|Abstract or Summary
- In October 1977, a study was undertaken to determine the role of bovine adenovirus type 3 in enzootic pneumonia of calves, and the efficacy of using a vaccine for prevention of disease. Bovine adenovirus type 3 was isolated from the herd under study in the previous year. Calves in the herd were experiencing enzootic pneumonia associated with conjunctivitis and keratoconjunctivitis. Initial signs of disease included excessive lacrimation, pyrexia, nasal discharge and coughing. As the disease progressed, effected animals exhibited respiratory embarassment (especially upon exertion), malaise, low weight gains, and pneumonitis (as determined by the presence of dyspnea, and by stethoscopic examination for the detection of abnormal lung sounds). Forty-two one to five day old calves were randomly chosen for the study. Twenty-one calves were vaccinated with bovine adenovirus type 3 experimental vaccine. The vaccine consisted of a killed viral preparation with an aluminum hydroxide adjuvant, and was prepared by a commercial biological firm. The remaining twenty-one calves were unvaccinated controls. Two of the vaccinated calves experienced pneumonia, nine-conjunctivitis and two--keratoconjunctivitis. No fatalities occurred among the vaccinated calves. Fourteen of the vaccinated calves produced a four-fold or greater rise in the titer of serum-viral neutralizing antibodies to bovine adenovirus type 3, strain 5C. Five calves had high levels of colostral viral serum-neutralizing antibodies which interferred with active antibody production. Two calves had low levels of colostral antibodies and low levels of active antibody production. No adverse side-effect was noted at the vaccination site in any of the vaccinated animals. Eleven of the control calves experienced pneumonia, three--conjunctivitis and eleven--keratoconjunctivitis. Eight of the control calves died. Seven of the control calves produced a four-fold or greater rise in the serum-viral neutralizing antibody titer to bovine adenovirus type 3, strain 5C. Bovine adenovirus type 3 was isolated from five of the 42 calves. A second virus, believed to be bovine papular stomatitis virus, was isolated from seven calves. In only one case were both viruses isolated from the same calf.