Hoof Shape in Nigeria

Researchers in Nigeria conducted a survey of the hoof size and shape of Sudanese mares at several polo clubs throughout the country.

Thirty-four healthy shod and barefoot mares aged 12-15 years were selected for the study. Five physical measurements of hoof size and four measurements of body size (including an estimate of weight) were obtained and analyzed for correlations and comparisons between shod and unshod horses.

Left and right hooves tended to be symmetrical, while front hooves tended to be longer and wider than hind. There was a strong positive correlation between hoof size and body size with taller horses having larger and wider feet and heavier horses having longer toes. Dorsal hoof wall width (circumference) and solar length and width were significantly different between shod and unshod horses with shod horses tending to have wider and shorter hooves measured at the ground surface along with a greater hoof wall circumference.

— Oyenekan IO et al. Sahel J Vet Sci 2024;21:35-44 

Shod v. Barefoot Changes in Hoof Shape over Time

Eleven Quarter Horse mares in Michigan were used in a cross-over trial design to investigate the effects of shoeing on hoof measurements over a 7-week shoeing interval.

Hooves were trimmed and measured, then half were shod and half were left barefoot. Shoes were pulled after 7 weeks, measurements repeated and the barefoot horses were then shod and the shod horses were left barefoot. After another 7 weeks, the shoes were pulled and measurements were repeated a final time. In addition, hoof growth and wear were measured by marking the hoof wall and measuring to the hairline and ground surface before and after the 7-week interval.

Proximal hoof circumference decreased more when horses were shod, and solar circumference decreased when shod but increased when barefoot. Hoof angle increased when barefoot and decreased when shod. As expected, hoof wear was decreased with shoes. Dorsal, lateral and medial hoof growth increased during the study but surprisingly this was not affected by shoeing. The authors suggest a shorter shoeing interval may benefit horses by minimizing decreases in hoof angle and proximal hoof circumference.

— Malone SR et al. Animals 2019;9:1017

CT Measurements of Hoof Wall Thickness

Researchers in Hungary conducted two different studies using computed tomography (CT) to measure hoof wall thickness.

The first compared dorsal hoof wall thickness measurements obtained by CT with those obtained from radiographs and hands-on examination of 30 cadaver limbs from horses euthanized for unrelated reasons. The repeatability of the measurements was confirmed. The dorsal hoof wall appeared about 3 mm thicker in radiographs compared with CT images, while the hands-on anatomical measurements were only different from the CT measurements by about 0.5 mm. This study suggests measurements obtained by CT and radiographs are not directly comparable, and CT measurements may better represent the thickness of the hoof wall.

In the second study, dorsal and lateral hoof wall thickness measurements were obtained from 30 non-lame Thoroughbred racehorses and 29 non-lame warmblood show jumpers. The measurements were examined for associations with age, breed, weight and height. The warmbloods had thicker hoof walls compared with the Thoroughbreds, and the hoof walls were a little thicker medially than laterally. Heavier horses had thicker dorsal and lateral hoof walls.

— Obitayo SM. 48 and Szabo L. 49 Abstracts of the BEVA Congress EVJ 2024;56:14184

Shoeing Intervals Explored

Equine scientists worked in collaboration with a team of farriers in the United Kingdom to study changes in hoof shape before and after shoeing on a 4- to 6-week cycle.

Twenty-six sound mixed breed school horses were digitally photographed before and after trimming and shoeing with 17 measurements of the left front hoof and lower limb subsequently obtained using image analysis software. A predictive equation based on the hoof measurements was used to estimate changes in the center of pressure location before and after trimming.

As one would expect, most of the hoof measurements changed after trimming and shoeing. Overall, the vertical orientation of the hoof increased. Toe length decreased more relative to heal length resulting in increased toe and heel angles as well as increased heel height improving dorsopalmar alignment.

During the growth period, the weight-bearing surface lengthens in a forward direction negatively influencing dorsopalmar balance. Hoof-pastern axis alignment significantly improved following trimming. The center of pressure location shifted in a palmar direction during the 4- to 6-week shoeing cycle, and toe angle decreased by about 2 degrees during this time.

Regarding mediolateral balance the authors observed lateral wall angles becoming slightly more acute while medial wall angles became more upright. The authors emphasized that the changes in hoof shape and orientation during the shoeing cycle will increase palmar loading, potentially leading to underrun and collapsed heals and increased loading of the suspensory apparatus increasing susceptibility to injury. The authors advocate for a shoeing interval tailored to each individual horse, but not exceeding 6 weeks. Further, they suggest perfect mediolateral symmetry might not be the best goal when balancing the hoof instead favoring a slight lateral shift of the ground surface to reflect more normal lateral landing and unrollment patterns.

— Lesniak K et al. Animals 2017;7;0029