In situ determination of the extreme damage resistance behavior in stomatopod dactyl club.

The structure and mechanical properties of the stomatopod dactyl club have been studied extensively for its extreme impact tolerance, but a systematic in situ investigation on the multiscale mechanical responses under high-speed impact has not been reported. Here the full dynamic deformation and crack evolution process within projectile-impacted dactyl using combined fast 2D X-ray imaging and high-resolution ex situ tomography are revealed. The results show that hydration states can lead to significantly different toughening mechanisms inside dactyl under dynamic loading. A previously unreported 3D interlocking structural design in the impact surface and impact region is reported using nano X-ray tomography. Experimental results and dynamic finite-element modeling suggest this unique structure plays an important role in resisting catastrophic structural damage and hindering crack propagation. This work is a contribution to understanding the key toughening strategies of biological materials and provides valuable information for biomimetic manufacturing of impact-resistant materials in general.

Effect of trimming of overgrown and deformed claws in goats on morphometric measurements.

Reduced welfare and productivity of dairy goats have often been associated with poor claw health, especially conditions such as claw overgrowth and deformations. It is known that periodic claw trimmings have prophylactic and therapeutic effects on these problems, and this study aimed to evaluate if the additional use of an angle grinder to finish trimming overgrown and deformed goat claws, after the usual trimming using hoof shears, could provide further changes in these claws. For this, twelve Saanen goats (57.29 ± 11.15 kg of body weight, 3.08 ± 1.78 years old) were selected by presence of severe claw overgrowth, and absence of claw alterations of other nature. Their claws were trimmed in two steps, first using hoof shears and then using an angle grinder. Morphometric, baropodometric, and conformational aspects of all claws were assessed before claw trimming and after each trimming step. To analyse the effects of the trimming steps in each claw, the Tukey's test was used on parametric data, with 5% probability, and descriptive statistics were used on non-parametric data. Although this is a small pilot study, results suggest that using an angle grinder after the use of hoof shears, could further reduce heel length and sole width of claws, as well as reduce the number of deformed claws. The incorporation of the second trimming tool, could also further increase the frequency with which the point of maximum pressure was found in the toes, rather then in the heels of the claws as seen in deformed claws.

Three-dimensional structure analysis of mouse nails using synchrotron radiation.

Until now, studies on nail diseases have been performed through microscopic diagnosis and microscopic computed tomography (micro-CT). However, these kinds of conventional methods have some limitations. Firstly, the microscopic method is considered the gold standard for medical diagnosis. However, due to the use of fluorescent materials, the sample is damaged and it takes a long time to get results. Secondly, while micro-CT is a noninvasive method to get inner structure images of the sample with high resolution, the penetration and spatial resolution are insufficient for studying the microstructures of the sample, such as the sponge bone and the muscle fibers. In contrast, synchrotron radiation (SR) X-ray imaging technology has the advantage of very vividly demonstrating the anatomic structure of the sample with high penetration, sensitivity and resolution. In this study, we compared the optical microscopic method using hematoxylin and eosin staining and SR imaging to analyze the nail tissue in a mouse model. The results showed that SR could depict the inner structures of a mouse nail without any physical damage. Additionally, we could divide the important anatomical structures of the nail unit into three parts with three-dimensional (3D) images: the nail bed, nail matrix and hyponychium. The images showed that SR could be used for analyzing nails by visualizing the relatively clear and medically semantic structures in a 3D section. We expect that the results of this study will be applied to study nail diseases and conduct pharmaceutical research on their treatment.

Functional morphology of vertebrate claws investigated using functionally based categories and multiple morphological metrics.

The link between claw morphology and function has been historically difficult to quantify, analyze, and interpret. In this study, the functional morphology of vertebrate claws is analyzed using measurements taken from 80 modern claw specimens spanning birds, mammals, and one reptile. Claw measurements were chosen for their potential biomechanical significance and a revised, expanded categorization of claw function is defined and used. This categorization scheme is the result of an extensive literature review and is based on the observed mechanics of claw function rather than the animal's overall ecology, an important departure from the norm followed in previous studies. A principal component analysis of the claw measurements reveals that some of the morphological disparity is related to functional differences; however, different functional categories are not clearly separated based solely on morphology. A linear discriminant analysis successfully classifies 81.25% of the claw specimens to their documented functional categories. When the posterior probabilities of each classification are examined, and the next highest probabilities are considered, the analysis is able to successfully classify 96.25% of the claw specimens. Expressing angle measurements in terms of lengths prior to analysis and incorporating cross-sectional shape data both serve to reduce the misclassification rate. The use of biomechanically meaningful claw measurements and categories based on function (rather than ecology) improves confidence in the ability to infer claw function based on morphology using discriminant analysis methods. While overall claw morphology is most certainly the result of multiple factors (e.g., growth, size, etc.), this study establishes that it reflects mechanical function more than previously demonstrated.

