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Stuart McArthur B Vet Med MRCVS
Veterinary Liaison Officer of the British Chelonia Group
The Tortoise Clinic
Holly House Veterinary Surgery
468 Street Lane
Moortown
Leeds
LS17 6HA
email: hohovet@aol.com
www.hollyhousevets.co.uk
Tel 1: 0113 269 0627
Tel 2: 0113 236 9030
Fax : 0113 266 3048
Introduction
Euthanasia of a chelonian, especially in the presence of its loving owner, presents veterinary staff with many unique challenges. Everyone would wish a quick, smooth end without suffering, however in the case of chelonians, we may struggle with this for a variety of reasons. For example, the animal may be aggressive and able to inflict serious injury (see plate 1), it may not be easy to access a blood vessel, or the animal may not respond to the euthanasia technique employed within what observers would judge to be a reasonable time. Further to this, there may be a waiting room full of impatient, agitated people hoping that the consulting room you are in will quickly become available to them!
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Plate 1 |
A Snapping Turtle Chelydra serpentina. In some larger species, protective clothing and appropriate techniques should be considered and/or employed.
Such species should be examined wearing gloves. Alternatively they can be examined in greater safety after they have bitten and locked onto an object such as a towel. The handler in this picture may be better advised to wear long sleeves. |
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Whatever method is employed the animal should be exposed to the minimum of pain, trauma and distress possible during the procedure. This short article attempts to give guidelines in the humane euthanasia of chelonians under our care in order to help minimise distress to our patients, their owners and to ourselves.
Indications For Euthanasia
In general practice many animals requiring euthanasia will either have experienced horrific trauma, or they may be severely debilitated by chronic disease. However, clinicians should not underestimate a chelonians ability to respond to appropriate care. Decision making in the process of chelonian euthanasia is not easy!
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Plate 2 |
This Turkish Tortoise (Testudo graeca ibera) has been attacked by rats during its hibernation. Unfortunately chilled chelonians hibernated in boxes in out- houses are highly attractive food sources for rats.
This chelonian does not necessarily require euthanasia. It is capable of a relatively normal lifestyle with only three limbs. The animal was offered analgesia, antibiosis wound care, surgery and with appropriate nursing and she made an excellent recovery within three weeks. |
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Plate 3 |
This hatchling Russian Tortoise (Testudo horsfieldii) has been attacked by a pet dog. Extensive damage has been caused to the cranial carapace and plastron. Like the animal in plate 2 this hatchling is capable of recovery given rapid appropriate care. Analgesia, lavage of wounds and protective dressings are urgently required. Euthanasia is a serious option because recovery from such trauma is likely to be prolonged, extensive and without absolute guarantee. This animal will probably benefit from rapid referral to a specialist treatment centre. |
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Plate 4 |
This Leopard tortoise (Geochelone pardalis) is seriously ill. Several animals from the recently imported group from which this animal has come have already died and the history of the group suggests that they have been overwhelmed with a viral infection following the stress of capture and relocation. There is evidence of profound dehydration and wasting. The animal is plainly suffering and would benefit from urgent euthanasia. Histopathology and virological investigations may yield important information helpful to the future management of the remainder of the group. |
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Plate 5 |
This Testudo graeca ibera has not coped well with hibernation. It has a blood uric acid level greater than 2000um/l and a blood potassium of 9 mmol/l. The animal has not responded to fluid therapy and nursing support. It is not going to survive (McArthur 2000). Euthanasia should be undertaken and following appropriate investigation of the hibernation preparation, duration, conditions and their combined suitability, advice should be given to prevent similar future losses.
