thread my gut feel is that for those animals that are cold blooded a cooling quite probably is the most humane way of easing them along.

My thought is that the lethargy and reduced metabolism induced by such an event will be less significant than blunt trauma. Not having experienced either, it's difficult to say with certainty. Just have to trust the science as we know it.

Regards,
Jeff

N/P

It came up on another forum, some guy had some very sick iguanas that had been neglected and were "homeless".

There was a paper cited that stated a study that indicated that freezing would be very painful.

Not sure if I buy it or not...I guess the freezing, ice piercing of tissue would be very painful if the animal was "awake"...but I'd have to think they'd be deep "asleep" by the time that happened. Dunno though...

Paul Hollander provided this ...

http://www.bvzs.org/euthansiaguidelinesreptiles.htm

I wish it said WHY freezing was unacceptable.

Personally, I believe freezing is the most humane way to euthanize a reptile, though I would suggest a gradual process of cooling the animal down, rather than simply sticking it directly into the freezer, such as cooling the specimen near an A/C vent, then placing into a cooler or refrigerator, then placing it into a freezer.
Having spent some time mountaineering, I have heard a few friends, who have been trapped in a storm above base camp on Denali, mention you reach a point of euphoria when going severely hypothermic, though trying to base what an animal will feel, as relative to what a human would feel, is an anthropomorphic view and just doesn't mesh.
In the lab, the use of Ketaset – Rompun is used to sedate certain mammals, prior to injecting them with Phenobarbitol, for euthanasia, though I have heard, from an animal services euthanasia technician, the use of such on a large python proved to be less effective then gradual cooling and freezing…

Best regards,

Jeff
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Jeff Snodgres
University of Arkansas
snodgresjeffreys@uams.edu
501.603.1947

It may very well be a painless way to go when gradually freezing reptiles but I certainly would question what criteria an animal services euthanasia technician would be using when he surmised that cooling was more "effective" than euthanasia. I wonder if he means effective as in less movement or difficulty in handling or if there is actually some kind of methodology involved that would enlighten as to the python's detachment from feeling anything. From what I know of reptiles, they become less able to move as they get colder. But whether they become numb to the cold I do not know. I think if I went with freezing an animal that I would want to sedate it as well just to remove doubt.

The euthanasia technician simply described a couple of scenarios for me, regarding the use of Ketaset-Rompun and Phenobarbitol, when euthanizing a couple of large pythons, while the summarization of gradual cooling to freezing was of my own summarization, based on the description of the events given me from the euthanasia technician, as it was described both snakes appeared to have suffered severe seizures and over two hours elapsed before the snakes expired. I also based my summarization on information provided me from a zoological veterinarian, regarding the euthanasia of a geriatric specimen several years ago, though there are several new generations of anesthesia available since that time.
Unfortunately, very little research has been conducted regarding the effects of traditional anesthesia and euthanasia agents in regards to reptiles and I would be very interested in what Dr. Fredrick Frye or Dr. Douglas Mader has to say on the subject. Perhaps we can solicit a response from one of them, as this is certainly an area for which I believe there is much work to be done…

Regards,

Jeff
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Jeff Snodgres
University of Arkansas
snodgresjeffreys@uams.edu
501.603.1947

Jeff

Based on what you described concerning having seizures, I think I would definately gravitate towards freezing. At least in comparison with that type of euthanasia.

I agree that there should be more research into a variety of painless and useful methods for euthanizing reptiles. I would also be very interested in what Dr. Fredrick Frye or Dr. Douglas Mader has to say on the subject as well.

Unfortunately this would mean testing different methods of euthanasia, some of which will be found to be painfull.

In herptiles, often the heart will beat for hours after the animal has expired. (I personally have necropsied a 3/4inch tree frog 6-8hrs after death and the heart was still beating--creepy).

