[Case report: photosensitization followed by chronic exungulation in cattle].

Isolated cases of photosensitization in grazing cattle are observed in a greenland district of North West Germany close to the North Sea. With adequate treatment the disease usually takes a benign course. Sometimes, however, also the claws are involved in the disease process with the consequence that the photodermatitis later on is followed by chronic exungulation. Details of a respective case are described and documented by pictures: A non-pregnant heifer (age 2 years) was falling sick with acute photodermatitis and Pododermatitis/-dermatosis coronaria aseptica in late autumn (November). After treatment and housing of the patient the acute symptoms (dermatitis, lameness) subsided. About 3 months later deep horizontal circular fissures of the horn wall about 2 cm beneath the coronary band could be observed in all 8 claws - the beginning of chronic exungulation. Subsequently the distally growing "old" horn-capsulars became progressively smaller and movable. The patient, being again on pasture (on soft ground) in the next grazing season, showed recurring lameness. The lameness could be improved by repeated cutting of the horn-wall at the tip of the claws. The "new horn-shoes" had normal conformation and full weightbearing capacity. The heifer calved in September; her milkproduction was in the average of 3 years 9.428 kg. The cause of the photosensitization could not be identified.