Evaluation of on-farm euthanasia of broiler breeders utilizing captive bolt, electrocution, mechanical cervical dislocation, and carbon dioxide

Authors: BOYAL, RANJIT - Auburn University; JACOBS, LEONIE - Virginia Tech; Buhr, Richard - Jeff; Harris, Caitlin; Bartenfeld Josselson, Lydia; COWLES, SAM - Aviagen; BERGANZA, ILEANA - Auburn University; BOURASSA, DIANNA - Auburn University

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2019
Publication Date: 7/14/2019
Citation: Boyal, R.S., Jacobs, L., Buhr, R.J., Harris, C.E., Bartenfeld Jossel, L.N., Cowles, S., Berganza, I.M., Bourassa, D.V. 2019. Evaluation of on-farm euthanasia of broiler breeders utilizing captive bolt, electrocution, mechanical cervical dislocation, and carbon dioxide. Poultry Science Association Meeting Abstract. 98(E-Suppl.1):27. p.11.

Interpretive Summary: none

Technical Abstract: Using manual cervical dislocation to euthanize broiler breeders can be challenging due to their size and the strength required by the operator, which can impact animal welfare. The objective was to investigate the efficacy of euthanasia with alternative methods of carbon dioxide (CO2), Turkey Euthanasia Device (TED), Koechner Euthanizing Device (KED), and electrocution in achieving rapid unconsciousness and death in broiler breeders. Euthanasia methods were applied to both males and female broiler breeders (4.4, 3.9 kg). A subset of birds (n=17) were equipped with cutaneous electrodes to monitor heart rate (electrocardiogram). To improve safety and ease of use for a single operator, all methods were performed with birds placed in a mobile bird euthanasia apparatus (MBEA). For CO2 euthanasia the head was enclosed in a small portable device for 4 min (n=64). TED was applied at the base of the comb (n=69). KED was placed at the base of the skull, perpendicular to the neck, after which the handles were pressed together (n=59). Electrocution was applied at 110 V AC for 15 s to induce cardiac fibrillation (n=70). Effectiveness was assessed based on kill success after one attempt, broken skin (presence/absence), external blood loss (presence/absence), and durations of persisting nictitating membrane reflex, gasping (rhythmic opening/closing), and musculoskeletal movements. Nonparametric data were analyzed using Chi-square and duration data using the GLM procedure of SAS with means separated by Tukey’s HSD test. There were no differences in kill success with TED and electrocution consistently reliable (100%) followed by CO2and KED (98, 97%). Broken skin and blood loss were more frequent in TED (93, 97%) than in KED (72, 68%, P=0.0032, P<0.0001), with both TED and KED resulting in more frequent skin damage and blood loss than CO2(0, 6%, P<0.0001) and electrocution (0, 3%, P<0.0001). The induced nictitating membrane reflex duration for KED (89 s) was longer than TED, CO2, and electrocution (1, 0, 0 s, P<0.0001). Gasping durations after KED application persisted significantly longer (158 s) than TED, CO2, and electrocution (4, 0, 0 s, P<0.0001). KED and TED (210, 204 s) resulted in significantly longer durations of body movement when compared to CO2 and electrocution (4, 4 s, P<0.0001). Heart rate was depressed (<180 bpm) within 88 s for all euthanasia methods. Heart beat cessation occurred more quickly for electrocution (0 s) than TED, CO2, and KED (427 to 659 s, P<0.0001). All methods were successful with CO2and electrocution resulting in minimal skin damage and blood loss. Euthanasia by electrocution resulted in the shortest duration of physiological and behavioral responses, followed by CO2, TED, and KED.