Bovine farmers' lung: a clinical syndrome in a herd of cattle

Haemophilus somnus-induced IgE in calves vaccinated with commercial monovalent H. somnus bacterins

The ability of commercially available Haemophilus somnus bacterins to elicit an immunoglobulin E (IgE) response was examined in healthy calves using enzyme-linked immunosorbent assay (ELISA) and western blotting techniques. Thirty five calves were utilized in this study. Calves in Group 1 (n=7) did not receive any H. somnus vaccination and served as negative controls. Calves in each of Groups 2-5 (n=7 each) were vaccinated on days 0 (primary) and 14 (booster) with one of four commercially available H. somnus bacterins. Sera were harvested on days 0 and 14 and at weekly intervals for a total of 45 days. Sera were tested for the presence of IgE antibodies using a bovine IgE-specific ELISA. Low levels of H. somnus-specific IgE were detected by ELISA in all animals prior to the initiation of the study. All bacterins induced IgE levels that were significantly higher than control levels. Two bacterins elicited higher IgE levels at all time points. Sera were adsorbed against washed whole cells of either Salmonella typhimurium, P. multocida, or H. somnus or extracts of H. somnus. ELISA absorbance values were significantly decreased by adsorption with washed whole cells or extracts of H. somnus, whereas adsorption with other gram-negative bacteria only minimally decreased ELISA absorbance values. These results indicate that commercially available H. somnus bacterins can induce IgE antibody as early as 14 days post-vaccination. This IgE can be detected 45 days after the primary vaccination. Results also indicate that H. somnus-specific IgE antibodies can be found in serum of some cattle, possibly induced by existing or previous sensitization.

Allergic respiratory disease

Allergic rhinitis and extrinsic allergic alveolitis are the most common allergic disorders of the bovine respiratory system. Environmental and management factors play significant roles in the pathogenesis of these disorders. When compared to infectious or toxic respiratory disease, allergic respiratory disease is relatively rare and of far less economic importance in North American cattle; however, the environmental and management conditions conducive to these diseases exist in many regions. Therefore, familiarity with the clinical and epidemiologic features of these unique diseases will aid the veterinarian in establishing an accurate diagnosis. Signs of respiratory dysfunction are common to anaphylactic and anaphylactoid reactions. Early recognition of these adverse reactions will provide the practitioner with the greatest chance of successful treatment.

Respiratory diagnostic pathology

Effective treatment and control of bovine respiratory disease is dependent upon an accurate diagnosis. This article discusses the approach to diagnosis of bovine respiratory disease from the perspective of respiratory pathology. Topics covered include necropsy examination of the respiratory system, sample collection and submission, and the gross, and histopathologic lesions of the upper and lower bovine respiratory system.

The presence of precipitating antibodies in the sera of horses with chronic obstructive pulmonary disease (COPD)

The sera of horses affected and not affected with chronic obstructive pulmonary disease (COPD) were examined for precipitins to Micropolyspora faeni and Aspergillus fumigatus. Precipitins to both antigens were not restricted to COPD cases but occurred more frequently in animals affected with COPD. Many animals without detectable precipitins responded clinically to inhalation challenge with these antigens.