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Submitted to: Southern Poultry Science Society Meeting Abstracts
Publication Type: Proceedings Publication Acceptance Date: 1/12/2007 Publication Date: 1/23/2007 Citation: Buhr, R.J. 2007. Bioethics Symposium: Electric, Gas, or Religious Slaughter Alternatives. Southern Poultry Science Society Meeting Abstracts. P. 18-22. Interpretive Summary: Technical Abstract: The question that I was asked to address was: Is electrical stunning ethical? A stunning method would be considered ethical if the following criteria were attained. 1) Stunning results in a rapid onset of unconsciousness within a minimal time and with a minimal perception of pain. 2) The duration of the unconsciousness persists until death intervened. 3) There was a near zero occurrence of “under stunned” conscious broilers. Stunning by definition must permit the broiler to recover consciousness. Adequately electrically stunned broilers should recover consciousness, to the level of regaining the ability to maintain an erect posture, within 120 seconds following the stun. However, electrical stunning and exsanguination (bleeding) are integral steps in the slaughter of poultry and should be evaluated together in the progression to death. The term electric anesthesia is defined as, anesthesia induced from the passage of an electric current through the nervous system. This is analogous to electrical stunning and corresponds an unconsciousness level approximating the anesthesia Stage 3-medium. Electrical stunning does induce unconsciousness in poultry, but how can one determine the level of unconsciousness and therefore the inability of the broiler to perceive a pain stimuli? To answer this question the relationships of unconsciousness level and the perception of pain need to be described and agreed upon. Arthur Guedel in 1937 was the first to designate the four stages of anesthesia from consciousness through unconsciousness to death and the perception of pain. Guedel’s stages of anesthesia are listed below: Stage 1. Analgesia may be local or general - Loss of pain sensation, some disorientation or numbness, subject may remain conscious Stage 2. Excitement, delirium, epileptiform brain activity (human grand mal epileptic seizure in an unconscious state) - Loss of the ability to perceive pain, muscle reflexes are still present, involuntary struggling occurs, rapid respiration rate Stage 3. Surgical anesthesia, 3-planes Light - Skeletal muscle relaxation but reflexes are present, no voluntary muscle movement, regular respiration, palpebral and corneal reflexes present Medium - Skeletal muscle reflexes absent, palpebral reflex absent, corneal reflex sluggish Deep - Early overdose, respiration depresses (forced ventilation required), corneal reflex absent Stage 4. Medullary paralysis, death, overdose, flat line EEG - All reflexes absent, no initiation of respiration, cardiac function depressed Electroencephalograms (EEGs) record brain waves by measuring the electrical activity of the brain and are very temporally precise. EEGs from brain implanted electrodes have been used to determine the level of consciousness and activity of subjects, including broilers (Kuenzel and Walther, 1978; VanKampen, 1979). Collier et al. (2003) reported the protocol to record EEGs from conscious and stunned broiler chickens using noninvasive cutaneous electrodes and telemetry. Using these techniques, Buhr et al. (2003) were successful in recording EEGs in broilers stunned (at low or high voltages) and bled as they proceded to death. This work is being continued by ARS-Mississippi State (Poultry Research Unit) with goals to delineate the levels of unconsciousness in broilers resulting from anesthetics and then comparisons are to be made to various commercial stunning methods. The American Veterinary Medical Association panel on euthanasia (2001) describes three physical methods for euthanasia appropriate for poultry: 1) stunning with an apparatus that assures passage of the current through the brain and followed immediately by a method that ensures death such as exsanguination, decapitation, or electrocution; 2) cervical dislocation by trained personnel, and 3) electrocution if the animal is first rendered unconscious (stunned). |
