Feeder Live-Kill Mice/Rats

[ryoverde]

Question: For those critters (small/large mice, rat pups) of size not economical to get frozen, what is the most humane way to pre-kill them for feeding? I'm not very good at breaking necks on table-top edges. The guilt of the pain I'm causing is getting to me.

I'm actually, right now, considering, of all things, a cheap electronic mouse trap that claims humane kills via high voltage.

And yet, ages n' ages ago, I seem to recall the pharmacology prof in college having a really nice spring loaded neck breaker, but of course cannot find any such thing.

Local pet store subscribes to the "snake needs the exercise of killing its own prey" dogma and will not kill'em for me.

Any suggestions would help.

Thx in advance.
Cara B, SA TX
user id ryoverde

[AliCat37]

Electrocution is probably worse than what you have been doing.

I have found it easiest with large mice or any rats, to place the long end of a screwdriver or something else solid with a handle, right behind their heads with the mouse or rat on a slick surface. All you need to do is push the screw driver down wards (not very hard, you don't want them to panic, but you need them to be still) and then give a swift pull to the base of the animal's tail, or body. This dislocates the neck/spinal cord. The best part is there is no swinging the animal through the air to a table top or brick, so the animal experiences as little fear before dying as possible.
A warning though is that I have found they get nose bleeds a lot after being dislocated, so be prepared for that.

I think I sound like a serial killer. :(

[VampMN]

Have you considered CO2? I haven't done it personally, but it seems like it would be a humane way to do it, if done correctly. There are loads of tutorials and such online about building a CO2 box.

[Nanci]

I don't understand why it isn't economical to order these feeders frozen. My suppliers have all sizes of rats/mice.

AVMA Guidelines on Euthanasia (https://www.avma.org/KB/Policies/Documents/euthanasia.pdf)

[Nanci]

ELECTROCUTION

Electrocution, using alternating current, has been used as a method of euthanasia for species such as dogs, cattle, sheep, swine, foxes, and mink.113,133-138 Electrocution induces death by cardiac fibrillation, which causes cerebral hypoxia.135,137,139 However, animals do not lose consciousness for 10 to 30 seconds or more after onset of cardiac fibrillation.

It is imperative that animals be unconscious before being electrocuted. This can be accomplished by any acceptable means, including electrical stunning.25 Although an effective, 1step stunning and electrocution method has been described for use in sheep and hogs, euthanasia by electrocution in most species remains a 2-step
procedure.25, 63,140

Advantages—(1) Electrocution is humane if the animal is first rendered unconscious. (2) It does not chemically contaminate tissues. (3) It is economical.

Disadvantages—(1) Electrocution may be hazardous to personnel. (2) When conventional single-animal probes are used, it may not be a useful method for mass euthanasia because so much time is required per animal.
(3) It is not a useful method for dangerous, intractable animals. (4) It is aesthetically objectionable because of violent extension and stiffening of the limbs, head, and neck. (5) It may not result in death in small animals (< 5 kg) because ventricular fibrillation and circulatory collapse do not always persist after cessation of current flow.

Recommendations—Euthanasia by electrocution requires special skills and equipment that will ensure passage of sufficient current through the brain to induce loss of consciousness and cardiac fibrillation in the 1-step method for sheep and hogs, or cardiac fibrillation in the unconscious animal when the 2-step procedure is used. Although the method is conditionally acceptable if the aforementioned requirements are met, its disadvantages far outweigh its advantages in most applications. Techniques that apply electric current from head to tail, head to foot, or head to moistened metal plates on which the animal is standing are unacceptable.

[Nanci]

CERVICAL DISLOCATION

Cervical dislocation is a technique that has been used for many years and, when performed by well-trained individuals, appears to be humane. However, there are few scientific studies to confirm this observation. This technique is used to euthanatize poultry, other small birds, mice, and immature rats and rabbits. For mice and rats, the thumb and index finger are placed on either side of the neck at the base of the skull or, alternatively, a rod is pressed at the base of the skull. With the other hand, the base of the tail or the hind limbs are quickly pulled, causing separation of the cervical vertebrae from the skull. For immature rabbits, the head is held in one hand and the hind limbs in the other. The animal is stretched and the neck is hyperextended and dorsally twisted to separate the first cervical vertebra from the skull.72, 111 For poultry, cervical dislocation by stretching is a common method for mass euthanasia, but loss of consciousness may not be instantaneous.134
Data suggest that electrical activity in the brain persists for 13 seconds following cervical dislocation, 127 and unlike decapitation, rapid exsanguination does not contribute to loss of consciousness.128, 129

Advantages—(1) Cervical dislocation is a technique that may induce rapid loss of consciousness.84, 127
(2) It does not chemically contaminate tissue. (3) It is rapidly accomplished.