Development, structure, and protein composition of reptilian claws and hypotheses of their evolution.

Here, we review the development, morphology, genes, and proteins of claws in reptiles. Claws likely form owing to the inductive influence of phalangeal mesenchyme on the apical epidermis of developing digits, resulting in hyperproliferation and intense protein synthesis in the dorsal epidermis, which forms the unguis. The tip of claws results from prevalent cell proliferation and distal movement along most of the ungueal epidermis in comparison to the ventral surface forming the subunguis. Asymmetrical growth between the unguis and subunguis forces beta-cells from the unguis to rotate into the apical part of the subunguis, sharpening the claw tip. Further sharpening occurs by scratching and mechanical wearing. Ungueal keratinocytes elongate, form an intricate perimeter and cementing junctions, and remain united impeding desquamation. In contrast, thin keratinocytes in the subunguis form a smooth perimeter, accumulate less corneous beta proteins (CBPs) and cysteine-poor intermediate filament (IF)-keratins, and desquamate. In addition to prevalent glycine-cysteine-tyrosine rich CBPs, special cysteine-rich IF-keratins are also synthesized in the claw, generating numerous SS bonds that harden the thick and compact corneous material. Desquamation and mechanical wear at the tip ensure that the unguis curvature remains approximately stable over time. Reptilian claws are likely very ancient in evolution, although the unguis differentiated like the outer scale surface of scales, while the subunguis might have derived from the inner scale surface. The few hair-like IF-keratins synthesized in reptilian claws indicate that ancestors of sauropsids and mammals shared cysteine-rich IF-keratins. However, the number of these keratins remained low in reptiles, while new types of CBPs function to strengthen claws.

Phylogenetic tree of Litopterna and Perissodactyla indicates a complex early history of hoofed mammals.

The Litopterna is an extinct clade of endemic South American ungulates that range from Paleocene up to late Pleistocene times. Because of their unique anatomy, litopterns are of uncertain phylogenetic affinities. However, some nineteenth century authors, considered litopterns as related to perissodactyl ungulates, a hypothesis recently sustained by molecular data. The aim of the present contribution is to include litopterns and other South American related taxa in a comprehensive phylogenetic analysis together with several extant and extinct basal perissodactyl ungulates. The analysis resulted in the nesting of litopterns and kin as successive stem-clades of crown Perissodactyla. Further, litopterns are not phylogenetically grouped with any North American basal ungulate, in agreement with some previous proposals. Presence of pan-perissodactyls in South America and India indicates that southern continents probably played an important role in the early evolution of hoofed mammals.

Exploring physiological and genetic variation of digital cushion thickness in Holstein and Jersey cows and bulls.

The objectives of our study were to expand phenotypic characterization of digital cushion thickness (DCT) to the Jersey breed and include mature bulls and to identify breed-specific quantitative trait loci (QTL) for DCT within the Jersey or Holstein breeds and common QTL across breeds and sexes to better understand biological regulation and guide future use of marker-assisted selection. In a cohort of 698 cows and 85 bulls (Holstein and Jersey) from 8 farms in New York State, data were collected on DCT, body condition score (BCS), withers height, and sacral height. All animals underwent sonographic examination of the digital cushion evaluated at the sole ulcer site for the right front and hind feet. Linear mixed models were conducted on DCT separately for cows and bulls with fixed effects of time point, breed, age, digit, and BCS group. The models included random effects to control for the random subset of animals per farm, repeated measures, and multiple measurements from each animal. The phenotypic results indicated that DCT varied by time point, breed, age, digit, and BCS group for cows and by breed, age, digit, and BCS group for bulls. For the genotypic study, 616 cow DNA samples were genotyped on the Illumina BovineHD 777K BeadChip (Illumina Inc., San Diego, CA), whereas 76 bull DNA samples were genotyped on different platforms ranging from 5K to 150K. Multiple genome-wide association studies were conducted to highlight pertinent phenotyping parameters and genetic markers for genomic selection. Data were separated into 8 data sets based on different combinations of breed and sex. Each data set was assessed for quality of markers and samples before conducting genome-wide association studies for DCT, testing the inheritance models and genetic variation of digit, foot, and average thickness. Ten markers passed the Bonferroni correction threshold and 9 passed false discovery rate from 10 genome-wide association studies using a combination of the covariates breed, sex, genotyping batch plate, age, BCS, withers height, and sacral height. Of the 43 candidate genes, 8 novel biologically plausible genes were identified on Bos taurus autosomes 3, 4, 7, and 9: SFRS18 and LRRFIP1 function in fat deposition, whereas AHR, BZW2, EFNA5, USP45, and VAV3 effect bone growth, and SOSTDC1 is related to epidermal keratinocyte function. The genetic markers associated with DCT in this study were explored for variation between cows and bulls within and across breeds for their potential use in marker-assisted selection.

