Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection
This study investigated changes in the electroencephalograph (EEG) power spectrum as well as physiological and behavioral responses to on-farm killing via mechanical cervical dislocation (MCD), manual cervical dislocation (CD) or intravenous pentobarbital sodium administration in lightly anesthetize...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-09-01
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| Series: | Frontiers in Veterinary Science |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fvets.2019.00297/full |
| _version_ | 1819092600715476992 |
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| author | Elein Hernandez Fiona James Stephanie Torrey Tina Widowski Karen Schwean-Lardner Gabrielle Monteith Patricia V. Turner |
| author_facet | Elein Hernandez Fiona James Stephanie Torrey Tina Widowski Karen Schwean-Lardner Gabrielle Monteith Patricia V. Turner |
| author_sort | Elein Hernandez |
| collection | DOAJ |
| description | This study investigated changes in the electroencephalograph (EEG) power spectrum as well as physiological and behavioral responses to on-farm killing via mechanical cervical dislocation (MCD), manual cervical dislocation (CD) or intravenous pentobarbital sodium administration in lightly anesthetized laying hens, to evaluate the welfare impact of each method. A mixed group of 44 white Leghorn and Smoky Joe laying hens (60 weeks-old) were anesthetized with isoflurane in oxygen and maintained at 1.5–2% isoflurane/O2 until the killing method was applied. Birds were randomly assigned to one of three experimental groups on each trial day. The EEG was recorded bilaterally in a four-electrode montage. After recording a 5-min baseline, the killing method was applied and EEGs and other behavioral and physiological responses, including convulsions, gasping, cessation of body movements and feather erection were recorded for 5 min. Changes in EEG frequency bands (alpha, beta, delta, theta), median frequency (F50), 95% spectral edge frequency (F95), and total power (Ptot) were used to assess the quality of the on-farm killing event. Within 15 s after administration of pentobarbital sodium, there were significant decreases in mean frequency bands, increases in mean F50 and F95, and decreases in Ptot, suggesting brain death. In addition, birds presented a shorter latency to cessation of movement after pentobarbital sodium injection compared to MCD and CD (22 vs. 115 s and 136 s, respectively). There were significant increases in F95 and decreases in Ptot at 120 s after application of CD; and a concomitant decrease in the frequency bands at 135 s and isoelectric EEG at 171 ± 15 s. Changes consistent with brain death after MCD included isoelectric EEG at 207 ± 23 s and a significant decreases in some frequency bands at 300 s post-application. No other significant spectrum frequency changes were observed in the MCD group, suggesting brain death likely occurred near the 5-min endpoint. There was no clear association between behavioral, physiological, and EEG responses within CD and MCD treatments. The data demonstrate that pentobarbital sodium induced a rapid death with minimal behavioral and physiological responses regardless of strain of hens. In comparison, use of CD and MCD resulted in a slow onset of brain death in hens. |
| first_indexed | 2024-12-21T22:58:12Z |
| format | Article |
| id | doaj.art-6964802930a64fcc8e3e046065e56930 |
| institution | Directory Open Access Journal |
| issn | 2297-1769 |
| language | English |
| last_indexed | 2024-12-21T22:58:12Z |
| publishDate | 2019-09-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Veterinary Science |
| spelling | doaj.art-6964802930a64fcc8e3e046065e569302022-12-21T18:47:23ZengFrontiers Media S.A.Frontiers in Veterinary Science2297-17692019-09-01610.3389/fvets.2019.00297474810Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium InjectionElein Hernandez0Fiona James1Stephanie Torrey2Tina Widowski3Karen Schwean-Lardner4Gabrielle Monteith5Patricia V. Turner6Department of Pathobiology, University of Guelph, Guelph, ON, CanadaDepartment of Clinical Studies, University of Guelph, Guelph, ON, CanadaDepartment of Animal Biosciences, University of Guelph, Guelph, ON, CanadaDepartment of Animal Biosciences, University of Guelph, Guelph, ON, CanadaCollege of Agricultural and Bioresources, University of Saskatchewan, Saskatoon, SK, CanadaDepartment of Clinical Studies, University of Guelph, Guelph, ON, CanadaDepartment of Pathobiology, University of Guelph, Guelph, ON, CanadaThis study investigated changes in the electroencephalograph (EEG) power spectrum as well as physiological and behavioral responses to on-farm killing via mechanical cervical dislocation (MCD), manual cervical dislocation (CD) or intravenous pentobarbital sodium administration in lightly anesthetized laying hens, to evaluate the welfare impact of each method. A mixed group of 44 white Leghorn and Smoky Joe laying hens (60 weeks-old) were anesthetized with isoflurane in oxygen and maintained at 1.5–2% isoflurane/O2 until the killing method was applied. Birds were randomly assigned to one of three experimental groups on each trial day. The EEG was recorded bilaterally in a four-electrode montage. After recording a 5-min baseline, the killing method was applied and EEGs and other behavioral and physiological responses, including convulsions, gasping, cessation of body movements and feather erection were recorded for 5 min. Changes in EEG frequency bands (alpha, beta, delta, theta), median frequency (F50), 95% spectral edge frequency (F95), and total power (Ptot) were used to assess the quality of the on-farm killing event. Within 15 s after administration of pentobarbital sodium, there were significant decreases in mean frequency bands, increases in mean F50 and F95, and decreases in Ptot, suggesting brain death. In addition, birds presented a shorter latency to cessation of movement after pentobarbital sodium injection compared to MCD and CD (22 vs. 115 s and 136 s, respectively). There were significant increases in F95 and decreases in Ptot at 120 s after application of CD; and a concomitant decrease in the frequency bands at 135 s and isoelectric EEG at 171 ± 15 s. Changes consistent with brain death after MCD included isoelectric EEG at 207 ± 23 s and a significant decreases in some frequency bands at 300 s post-application. No other significant spectrum frequency changes were observed in the MCD group, suggesting brain death likely occurred near the 5-min endpoint. There was no clear association between behavioral, physiological, and EEG responses within CD and MCD treatments. The data demonstrate that pentobarbital sodium induced a rapid death with minimal behavioral and physiological responses regardless of strain of hens. In comparison, use of CD and MCD resulted in a slow onset of brain death in hens.https://www.frontiersin.org/article/10.3389/fvets.2019.00297/fullanimal welfareEEGchickenpoultryeuthanasiacervical dislocation |
| spellingShingle | Elein Hernandez Fiona James Stephanie Torrey Tina Widowski Karen Schwean-Lardner Gabrielle Monteith Patricia V. Turner Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection Frontiers in Veterinary Science animal welfare EEG chicken poultry euthanasia cervical dislocation |
| title | Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection |
| title_full | Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection |
| title_fullStr | Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection |
| title_full_unstemmed | Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection |
| title_short | Evaluation of Brain Death in Laying Hens During On-Farm Killing by Cervical Dislocation Methods or Pentobarbital Sodium Injection |
| title_sort | evaluation of brain death in laying hens during on farm killing by cervical dislocation methods or pentobarbital sodium injection |
| topic | animal welfare EEG chicken poultry euthanasia cervical dislocation |
| url | https://www.frontiersin.org/article/10.3389/fvets.2019.00297/full |
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