Much work has been done on anesthetics and analgesics in reptiles, however euth. agents have been left out. It's not work many are happy to do. Monitoring brain electrical function would probably be the best way to define death, and thus speed of euthanasia can be compared to time of pain endured. It may be possible to measure what would be defined as pain, but that would include a whole other experiment. Perhaps Mader will have revealing evidence in his new text due out this fall I believe.

As mentioned below, I still believe a clean IC injection is the fastest way to go.

Ian

if the heart's still beating, how do you conclude the animal died 8 hrs earlier? wouldn't heartbeat often be defined as the measure of life/death?
terry

This is a sticky situation with herps. It would actually take an EEG to determine brain activity which would be assumed gone once death has occured.

The continuation of a heart beat post mortem is one reason why I guestimated 8 hours. I would never cut a herp open if there were any chance it was still alive. Other signs of death appear. Obviously complete limpness without the aid of anesthetic, the lack of breathing for a long enough time to cease brain function (again, debatable and guestimated), the sunken eyes only seen on dead animals, and once begun, the lack of reflexes to painfull stimuli (like first pinching the toes, ect) without any reason for otherwise paralysis. The big picture has to be taken in and there is no one correct answer to your question.

If you are not well versed in all of this, don't assume your herp is dead until your vet has examined it. Many conditions will mimic death.

Ian

I agree with Jeff's take on this. I worked as a vet tech in the early 90's and had the unfortunate experience of euthanizing several iguanas that had such advanced MBD that their owners declined to treat them. I also euthanized some snakes during that time. We used Sodium Pentobarbital (Socumb) and although it eventually did the job it was pretty slow and it took very large doses. It seemed like the dose that it would take to euthanize a juvenile iguana in a reasonable amount of time would take down a 60lb dog.

Also consider with these medications the reptile has to experience the discomfort of either having an iv established or a cardiac injection.
Chris

Dean,

Understand the concern. Tough thing to deal with, have to accept the position of the good Mr. Snodgres. I expect he's on the money. Gentle cooling is the way to go.....IMHO.

Regards,
J.

I had read some posts about that too a while ago.I was under the impression from reading that people fall asleep when they expire from hypothermia. I once had to ride a motorcycle in EXTREMELY cold weather, not real cold but EXTREMELY cold weather and I remember beggining to lose balance, reacting very slowly and feeling very sleepy as well as getting a bit disoriented if that helps any.

Dean, we struggle with this very issue at my facility. I have found that a gradual freezing process is the best way to go for smaller sized snakes (not large constrictors like burms, etc.). We will first place a snake that needs to be put down, in a snake bag in a plastic storage container in a refrigerator for a couple of days. This brings about a gradual process of "shutting down". Once sufficiently cooled, the snake/bag/container is then placed in a freezer and the snake is typically in a restful coil at the time of death. Meds are certainly a viable and perhaps good option and we have gone that route as well but it must be done by a vet who has a lot of experience with herps.

Rob Carmichael, Curator
The Wildlife Discovery Center
Lake Forest, IL

>>This interesting topic came up on another forum and I thought I'd bring it up here....
>>
>>see: http://www.b2g2.com/boards/board.cgi?action=read&id=1125439062&user=kyherpsoc
>>
>>What do you think?
>>Is freezing painful?
>>
>>I have often wondered if over the counter barbituates (given in human dosages)...like sleep-aid, etc. would be more humane in just causing sleep and the heart to stop.
>>
>>Thoughts?
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Rob Carmichael, Curator
The Wildlife Discovery Center at Elawa Farm
Lake Forest, IL

I can't imagine that freezing is an acceptable way of euthanizing a reptile but there are better methods. I feel euthanasia should be done swiftly. It is well documented in veterinary textbooks that the heart of an iguana will beat for several hours after they have been injected with euthasol. Many unseasoned veterinarians usually will give enough to euthanize a herd of cows yet still hear a heartbeat.
At our practice we use tail veins but I feel the no lose way is the cardiac stick. It is very effective and seems to be minimally painful.
As for the topic of pain, well that is very subjective and most veterinarians could not identify pain in reptiles. We know that they have the anatomy for nerve endings that produce pain. We also know that pain is subjective, so therefore it is very hard to judge. Most veterinarians didn't start addressing pain issues in dogs and cats until the last 6 or 7 years, while some still don't.
Anyhow my $0.2
Roly

