title: Hoof shape and loading in sound and lame horses; how this is influenced by farriery
Creators: name: Seery, Sarah
Publisher: name: University of Liverpool Repository
Year: 2022

description: Hoof abnormalities and lameness events are associated with foot shape and loading patterns. Farriery has an important role in maintaining optimal foot shape and manipulating foot loading, yet there are few published data on long-term changes in these features, or on optimal foot trimming. Previous clinical studies of lame horses have not evaluated foot shape alongside loading and clinical findings. Epidemiological studies have linked equine lameness events with the use of arena surfaces, however arenas have not previously been studied over different seasons, or longitudinally. This thesis examined the following hypotheses: farriery affects foot shape and loading, both at a single time point and over time; foot shape is influenced by both genetic and environmental factors; lameness results in poor foot balance and decreased loading of affected limbs; arena surfaces are used by a majority of horses and their surface properties change significantly between seasons. In the first study horses free from lameness were recruited. Photographs of forelimb feet enabled acquisition of foot shape measurements pre- and post-trimming by a farrier at a single timepoint. This highlighted a decrease in foot lengths and increase in foot angles post-trimming. A Tekscan™ commercial pressure mat was used to collect objective foot loading data pre-and post-trimming, demonstrating that post-trimming the most common change to loading was increased pressure on the central region of the foot. Collection and analysis of a questionnaire identified that farrier, breed and exercise were the most important factors influencing foot shape. The second study was longitudinal. Digital photographs and pressure mat readings were obtained for forelimb feet, pre- and post-trimming. This study revealed that the hoof capsule enlarged over time. Lame and sound limbs showed different loading patterns at the end of the study period, with some horses exhibiting greater loading by the lame limb than the sound limb. The third study recruited horses referred to the Philip Leverhulme Equine Hospital for investigation of lameness localised to the foot. Digital photographs and pressure mat readings were collected at a single time point. Clinical history and magnetic resonance imaging (MRI) findings were compared with foot shape and loading results. Lame feet in this study had different loading patterns from sound feet in the first study. Feet affected by navicular disease were shown to be smaller in size with steeper angles compared with other MRI findings. The fourth study comprised a questionnaire on the use of arena surfaces by horses in the first study and surface testing of 11 arenas for hardness (Clegg Hammer), resistance to penetration (Longchamps penetrometer) and moisture content. Testing was carried out once in June and once in December to assess differences between seasons. Hardness and moisture content were significantly lower in June compared with December. Base material, wax and indoor surfaces significantly changed arena hardness and moisture content. Surface membrane was the most important factor affecting resistance to penetration. These studies highlight the significant impact farriery has on foot shape and loading. Changes in these outcomes over time were found to oppose that observed following foot trimming, raising concerns about maintenance of optimal foot shape over time. Loading of lame limbs of horses affected by lameness was not always less than sound limbs. Use of arena surfaces is almost universal and surface properties can be influenced by season as well as arena construction factors.