Broiler euthanasia by cervical dislocation or koechner euthanizing device: severing both carotid arteries immediately after application does not hasten the time to death

Authors: Buhr, Richard - Jeff; Harris, Caitlin; Bartenfeld Josselson, Lydia; JACOBS, LEONIE - Virginia Tech; BOYAL, RANJIT - 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: Buhr, R.J., Harris, C.E., Bartenfeld Jossel, L.N., Jacobs, L., Boyal, R., Bourassa, D.V. 2019. Broiler euthanasia by cervical dislocation or koechner euthanizing device: severing both carotid arteries immediately after application does not hasten the time to death. Poultry Science Association Meeting Abstract. 98(E-Suppl.1):130. p.53.

Interpretive Summary: none

Technical Abstract: The time to brain death during euthanasia of broilers using cervical dislocation (CD) has been partially attributed to the stretching and/or severing of the carotid arteries that would contribute to ischemia and accelerate brain hypoxia. The current study was undertaken to determine if immediately severing both carotid arteries in broilers euthanized by CD or using the Koechner Euthanizing Device-C (KED) impacted the time to cessation of musculoskeletal movements (indication of brain stem and spinal cord death). Male broilers (22/treatment) at 6 wk-of-age were assigned to either CD, CD+bled, KED, or KED+bled in sequential-rotating order. Each broiler was placed into a metal bleeding cone, either CD or KED was performed, and the bled treatments immediately had the carotid arteries severed with a handheld knife mid neck (to avoid cutting the damaged spinal cord at the base of the skull). CD was performed by 1 individual, KED and post-application observations by 2 individuals, and the necropsy and identification of the carotid arteries by 1 individual. The persistence of musculoskeletal movements was observer every 15 s for 4 min, or until there was cessation of movement for 1 min. The cessation of movement following CD occurred at 114±33 s and was significantly (P =0.0387) shorter compared to KED at 142±42 s. Compared to the not bled treatments, immediately severing both carotid arteries did not alter the cessation of movement for either CD+bled (125±38 s P=0.7281) nor KED+bled (134±40 s P=0.8339). During necropsy dissection, the severing of both carotid arteries during CD or KED was not observed and the frequency of 1 carotid artery being severed was 4/22 (18%) for CD and 2/22 (9%) for KED. Five of the 6 (CD and KED) broiler carcasses with 1 severed carotid artery had shorter than average time to cessation of movement. However, 15/38 (39%) broilers with both carotid arteries intact had the same or shorter time to cessation of movement, compared the carcasses with 1 severed carotid artery. Although the carotid arteries are frequently stretched and displaced laterally by the disarticulated neck vertebra, they predominately (86%) remain intact during both CD and KED euthanasia. These results indicate that reducing blood flow to the brain by severing the carotid arteries during euthanasia did not accelerate the time to death, and were unable to aid in explaining the physiology underlining the earlier attainment of death following CD when compared with KED. Brain ischemia most likely occurs by the severing of the bilateral vertebral arteries that occurs during both CD and KED. The ruptured vertebral arteries are likely the source of the pooled blood at the skull-vertebra gap during CD and KED euthanasia.