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 epidem iology of fatal fibrinous pneumonia as it affected beef calves enterin g a large commercial feedlot in southwestern Alberta during the fall m onths of y 1985 to 1988, A chute-side computer system was used to reco rd processing and health data on 58 885 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 u sed in epidemiological studies as a surrogate measure of fibrinous pne umonia mortality, Yearly epidemic curves for fatal fibrinous pneumonia were very similar, with a short time interval (median, 19-22 d) betwe en arrival and fatal disease, Fully 75% of the calves that died of fib rinous pneumonia already were sick within 2 weeks of arrival. Studies of the biological, environmental, and population factors that are pres ent before and shortly after arrival at the feedlot are needed to iden tify strategies for reducing the incidence of fatal fibrinous pneumoni a.