Assessing the efficacy and welfare impact of euthanasia methods for broiler chickens
| dc.contributor.advisor | Schwean-Lardner, Karen V | |
| dc.contributor.committeeMember | Buchanan, Fiona | |
| dc.contributor.committeeMember | Classen, Henry L | |
| dc.contributor.committeeMember | Brown, Jennifer | |
| dc.contributor.committeeMember | Gomis, Susantha | |
| dc.creator | Baker, Bethany Imogen 1992- | |
| dc.creator.orcid | 0000-0001-7642-190X | |
| dc.date.accessioned | 2019-07-05T20:49:06Z | |
| dc.date.available | 2019-07-05T20:49:06Z | |
| dc.date.created | 2019-11 | |
| dc.date.issued | 2019-07-05 | |
| dc.date.submitted | November 2019 | |
| dc.date.updated | 2019-07-05T20:49:06Z | |
| dc.description.abstract | This research investigated the efficacy and welfare impact of various euthanasia methods for broilers (hatchery and on-farm) by evaluating their ability to induce instantaneous insensibility and reliably result in death with minimal pain and distress. One component compared three on-farm euthanasia methods; manual cervical dislocation (CD), a mechanical cervical dislocation device (KED), and a non-penetrating captive bolt device (Zephyr). The physical damage resulting from the methods was evaluated on cadavers in the first experiment. This was followed by a second experiment using live birds evaluating the time to insensibility and death with each method. Another experiment investigated water deprivation and its effect on the efficacy of on-farm euthanasia. The KED occasionally resulted in incomplete spinal cord severing and frequently produced complex bone fractures. The Zephyr induced insensibility the fastest (under 2s post-application), however it was not reliable at successfully killing birds. CD had the shortest time to death (TTD) with 100% success rate; but had a longer time to insensibility than the Zephyr. Water deprivation increased time to death, but had no effect on the onset of insensibility. The second component examined hatchery euthanasia investigating the best method to use CO2 for neonate euthanasia. Four gradual induction (GI) flowrates and immersion (IM) into a pre-filled chamber at concentrations of 70, 80, 90 or 100% CO2, were evaluated focusing on measures of distress, insensibility and death. Distress was observed with all treatments. Distress occurred at CO2 concentrations of 0.4-1.1%, insensibility occurred at 11-18% CO2 and death at 61-78% CO2. Compared to GI, IM was more efficacious at producing rapid insensibility and death with a shorter duration of distress. For GI, increasing flowrate resulted in a linear decrease in duration of distress, latency to insensibility and death. Overall, IM into 100% CO2 was most effective, with the shortest time to insensibility and death, and lowest frequency and duration of distress. Lower IM concentrations also resulted in rapid insensibility, but increased measures of distress and TTD. In conclusion, none of the methods tested were completely efficacious and without negative welfare impact, however the majority were successful at inducing insensibility and death. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10388/12160 | |
| dc.subject | Insensibility | |
| dc.subject | Death | |
| dc.subject | On-farm euthanasia | |
| dc.subject | Culling | |
| dc.subject | Non-penetrating captive bolt | |
| dc.subject | Cervical dislocation | |
| dc.subject | Brain stem reflexes | |
| dc.subject | Behavior | |
| dc.subject | Unconsciousness | |
| dc.subject | Water deprivation | |
| dc.subject | Neonate | |
| dc.subject | Day of hatch | |
| dc.subject | Hatchery euthanasia | |
| dc.subject | Carbon dioxide | |
| dc.subject | Distress | |
| dc.title | Assessing the efficacy and welfare impact of euthanasia methods for broiler chickens | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Animal and Poultry Science | |
| thesis.degree.discipline | Animal Science | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy (Ph.D.) |