The role of endotoxin in the pathogenesis of acute bovine laminitis.

To study the possible role of endotoxin in the pathogenesis of bovine laminitis, local and systemic injections of endotoxin (E. coli 0111 B4) with different doses were given to three groups of four cows each. Clinical and haematologic parameters indicated an acute-phase response, including positive plasma ethanol gelation (soluble fibrin), the occurrence of fibrin degradation products and decreased thrombocyte counts. Local Shwartzman reactions were not evoked. Clinical examination of the claws and the gait of the animals revealed no signs of laminitis. However, on histopathological examination of the claw corium signs of laminitis such as vacuolisation of the Stratum basale, lymphocyte and leucocyte infiltration and thrombosis were found. These results indicate that endotoxin indeed may be involved in the pathogenesis of laminitis. For the development of a clinical acute laminitis model in cattle either another dosage, other toxins or factors in addition to the endotoxin used in this experiment are needed.