Cost-effective functional evaluation of the equine hoof: solear surface pressure distribution.

Cost-effective functional evaluation of the equine hoof: solear surface pressure distribution. | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 23 September 2025 V1 Latest version Share on Cost-effective functional evaluation of the equine hoof: solear surface pressure distribution. Authors : Bethânia da Rocha Medeiros 0000-0002-3684-8789 [email protected] , Lucimara Strugava , Fábio Wacheski , Simone Machado Pereira , Vanessa Peripolli , Jose Aguiomar Foggiatto , and Peterson Triches Dornbusch Authors Info & Affiliations https://doi.org/10.22541/au.175862893.31193553/v1 223 views 143 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Farriery and hoof trimming currently lack objective metrics for quantifying outcomes, relying heavily on individual practitioner skill. Advanced biomechanical instrumentation for characterizing equine plantar pressure profiles exists but is cost-prohibitive and lacks portability for routine, non-research applications. This study aimed to establish the scientific validity of a mechanically-based methodology to indirectly quantify plantar pressure distribution across the equine hoof’s solear surface. Considering the inherent plasticity of the hoof wall, it was hypothesized that footprints collected over a flexible, graduated depth architected plate would reflect the hoof’s solear pressure distribution. A 3D-printed Graduated Depth Plate (3D-GDP) prototype, fabricated from two distinct flexible materials, was utilized. Footprints were collected on paper over the 3D-GDP, twice for each plate material, both before and after routine trimming. Data comprised 286 footprints from 36 forelimbs, of 18 horses. Ink distribution patterns were quantified across the entire footprint area and within four specified quadrants. Principal Component Analysis (PCA) and General Linear Models (GLM) were applied to identify trimming-induced alterations. Components 1 and 2 from PCA explained 87.67% of total variance. PCA identified three traits: area, intensity, and distribution. All GLM’s coefficients of determination were above 0.81 and individual limb effect (p<0.001). The 3D-GDP promoted differential contact, resulting in solid pigmentation in high-force areas and repetitive patterns in distributed loading regions. Trimming generally redistributed load without altering its total amount, notably transferring loading from heels to the lateral toe (p<0.001). Kurtosis significantly increased on toes (p<0.001) and tended to decrease on heels. Plate material did not influence results. The 3D-GDP, made from flexible materials, represents a valuable tool for guiding routine equine podiatric interventions in field conditions. Cost-effective functional evaluation of the equine hoof: solear surface pressure distribution. Keywords: Horse, Hoof, 3D printing, pressure, hoof balance. Summary: Farriery and hoof trimming currently lack objective metrics for quantifying outcomes, relying heavily on individual practitioner skill. Advanced biomechanical instrumentation for characterizing equine plantar pressure profiles exists but is cost-prohibitive and lacks portability for routine, non-research applications. This study aimed to establish the scientific validity of a mechanically-based methodology to indirectly quantify plantar pressure distribution across the equine hoof’s solear surface. Considering the inherent plasticity of the hoof wall, it was hypothesized that footprints collected over a flexible, graduated depth architected plate would reflect the hoof’s solear pressure distribution. A 3D-printed Graduated Depth Plate (3D-GDP) prototype, fabricated from two distinct flexible materials, was utilized. Footprints were collected on paper over the 3D-GDP, twice for each plate material, both before and after routine trimming. Data comprised 286 footprints from 36 forelimbs, of 18 horses. Ink distribution patterns were quantified across the entire footprint area and within four specified quadrants. Principal Component Analysis (PCA) and General Linear Models (GLM) were applied to identify trimming-induced alterations. Components 1 and 2 from PCA explained 87.67% of total variance. PCA identified three traits: area, intensity, and distribution. All GLM’s coefficients of determination were above 0.81 and individual limb effect (p<0.001). The 3D-GDP promoted differential contact, resulting in solid pigmentation in high-force areas and repetitive patterns in distributed loading regions. Trimming generally redistributed load without altering its total amount, notably transferring loading from heels to the lateral toe (p<0.001). Kurtosis significantly increased on toes (p<0.001) and tended to decrease on heels. Plate material did not influence results. The 3D-GDP, made from flexible materials, represents a valuable tool for guiding routine equine podiatric interventions in field conditions. Clinical relevance: the 3D-GDP provides an accessible, cost-effective information to