Effects of sex and age on the ossification of the collateral cartilages of the distal phalanx of the Finnhorse and the relationships between ossification and body size and type of horse.

The ossification of the collateral cartilages of the distal phalanx was evaluated in dorsopalmar radiographs of the front feet of 202 Finnhorses (101 females and 101 males, aged six months to 20 years) with reference to the sex, age, body measurements and type of horse. Ossification was more common and more extensive in females than in males from about two years of age. In females, the lateral cartilages were significantly more ossified than the medial cartilages; in males, ossification was more symmetrical in the cartilages of each foot. The amount of ossification increased rapidly during the second and third years of life, and more slowly in adults. The low positive correlation coefficients between ossification and different body measurements of the horse suggested that there was more ossification in large horses, and the correlation between chest-width in adults and the extent of ossification was statistically significant. The working type of horses showed slightly more ossification than trotters and riding horses. Ossification variables, which included ossification at both the base of the cartilage and at the possible separate centres of ossification (total ossification of individual cartilages and "possibly significant' ossification in the front feet), were found to be most satisfactory for expressing the extent of ossification.