|JACOBS, LEONIE - Virginia Tech|
|BOURASSA, DIANNA - Auburn University|
|Buhr, Richard - Jeff|
Submitted to: Animals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/28/2019
Publication Date: 2/1/2019
Citation: Jacobs, L., Bourassa, D.V., Harris, C.E., Buhr, R.J. 2019. Euthanasia: Manual versus mechanical cervical dislocation for broilers. Animals. 9:47. https://doi.org/10.3390/ani9020047.
Interpretive Summary: Poultry are euthanized for several reasons, most commonly because a bird is sick or injured and unable to eat or drink. Euthanasia can be a challenge to perform, especially when birds are older and larger, like broiler chickens (produced for meat). Manual cervical dislocation “breaking the neck” (MCD) is the most commonly applied method, but can be challenging. Therefore, using a tool - mechanical method - such as the Koechner Euthanizing Device (KED) could be an alternative. Here, we aimed to compare MCD with KED application for their impact on duration of induced reflexes and time to brain death. We assessed loss of brain stem reflexes, which indicate deep unconsciousness and/or brain stem death, and cessation of musculoskeletal movements. We applied both methods (MCD, KED) to 200 broilers of 35 and 42 days old on three experimental days. On day two and three, we added an additional method, in which the bird’s head was extended at a ~90° angle after the application of the KED (KED+). Our study indicated brain stem death occurred sooner when birds were euthanized with MCD compared to KED or KED+; all reflex durations were sustained for longer in the KED and KED+ birds.
Technical Abstract: The aim was to assess the onset of brain stem death for two euthanasia methods: Manual Cervical Dislocation (MCD) vs. Koechner Euthanizing Device (KED). On three days broilers were euthanized at 36 (n=60), 42 (n=80), or 43 days old (n=60). On days 2 and 3, a treatment was added in which the bird’s head was extended at a ~90° angle after application of the KED (KED+). On those days, gap size was estimated between the skull and the atlas vertebra. The onset of brain death was assessed by recording the nictitating membrane reflex, gasping reflex and musculoskeletal movements (sec). Additionally, skin damage and blood loss were recorded (y/n). In each batch, MCD resulted in quicker loss of reflexes and movements compared to KED or KED+. The nictitating membrane reflex returned in 0-15% of MCD birds, 50-55% of KED birds, and 40-60% of KED+ birds. Skin damage occurred in 0% of MCD birds, 68-95% of KED birds, and 85- 95% of KED+ birds. In batch 2 (P=0.065) and 3 (P=0.008), KED birds had or tended to have a narrower skull-to-atlas gap compared to MCD and KED+ birds. Based on our results, MCD would be the recommended method for broilers.