Going for 7 in a row!!!!!!!!!!
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Miami Hurricanes #1
NATIONAL CHAMPS 83,87,89,91,01

Though not seemingly likely, wouldn't it be awful if reptiles become simply unable to move yet still able to feel pain when in a cold, beyond hybernative state. I guess that would be my fear for a beloved pet. Your point about pain being "subjective" is a very key factor. How can pain be measured in a subject without reaction or the ability to react?

Even though it makes sense to me that by the time freezing takes place, causing the rupturing of tissues, that the animal would be already dead ... I still can't help but wonder if there would be some considerable amount of pain involved in part of the process where the animal is still alive.

Thanks for your thought provoking input. This is a really interesting topic. One in which I could see myself on either side of the fence on.

great topic.

people working in museum collections (back in the day) used NEMBUTOL to put down specimens. i've used pentobarbitol during lizard surgeries (for research). both of these are controlled substances, so not as easy to purchase. DEA permits can be cumbersome.

the method that gives us the best survival rate following surgery is hypothermia. this method works great for cnemidophorus. they are up and active and eating within 10 minutes of being "completely" out. do they feel pain, hard to say, but doubtful. cold is a general neurosupressor. it doesn't appear to affect one branch of the nervous sytem over another. the spinal relex is completely removed, and one would be hard pressed to explain a mechanism that preferentially knocks out motor over sensory.

hypothermia-induced torpor, followed by placing the specimen in the freezer has always been my preference.

my $0.02,

matt

"Do they feel pain?"

Doubtful is farthest from the truth. would you agree pain is subjective? A cut to me is not that bad while to some they may scream and pass out. We also know that animals have the normal pain receptors and nerves that we do. Then we must assume the foundation for sending noxious stimuli signals to the brain and therefore they can without a doubt in my mind that they feel pain. Today most are finally addressing pain, now we must get those up to the present and give it BEFORE the painful episode.

"refrigeration technique with the highest survival rate following surgery"

Could you elaborate I'm very interested in learning what you are doing. I agree the DEA makes you fill out forms but thats only for higher controlled substances. We use morphine, buprenorphine, ketoprofen, butorphanol with excellent success. Let me know I look foward to your reply!
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Miami Hurricanes #1
NATIONAL CHAMPS 83,87,89,91,01

It’s always interesting to see how different people approach differing opinions. Usually before I engage in a “discussion” I like to know who’s on the other side of the discussion. Name only, rank and serial number not so important.

I am guilty of writing a message that is not as clear as I intended – I meant to only toss in a couple of pennies. However, now that a dewlap has flared, I must at least attempt to defend what I tried to say.

“this method works great for cnemidophorus. they are up and active and eating within 10 minutes of being "completely" out. do they feel pain, hard to say, but doubtful. cold is a general neurosupressor.”

The “do they feel pain” portion of the above quote was in reference to feeling pain during the surgery, while under hypothermic anesthesia. I was not questioning whether or not they feel pain, in general, while conscious.

“I agree the DEA makes you fill out forms but thats only for higher controlled substances.”

This entire discussion was based on gathering information and opinion on what people on this forum do about euthanasia. I sincerely doubt that the DEA is going to issue permits to anyone who wants narcotics (no matter which schedule they are listed on) to knock down their snake -- hence my “cumbersome” comment. It’s not about whether you have to fill out forms, it’s about whether you can get the permit to purchase the narcotics. I have to obtain a DEA permit to use pentobarbital, phenobarbital, morphine, and testosterone. These are all controlled substances.

