Reptile Wildlife Euthanasia Techniques

Lecture objectives

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  • Define euthanasia and discuss where suffering occurs within the brain
  • Provide a framework under which to evaluate euthanasia methods
  • Provide a practical process flow
  • Use the following cases to illustrate various euthanasia methods and evaluate these cases using the framework
    •  Painted turtle presents to veterinary clinic bright, alert and feisty but with a carapace fracture over the caudal spine, rear end paralysis, no deep pain in rear limbs, gross spinal fracture
    • Snapping turtle brought to a home rehabilitator, obtunded from trauma, barely alive
    • Snake, bright alert feisty, spinal fracture, no deep pain in tail

 

Abstract

The question is not, can they reason? Nor, can they talk? But, can they suffer?” –Jeremy Bentham, philosopher, 1780

Wildlife often present to veterinarians and wildlife rehabilitators with conditions that warrant euthanasia. It can be difficult, however, to apply mammalian methods of euthanasia to species with unique physiology such as reptiles. This interactive presentation will use cases to discuss practical euthanasia methods for reptiles and the (brief) physiology behind these methods compared to others. Emphasis will be placed on freshwater turtles as these represent some physiological extremes.

Please Note:  The decision whether or not to euthanize will not be covered in this course. Visit Basic Wildlife Rehabilitation Triage by Dr. Renée Schott for some guidance on this matter.

 

Recommended reading

Before the live session, Dr. Schott strongly recommends attendees read the brief article “Euthanasia: Quality of the Life” by Katherine McKeever.

This copyrighted material is reprinted with permission of the National Wildlife Rehabilitators Association from Principles of Wildlife Rehabilitation, 2nd edition, 2002 (pp 215-216).

 

Outline

This PDF version of Dr. Schott’s outline and references was available before the live event. The following PDF has extended notes for each case example.

Outline with extended case example notes

 

Define wildlife rehabilitation

Wildlife rehabilitation is the act of providing temporary care to injured, sick, or orphaned wildlife with the goal of releasing them back into the wild.1

Pain?

Reptiles have all the anatomy necessary to feel pain and suffer and therefore should be treated with the same humane standards as other species, which includes providing them with proper analgesics.2 Sladky and Mans provide a review of clinical analgesia in reptiles. 3

Legality

  • If the animal is wild, its “owner” is the State, Federal, or Tribal authority. 4
  • Some endangered or migratory species may require approval by the appropriate federal agency prior to euthanasia, however, if the animal is actively suffering, agencies will usually defer to the veterinarian’s discretion.
    • Migratory birds = U.S. Fish and Wildlife Service (USFW)
    • Marine mammals = National Oceanic and Atmospheric Administration (NOAA)
    • Rest usually = State

Define euthanasia

  • Derived from the Greek terms “eu” = well or good and “thanatos” = death. 5,6
  • Definition: ending the life of an animal in a way that eliminates or minimizes pain and distress.5,6 The technique employed should result in rapid loss of consciousness followed by cardiac or respiratory arrest and, ultimately, a loss of brain function.
  • Actually determining the pain/distress of a method of euthanasia can be very difficult because as humans we will never fully know/understand the subjective experience of the animal. 7 We use our best judgement; paddling, vocalizations, convulsions before apparent loss of consciousness is obviously suffering. We also use our knowledge of physiology and assume suffering in the absence of behaviors if a physiological process theoretically leads to suffering.
  • Pain, distress and suffering are subjective affective experiences that are perceived in the brain. Therefore, one must be conscious and alive to suffer.
  • General rule: a gentle death that takes longer is preferable to a rapid but more distressing death and conversely, if all other methods are equally humane, the quickest method should be chosen. 8
  • Taking a life is abhorrent to many. We often forget this and need to keep it in mind. 9
  • What’s the difference between euthanasia and humane killing? 6,7,9
    • Most veterinary/animal fields define euthanasia simply as “good death”, however, the human field does not. Consider the death penalty—we don’t consider these humans “euthanized” or eligible for “euthanasia”.  Applying this to animals, we do not consider healthy cattle going to slaughter to be going for euthanasia.  That’s because the decision whether or not to end a life, is central to the euthanasia definition.The decision of whether or not to end a life must be based on the animal’s welfare, that is, to anticipate what the animal would want and what is in the animal’s best interest. So even though we won’t be discussing today the decision on whether or not to euthanize, we should keep this in mind.  And finally, even though humane slaughter and humane depopulation (i.e. with animal disease outbreaks) may not be considered true euthanasia, we can consider these techniques when we are looking for the most humane way to euthanize our patients in wildlife rehabilitation.

