A FIELD TRIAL EVALUATING THE EFFICACY OF A PASTEURELLA HEMOLYTIC BACTERIAL EXTRACT VACCINE IN CALVES

A field trial was conducted in a closed bovine fattening unit to evalu ate the efficacy of a Pasteurella haemolytica bacterial extract vaccin e in the prevention of bronchopneumonia in calves. Two groups of twent y calves were randomly selected. The first group was vaccinated agains t most viral respiratory pathogens and served as controls. The second group was additionally vaccinated with the bacterial extract vaccine. During one year the mortality, the post mortem findings and the body w eight gain of the calves were monitored. Monthly bronchoalveolar lavag e fluids were collected for bacteriologic examination. In the calves v accinated against Pasteurella haemolytica a significantly higher body weight gain and a tendency to a reduced mortality were recorded. The v accination also resulted in a reduction of the isolation frequency of Pasteurella haemolytica, Pasteurella multocida and Actinomyces pyogene s. The results of this field trial are very promising with regards to the use of a bacterial extract vaccine against Pasteurella haemolytica in cattle.