objectively assess hoof pressure distribution, enhancing precision beyond subjective evaluation. Enables targeted trimming and offers a practical method for monitoring the immediate effects of trimming or long-term effects of a treatment, facilitating evidence-based decision-making in equine podiatry. Background : Farriery and hoof trimming remain constrained by their inherent subjectivity and dependence on the individual practitioner’s skill set. Although advanced biomechanical instrumentation has been employed in academic research to characterize equine plantar pressure profiles, the prohibitive expense and lack of portability of these devices restrict their utility in routine, non-research environments. Objectives : Establish the scientific validity of a mechanically-based methodology for the indirect quantification of plantar pressure distribution across the solear surface of the equine hoof, addressing the need for cost-effective assessment tools. It is hypothesized that the synergic mechanical interplay between design and flexibility of materials (3D-GDP and hoof capsule) promote differential contact between the painted hoof and the paper. Therefore, footprints collected over the 3DGDP should reflect the pressure distribution over the hoof’s solear surface. Study design : In vivo interrupted time series. Methods : A Graduated Depth Plate (3D-GDP) prototype was designed and fabricated via additive manufacturing (3D printing), utilizing two distinct flexible materials. Data was obtained from forelimb footprints of 18 horses. Each forelimb had its footprint collected twice for each 3D-GDP material, both before and after routine trimming, yielding 8 images per limb and a total of 288 footprints stamped on paper. Ink distribution patterns were quantified across the entire footprint area and within four specified quadrants/quarters (medial and lateral toe, medial and lateral heel). Principal Component Analysis (PCA) and General Linear Model (GLM) were applied to identify trimming-induced alterations. Results: 3D-GDP enabled differential contact between the painted hoof and paper, leading to solid pigmentation in areas of concentrated forces and a discernible repetitive pattern in regions of distributed loading. PCA identified three distinct traits: area (quarter and Footprint), intensity (quarter density and mean), and distribution-related factors (quarter skewness and kurtosis). All General Linear Models (GLMs) revealed significant limb individuality (p<0.001). Trimming generally resulted in a redistribution of load without altering its total amount. The plate’s material did not influence these results. The complete equalization of forces over the solear surface was limited by inherent anatomical-physiological boundaries. A distinct transference of loading from the heels to the lateral toe was observed (p<0.001). Kurtosis significantly increased on heels (p<0.001) and tended to decrease on toes, suggesting a convergence of values. Main limitations: While the study uses pigmentation as an indicator of force concentration, it doesn’t state that a direct, calibrated relationship was established between the amount of pigmentation/pixel and actual force units (e.g., Newtons or Pascals). Without such a calibration, the pixel analysis serves as a relative indicator of force distribution rather than a quantitative measurement. This means comparisons are descriptive but not absolute. Conclusions : The 3D-printed graduated depth plate produced from flexible materials is a valuable tool to guide routine equine podiatric interventions on field conditions. Main text Introduction The equine hoof capsule is a highly specialized, keratinized epidermal tissue that encases the distal aspect of the equine digit. Its epidermal component comprises an organized composite of hard keratins, exhibiting significant regional variations [1,2]. It dynamically interacts with the internal structures to attenuate and distribute Ground Reaction Force (GRF), transmitting the remaining energy to the proximal components of the limb. At each sequential stride, the primary burden of the horse’s gravitational load is bearded by the hoof wall and its immediately adjacent solear margins. However, according to the specific characteristics of the ground substrate, the remaining sole and the frog may additionally contribute to the overall weight-bearing capacity [3]. The energy dissipation is predominantly mediated by the transient deformation of the hoof capsule during the stance phase of the gait. Such deformation is possible due to the molecular organization and mechanical properties of the hoof wall [1,4,5]. This phenomenon is modulated by the individual hoof conformation [6–8], and the resultant GRF is represented by the centre of pressure (COP)[7]. The COP constitutes a theoretical locus that places the total sum of the pressure field, representing the location of the resultant GRF beneath the foot. The COP path tracks how this point moves across the hoof from the moment the hoof strikes the ground to