FOOT RADIOGRAPHY IN EUROPEAN BISON (BISON BONASUS)

Bone lengths of paired digits of front and hind limbs from 12 captive European bison (Bison bonasus) of different ages (from nine to 175 months) and sexes were measured on digital radiographs in palmarodorsal (PaD) and dorsoplantar (DPl) projections of each limb. All bone lengths were measured, and lateral/medial ratios calculated. The bone measurements included length of the canon bone condyle (LCBC), length of the first, second, and third phalanges (LP1, LP2, LP3), and overall digit length (OL). Furthermore, radiographic abnormalities such as new bone formation (NBF), soft tissue mineralization (SFT), osteolysis (OS), widened vascular channels (WVC), and soft tissue swelling (STS) were recorded using PaD, DPl, and oblique projections. NBF and SFT received a single combined grade as without radiographic changes (0), mild (one to 10 changes = 1), moderate (11 to 20 changes = 2), and severe (>20 changes = 3). OS, WVC, and STS were graded as 0 = absent and 1 = present. There were no significant differences (P > 0.1) of lateral to medial ratios for LCBC, LP1, LP2, and OL in front limbs as compared with hind limbs. Only LP3 was significantly longer (P = 0.004) in the lateral digit of the hind limbs as compared with the front limbs. For both the front and the hind limbs, the lateral LCBC, LP1, LP2, LP3 and OL were significantly longer than the respective measurements of the medial bones (P < 0.05), except for LP2 and LP3 of the hind limbs. Length measurement ratios did not vary significantly with age (P > 0.1). The most common radiographic changes were both NBF and SFT, observed in all animals from 39 months of age and older. This study provides baseline data on in vivo radiographic anatomy and evaluation of feet of European bison under field conditions.