# External Hoof Measurements of Untrimmed and Unshod Mules in Northern Thailand

## TL;DR

This study examines the hoof shape and symmetry of untrimmed and unshod mules in northern Thailand, revealing insights into their health and management.

## Contribution

The first detailed analysis of untrimmed mule hoof conformation in northern Thailand, highlighting symmetry and body condition associations.

## Key findings

- Mules showed high hoof symmetry despite no trimming or shoeing.
- Body condition scores influenced several hoof measurements.
- Sex and age had no significant effect on hoof parameters.

## Abstract

The mule has been the partner of humans for millennia, with extensive use in pack saddle and military work. Mule hoof conformation plays a crucial role in the animal’s health, performance, and welfare. Despite the long working history of mules, there has been limited published scientific research on the untrimmed and unshod mule hoof, especially considering its normal shape and sound condition. This study is the first to report on the external hoof conformation of the forelimbs of mules in northern Thailand, accompanied by an assessment of body condition scores. The mules presented homogenous hoof sizes and a high level of symmetry, with small and oval-shaped hooves featuring an upright dorsal wall angle that protrudes more palmar, influenced by the base of the frog. The body condition scores were associated with some external hoof conformation parameters. The study identified and highlighted essential parameters and features of the forelimb hooves in the mule, contributing to a better understanding of this essential aspect of the mule’s external characteristics, which should be useful in hoof management and welfare.

External hoof characteristics, balance, and conformation have been extensively studied in horses; however, mules remain understudied in these aspects. This study evaluated the size, shape, and symmetry of untrimmed and unshod forelimb hooves, compared the symmetry between forelimb hooves and stratified external forelimb hoof measurements based on the body condition score of mules raised in the foothill plains of northern Thailand. The forelimb hooves of 38 mules were photographed and 33 parameters, including angular and linear measurements, were analyzed. A multivariate analysis was used to explore the influence of sex, age, and body condition scores (BCS) on angular, linear, and area parameters. Additionally, one-way ANOVA followed by Tukey’s test was used to compare these parameters across different BCS groups. Despite the absence of shoeing and trimming, these mules exhibited optimal left–right forelimb hoof symmetry, with no significant (p < 0.05) differences in: outer wall length and inner wall length (OWL–IWL: Left 0.11 ± 0.66 cm; Right −0.12 ± 0.43 cm); sole length and sole width (SLS–SW: Left 1.65 ± 0.76 cm; Right 1.46 ± 0.89 cm); dorsal hoof wall length and heel length (DHWL–HL: Left 4.00 ± 0.80 cm; Right 3.81 ± 0.72 cm); and frog length and frog width (FL–FW: Left 3.88 ± 1.13 cm; Right 3.82 ± 0.18 cm). However, significant (p < 0.05) differences were observed within each body condition score group for forelimb hoof measurements for DHWL, IWL, heel separation (HS), heel bulb distance (HBD), SW, FW, and FL, while sex and age had no significant differences across the study variables. These findings provide valuable insights into mule welfare and management, contributing to understanding of the interplay between overall health and hoof conformation in the study area.