The pattern of fatal fibrinous pneumonia (shipping fever) affecting calves in a large feedlot in Alberta (1985-1988).

Data from a retrospective field study were used to describe the epidemiology of fatal fibrinous pneumonia as it affected beef calves entering a large commercial feedlot in southwestern Alberta during the fall months of y 1985 to 1988. A chute-side computer system was used to record processing and health data on 58885 calves during this period. The large annual variation (10%-57%) in the proportion of total mortality due to fibrinous pneumonia indicated that crude mortality cannot be used in epidemiological studies as a surrogate measure of fibrinous pneumonia mortality. Yearly epidemic curves for fatal fibrinous pneumonia were very similar, with a short time interval (median, 19-22 d) between arrival and fatal disease. Fully 75% of the calves that died of fibrinous pneumonia already were sick within 2 weeks of arrival. Studies of the biological, environmental, and population factors that are present before and shortly after arrival at the feedlot are needed to identify strategies for reducing the incidence of fatal fibrinous pneumonia.