Disadvantages—(1) Cervical dislocation may be aesthetically displeasing to personnel. (2) Cervical dislocation requires mastering technical skills to ensure loss of consciousness is rapidly induced. (3) Its use is limited to poultry, other small birds, mice, and immature rats and rabbits.

Recommendations—Manual cervical dislocation is a humane technique for euthanasia of poultry, other small birds, mice, rats weighing < 200 g, and rabbits weighing < 1 kg when performed by individuals with a demonstrated high degree of technical proficiency. In lieu of demonstrated technical competency, animals must be sedated or anesthetized prior to cervical dislocation. The need for technical competency is greater in heavy rats and rabbits, in which the large muscle mass in the cervical region makes manual cervical dislocation physically more difficult.130 In research settings, this technique should be used only when scientifically justified by the user and approved by the Institutional Animal Care and Use Committee.
Those responsible for the use of this technique must ensure that personnel performing cervical dislocation techniques have been properly trained and consistently apply it humanely and effectively.

[Nanci]

CARBON DIOXIDE

Room air contains 0.04% carbon dioxide (CO2), which is heavier than air and nearly odorless. Inhalation of CO2 at a concentration of 7.5% increases the pain threshold, and higher concentrations of CO2 have a rapid anesthetic effect.53-58

Time to loss of consciousness is decreased by use of higher concentrations of CO2 with an 80 to 100% concentration providing anesthesia in 12 to 33 seconds in rats and 70% CO2 in O2 inducing anesthesia in 40 to 50 seconds.61,62 Time to loss of consciousness will be longer if the concentration is increased slowly rather than immersing the animal in the full concentration immediately.

Several investigators have suggested that inhalation of high concentrations of CO2 may be distressing to animals,63-66 because the gas dissolves in moisture on the nasal mucosa. The resulting product, carbonic acid, may stimulate nociceptors in the nasal mucosa. Some humans exposed to concentrations of around 50% CO2 report that inhaling the gas is unpleasant and that higher concentrations are noxious.67,68 For rats, exposure to increasing concentrations of CO2 (33% achieved after 1 minute) in their home cage produced no evident stress as measured by behavior and ACTH, glucose, and corticosterone concentrations in 70 serum.

Carbon dioxide has been used to euthanatize groups of small laboratory animals, including mice, rats, guinea pigs, chickens, and rabbits,5,71-76 and to render swine unconscious before humane slaughter. 22,63,64


Advantages—(1) The rapid depressant, analgesic, and anesthetic effects of CO2 are well established. (2) Carbon dioxide is readily available and can be purchased in compressed gas cylinders. (3) Carbon dioxide is inexpensive, nonflammable, nonexplosive, and poses minimal hazard to personnel when used with properly designed equipment. (4) Carbon dioxide does not result in accumulation of tissue residues in food-producing animals. (5) Carbon dioxide euthanasia does not distort murine cholinergic markers82 or corticosterone concentrations.83

Disadvantages—(1) Because CO2 is heavier than air, incomplete filling of a chamber may permit animals to climb or raise their heads above the higher concentrations and avoid exposure. (2) Some species, such as fish and burrowing and diving mammals, may have extraordinary tolerance for CO2. (3) Reptiles and amphibians may breathe too slowly for the use of CO2. (4) Euthanasia by exposure to CO2 may take longer than euthanasia by other means.61 (5) Induction of loss of consciousness at lower concentrations (< 80%) may produce pulmonary and upper respiratory tract lesions.67,84 (6) High concentrations of CO2 may be distressful to some animals.

Recommendations—Carbon dioxide is acceptable for euthanasia in appropriate species (Appendices 1 and 2). Compressed CO2 gas in cylinders is the only recommended source of carbon dioxide because the inflow to the chamber can be regulated precisely. Carbon dioxide generated by other methods such as from dry ice, fire extinguishers, or chemical means (eg, antacids) is unacceptable. Species should be separated and chambers should not be overcrowded. With an animal in the chamber, an optimal flow rate should displace at least 20% of the chamber volume per minute.85 Loss of consciousness may be induced more rapidly by exposing animals to a CO2 concentration of 70% or more by pre-filling the chamber for species in which this has not been shown to cause distress. Gas flow should be maintained for at least 1 minute after apparent clinical death.86 It is important to verify that an animal is dead before removing it from the chamber. If an animal is not dead, CO2 narcosis must be followed with another method of euthanasia. Adding O2 to the CO2 may or may not preclude signs of distress.67,87 Additional O2 will, however, prolong time to death and may complicate determination of consciousness. There appears to be no advantage to combining O2 with carbon dioxide for euthanasia.87

