[An attempt to create a factorial model of the epizootic process in sheep infected with S. abortus ovis]

Experiments were carried out to build up a factorial model with a group of sheep at different age in an infected region. Studied were the aspects of the disease as caused by Salmonella abortus ovis alone and in combination with Chl. ps. var. ovis. It was found that the factorial model can explain sufficiently well (77.22 per cent) the discussed system--the epizootic process with year-old females and sheep affected with pure and mixed infection. The epizootic process with a mixed infection in these animals ran its course at high intensity. In the case of a pure infection the process was more intensive with young females. With lambs it showed higher intensity when a mixed infection was present.