Presented in WPSA- 2017- Orlando, USA

1. Efficacy of Koechner euthanizing device in comparison
to manual cervical dislocation and assisted manual
cervical dislocation in anesthetized layer chicks
R.M.A.S. Bandara1, S. Torrey1, A. Bolinder2, K. Schwean-Lardner3, P.V. Turner2,
and T. M. Widowski 1
1 Department of Animal Biosciences, University of Guelph, Canada
2 Ontario Veterinary Collage, University of Guelph, Canada
3 Department of Animal and Poultry Science, University of Saskatchewan, Canada

2. Introduction
• Euthanasia – good death/humane killing
• Ending of a life of an individual to minimize or
eliminate pain and distress ( AVMA, 2013)
• Humaneness of methods based on how quickly
animals lose consciousness
(AVMA, 2013; Raj et al.,2006: Erasmus et al., 2010)
Brain death and
cardiac/
respiratory
arrest
Loss of
consciousness
Rapid loss of
consciousness
Reliable
and
irreversible

3. Pain and unconsciousness
• Pain: “an unpleasant sensory and emotional experience
associated with actual or potential tissue damage”
(IASP, 1979)
• Unconscious/insensible: “a state of unawareness in
which the individual is unable to respond to normal
stimuli, including pain” (EFSA, 2006)
• Insensibility results from lesions to the reticular formation and direct injury to the
cerebral cortex or brain stem
(Parvizi, J., and A. R. Damasio. 2003, Brierley et al., 1971. French, J. D., and H. W. Magoun. 1952)
Reticular formation

4. • Death occurs due to
• Cerebral ischemia
(Insufficient blood flow to the brain to meet metabolic demand)
• Cerebral hypoxia
(Reduced supply of oxygen)
• Ideal cervical dislocation
• Between occipital lobe and the first cervical bone (C1)
Cervical dislocation
Occipital lobe
C1
(Gregory and Wotton, 1990; Erasmus et al., 2010)

5. • Mechanical cervical dislocation of poultry
• Not yet scientifically evaluated
Does the device cause immediate insensibility ?
• Preliminary study – Anesthetized chicks
(unconscious chicks)
Three different sizes of KED
Koechner Euthanasia Device (KED)

6. Objectives
• To determine the effect of anesthesia on brain stem reflexes and time of
death in layer chicks
• To determine the effect of euthanasia methods on anesthetized layer
chicks

7. Methodology
Conscious Anesthetized
Manual CD
Conscious Anesthetized
Assisted Manual CD Mechanical CD with
KED
n=8 n= 8 n=8 n=8 n= 8
Anesthetized
(2-3 day old layer chicks , BW= 41.8 ± 3.5g)

8. Anesthesia Protocol
Medetomidine
0.3 mg / kg BW
( 1mg/ml)
+
Ketamine
30mg / kg BW
(100mg/ml)
Kept in a dark
room for
10 minutes
Reflexes tested Euthanized
Only pupillary
reflex was remained

9. Assessment of insensibility
• Brain stem reflexes
• Time at loss of pupillary reflex
• Time at loss of nictitating membrane reflex
• Time at loss of corneal reflex
• Spinal reflex
• Time at loss of pedal reflex
(pinching of toe) Nictitating
membrane
Dilated
pupil
Constricted
pupil
(Erasmus et al., 2010; Dawson et al., 2009; Raj et al.,1990)

10. Assessment of brain failure and death
• Time at onset of tonic convulsions
• Time at cessation of all convulsions
• Time at cessation of heart beat
(Erasmus et al., 2010; Dawson et al., 2009; Raj et al.,1990; Blackmore and Delany. 1987)
Tonic convulsions
Stretching of leg and neck
Clonic convulsions
Severe wing flapping + Leg paddling

11. Assessment of postmortem lesions
• Neck trauma
• Skin laceration (Y/N)
• Subcutaneous hemorrhages ( 0-4 scale system)
• Transection of spinal cord (Y/N)
Hemorrhage
(score 4)
Hemorrhage scoring scale system
0 1 2 3 4
0 < 25% 26 - 50% 51 - 75% >75%

12. Brain trauma
• Macroscopically - Gross subdural hemorrhages
• Microscopically - Subdural and Parenchymal hemorrhage
0 1 2 3 4
0 < 25% 26 - 50% 51 - 75% >75%
A
B
C
Chicken brain
A • Cerebrum
B • Mid brain
C • Hind brain + Cerebellum
0 1 2 3 4
0 < 5% 5% - 10% 10 - 30% >30%

13. Statistical analysis
• Proc Glimmix procedure of SAS ver. 9.4
• Variables used to assess of insensibility and brain death
• Residuals were normally distributed
• To assess the effect of anesthesia
Comparison was done in between conscious vs anesthetized
• To assess the effect of euthanasia technique
Comparison was done among A- MCD, A- AMCD and A- KED
• Mean separation – Tukey’s Test

14. Results - Clonic and tonic convulsions
• Convulsions were seen in all conscious chicks
• 87.5% of anesthetized chicks did not show convulsions in any
methods
Treatment Abbreviation Convulsion seen
Conscious Manual CD MCD 100%
Conscious Assisted Manual CD AMCD 100%
Anesthetized Manual CD A- MCD 12.5 %
Anesthetized Assisted Manual CD A- AMCD 12.5%
Anesthetized KED A- KED 12.5%

15. Results - Effect of anesthesia on reflexes and time of death
Variable
(Time in seconds)
Conscious Anesthetized P
Duration of gasping 91.9±10.1 53.9±11.2 0.0221
Loss of pupillary reflex 95.2±5.7 72.2±5.9 0.0021
Cessation of heart beat 170.2±11.7 138.6±12.1 0.007

16. Results - Effect of euthanasia technique in anesthetized chicks
Variable
(Time in seconds)
CD Assisted Manual CD KED P
Duration of gasping 32.2±16.1b 75.7±14.9ab 103.4±13.9a 0.0233
Loss of pupillary reflex 66.7±10.6 76.7±9.6 94.4±9.6 0.0834
Cessation of heart beat 130.9±33.2b 137.9±32.5b 196.4±32.5a 0.0015

17. Results - Postmortem trauma
Skin trauma Transection of
spinal cord
Conscious Manual CD 50 % 100 %
Conscious Assisted Manual CD 25 % 100 %
Anesthetized Manual CD 12.5 % 100 %
Anesthetized Assisted Manual CD 37.5 % 100 %
Anesthetized KED 0 % 12.5 %
Spinal cord

18. Results - Subcutaneous hemorrhage in the neck
Score 1 (<25%) > Score 1
Conscious Manual CD 12.5 % 87.5 %
Conscious Assisted Manual CD 12.5 % 87.5 %
Anesthetized Manual CD 16.6 % 83.4 %
Anesthetized Assisted Manual CD 37.5 % 62.5 %
Anesthetized KED 100 % 0 %

19. Results - Brain hemorrhages in chicks
• Macroscopic and microscopic evaluation
• No subdural and parenchymal hemorrhages for any method and
any condition
Histopathology slides of brain tissues

20. Conclusion
• Conscious chicks
• longer time to loss of reflexes and death
• Anesthetized KED
• longer time of gasping and longer time to cessation of heart beat
• less neck damage.
• We predict that the KED will result in a longer time to onset of insensibility and
cessation of heart beat in conscious chicks.

21. Acknowledgements
Students and volunteers
• Kahlee Latreille
• Linda J. Caston
• Animal behavior and welfare group
• Staff- Arkell Poultry Rsearch Station