Effect of shoeing conditions on hoof dimensions in Icelandic and Warmblood horses.

In Icelandic horses (ICE), high, long hooves with added weights are often used to improve gait quality in competitions. From a biomechanical point of view, excessively long hooves can be problematic as they increase forces acting on the distal limb. The study aimed to determine if hoof capsule size and angle of ICE at competitions are comparable to those of Warmblood horses (WB) requiring shoeing. Hoof dimensions and balance were quantified in 13 horses of each breed at the beginning of a shoeing period (BSP), allowing a baseline comparison between breeds, as well as for WB at the end of a shoeing period (ESP) and for ICE when shod for competition (COMP). Left front and hind hoof capsules and bony structures of the hooves were measured on lateromedial and dorsopalmar/dorsoplantar radiographs at BSP (ICE, WB), ESP (WB) and COMP (ICE), respectively, using the software Metron-Hoof-Pro. Compared to WBBSP, ICEBSP had larger hoof capsules relative to the size of P3 and, when controlled for withers height, longer dorsal hoof wall lengths. The comparison of ICECOMP to WBESP indicated that the relative increase in hoof length and volume was greater in ICECOMP compared to WBESP. Hoof balance was closer to previously published values in WBs, while hoof angles in ICE (particularly palmar/plantar angle of P3) were generally larger and thus less problematic. In conclusion, hooves of ICECOMP were relatively larger and less balanced than WBESP, but hoof angles in WB were smaller than in ICE.

Hoof conformation in Icelandic competition horses and its interrelationship with hoof pathologies and tölt performance.

In order to improve the four-beat-rhythm and forelimb action of the tölt in Icelandic horses (ICE), special shoeing techniques are applied particularly in the front hooves by increasing hoof length and height, or by adding weight to the distal limbs. Although regulations limit dorsal hoof wall length (LDHW) in competition ICE, their shoeing often deviates from a biomechanically optimal distal limb conformation. This study aimed to qualitatively and quantitatively describe current shoeing practices of ICE in competition. Moreover, the influence of LDHW on the occurrence of deviations from a standard hoof conformation, as well as on tölt performance was investigated. At four European competition sites, hoof dimensions of 133 randomly selected ICE were measured manually, and limb conformation and hoof balance were described. Dorsopalmar/-plantar and lateromedial radiographs of the left front and hind hooves were taken of each horse. Various parameters related to hoof dimensions and balance were measured on radiographs using the Metron-Hoof-Pro software. Flares of the dorsal hoof wall had the highest prevalence of all investigated hoof deformities. Multiple logistic regression analysis revealed that longer LDHW was associated with the occurrence of toe flares (P = 0.045), a broken hoof pastern axis (P = 0.003), and asymmetry of the quarter wall heights (P = 0.015). However, horses with a longer LDHW achieved higher scores in competition. In spite of its positive effect on tölt performance, a long LDHW is not recommendable as it may be associated with a higher prevalence of certain hoof deformities.

Hind limb conformation has limited influence on claw load distribution in dairy cows.

