| Abstract | Eight hundred fourteen Polypay-cross lambs, 32 to 35 days old, were housed in an isolation barn under semiconfinement conditions. The lambs were observed twice daily for clinical signs of respiratory tract disease. During the 8-week observation period, an epizootic of respiratory tract disease developed, in which the combined morbidity and mortality was approximately 13%. The overall mortality was 4.1%, of which 57.6% was attributable to pneumonia. Pasteurella haemolytica was isolated from 11 (58%) of the 19 lung specimens obtained at necropsy. Serotyping revealed the presence of multiple serotypes: A1, A2, A5, A6, A9, and A12. Viruses with properties consistent with ovine adenovirus were isolated from 36% of the lung specimens. Five of the isolates were selected to determine their antigenic serotype. Results of virus neutralization testing indicated that in this group of lambs, there was concurrent infection with Mastadenovirus ovi type 5 and type 6. |
