The production of calf pneumonia with Escherichia coli and a bovine picornavirus

Abstract

Six calves were inoculated intratracheally with tissue culture fluid containing bovine picornavirus 63 355 , and one day later with a broth culture of Escherichia coli. All 6 calves developed a purulent bronchopneumonia. One of 5 calves inoculated with sterile tissue culture fluid and then with E. coli developed a similar pneumonia, and 2 others developed very slight pneumonic lesions. None of 5 calves receiving picornavirus and sterile broth, and none of 4 control calves receiving tissue culture fluid and sterile broth, developed pneumonia. E. coli was recovered from lesions for up to 6 days after inoculation, and from the bronchial lymph node only on the day after inoculation.