when it lifts off [9]. A balanced hoof provides an optimal phalangeal alignment and distribution of forces, crucial for absorbing and dissipating the stresses of movement and weight-bearing. Hoof balance encompasses both toe-heel and medio-lateral symmetry, ensuring even landing and loading, which is vital for maintaining soundness and reducing the risk of lameness or injury [9–13]. Still, a hoof’s shape, and balance, is dynamic; influenced by trimming, shoeing, and individual conformation, meaning no single geometric standard applies universally [14]. Therefore, individualized and periodic hoof care are paramount. Assessment of foot balance is largely subjective in nature and individual farriers apply different criteria [15–18]. Research methods, such as radiography [16], gait analysis [19,20] and pressure plates [21,22] have been used to quantify the effects of trimming or shoeing. However, their routine application may not economically feasible in typical field practice. The primary objective of this investigation was to assess the efficacy of an innovative, cost-effective methodology for quantifying alterations in solear hoof pressure distribution consequent to farriery interventions. It was hypothesized that a prototype Graduated Depth Plate (3D-GDP), fabricated from compliant materials, would enable the indirect quantification of intra-hoof pressure distribution under static load conditions, consequently affording a pragmatic modality for assessing static hoof balance. This methodological framework was underpinned by the mechanical principle that flexible materials, such as the equine hoof wall and some synthetic polymers are deformable under pressure. Materials and methods : This project received approval from the Ethics Committee on Animal Use (CEUA) of IFC Araquari under protocol number 479/2025. Construction of the Graduated Depth Plate (3D-GDP): A digital model for the 3D-GDP was developed using Computer-Aided Design (CAD) in an open-source software (Blender). The 3D-GDP was designed to measure 221 x 221 mm, corresponding to the approximate dimensions of a regular (A4) paper sheet’s width and the build platform available for additive manufacturing. All planning considered physical construction through additive manufacturing (3D printing) via material extrusion [23], using a 0.6 mm nozzle and a 0.18 mm layer height. The design consisted of a repetitive grid pattern on a solid base plane, of 0.54 mm total height. All heights and widths were multiples of 0.18 mm and 0.62 mm, respectively. The pattern was composed of strips and dots, alternately superimposed and interleaved, forming five distinct height levels: 0 mm (directly on the solid base plane); 0.18 mm; 0.36 mm; 0.54 mm; and 0.72 mm. A total of six plates were constructed in two different flexible materials: three in white co-polyester (CO) (Shore 112R) and three in blue thermoplastic polyurethane (TPU) (Shore 95A). Plates’ materials were easily identifiable by their colour/material, and were also individually numbered. All 3D- GDPs were constructed from a single CAD model (Figure 1), and 100% infill. The ones made from the CO material required 44 grams of filament and 2 hours and 7 minutes for production, at a printing speed of 120 mm/s. TPU plates were made out of 57 grams and necessitated 4 hours and 19 minutes, at 30 mm/s. All underwent visual inspection for structural quality. 1. Capture of equine hoof impressions (Footprints) : Data was collected during the routine hoof care of 18 clinically healthy, convenience sampled horses. The cohort comprised 18 individuals (10 males, 8 females), with a body weight (BW) range of 290 to 550 kg (438.50 ± 73.03 kg) and cannon perimeter (PC) from 17 to 21.5 cm (19.20 ± 1.55 cm). Horses underwent standard farriery procedures, executed by a single experienced farrier. These interventions aimed in achieving optimal geometric latero-medial symmetry, and establishing a rectilinear alignment of the hoof-pastern axis during a static, weight-bearing stance. Other visual cues employed on the process included: the estimated centre of rotation of the distal interphalangeal joint and the extension of the heels to the base of the frog [14]. For each animal, impressions of both forelimbs were recorded four times (two for each plate’s material/colour) both before and after trimming, resulting in 8 images per limb and 16 images per animal. Footprints were obtained as follows: A) The repetitive-pattern face of each 3D-GDP was covered with an A4 sulphite paper sheet (75gpm), which was folded and secured with metal clips. With the paper facing upwards, the assembly was placed on the ground, under the horse, and over a plywood board of 13 mm thickness to minimize local floor variations. B) The solear surface of the hoof was painted using a foam roller and black stamp ink. C) The hoof was carefully positioned on the plate by one handler, and the contralateral limb was suspended by a second handler, ensuring full weight-bearing for a short time. Then the first handler suspended the limb under examination once again. Footprints were considered invalid if the horse exhibited non-compliant behaviour or if limb placement deviated from the intended area. Procedure was then repeated. D) Each sheet was identified based on the animal, limb, timing (before or after trimming), and plate identification (colour and number). In total, 288 images were acquired. 