Potential for disruption of central nervous system tissue in beef cattle by different types of captive bolt stunners

The application of pneumatic-powered air injection stunners (PPAISs), pneum atic-powered stunners (PPSs), and cartridge-fired stunners (CFSs) in commer cial beef slaughter plants was evaluated to determine the extent of dissemi nation of central nervous system tissue. Fifteen beef slaughter plants in t he western and central United States were visited to observe stunning metho ds and the condition of the hearts at postmortem inspection. As inspectors performed the normal opening of the hearts, the research observer evaluated the contents of the heart for the presence of clots and/or visible tissue segments in the right ventricle. In eight plants where PPAISs were used, 33 % of hearts examined (n = 1,050) contained large clots in the right ventric les. In the four plants where CFSs were used, 1% of the hearts (n = 480) co ntained detectable clots. In three plants where the newly modified PPSs wer e used, 12% of the hearts (n = 450) contained detectable clots. Large segme nts of spinal cord were detected collected, photographed, and confirmed his tologically from two hearts in a plant that used a PPAIS. Most of the mater ial was found in a single right ventricle and was composed of 10 to 13 cm s egments of spinal cord.