Pre-weaning pneumonia in cow-calf herds

Field investigations

Abstract

The risk factors associated with outbreaks of pneumonia in pre-weaned beef calves are not as well characterized as those associated with bovine respiratory disease in post-weaned calves. Therefore, the expertise of veterinarians is often called upon to investigate these outbreaks with the goal of identifying pertinent risk factors that may be avoided in subsequent years. Field investigations of pre-weaning beef calf pneumonia cases should begin with a review of the facts surrounding the operation, their animals, and their management. Veterinarians should attempt to describe the outbreak in terms of the animals, their locations, and timing. Among the most critical items to determine are a workable case definition that differentiates an affected calf from a non-affected calf, and dates of illness onset. When a good understanding of the various risk factors present in the outbreak is obtained, the calves and their environment should be examined to further add to the information set. Antemortem diagnostics should be considered only when there is a clear understanding of how the results will be used. In many cases, however, testing for the presence of bovine viral diarrhea virus persistently infected animals may be a worthy consideration. Significant risk factors for the herd's pre-weaning beef calf pneumonia problems may be determined simply from review of the information gained from the history and examination. Otherwise, simple calculations of incidence rates between calves in different risk factor categories, as well as risk ratios and construction of histograms, may be useful to help determine significant risk factors for the herd.