2. Analysis of pigment distribution on footprints : The images were digitalized using a domestic scanner in grayscale at 300 dots per inch and saved in Portable Network Graphics format. They were subsequently analysed using the open-source software ImageJ/Fiji 1.46 [24]. It proceeded through the following steps: A) Scale adjustment. B) Transformation into a binary image by the software’s standard threshold adjustment. C) Positioning (rotation) of the hoof impression. D) Isolation (crop) of the hole footprint as the first Region Of Interest (ROI), herein referred to as Footprint. E) Centred division into four equal parts; establishment of the other four ROIs (herein referred to as Quarters) by the intersection of each fourth part and the Footprint. Finally, these ROIs received the correspondent identification of: medial (MH) and lateral (LH) heels (for palmar quarter parts), and medial (MT) and lateral (LT) toes (for cranial quarter parts). Quantitative analysis was enabled by encoding pixels corresponding to black ink with a value of 255, and those corresponding to white areas with a value of 0. This represents the standard methodology for analysing binary images within the ImageJ software. The following parameters were calculated for each of the 5 ROIs: area, mean, integrated density (area × mean), skewness and kurtosis. 3. Statistical Methods : Principal Component Analysis (PCA) was performed to elucidate the interrelationships among the variables. Body weight (BW) and cannon perimeter (CP) were incorporated as input variables in this analysis. Generalized linear models (GLMs) were fitted using SAS® software for each parameter, with the limb (n=36) considered as an independent experimental unit. In every model the limb was nested within the measurement moment (before or after trimming), and the 3D-GDP identifier was nested within its corresponding material. For parameters concerning the Quarters, the respective total Footprint value was included as a covariate. Results The 3D-GDP design was preceded by an iterative developmental process, which included the preliminary, qualitative assessment of seven preceding prototypes. This preceding phase of improvement was omitted from the formal methodological description due to its empirical and visually-driven nature. Preliminary functional evaluation of seven antecedent versions was conducted on a single, recently trimmed, 500 kg equine subject. Testing and model improvement persisted until the prototype demonstrated adequate structural integrity under applied loads and consistently yielded footprints reproducing the predefined repetitive pattern, thereby confirming reasonable absence of direct contact between the hoof and the deepest basal layer of the plate. Tests reported here resulted on 288 images/footprints. Two images exhibiting evident blurriness were discarded. Each image (286) generated four lines of data, one for every individual Quarter, yielding a dataset with 1144 entries. Results demonstrated a coherent grouping of variables that shared underlying characteristics. A high positive correlation among estimators of area (Footprint and Quarter) and of the body size indicators (BW and CP) was detected. Thus, larger animals had larger hoof footprint area (F.area) and quarter area (Q.area). Measurements of pixel intensity on quarters (Q.mean and Q.density) quantified the amount of ink deposited on paper. PC1 indicated a strong positive relationship (52.36%) of these to the horse’s body size. To a lesser extent (30.31%), PC2 states their inverse relationship to area. Measurements of the shape of pixel distribution, quarter skewness (Q.skew) and quarter Kurtosis (Q.Kurt), were strong and positively correlated to each other, and negatively correlated to overall size and area, as stated by PC1. An even stronger inverse relationship (PC1 and PC2) is present with intensity parameters Q.mean and Q.density. This indicate that these groups indeed separate parameters into two distinct characteristics of the images: the magnitude of ink (Q.mean and Q.density) and shape or asymmetry of ink distribution (Q.skew and Q.Kurt). Descriptive statistics and metrics of GLM (Table 1) characterize sample variation and quantify the proportion of total variance explained by the models. Overall, the GLMs presented high coefficients of determination (R²), indicating robust model performance. Parameter Q.kurt exhibited the greatest data amplitude, which resulted in comparatively lower R 2 and higher coefficients of variation (CV). The influence of the individual limb was significant (p<0.001) for all parameters. GLM analysis revealed no significant effect of the 3D-GDP