The high prevalence of claw lesions in dairy cows necessitates the investigation and hopefully elimination of factors involved in the etiology and pathogenesis of these disorders. Indirect genetic selection for specific conformation traits in feet and legs has been evaluated as a means of improving claw health but to date has not been successful. Claw disorders are commonly discussed in context with unequal claw load, and thus this study was designed to investigate the relationship between hind limb conformation and the load exerted on the respective claws. A total of 36 cows were divided into 3 groups of 12 based on the presence of parallel, straight, and cow-hocked hind limb conformation. The vertical ground reaction forces, claw prints, and mean and maximum pressures under the claws were measured in these cows before and after claw trimming. The principal characteristic of all 3 conformation traits was a significantly higher load on the lateral claws compared with the medial claws, which was least severe in cow-hocked cows. After functional foot trimming, the claws of the cows with straight conformation tended to have the most pronounced disproportion between the loads of the paired claws. Considering that a significantly higher load on the lateral claws occurred with all 3 conformations, the potential for improvement of claw health by means of indirect genetic selection for specific hind limb traits appears limited.

Inferring lifestyle for Aves and Theropoda: A model based on curvatures of extant avian ungual bones.

Claws are involved in a number of behaviours including locomotion and prey capture, and as a result animals evolve claw morphologies that enable these functions. Past authors have found geometry of the keratinous sheath of the claw to correlate with mode of life for extant birds and squamates; this relationship has frequently been cited to infer lifestyles for Mesozoic theropods including Archaeopteryx. However, many fossil claws lack keratinous sheaths and thus cannot be analysed using current methods. As the ungual phalanx within the claw is more commonly preserved in the fossil record, geometry of this bone may provide a more useful metric for paleontological analysis. In this study, ungual bones of 108 birds and 5 squamates were imaged using X-ray techniques and a relationship was found between curvatures of the ungual bone within the claw of pedal digit III and four modes of life; ground-dwelling, perching, predatory, and scansorial; using linear discriminant analysis with weighted accuracy equal to 0.79. Our model predicts arboreal lifestyles for Archaeopteryx and Microraptor and a predatory ecology for Confuciusornis. These findings demonstrate the utility of our model in answering questions of palaeoecology, the theropod-bird transition, and the evolution of avian flight. Though the metric exhibits a strong correlation with lifestyle, morphospaces for PD-III curvatures overlap and so this metric should be considered alongside additional evidence.

[Colonel Hermann Schwyter, equine surgeon, a formative personality of equine medicine]. / Oberst Hermann Schwyter, Oberpferdarzt, eine prägende Persönlichkeit der Pferdemedizin.

INTRODUCTION: The biography of Colonel Hermann Schwyter, equine surgeon of the Swiss Army from 1928 to 1937, and the history of training of farriers in Switzerland since the 18th century are presented. Hermann Schwyters dissertation examined the changes of equine hoof confirmation as a result of standing and gait in approximately 2,000 horses and numerous anatomical specimens. He defines the foot placement, describes possible variations, their causes and effects. Significant is also his study of the compression pathology in horses and mules. His recommendations are still valid today. The present article refers to his authored textbook "The Swiss military farrier" and to his established journal, which is bearing the same title.

INTRODUCTION: On présente la biographie du colonel Hermann Schwyter, vétérinaire en chef de l'armée suisse de 1928 à 1937 et l'historique de la formation des maréchaux en Suisse depuis le XVIIIe siècle. Dans sa thèse, Hermann Schwyter a examiné l'évolution de la forme du pied du cheval en fonction des aplombs et des allures sur environ 2000 chevaux et de nombreuses préparations. Il a défini la position normale du pied, décrit les déviations, leurs causes et leurs effets. Il faut également souligner son étude sur les dommages dus aux pressions chez les chevaux et les mulets. Ses recommandations sont toujours valables aujourd'hui. Il est également fait référence à son ouvrage «Le maréchal-ferrant militaire suisse¼ ainsi qu'au journal portant le même titre qu'il avait créé.

Convergent Evolution of Claw Shape in a Transcontinental Lizard Radiation.

Species occupying similar selective environments often share similar phenotypes as the result of natural selection. Recent discoveries, however, have led to the understanding that phenotypes may also converge for other reasons than recurring selection. We argue that the vertebrate claw system constitutes a promising but understudied model system for testing the adaptive nature of phenotypic, functional, and genetic convergence. In this study, we combine basic morphometrics and advanced techniques in form analysis to examine claw shape divergence in a transcontinental lizard radiation (Lacertidae). We find substantial interspecific variation in claw morphology and phylogenetic comparative statistics reveal a strong correlation with structural habitat use: ground-dwelling species living in open areas are equipped with long, thick, weakly curved, slender-bodied claws, whereas climbing species carry high, short, strongly curved, full-bodied claws. Species occupying densely vegetated habitats tend to carry intermediately shaped claws. Evolutionary models suggest that claw shape evolves toward multiple adaptive peaks, with structural habitat use pulling species toward a specific selective optimum. Contrary to findings in several other vertebrate taxa, our analyses indicate that environmental pressures, not phylogenetic relatedness, drive convergent evolution of similarly shaped claws in lacertids. Overall, our study suggests that lacertids independently evolved similarly shaped claws as an adaptation to similar structural environments in order to cope with the specific locomotory challenges posed by the habitat. Future biomechanical studies that link form and function in combination with genomic and development research will prove valuable in better understanding the adaptive significance of claw shape divergence.