[MysticExotics]

I have a home made CO2 chamber. I used a shoebox sized clear plastic container, a paintball CO2 canister from a sporting goods store, along with a hose attatchment that fits the canister, secured the end of the hose in a hole I drilled in the lower corner of the plastic box, then drilled three *small* holes in the opposite top corner of the bin.

[ryoverde]

I thank you all, this is very interesting reading. Heather & CO2 generators, how do you generate your CO2? i.e. via tank, baking soda/vinegar, dry ice??? and if you separate the animals from the generation point, how?

Since I do a (whole) 4 mice a week, plus 1 rat pup a week, ordering a hundred of them would exceed recommended freeze time (3 mos). Just a smashing large quantity, eh? <g> But they keep getting back up on me.

I'm thinking cervical sep is probably the way for *me*, with my minute (/my-noot/ <g>) numbers, to go, using a long screwdriver to avoid "hands on" (and "scent on") as much as possible. Based on the (nice) information ya'll have given me, the electronic mouse trap's a losing proposition, if I've got to "whack" the poor things unconscious 1st....

As for frozen fully grown, half a dozen frozen mice costs me as much as 50 fuzzies to buy - *and* ship!!!! And 50 full grown mice at 4 mice/week...would leave me 2 mice wasted to freezer-burn every 3 mos. Factor in that *I* never expected Luke ol' boy (my biggest cornsnake <g>, but just in case it's only 'obvious' to *me*) would be big enough to need a rat pup to make him "bulge" just a wee little bit...

For *right now* at least, the live-killed is more effective for me. 6 or 8 months from now, it may be a different story.

Besides, this pet store, or one nearly like it a mile further, is my "fall back" feeding plan; what happens on the day frozen mice are *back-ordered* and I have to "fall back" on getting, say, 2 dozen mice, for hungry snakes??? There's a boy scout motto, yes? Be prepared, or something like that.

PS: To anyone reading this post whom I may have offended or anything like that by being overly blunt, etc, I hereby unreservedly apologize. As I currently have a migraine and am on a fairly high dose of migraine medications, some of which are narcotic in nature, my tendency to be blunt and "call the kettle black" is at an all time high. In fact, I probably ought to wait to reply till the meds wear off, but I am a "stubborn git." However, not a single syllable is *intended* as a slight, personal or otherwise, to anyone on this list or especially anyone who was kind enough to reply to my (stupid) query. Personalized apologies can be obtained via PM or email....

Thank you (thank you, thank you!!!!) again for your input!!!!
Cara B in SA TX
user id ryoverde (also iHerp id)

[Nanci]

One thing to consider with live or FK mice, you aren't killing off any parasites they have. Every single snake I know has a history of being fed live (never frozen) has tested positive for parasites. No big deal, except they have to be dewormed, checked, dewormed, checked again, until they are clear. One even required injections.

I also keep mice with fur longer than 3 months- the fur protects against freezer burn, and you can vacuum seal the mice easily with the sealer you can buy at the grocery store for $5.

[Lyreiania]

My mice are in my freezer for longer than three months, no harm has befallen the snakes as a result. Many areas also host reptile shows where you can buy frozen mice of all sizes directly from vendors and so can avoid high shipping costs. I know NY has reptile expos, but I do not know if Texas does. Hope that helps!

[heatwave]

I have a home made CO2 chamber. I used a shoebox sized clear plastic container, a paintball CO2 canister from a sporting goods store, along with a hose attatchment that fits the canister, secured the end of the hose in a hole I drilled in the lower corner of the plastic box, then drilled three *small* holes in the opposite top corner of the bin.

^^^ this.

I have one too. It works great and its much less horrifying then bashing them on the head, especially when I have grown attached to my little feeders.

[AliCat37]

Just like Nanci said, smaller mice get freezer burn really fast, but I keep adults for six months. I always try to have enough rodents to last me that long, otherwise it's a bit of a drive for me and my mouse guy.

[dave partington]

Here's an old thread with pics of a homemade C02 Chamber
http://www.cornsnakes.com/forums/showthread.php?t=91289