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Electroencephalographic, physiologic, and behavioural evaluation of cervical dislocation methods for on-farm euthanasia of poultry

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Title: Electroencephalographic, physiologic, and behavioural evaluation of cervical dislocation methods for on-farm euthanasia of poultry
Author: Hernandez Trujillo, Elein
Department: Department of Pathobiology
Program: Pathobiology
Advisor: Turner, Patricia V.
Abstract: Poultry euthanasia is a routine procedure with several welfare issues and on-farm limitations. Cervical dislocation is conditionally acceptable euthanasia method due to prolonged time to loss of sensibility and death; while barbiturate overdose is considered the gold standard method across species but is limited in practical use on-farm because barbiturates are controlled drugs. The main goal of this research was to evaluate manual cervical dislocation (CD) and mechanical cervical dislocation (MCD, using a novel device) in two different age groups of turkeys and two strains of chicken using electroencephalography (EEG) and physiologic and behavioural analysis, and compare them to barbiturate overdose. Method efficacy was assessed using spectral analysis measures and latency to isoelectric EEG (electrocerebral inactivity). Finally, EEG changes were compared to commonly used behavioural and physiologic responses as indicators of death. A minimal anesthesia model (1.5% isoflurane/O2) was used and anesthesia was discontinued immediately prior to euthanasia application to minimize welfare concerns related to physical method use. Intravenous pentobarbital sodium (1 mL/4.5 kg) induced immediate brain death in all birds with EEG activity significantly decreased at 15s post injection and corresponding isoelectric EEG in all recordings, regardless of age, strain or species. In turkeys, EEG activity during the 300s evaluation period showed changes related to brain death at 120-135s after CD and 300s after MCD application. Isoelectric EEG patterns were consistently observed after CD but not after MCD. Similarly, in end-of-lay hens, time to brain death was observed either at 135s and 285s following CD and MCD application, respectively. Again, isoelectric EEG patterns were particularly inconsistent after MCD application. The association between EEG changes and behavioural and physiologic responses was inconsistent between methods. These studies demonstrate that the MCD device used is not suitable for euthanasia of mature and young turkeys or end-of-lay hens due to prolonged time to brain death. CD was a more effective euthanasia method than MCD but showed a prolonged time to brain death. In contrast, intravenous barbiturate overdose is the preferred method of euthanasia for poultry but has practical limitations. Our findings provide quantitative information for recommendations concerning on-farm euthanasia of poultry.
Date: 2018-12
Rights: Attribution-NonCommercial-NoDerivatives 4.0 International
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Attribution-NonCommercial-NoDerivatives 4.0 International Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivatives 4.0 International