The oldest freshwater crabs: claws on dinosaur bones.

With approximately 1,500 extant species, freshwater crabs (Decapoda: Brachyura) are among the most diverse decapod crustaceans. Nevertheless, their fossil record is extremely limited: only Potamidae, Potamonautidae and Trichodactylidae are reported up to the Eocene of the Neotropics so far. This work documents unusually large decapod claws from the Upper Cretaceous (Campanian) continental deposits of Velaux and vicinity (southern France), in close association with large vertebrate remains. In addition to (1) the systematic assignment of these claws, the study addresses (2) the salinity trends in the deposit environment from its faunal assemblage and the elementary chemical patterns of fossils, and (3) the likely scenario for their auto/allochthony in the Velaux fluvial system. These claws belong to a new taxon, Dinocarcinus velauciensis n. gen. n. sp., referred to as Portunoidea sensu lato, a group of "true" crabs nowadays linked to marine systems. However, the faunal assemblage, the claw taphonomy and the carbonates Y/Ho signatures support their ancient freshwater/terrestrial ecology, making them the oldest reported continental brachyurans and extending the presence of crabs in freshwater environments by 40 Ma. Either as primary or as secondary freshwater crabs, the occurrence of these portunoids in Velaux is an evidence for the independent colonizations of continental environments by multiple brachyuran clades over time, as early as the Campanian.

Relação espacial entre o estojo córneo e a falange distal em éguas Campolina adultas com e sem obesidade / Spatial relationship between the hoof capsule and the distal phalanx in adult Campolina mares with and without obesity

A laminite endocrinopática tem acometido um número crescente de equinos com sinais de obesidade. Em um estudo recente com fêmeas jovens (até cinco anos) da raça Campolina, demonstraram-se indícios de alterações no dígito, ainda discretas, aparentemente associadas ao aumento da adiposidade. Com a hipótese de que essa associação é mais evidente em animais em faixa etária superior, o objetivo do presente estudo foi estudar éguas adultas (acima de cinco anos) da raça Campolina com e sem obesidade, avaliando-se radiograficamente a relação espacial entre estojo córneo e falange distal. Foram utilizadas 27 éguas entre seis e 14 anos de idade, sendo analisadas variáveis de adiposidade e medidas radiográficas dos cascos dos membros torácicos de equinos com escore corporal de 5 a 7/9 (grupo controle) e de 8 a 9 (grupo obeso). Foram feitas comparações entre os grupos e correlacionaram-se as variáveis de adiposidade com variáveis casco. A distância de afundamento da falange distal foi cerca de 20% superior nas éguas obesas (12,3±2,5 contra 10,2±2,2mm no grupo controle). Esse parâmetro também correlacionou (P<0,01) com vários parâmetros de adiposidade, com destaque para o escore de condição corporal (r=0,47) e a circunferência de pescoço a 75% (r=0,42). Os resultados corroboram estudos prévios que demonstraram associação entre obesidade e indícios de separação entre falange distal e estojo córneo em equinos de raças nacionais, comprovando, assim, a utilidade da avaliação radiográfica nesses animais. Em conclusão, éguas da raça Campolina com obesidade possuem alterações evidentes na relação espacial entre estojo córneo e falange distal, que se intensificam com o aumento da idade e da adiposidade.(AU)

In a recent study with young females (up to 5 years old) of the Campolina breed, there were discrete indications of alterations in the digit, apparently associated to the increase in adiposity. With the hypothesis that this association is more evident in horses in the upper age group, the objective was to study Campolina adult mares (above 5 years) with and without obesity, evaluating radiographically the spatial relationship between the horn and distal phalanx. Eighteen mares between six and fourteen years and with a body score of 5 to 7/9 (Control Group) and 8 to 9 (Obeso Group) were used. Adiposity and radiographic measurements from the forelimbs were analyzed. Comparisons were made between groups and adiposity variables were correlated with hoof variables. The sinking distance of the distal phalanx was about 20% higher in obese mares (12.3±2.5 versus 10.2±2.2mm). This parameter also correlated (P< 0.01) with several adiposity parameters, with emphasis on body score condition (r= 0.47) and neck circumference at 75% (r= 0.42). In conclusion, Campolina mares with obesity have obvious alterations in the spatial relation between the corneal and the distal phalanx, which get intense according to increases in age and adiposity.(AU)

Rapid and non-destructive identification of claws using ATR-FTIR spectroscopy-A novel approach in wildlife forensics.