If someone is at an institution that allows the use of these substances for euthanasia, then they have several options. Veterinarians have these options and can offer advice. But for the hobbyist who is not associated with an institution and cannot afford to pay for the vet office call and the narcotics, it is at least worth hearing that there may be other options to consider – hence the discussion.

Matt

Matt,
I understand where you are coming from, I think you missed my message as well. It was not to raise any hairs and if my comments did, please accept my apologies. I was just curious about the hypothermia technique and wanted more info. My thoughts on pain are only an opinion. I have been a veterinary tech for 12 years and a paramedic for 2 years. Pain management is a hot topic in both fields.
From the way I understood, I assumed you were speaking from more than just a hobby standpoint (your reference to surgery). That's the reason for the DEA comments, I fill out our controlled substance paperwork and its a tedious and lengthy ordeal.
I only wanted my point of view heard and was not meaning to come off as arrogant, sorry!
Roly
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Miami Hurricanes #1
NATIONAL CHAMPS 83,87,89,91,01

hi roly,

no need for an apology. i just wanted to clarify what i was trying to say in my hastily typed contribution. this is an important and volatile issue, and i should have taken proper care in explaining my points. (dewlaps retracted)

i study sex behavior in lizards (and tortoises). in experiments where we need to manipulate steroid levels, i perform gonadectomies on the lizards. i've worked with Sceloporus, Anolis, and Cnemidophorus, and have found a higher survival rate using ice emersion than several different injectables. though we don't know for sure, the complete lack of spinal reflex suggests to us that pain is not an issue during the procedure.

matt

Your work sounds interesting. You say you have more success with cold, have you had negative results with injectables? I learned what I know of reptile anesthesia from Dr. Hernandez-Divers and harped how safe it actually is and that it is way under used in practice (provided you have little tiny ventilators for them )

Ian

i used a crude delivery method of inhalation anesthetics (isofluorane) on Sceloporus years ago and had trouble with OD. they recovered okay, but it took great amounts of time and effort during recovery.

ice worked great for Anolis and Cnemidophorus. i wouldn't want to try it for lizards any larger -- certainly no larger than Dipsosaurus. injectables were very difficult to dose correctly. too often they either didn't go down or they went down hard and we had trouble getting them to ventilate on their own. if a gonadectomy was not going well, we could keep them on ice a little longer (up to 30 minutes) without regaining consciousness during the procedure.

just my experience.

matt

For small lizards and snakes you can use the old iso/gauze in the tank gig and pull out the gauze when movement ceases. Coincidently I just did this last night with a young boa constrictor that had a rectal prolapse. It worked superb, recovery was smooth. Larger animals fight to much with this method. I would imagine it's because it takes much longer to get the lung air percentage up to the 3-5% desired.

If your patients are still breathing then they probably arn't under surgical plain anesthesia. Remember that breathing is voluntary in reptiles and this movement is lost with adequate anesthetic. No breathing is fine for short procedures (such as my rectal prolapse) but if yours are lasting over 30 minutes I would suggest getting a ventilator. There was an awesome one discussed by Dr. Hernandez-Divers in his last VIN class, but I can't recall the brand name. I don't think it's very expensive either. You can contact him via the ARAV or the University of Georgia (I"m pretty sure that's the school, let me know in a new post if I'm wrong and I"ll look it up for you).

As you know, tubing herps is easy of course and various gage cathetors are readily available.

Ian

I agree with you, but as far as cost goes, it shouldn't be a consideration with pets. I do realize that it is though, and pet's never seem to get sick at a convienient time.

Anyways, every clinic that I know of will offer a humane euthanasia without an exam or office visit fee. Many will also do it for free... The goal is to supply what's best for the animal; and taking a deathly ill, suffering pet home because you can't afford to euthanize it is not on any vet's agenda.
Remember though that they will use their judgment. The fees for this service are to pay for expertise, not materials. They can volunteer this service if they need to, but obviously it isn't fair for them to do so if the funds are available, however inconvenient.

