Surfactant protein D as a biomarker of bronchopneumonia in calves

Jennifer Storer, University of Tennessee

Cases/Abstracts, Honorable Mention

Title: Surfactant protein D as a biomarker of bronchopneumonia in calves.

 
Bronchopneumonia in cattle is a costly disease caused by multiple pathogens. Mannheimia haemolytica is the most frequently isolated etiologic agent and induces tremendous inflammation through the production of a leukotoxin. Surfactant protein D is produced by type II pneumocytes and is tissue specific for the lungs. During alveolar inflammation these proteins are up-regulated and may be released into the blood. We hypothesized that these proteins could be detected in the serum and serve as biomarkers for alveolar membrane damage and overall pulmonary inflammation. This study used bronchoselective endoscopic inoculation of Mannheimia haemolytica or sterile saline of the right apical lung lobe in twelve 4 month old dairy calves. Six principal calves received 3-5 x 109 colony forming units of M. haemolytica in a 5mL suspension of phosphate-buffered saline, while 6 control calves received an equivalent volume of sterile phosphate buffered saline (PBS). Serum and bronchoalveolar lavage (BAL) samples were collected to analyze surfactant protein D with a bovine specific ELISA. Serum samples were collected daily for seven days, while BAL samples were collected on days 0, 1, 3, 5, and 7. Calves were additionally assigned a clinical illness score twice daily and a datalogger outfitted with accelerometers were placed on the left rear fetlock of each calf to assess behavioral changes. We hope the results of this study will provide information for the use of surfactant proteins in the diagnosis of BRD.