Differentiation and identification of Royal Bengal Tiger (Panthera tigris tigris) and Indian Leopard (Panthera pardus fusca) claws is a challenging task in wildlife forensics, due to similarity in their morphology, anatomy and chemical compositions as both the species are closely related to each other genetically. ATR-FTIR spectroscopy, which offers a non-destructive and safe alternative technique to other conventional methods, has been employed in the present work to differentiate claws of Royal Bengal Tiger and Indian Leopard. An attempt has been made to differentiate 31 reference claw samples from 16 different Royal Bengal Tigers, 15 different Indian Leopards, and 10 fake claws using ATR-FTIR spectroscopy supplemented with PCA, PLS-DA, and LDA. PCA could not distinguish the samples of two closely related species among themselves as well as from the fake claws. On the other hand, PLS-DA and LDA models both yielded highly significant classification rate for differentiation among the samples of Royal Bengal Tiger, Indian Leopard, and their fake counterparts. Further, seven blind claw samples that were pretended to be unknown to the analyst of both the species are also examined and identified correctly to their respective groups. The R-Square value obtained for PLS-DA model to differentiate Royal Bengal Tiger, Indian Leopard, and fake claws is 0.99, which is highly significant for predictive accuracy. This study shows that ATR-FTIR spectroscopy with PLS-DA/LDA has a potential to present a rapid, non-destructive, reliable, and eco-friendly approach for the accurate identification and differentiation of Royal Bengal Tiger and Indian Leopard claws.

Structure, mechanics and material properties of claw cuticle from mole cricket Gryllotalpaorientalis.

Powerful shovel-like forelimbs with special shape, structure and biological materials enable mole cricket to digging efficiently. During digging, the tip of the claw needs to wedge into the soil, and the base needs to withstand considerable anti-shear force. In this study, we analysed the structural characteristics, material composition and mechanical properties of the claw teeth using scanning electron microscopy, plasma atomic emission spectroscopy, nanoindentation and finite element analysis. The results show that the tips of claw teeth have a dense and homogeneous structure and a higher hardness and contents of Mn and Zn compared with the base. The structure of the base of claw teeth has an obvious laminar structure and higher fracture resistance. Moreover, it is speculated from the simulation results that basal position of the claw teeth is tough enough to withstand high stress, and the presence of the ribs effectively improves the mechanical stability and load-bearing capacity of the teeth during excavation. The results of this study can provide inspiration for the design of efficient mechanical components and agricultural implements.

The expression of equine keratins K42 and K124 is restricted to the hoof epidermal lamellae of Equus caballus.

The equine hoof inner epithelium is folded into primary and secondary epidermal lamellae which increase the dermo-epidermal junction surface area of the hoof and can be affected by laminitis, a common disease of equids. Two keratin proteins (K), K42 and K124, are the most abundant keratins in the hoof lamellar tissue of Equus caballus. We hypothesize that these keratins are lamellar tissue-specific and could serve as differentiation- and disease-specific markers. Our objective was to characterize the expression of K42 and K124 in equine stratified epithelia and to generate monoclonal antibodies against K42 and K124. By RT-PCR analysis, keratin gene (KRT) KRT42 and KRT124 expression was present in lamellar tissue, but not cornea, haired skin, or hoof coronet. In situ hybridization studies showed that KRT124 localized to the suprabasal and, to a lesser extent, basal cells of the lamellae, was absent from haired skin and hoof coronet, and abruptly transitions from KRT124-negative coronet to KRT124-positive proximal lamellae. A monoclonal antibody generated against full-length recombinant equine K42 detected a lamellar keratin of the appropriate size, but also cross-reacted with other epidermal keratins. Three monoclonal antibodies generated against N- and C-terminal K124 peptides detected a band of the appropriate size in lamellar tissue and did not cross-react with proteins from haired skin, corneal limbus, hoof coronet, tongue, glabrous skin, oral mucosa, or chestnut on immunoblots. K124 localized to lamellar cells by indirect immunofluorescence. This is the first study to demonstrate the localization and expression of a hoof lamellar-specific keratin, K124, and to validate anti-K124 monoclonal antibodies.