material on any variable (Table 2). In contrast, most of the Footprint parameters displayed a distinct plate effect which did not extend to the quarter measurements. As illustrated in Figure 3, inter-plate agreement was generally observed. Minor disparities concerning Footprint area were driven by frog-ground contact before trimming. Specifically, images displaying frog contact at the palmar extremity exhibited objectively larger total areas. This area augmentation presumably impacted other derived metrics, as the expanded pixel count modified mean, density, kurtosis, and skewness calculations. Slight differences concerning toe staining or lateromedial ink distribution were also observed. However, the high R² values indicated that these variations were largely accounted for by the models. As evidenced in Table 3, the average surface area of the heels (lateral and medial) exceeded that of its toe counterpart. Even so, Q.mean and Q.density indicated predominant staining on the cranial (toe) regions of the solear surface, despite being dimensionally smaller than the palmar (heel) ones. The trimming intervention exacerbated this difference, further marking the toe. Another average consequence of trimming was an increase in Footprint area, without a corresponding change in overall ink intensity (F.mean and F.density). Changes in the distribution parameters (Q.kurt and Q.skew) for the cranial and palmar regions of the hoof exhibited distinct responses following trimming (Table 3). A non-significant tendency toward decreased values was observed in the toes, whereas a significant increase was recorded in the heels. This is further elucidated in Figure 4, which illustrates a trend towards the equalization of kurtosis and skewness between the heel and toe. However, density exhibited an opposing behaviour, evidenced by the increased divergence between heel and toe density values, as described above. Hence, improvement on staining distribution withing hoof quarters was better assessed by Q.Kurt than by Q.Skew (Table 3, Figure 4). A common and visually assessed trimming-induced modification was a profound redistribution of ink. A solid staining was found on the majority of hooves prior to trimming. This is then supplanted by a repetitive pattern of variable geometry and intensity, composed of alternating plaid lines and isolated dots. Such post-trimming repetitive pattern is fully compatible with the textured surface of the 3D-GDP, designed in the digital model. Such phenomenon was evident across most limbs and was quantitatively assessed through Q.skew and Q.kurt. This is well pictured in Figure 5. Estimates on this figure show the improved uniformity between toes’ load (Q.density), and the overall balance reached between Q.Kurt. Likewise, it illustrates the physiological limits to further improvement through augmentation in load bearing by the peripheral sole and frog contact. Hooves that were well-balanced before trimming revealed limitations in further improvement. Figure 6 illustrates a very symmetric footprint with pre-existing balance. Despite this, trimming was necessary and resulted in increased the footprint area, which led to a recalculation of parameters and a marginal amplification of lateromedial discrepancies. Discussion While advanced and precise methodologies for pressure evaluation, like pressure plates/mats, have been validated [25–30], the approach presented here diverges fundamentally. Our theory was based on the renowned deformability and plasticity of the equine hoof capsule [1,4,5,31]. We hypothesized that load may be inferred from the ink amount and distribution over a footprint acquired through the flexible plate with graduated depth architecture. It assumes that the synergistic mechanical interplay between design and flexibility of materials (3D-GDP and hoof capsule) promote differential contact between the painted hoof and the paper. This interaction would yield high-density pigmentation (solid impressions) in areas subjected to elevated compressive forces; and variations of repetitive pattern from the digital model in those under well-distributed loading. Such repetitive pattern comprises alternating plaid and dot formations, wherein the proportionality of these elements would correlate to contact pressure. Such theorical manifestation aligns with the steady solid impression found on the majority of horses prior to trimming, which was largely replaced by diverse presentations of the model’s repetitive pattern post-trimming (Figures 3 and 5). The phenomenon was visible across most limbs and was quantitatively assessed through kurtosis and skewness measurements (Table 3) within the hoof quarters. The direct relationship between various hoof dimensions and morphology with an animal’s body mass has been indicated [32,33]. It highlights the essential connection between GRF and hoof size, aligning with our PCA results. Asymmetries between left and right hooves have been reported to be common [32] and resonate with the stated individuality of each limb