Potential for carcass contamination with brain tissue following stunning and slaughter in cattle and sheep

The risk associated with the use of captive bolt guns (CBGs) in dissemination of brain tissue during preslaughter stunning has been investigated. Such dissemination poses a threat to public health in relation to possible slaughter of animals with preclinical BSE. Fragments of brain tissue were detected in the jugular venous blood of cattle and sheep slaughtered after the use of a pneumatically operated or a conventional cartridge-operated penetrating CBG. The results indicate that there is a risk of haematogenous dissemination of central nervous system (CNS) tissue with the use of penetrating CBGs. However, use of a non-penetrating CBG in either species neither caused any embolism nor did electrical stunning in sheep. We recommend further study of procedures for the stunning and slaughter of ruminants in abattoirs.