Differences in mineral concentrations on hooves of horses, mules and donkeys / Diferenças nas concentrações de minerais nos cascos de equinos, muares e asininos

This study aimed to measure the concentrations of minerals in different regions and pigmentation of horses' hooves, mules and donkeys. A total of 20 Crioulo horses, 20 mules and 20 Pega donkeys were used. They formed two groups: pigmented (dark) or non-pigmented (bright) hooves. All animals were unshod and with adequate foot conformation. Females were non-pregnant and without foal and no animals were in training. Samples were collected from the hooves of all limbs in the regions of wall, sole and frog. The concentrations of calcium, magnesium, copper, iron and zinc were determined by atomic absorption spectrophotometry; sodium and potassium concentrations were determined by atomic emission spectrophotometry. Among the groups it was observed that the wall, sole and frog of donkeys' hooves presented higher concentrations of sodium and calcium and with the exception of the frog that also obtained higher levels of copper in this species. Mules had lower concentrations of zinc in the wall and the horses had higher concentrations of potassium and zinc in the sole and higher magnesium in the frog and wall. There was no difference (P>0.05) in concentrations regarding the pigmentation of the hooves. The different regions of the hooves in each group presented similar concentrations of minerals and it was regardless of the pigmentation. The mineral concentrations may be related to desirable functional properties of the donkeys' hooves. Pigmented and non-pigmented hooves have similar concentrations of minerals.

O objetivo desse trabalho foi mensurar os teores de minerais nas diferentes regiões e pigmentações dos cascos de equinos, muares e asininos. Utilizaram-se 20 equinos da raça Crioula, 20 muares e 20 asininos da raça Pêga. Formaram-se dois grupos conforme os cascos pigmentados (escuros) e não pigmentados (claros). Todos os animais estavam desferrados e com adequada conformação podal e as fêmeas estavam não gestantes e sem potro ao pé e nenhum animal estava em treinamento. Amostras foram coletadas dos cascos de todos os membros nas regiões de parede, sola e ranilha. As concentrações de cálcio, magnésio, cobre, ferro e zinco foram determinadas por espectrofotometria de absorção atômica e as concentrações de sódio e potássio foram determinadas por espectrofotometria de emissão atômica. Entre os grupos observou-se que a parede, sola e ranilha nos asininos apresentaram maiores valores de sódio e cálcio e, exceto para a ranilha, também obteve-se maiores teores de cobre nesta espécie. Os muares apresentaram menores teores de zinco na parede e, os equinos, maiores teores de potássio e zinco na sola e ranilha e de magnésio na ranilha e parede. Não houve diferença (P>0,05) nos teores dos minerais quanto à pigmentação dos cascos. As diferentes regiões dos cascos em cada grupo apresentaram teores similares de minerais e este independeu da pigmentação. As variações dos teores de minerais entre os grupos podem estar relacionados a propriedades funcionais desejáveis dos cascos dos asininos. Cascos pigmentados e não pigmentados apresentam teores similares dos minerais.

Physics of animal health: on the mechano-biology of hoof growth and form.

Global inequalities in economic access and agriculture productivity imply that a large number of developing countries rely on working equids for transport/agriculture/mining. Therefore, the understanding of hoof conditions/shape variations affecting equids' ability to work is still a persistent concern. To bridge this gap, using a multi-scale interdisciplinary approach, we provide a bio-physical model predicting the shape of equids' hooves as a function of physical and biological parameters. In particular, we show (i) where the hoof growth stress originates from, (ii) why the hoof growth rate is one order of magnitude higher than the proliferation rate of epithelial cells and (iii) how the soft-to-hard transformation of the epithelium is possible allowing the hoof to fulfil its function as a weight-bearing element. Finally (iv), we demonstrate that the reason for hoof misshaping is linked to the asymmetrical design of equids' feet (shorter quarters/long toe) together with the inability of the biological growth stress to compensate for such an asymmetry. Consequently, the hoof can adopt a dorsal curvature and become 'dished' overtime, which is a function of the animal's mass and the hoof growth rate. This approach allows us to discuss the potential occurrence of this multifaceted pathology in equids.