MORPHOMETRICAL STUDY OF EQUINE HOOF AND N AVICULAR BONE

Hooves and navicular bones issuing from 95 horses, classified in 9 mor phological types, were studied. Anatomical bases were laid down about morphometry of the hoof and navicular bones and their variations accor ding to either front or hind leg, morphological type, gender, weight, size and age. Few significant differences were observed between fore a nd hind feet. Thus, the reason why navicular disease occurs most frequ ently in the front feet did not depend directly on its conformation bu t must rather be related to the weight distribution and the role of th e front leg during locomotion. All the dimensions of the navicular bon e (except for the length) were lerger in the forelimb. This phenomen r eflected probably an attempt to compensate the larger forces in the fo relimb during exercise and at rest. The hoof and navicular bone of the athletic half-blood were smaller than in the other morphological type s and this situation did not improve with increasing age. Shoeing, esp ecially if the horse is shed too precociously, might slow down hoof gr owth and result into hoof and navicular bone atrophy. Other investigat ions must determine whether adaptation in bone structure compensate fo r such unfavourable mecanical conditions. Histomorphometrical study of bone structure should be a good tool to quantify these differences. S ome hoof measurements, particularly heel height and sole surface were smaller in the gelding, but few differences were recorded between stal lion and mare. Some navicular bone dimension, particularly articular s urface width and length of the bone, were the smaller in the mare, int ermediate in the gelding and larger in the stallion. Though feet confo rmation varies little with weight, all the hoof and the navicular bone measurements were significantly correlated with body size. in the fut ure, it would be interesting to relate in farriery books standard hoov e measurements with heigth rather than with body weight. All dimension s of the navicular bone decreased with increasing age. This phenomenon is very interesting and should be taken into account when interpretin g the shape of the navicular bone in case of navicular disease.