regarding its dynamic load distribution [28,8]. These findings provided the rationale for designating the individual limb as the primary experimental unit within this study. This methodological choice was subsequently validated by the robust explanatory power and consistency of the limb effect observed on all GLM models. Static hoof load has been assessed in sedated horses. However, the theoretical nature of this ’static’ condition was recognized to be influenced by head movements, tendon tension, subtle weight shifts, hoof wall condition, and toe-first contact tendency [34]. We collected data from non-sedated standing horses under a unilateral loading protocol, wherein the limb of interest was fully weight-bearing through suspension of the alternate limb. We posited that this methodology would compile the complexities of dynamic forces in a simple and practical manner, making it suitable for field application. This approach was based on the recognition that equids are never truly static, and their conformation and conscious posture fundamentally reflect their biomechanics. Thus, our Footprint images capture a handler-guided, but yet conscious, variation of the stride’s stance phase, necessarily involving both limb landing and subsequent lift-off. In order to evaluate the efficacy of the 3D-GDP for indirectly quantify pressure and its distribution, footprints acquired prior to and following trimming were comparatively analysed. Given the established research on the trimming procedure, a comparative analysis of the observed parameter changes with previous findings may clarify the method’s applicability. Kinetic gait analysis demonstrated that the trimming intervention augmented hoof-ground contact area during the impact phase of the stride, without concomitant alterations in GRF [22]. Within the present investigation the impact phase of the stride was a natural part to the Footprint gathering procedure. Despite the absence of measurements for hoof-ground contact area, we found an increase in the overall Footprint area. Nevertheless, a notable expansion of the hoof-ground contact area is visually discernible in the post-trimming images (Figures 3, 5, and 6), characterized by the evident engagement of the peripheral sole and, in some instances, the frog. The duration of the entire gait cycle, encompassing both stance and swing phases, has been proven to be reduced after trimming, even at equivalent velocities to the pre-trimming assessment. This alteration led to increased vertical GRF and heightened contact pressure at midstance. These changes were postulated to arise from the animal’s proprioceptive system, and subsequent adaptive responses [21]. In our experimental protocol, handlers managed the duration of stance, controlling it just enough to allow the contralateral limb’s temporary suspension and subsequent release. Given this direct control, the horse’s intrinsic sensory perception did not serve as a primary modulator of force application. Consequently, the indirect measurements of force, specifically Q.mean and Q.density, exhibited no significant alterations. Punctual pressure measurements were used to determine the hoof’s COP [25–29,34,35]. Research on sedated standing horses indicated that COPs were predominantly located on the medial heel (46% directly, 30% at borders) [34]. In contrast, on our study the majority of weight was supported by the toes of non-sedated animals. This observation aligns with the anatomical reality of skeletal weight bearing, which is primarily transmitted through the distal phalanx (coffin bone) located in the toe and directly connected to the dorsal hoof wall [2]. Further reinforcing this conscient biomechanical perspective, literature reports that most forelimbs (up to 60%) land with the lateral hoof aspect, a smaller proportion (up to 40%) land symmetrically, and only a few initiate ground-contact with the medial side. From midstance to take-off the lateral side also prevailed and trimming did not alter the COP path itself on a 4-week trimming interval [29]. However, a 8-week interval led the midstance COP to migrate towards the palmar side of the foot [26]. Therefore, it was thought that the Cop’s lack of alteration was a positive outcome for a trimming procedure [30]. In our study, 10 horses had longer intervals (8 weeks), while 8 had an interval of approximately 6 weeks. Thus, the post-trimming shift in weight bearing (Q.mean and Q.density) from heels to lateral toe presented in our study is consistent with the literature, and reinforce the utility of the present methodology in measuring the relative force distribution. The farrier’s intentional strategy to achieve hoof equilibrium, aiming to homogenize the distribution of GRF across the toe and heel quarters was highlighted by the tendency to equalization of heel-toe kurtosis. The inability to do so, delineate the inherent physiological boundaries to trimming, dictated by individual equine conformation and biomechanics. A notable finding post-trimming was that 23 (64%) of the