Foot lameness in horses remains the most significant cause of musculo-skeletal problems; despite this there is little evidence-based literature to identify the cause of lameness in the horse’s hoof. The structures of the palmar hoof capsule have received little attention, despite the association with lameness in this area of the hoof, and the association with asymmetry. The study aimed to determine if the hoof capsule, in particular the heel angle and palmar collateral groove height and angle, had the potential to affect the health of the corium layer, and whether the health of the corium was likely to contribute to lameness and a decrease in performance. The characteristics of the continually growing external hoof were examined, including the scaling properties. A loading test compared the hoof wall displacement of the untrimmed and trimmed hoof shapes. The corium appearance was observed and quantified. A case study series provided examples of applied theory in a practical setting. The results showed that the hoof capsule scaling is unequal, and is different in small ponies <120cm compared to all other horse sizes. The scaling properties of the continually growing hoof describe two distinct hoof capsule shapes defined by the heel angle. The untrimmed hoof shape is described as converging with a shallower heel angle, which is different to the freshly trimmed hoof shape, which is described as diverging with a steeper heel angle. The displacement of the two hoof shapes differed in a loading situation, where the heel angle and palmar collateral groove angle of the two hoof shapes displaced in opposite directions, resulting in the weight-bearing length of the loaded converging hoof wall becoming shorter than that of the diverging hoof wall, which became longer. A higher heel angle was associated with improved appearance of the dorsal lamellae corium. All sample hooves showed that corium appearance was altered, which was not expected. A case study series showed all horses’ study key indicators of change improved from regular movement and intervals between trimmings of 4-21 days. The study concluded that there are benefits to performance and welfare by maintaining a steeper heel angle. The hoof has a quicker response time to changes in heel angle than previously quantified, requiring more frequent trimming than currently recommended. This study shows that the angle of the heel is a more important factor in hoof shape change than may have been previously understood. Furthermore, researchers must quantify the continually growing hoof shape more accurately to define hoof shape in comparative studies to reduce bias; including structures of the palmar hoof.
|Qualification||Master of Philosophy|
|Place of Publication||Australia|
|Publication status||Published - 12 Jul 2019|