A HEMOLYTIC CELL-FREE PREPARATION OF MORAXELLA BOVIS CONFERS PROTECTION AGAINST INFECTIOUS BOVINE KERATOCONJUNCTIVITIS

Protection conferred by a cell-free preparation from a haemolytic Mora xella bovis isolate, UQV 148NF, was compared to an equivalent fraction from a non-haemolytic M. bovis isolate, Gordon 26L3, and to a recombi nant DNA-derived pill vaccine. Three groups of ten calves were vaccina ted twice with one of the three preparations and, together with ten no n-vaccinated calves, challenged with virulent M. bovis isolate Dal 2d. Compared to the control group, significant protection was observed in the group receiving the pill vaccine and the group receiving the prep aration from haemolytic isolate, UQV 148NF.