Ossification of the collateral cartilages of the distal phalanx has been studied primarily in cold blooded horses. The clinical relevance of this condition is unknown. Despite this fact, since 1939, all Swedish Ardenner stallions have had to be classified as being free from this ossification to be approved for breeding. Initially, palpation was used as a diagnostic method, but since 1982 radiology has been the only method used. The aim of this study was to assess the outcome of 68 years of breeding program. Dorsopalmar radiographs were taken of the front feet of 58 Ardenners (30 mares, 8 geldings and 20 stallions) and the ossification of the collateral cartilages was evaluated and graded according to three different scales; - Ruohoniemi (grade 0-5), - Swedish University of Agricultural Science (grade 0-3), - and a new scale (grade 0-3), developed for this study.