Unfortunately, working in an emergency clinic I have a lot of experience on this topic.

Ian

"Pithing". I couldn't do it, it is too "hands on", but sever the spinal cord at the base of the skull and the animal is dead right then.

Of course, in some cases human beheading victims are reported to have looked around or mouthed words....

Heck...I don't know.

I would think that animals that hibernate normally would be better suited to cooling then freezing than a tropical animal like an iguana would. Pain is subjective enough in humans to be a difficult issue, with reptiles...who knows? I think the faster the better would be safest.

I sever from the tail and work my way back to the head, cutting 2 inch sections off until the animal stops moving.
It takes a lot of time and is quite messy, but it is fun and it works!.............. I'M KIDDING!!!!!!!!!!!!
I freeze them. I don't think I could do it any other way unless I had access to injectables.

There's a story that a scientist type was being executed via guillotine a few hundred years back. Wondering how long he would stay concious, he informed his assistant that he would blink as long as he was able to. Managed to blink 18 or so times after his head was cut off. (Afraid I don't remember where I heard the story) No telling how long brain activity would last with a snake.

IMO, for a layman (or woman) with a painfully/mortally injured animal and no way to get it to a good vet, direct blunt trauma to destroy the brain tissue immediately, (and a few whacks to make doubly sure afterwards) is probably the most humane and least botchable technique, even if very disturbing. (had to finish off a half-roadkill baby gophersnake once, and was a pathetically nervous wreck 2 days afterwards)
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0.1 chickens (Condor)
0.2 dog mutts (half ownership, only mine when they misbehave, Lucy & Amy)
0.1 Halflinger horse (Crissy)
0.1 Normal phase California Kingsnake (Sophia)
1.1 parents
Still searching for 1.0 WC human

I respect all of you in the indigo forum, it's more about the snakes than many of those other's... anyways.

Cooling a snake or any reptile for that matter reduces the metabolism of that animal. We all agree on this of course. What it does NOT reduce is the animal's awareness of what is going on. Just because they look asleep doesn't mean that they are. Cooling is not a method of anesthesia or analgesia.

Have any of you ever experienced frostbite? I know it's not just a Canadian phenomenom since I've been to Colorado when it was -20C. It burns. This is the crystalization of your cells. What happens when you freeze a reptile is that the cells begin to crystalize before death. I would imagine it feels like burning to death.

I believe the only recognized method of euthanitizing reptiles is through barbituate overdose. In snakes this is best done with an intracardiac injection. If the snake is stressed out by the handling necessary for a smooth, minimally painfull puncture, then sedation with any number of appropriate sedatives is indicated.
Dean had mentioned over the counter drug overdose. While I think this would be affective the con's to this method would include:
a)the dose needed would be huge... perhaps more than is feasable to ingest. The barbituates used to euthanatize are VERY concentrated. Euthanyl is 240mg/ml of pentobarbitol while euthanol is 350 I believe (don't have this one in clinic). I would begin with 10-20mls (2400-4800mg)for an indigo sized snake, but it's weight dependent.
b)this hasn't been used "in-clinic" before and there are no studies done on the effectiveness. It is very possible that it won't work simply because the rate of absorption via the GI tract is not fast enough to give a large enough blood concentration to cause death. Other problems would be the huge array of side effects that would be exasperated by the large amounts needed. Would the snake suffer from gastric ulceration prior to death?

Other forms of euthanatizing are used in lab animals mainly because barbituates sometimes get in the way with the studies done. They need to be done in a skilled, controlled manner or it will lead to a painfull death. An example is cervical dislocation. While quick (in small mammals), it is obvious how such a procedure could also be extremely painfull if death was not immediate.

My final recommendation is to have a veterinarian perform all euthanasias. Not only for legal concerns (yes, it is illegal to euthanitize your animals-falls under the practicing vet. med without a liscence), but morally, it's a small final reprieve for your captives.