hooves achieved a discernible degree of frog-ground contact. Yet, a truly complete ’V’-shaped frog imprint, indicative of full contact, was observed in only 3 (8%) of cases, not all off them with the solid pattern. The occurrence of frog pressure subsequent to trimming was considered an undesirable outcome, but was noted in 14% of cases [30]. Under this scenario, a dedicated ’Region of Interest’ (ROI) could objectively quantify pixel intensity and distribution over the frog area, mirroring our successful approaches to other hoof quadrants. However, the implementation of such ROI would require standardized criteria for delimiting the frog region on digital footprints. The inherent morphological variability of the frog often renders challenging boundary identification. This methodological change could empower farriers to refine their intervention strategies in a field-based context, thereby enhancing the efficacy and optimizing the outcomes of routine farriery services. Nevertheless, we integrated the detailed quantitative data derived from frog pixel analysis into our overall estimations of heel quarters’ parameters. Material Extrusion is emerging as an accessible and versatile process. However, two inherent characteristics; variability in dimensional precision and anisotropy; may affect the quality of manufactured parts [36]. While a detailed discussion of the relationship between printing parameters and product quality, or mechanical characteristics, is beyond the scope of this study, the significance of a ’plate effect’ was observed in some Footprint parameters. These findings underscore the fundamental knowledge required for the production of 3D printed functional parts. Pores and void formation can promote density variation or affect dimensional accuracy [35]. These issues can depend on how the material is deposited (flow, pressure, overlap, layer thickness, etc.) or on material condition (humidity, uneven filament diameters, etc.) Some defects can be mitigated by proper parameter settings (e.g., void formation can be reduced by decreasing layer thickness) [36]. Typically, a balance must be struck between different quality aspects such as void formation, surface roughness, and mechanical properties [37]. The paramount concern in the geometric design was to achieve a precisely graduated-depth repetitive pattern. Consequently, dimensional inaccuracies were prevented by employing a design strategy that specified all heights and widths as integer multiples of the constituent layer dimensions. Even so, most of the Footprint parameters displayed a distinct plate effect, indicating an inherent variability in the manufacturing process. However, this manufacturing-induced variation did not extend to the quarter measurements, meaning that the 3D printing quality was sufficient. Materials were chosen based on their mechanical resistance and flexibility, as indicated by their respective shore. Both served the purpose adequately and comparably. Finally, density and kurtosis of pixels in specific ROIs within Footprints did provide indirect quantification magnitude and distribution of force, respectively. This was tested by dividing each footprint into four quadrants and comparing the images obtained before and after a documented routine procedure: the hoof trimming. Magnitude results align with the reported response to routine farriery interventions. Pressure distribution, however, hasn’t been the object of previous investigations, since they focused on the location of COP and not on the pressure distribution itself. It is posited that within hoof regional pixel kurtosis comparisons can be interpretated as indicative of relative pressure distribution, orientating the trimming procedure in field conditions. Therefore, Footprints collected over the 3D-GDP provide valuable cost-effective information regarding indirect quantification of regional pressure intensity and distribution. Conclusion Pre- and post-trimming regional Footprint parameter comparisons allowed the demonstration of the 3D-GDP’s efficacy in detecting hoof-ground pressure variations within field conditions, under a cost-effective method. Given that the primary objective of podiatric intervention is to improve the distribution of forces, regional comparisons of density and kurtosis hoof parameters are suitable to guiding the targeted removal of equine hoof capsule material. However, improvement in GRF distribution is limited by the hoof’s intrinsic biological threshold and methods for quantifying force should not be the sole guide for balance assessment. Comprehensive morphological and dynamic visual assessment by a skilled farrier or veterinarian remains essential. Therefore, continued investigations into the relationship between pressure distribution patterns and hoof morphology are requisite to guide evidence-based farriery decisions.” Tables Table 1: Descriptive statistics (mean, sd, amplitude) and model performance metrics (R², CV) for the two categories of Regions of Interest (ROI) on images. Footprint