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In 2 Phases, determine the necessity for BSE risk mitigation practices associated with
stunning/immobilization of slaughter cattle by quantifying the concentration of GFAP in
blood from living animals and from animals exsanguinated with and without stunning
prior to sticking.
Phase I. Evaluate a post-stunning risk mitigation practice (heart defibrillation, HD)
to reduce the likelihood of nerve tissue dissemination in the blood of animals after
penetrating-captive bolt protocols.
Phase II. Establish baseline levels of a protein marker for nerve tissue (GFAP, Glial
Fibrillary Acidic Protein) in the blood of animals following stunning in commercial
processing plants within the United States.
Findings: Two studies were conducted to address the risk of material dissemination from the brain of cattle to edible tissues via blood circulation due to the utilization of penetrating captive bolt (PCB) stunning devices. In Phase 1, an electric shock (ES) was applied using a heart defibrillator after PCB stunning of cattle to stop heart activity. In Phase 2, baseline levels of a brain tissue-marker (Glial Fibrillary Acidic Protein, GFAP) were established in blood from animals following pneumatic-PCB stunning and Kosher slaughter (without stunning). In Phase 1, ES after PCB stunning produced heart fibrillation which reduced the heart rate and therefore blood circulation between stunning and sticking. In addition, GFAP was absent from the blood of cattle before and after PCB stunning with or without ES. In Phase 2, GFAP was present in the whole blood and buffy coat of 1 animal out of the 360 cattle (0.28%) stunned in twelve commercial plants with a pneumatic-PCB, and it was not detected in the blood of 30 Kosher-slaughtered animals in one commercial plant. According to that, post-stunning mitigation practices to reduce the likelihood of brain tissue dissemination in the blood would not be necessary when non-air inject PCB stunning protocols are employed.