Ian

>>Cooling a snake or any reptile for that matter reduces the metabolism of that animal. We all agree on this of course. What it does NOT reduce is the animal's awareness of what is going on. Just because they look asleep doesn't mean that they are. Cooling is not a method of anesthesia or analgesia.
>>
>>Have any of you ever experienced frostbite?

it's important not to forget mammals react to cold differently than reptiles (warm vs cold blooded). Have you ever seen a turtle or snake shiver as temps declined? Nope. But in mammals the body fights hard to resist the cooling body temps (something that would seem to be inocuous to reptiles). In mammals the muscles under the skin twitch in an effort to generate heat to fight the cold. We shiver, shake, and in general experience a reaction to cold that's at the least unpleasant and at the worst agonizing--because we're fighting it, because we must, for survival. A reptile on the other hand goes thru this dropping of body temps annually, in varying degrees depending on location. I can't lprove it, but i cast my lot with those here who believe the gradual cooling creates a condition of stupor that eventually passes into total shutdown of the systems (and death).

terry

they do move to a hibernaculum of some sort to avoid freezing (a few frogs are the exception). The react differently to cold, but they do react. Many other species never experience a cold day in their lives (relatively speaking). There is no evidence that they cannot feel the pain of freezing tissue like other animals, thus it is not a recognized form of euthanasia.

Ian

Links from the EXCELLENT Kaplan website
Euthanasia of reptiles

Decapitation of Reptiles

ciao
nazzza

"The preferred method of performing euthanasia is the injection of barbiturates into a vein or into the coelomic cavity".

Judging from what has been stated in this topic, I don't think that it is as simple as finding a single best method though. I'm sure that what may work well as an injection in one animal may cause problems in another. But from what I gather, the most humane method would involve sedation through an effective drug agent.

The most eye opening thing about this whole topic is the revelation of how very different the threshold of other animals nervous systems can be, compared to our own.

thanks for the great links Nazza

What about the way the mice are terminated at the "better" mouse and rat frozen feeder vendors?

mostly "brain-stem" animals. The frontal cortex which differentiates higher animal forms, is very small in reptiles. I do not mean to say they do not feel pain. We all know they do by our own experiences with them.
However, in medical terms..How would you want to die? Kidney failure is great, but long..Pneumonia used to be called the "old man's friend"(remember I'm an old fart)
Basically anything that just destroys the brain immediately is the "most" humane. I'm not sure decapitation falls into this catagory!

Failing that, freezing is, in my opinion, probably the best of the "other" methods. They don't immediately begin freezing cells. They lower their body temp gradually, as we would, and go quietly.
I live in CO and have experienced varying degrees of cold injury. It is not that painful and I used to be human...

Just because the heart is beating doesn't mean ANYTHING is alive(note to the beating heart of the frog post)..

(I probably should stop posting when I'm this tired!!)
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Carl W Gossett
Garage Door Herps
Monument,Colorado...northern territory of the Great Republic of Texas

Mice are often skillfully cervical dislocated. This is a recognized method of euthanasia in lab animals. Reptiles work differently enough where this may not be humane. Do we know... not really. But what about the iguana with a broken back that can still walk? Or a paralyzed reptile that 6 months down the road is up and about like nothing happened? Something to consider anyways.

Another very popular method of euthanasia in feeder rodents in carbon dioxide. A short period of suprise/exitation is followed by the anesthetic (but not analgesic) properties of the carbon dioxide, followed by suffocation by the lack of available oxygen. This doesn't work in reptiles because they utilize what is called anaerobic respiration. They can temporarily use oxygen withen the body without actually breathing. This is also considered with anesthesia in surgical patients.

All in all, I support the opinion of Dr. Barten as he is a well recognized herp vet and until his and/or the veterinary medical association's opinion changes following further research, I think it's best to run along with what they suggest.

Ian