F.area (cm 2 ) 121.46 (± 17.04) 87.87 - 168.70 0.965 2.64 F.mean 26.18 (± 10.06) 6.68 - 59.70 0.998 1.92 F.density 3221.89 (± 1404.69) 729.10 - 8444.54 0.997 2.41 F.Kurt 6.89 (± 6.09) -0.42 - 33.18 0.999 3.46 F.skew 2.84 (± 0.90) 1.26 - 5.93 0.999 0.83 Quarter Q.area (cm 2 ) 30.37 (±4.72) 17.42 - 44.56 0.986 2.12 Q.Mean 26.65 (± 15.45) 1.40 - 84.56 0.932 17.73 Q.density 805.24 (± 479.04) 43.92 - 2649.78 0.935 17.59 Q.Kurt 10.77 (± 15.90) -1.49 - 177.39 0.815 73.31 Q.Skew 3.17 (± 1.64) 0.72 - 13.39 0.910 17.94 * Determination Coefficient. ** Coefficient of variation. Table 2: Mean differences in hole footprint (F.) and regional (Q.) image parameters between 3D-Plates of two flexible materials. Termoplastic Poliurethane (TPU) TPU1 122.23 a 26.22 ab 6.93 a 2.84 b 30.36 a 26.60 a 802.56 a 10.92 a 3.17 a TPU2 121.29 bc 26.15 b 6.87 a 2.84 ab 30.38 a 26.70 a 805.89 a 11.53 a 3.21 a TPU3 121.59 b 26.38 a 6.87 a 2.84 ab 30.38 a 26.59 a 805.02 a 10.29 a 3.12 a Copoliester (CO) CO1 120.78 d 26.10 b 6.92 a 2.84 ab 30.37 a 26.65 a 805.21 a 10.99 a 3.18 a CO2 121.48 cb 26.18 b 6.85 a 2.85 a 30.37 a 26.64 a 805.88 a 10.01 a 3.14 a CO3 121.20 c 26.15 b 6.89 a 2.84 b 30.37 a 26.69 a 805.37 a 10.43 a 3.18 a * Different superscript letters within a column indicate a statistically significant difference (p < 0.001) Table 3: Comparison of estimated model means for image Regions of Interest in different moments: before and after trimming. Medial heel Before 31.95 b 18.09 de 570.38 de 19.10 a 4.21 a After 31.57 b 13.95 f 460.90 f 17.51 a 4.16 a Lateral heel Before 32.44 a 19.83 d 638.35 d 17.39 a 3.97 a After 31.75 b 16.17 ef 535.72 e 15.47 a 3.91 a Medial toe Before 29.32 c 35.47 bc 1051.27 b -0.52 c 1.93 d After 29.25 c 36.88 b 1083.14 ab 6.88 b 2.48 b Lateral Toe Before 27.78 d 33.12 c 960.34 c 0.92 c 2.13 cd After 28.92 c 39.59 a 1140.65 a 6.41 b 2.37 bc Footprint Before 120.67 e 26.64 g 805.28 g 6.82 d 2.85 e After 122.57 f 26.67 g 805.27 g 6.94 e 2.84 f * Different superscript letters within a column indicate a statistically significant difference (p < 0.001) List of Figure legends Figure 1: Digital model visualization of the graduated depth plate (3D-plate) with the basal plane intentionally excluded to optimize visual clarity. (A) Magnified view of one unit of the repetitive pattern and its height profile: Level 0 corresponds to the basal plane (here excluded); subsequent levels 1, 2, 3, and 4 represent incremental depths of 0.18 mm, 0.36 mm, 0.54 mm, and 0.72 mm, respectively. (B) Full spatial extent of the repetitive pattern (20 x 20 units partially overlapping). Figure 2: Graphical representation the interrelationships among the original parameters and their respective contributions to the first two principal components, which explained 82.67% of the total variance. Figure 3: Inter-plate * agreement of Footprint impressions from the right thoracic limb of equine subject 2. The upper row presents pre-trimming images, and the lower row displays post-trimming images. All displayed images maintain proportional scaling. Figure 4: Visual representation of the directional tendency of trimming effect on hoof parameters: mitigation of differences between the Toe and Heel quarters regarding kurtosis, skewness, and density. Figure 5: Right thoracic limb footprints of equine subject 19, highlighting the natural boundaries to attaining optimal hoof balance. Note the sustained asymmetry in heel shape, and the post-trimming frog-ground contact. Figure 6: Left thoracic limb footprints of equine subject 7. This illustration demonstrates that balance improvement is constrained by individual equine biomechanics, even in cases of prior well-distributed loading. It is evident that attempts by farriers to achieve morphological symmetry did not lead to numerical equalization of load distribution. References [1] Huang, W. et al. (2019). A natural energy absorbent polymer composite: The equine hoof wall. Acta biomaterialia . https://doi.org/10.1016/j.actbio.2019.04.003. [2] Gerard, M.P. (2021). 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Authors Affiliations Bethânia da Rocha Medeiros 0000-0002-3684-8789 [email protected] Universidade Federal do Parana View all articles by this author Lucimara Strugava Universidade Federal do Parana View all articles by this author Fábio Wacheski Independent veterinary practitioner View all articles by this author Simone Machado Pereira Instituto Federal de Educacao Ciencia e Tecnologia Catarinense View all articles by this author Vanessa Peripolli Instituto Federal de Educacao Ciencia e Tecnologia Catarinense View all articles by this author Jose Aguiomar Foggiatto Universidade Tecnologica Federal do Parana View all articles by this author Peterson Triches Dornbusch Universidade Federal do Parana View all articles by this author Metrics & Citations Metrics Article Usage 223 views 143 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Bethânia da Rocha Medeiros, Lucimara Strugava, Fábio Wacheski, et al. 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