Collateral damage: brain tissue in bovine lung

Transfusion, Vol. 41, No. 11, 1325, November 2001 by Lois Roth 

For veterinary pathology instruction, sections of various tissues were taken from a healthy cow killed at a United States slaughterhouse. The slaughter method involves a pneumatically activated penetrating captive bolt; during firing, the bolt, which remains attached to the barrel of the gun, protrudes about 4 inches and injects compressed air into the cranial vault. In addition to the mechanical trauma caused by the bolt, injection of air into the brain causes acute, severe fragmentation of brain tissue, with the purpose of ensuring rapid death. This method of killing has been used in the United Kingdom since 1980 and in the United States since 1982. In the photomicrograph presented here (Specimen provided by John M. King, DVM, PhD, Diplomate ACVP, Department of Biomedical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY), bovine lung tissue is visible in the lower right corner; a large plug of brain tissue sits in a branch of the pulmonary artery. Fragments of neural tissue up to 3 cm in dimension were also found in the vessels of the liver, kidney, and right ventricle of the heart; muscle tissue was not available. Bovine spongiform encephalopathy and new variant CJD have not been diagnosed in the United States, but the presence of central nervous system tissue in the vessels of visceral organs after slaughter is a cause for concern, as it may contribute to transmission of these diseases. By law, bovine products may not be fed to cattle, but they may be fed to other farm animals, providing a route of entry into the food chain. Although most organ meats are used to produce pet food, sweetbreads are also delicacy items used for human consumption. Furthermore, the wide dissemination of brain tissue by this slaughter process is likely also to involve muscle meat.


