Suspected cresol poisoning in cattle presented for slaughter.

Cresol poisoning was suspected in agroup of cattle presented for slaughter at a federaly inspected plant in Illinois. Four cattle died shortly after being unloaded at the slaughter facility, while another animal died after being returned to the feedlot of origin in Iowa. The clinical signs in the affected cattle were lethargy, depression, ataxia, leg weakness, sternal recumbency, dehydration, and severe bloating. Metacresol (3-methyl phenol), commonly found in disinfectants used to clean and sanitize farm equipment and barns, was detected in rumen content from 4 necropsied animals ranging from 25.3 to 52.6 ppm. The exact source of exposure was not identified, but was probably accidental on the farm of origin or on the trailers used for animal transit to the slaughter plant.