Evaluating euthanasia methods

  • ANIMAL FACTORS
    • Ability to induce loss of consciousness and death with a minimum of pain and distress10; compatibility with species, age, and health status
    • Minimize exposure to human presence and other animals that could be perceived as predators, loud noises, stress vocalizations that can serve as sources of anxiety. 10,11
    • Time required to induce loss of consciousness5
    • Reliability/irreversibility
  • HUMAN FACTORS
    • Safety of personnel
    • Documented emotional effect on observers or operators
      • Emotional impact : The potential emotional and psychological effects on the people performing the euthanasia, and on observers must be acknowledged5
      • No matter what the situation, the act of performing euthanasia on a wild animal involves emotions. While we can’t remove the emotions, we can develop guidelines which will help make the actual decision a little easier and hopefully remove some of the doubt.”12
    • Drug availability, human abuse potential, legal requirements
      • Lay rehabilitators are often left to perform euthanasia without a veterinarian (emergency situations, evenings, weekends, etc.); alternatives need to be available for these situations in which controlled drugs, advanced training or equipment is not available.13
    • Ability to maintain equipment in proper working order
  • REMAINS (CARCASS) FACTORS: Compatibility with intended animal use and purpose
      • Intracardiac injections can potentially damage heart tissue both mechanically and chemically
      • Commercial euthanasia solutions are NOT sterile
      • Barbiturates can precipitate in tissues.14
      • Environmental impacts of the method or remains, including safety for predators or scavengers should the animal’s remains be consumed; Barbiturates should not be used where carcasses can potentially be consumed.15

We must view the above within a practical systems view/process flow

    • Handling/restraint
    • Euthanasia methods/agents: 2+ phases16; multi-stage process recommended.2,17,18,19
      • Loss of consciousness (unaware of surroundings, cannot feel pain, fear, distress)
        • Sedation = animal may be aroused to a conscious state with sufficient stimulation6
        • Anesthesia = unconsciousness and cannot be aroused6
      • Causing death
    • Confirmation of death
    • Disposal of remains, necropsy needed (and why)

 

Case examples

Case #1:  Common snapping turtle (Chelydra serpentina) brought to a wildlife rehabilitator, obtunded from trauma, barely alive

Case #2:  Painted turtle (Chrysemys picta) presents to veterinary clinic bright, alert and feisty but with an obvious carapacial fracture over the caudal spine, rear end paralysis, and no deep pain in the rear limbs

  • Use of preanesthetic medication
  • Physical methods of euthanasia
  • Unacceptable methods

Case #3:  A common garter snake (Thamnophis sirtalis) that presents bright, alert, and feisty, but with a spinal fracture and no deep pain in the tail.

  • Recommended techniques for lizards, snakes, chelonians versus crocodilians
  • Guidelines for tiny (<4 gram) patients

 

About the presenter

Renée Schott is the Medical Director and a Senior Veterinarian at the Wildlife Rehabilitation Center of Minnesota (WRCMN), one of the largest rehabilitation centers in the country. She has been involved in wildlife rehabilitation for over 15 years and has worked at WRCMN for over 8 years. Additionally, Renée is involved in teaching courses at the University of Minnesota-College of Veterinary Medicine and she is a Course Instructor for the International Wildlife Rehabilitation Council.  [MORE]

 

Webinar recording

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Expert Q&A

Although Dr. Schott was able to answer most questions during the live event, the remaining questions were answered by email and are posted below:

Which will be the appropriate volume to apply IM in forelimbs?​

I anecdotally find they tolerate their body weight in kgs = mls.

So a 0.3 kg turtle will tolerate 0.3 ml in a forelimb.

 

We do not have alfaxalone but do have midazolam, ketamine, butorphanol, and dexdomitor. What would you suggest for snappers or painted turtles?

I do not know because I haven’t had good experiences combining these drugs, but I’m sure there are others who have. I am sorry I do not have an answer for you!

Visit the LafeberVet webinar recording “Spotlight on Anesthesia & Analgesia in Reptiles” by Dr. Javier Nevarez. Although Dr. Nevarez does not focus on wildlife, he does discuss various regimens.

 

Would xylazine suffice as an anesthetic if there is no access to controlled drugs?

It is unlikely that you would be able to achieve full anesthesia with xylazine alone, but this is going to be species specific.

 

Should this [these concepts] be applied to amphibians, too?

Yes, BUT there are some species of amphibians that ARE tolerant to freezing and there is talk amongst biologist that freezing should be considered appropriate euthanasia. I DISAGREE with this because if their natural history says they freeze as part of their life cycle, freezing wouldn’t kill them. So it would need to be followed by pithing, but this is only for amphibians that freeze every winter (i.e. wood frogs).

 

RACE approval

This program 776-41764 is approved by the American Association of Veterinary State Boards (AAVSB) Registry of Continuing Education (R.A.C.E.) to offer a total of 1.00 CE credits to any one veterinarian and/or 1.00 veterinary technician CE credit. This RACE approval is for Category Two: Non-Scientific Clinical using the delivery method of Interactive-Distance/Non-Interactive Distance. This approval is valid in jurisdictions which recognize AAVSB RACE; however, participants are responsible for ascertaining each board’s CE requirements. RACE does not “accredit” or “endorse” or “certify” any program or person, nor does RACE approval validate the content of the program.

 

References