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Failure to find a suitable captive environment for an unwanted chelonian is also a possible reason for chelonian euthanasia, but given the fact that most species presented to us are recognised as endangered or seriously endangered, this author would encourage colleagues to seek assistance in rehoming these animals, rather than merely undertaking euthanasia. A "Turtle Airlift" is currently operated by the BCG. This projects prevents the release of unwanted Red eared Terrapins Trachemys scripta elegans into the wild where they devastate local amphibian populations, and removes the need for euthanasia of unwanted animals because they cant be found suitable homes. The animals are airlifted with the help of Virgin Airways to CARAPAX in Tuscany Italy, where they are maintained in a suitable captive environment without the ability to breed {Contact the author if you wish more details}.
Euthanasia Techniques
Many chelonians are capable of long periods of hibernation and possess physiological adaptations that will help them to attempt to metabolise drugs commonly employed during mammalian euthanasia whilst simultaneously surviving the vast periods of respiratory depression, anoxia and bradycardia such drugs induce. Apnoea alone may not be sufficient to precipitate death. Trachemys scripta elegans has been shown to survive up to 27 hours in a 100% nitrogen environment (Johlin and Moreland 1933). Freezing of reptiles as a method of euthanasia is not advised. There is evidence from sub-zero post-hibernation damage observed in tortoises, that painful brain and eye damage may occur prior to death from freezing. Even as a method of immobilisation prior to the employment of other methods, the operator should remember that a chilled reptile might experience pain and distress if handled inappropriately. However, freezing may be appropriate after lethal injection and pithing as described below to leave no doubt of death.
This author gives a pre-medication dose of ketamine IM (100-200mg/kg) and follows this with an intracardiac injection of 200mg/kg pentobarbitone solution and pithing. This has proven consistently effective and is currently this authors method of choice.
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Plate 6 |
Pre-medication with intramuscular ketamine (100-200mg/kg) facilitates subsequent intravenous or intracardia injections in active animals. This makes the whole process less distressing for everyone.
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Plate 7 |
Intracardiac injection of pentobarbitone is easiest achieved by a cranial approach parallel to the neck, directed towards the midline. Here a 19-gauge inch and a half needle is attached to a 5ml syringe. Intravenous injection into the jugular, subcarapacial, or dorsal tail vein is usually simple following the earlier injection of ketamine.
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Plate 8 |
Following a suitable response to the injection of lethal agents, the animal should be pithed. In small chelonians, pithing is easily performed through the roof the mouth using a dental probe. In large chelonians decapitation may need to precede pithing. Injection of formalin will achieve a similar result.
If the brain is intended for microbiology or virus isolation, making pithing impractical, it may be best to remove the central nervous system from the cranial vault as soon as is possible.
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Plate 9 |
Pithing can also be performed through the foramen magnum.
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Criteria for diagnosing death
This author regards death as the point at which recovery of brain activity is not possible. Therefore a chelonian heart that continues to beat for many hours outside of a pithed animal, in which brain function has been destroyed, should not be misconstrued as an indication of the continuation of life. The following criteria are given as a guide:
- Absence of detectable pulse or heartbeat using doppler ultrasonography, oesophageal stethoscopy, ultrasonography, ECG or pulse oximetry
- Absence of unaided respiration and a failure to return despite appropriate ventilation attempts with oxygen or air.
- Absence of reflex responses to external stimulus over several hours. Corneal and cloacal reflexes are maintained until very near death, even in hibernating animals.
- Absence of response to warming and warm fluid administration if the animal may be chilled or hibernating.
- Tissue changes such as rigor mortis, Grey / cyanotic mucous membrane colour, Sunken and deflated eyes and post mortem tissue necrosis are strongly suggestive or indicative of death.
- Absence of brain activity, or a reduction in brain activity to a point where recovery is impossible.
Johlin J.M. and Moreland F.B. (1933)
Studies on the blood of the turtle after complete anoxia.
J Biol Chem 103: 107-114
McArthur S.D.J. (2000).
Renal function in chelonians, dehydration and the stabilisation of post hibernation hyperuricaemia, hyperkalaemia and anuria.
Proc BVZS Autumn 2000 |
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