Ultrasonographic measurement of the sole horn thickness in bovine claw

Ultrasonographic thickness measurement and imaging of sole horn and the encapsulated soft tissue layers was evaluated in 100 bovine claw specimens. The claws were trimmed and examined in longitudinal planes using a 7.5 MHz linear transducer. In each claw, ultrasonographic measurements of horn thickness of sole and distance from outer claw surface to distal phalanx surface were made at three marked points on the weightbearing surface. All claws were then frozen, transected and anatomical reference measurements were made after thawing. The sole horn, corium, subcutis and distal surface of the distal phalanx of all claws were clearly visualized. The sole horn had a heterogeneous hypoechoic appearance, the underlying soft tissue layer was predominantly anechoic. Corium and subcutis could be differentiated. Best imaging of these structures was achieved in claws with less than 10 mm sole horn thickness and soft sole horn. Statistical correlation coefficients of 0.88 to 0.91 were found for ultrasonographic and anatomical measurements of sole horn thickness. Therefore, B-mode ultrasonography proved to be an accurate, non-invasive technique for measurement of the sole horn thickness in bovine claws.     

Ultrasound measurement of sole horn thickness in trimmed claws of dairy cows

OBJECTIVE: To determine whether ultrasound could be used to measure sole horn thickness in dairy cattle after claw trimming with an adaptation of the Dutch method. DESIGN: Case series. ANIMALS: 24 adult Holstein dairy cows. PROCEDURE: Cows were restrained in a standing position, and claws were trimmed with an adaptation of the Dutch trimming method. B-mode ultrasonography was then performed. The transducer was placed on the sole just caudal to the apex of the toe and immediately medial and parallel to the abaxial white zone. The inner margin of the sole was identified as a thin hyperechoic line. Soles were considered to be too thin if sole horn thickness, determined by use of ultrasonography, was < 5 mm. RESULTS: Sole horn, underlying soft tissues, and the distal surface of the third phalanx were imaged in 151 claws. The inner margin of the sole could not be identified in 4 claws, and 37 claws could not be imaged because cows collapsed in the restraining chute. Mean +/- SD sole thickness for all claws was 71 +/- 1.3 mm. Only 1 sole was < 5 mm thick. The lateral front claws were significantly thicker than the medial hind claws. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that ultrasound imaging can be used to determine sole thickness in dairy cattle after routine claw trimming.     

Measurements of claw dimensions in cows before and after functional trimming: a post-mortem study

The aim of this study was to compare measurements of the medial and lateral claws of the hind feet in cattle, and to establish reference values to aid in functional claw trimming. Variables of the medial and lateral claws of 40 hind feet obtained from 40 slaughtered German Simmental cows were measured. To standardise the observations the soles of both the medial and lateral claws were first trimmed to a defined thickness of 5mm at the apex and 8mm at the heel, before measurements were taken. After this standardisation, the mean lengths of the dorsal walls of the two claws were not significantly different (means, lateral 76.8, medial 77.1 mm). However, there were considerable other differences. For example, the soles of the lateral claws were significantly (P < 0.01) longer (means, 120.1mm versus 112.7 mm, and wider (means, 52.0 mm versus 42.5 mm). In 36/40 feet, the sole of the lateral claw protruded approximately 2-3mm above the sole of the medial claw after the standardisation. The soles of the lateral claws were therefore then trimmed to the height of the medial claw ("levelling") and the measurements were repeated in the lateral claws. The dorsal wall of the lateral claw was then significantly shorter than that of the medial claw (means, 74.8 mm versus 77.1 mm) and, most importantly from a functional point of view, the sole was significantly thinner than that of the medial claw (means, 2.71 mm versus 5mm at the toe tip, 4.9mm versus 8 mm at the heel). Finally, the horn capsule of all claws was removed and various measurements of the corium surface were made. The length of the dorsal corium surface did not differ statistically (P > 0.05) between the lateral (mean, 62.6 mm) and medial (mean, 62.5 mm) claws. Strict adherence to the principles of functional trimming thus reduces the thickness of the sole, the length of the dorsal wall and the length and height of the bulb of the lateral claw. This suggests that the sole of the medial claw should be left an extra 3 mm thicker than previously recommended such that, after "levelling", the sole of the lateral claw remains thick enough to protect fully the corium and the claw retains a more normal shape.     

Ultrasonographic and macroscopic comparison of the thickness of the capsule,corium, and soft tissues in bovine claws: an in vitro study

This study aimed to compare thickness of the capsule, corium, and soft tissues measured ultrasonographically and macroscopically in selected regions of bovine claws. A hundred and twenty claws (n = 120) of 15 healthy Holstein bovines were obtained. After cleaning the claws, ultrasonographic measurement of the capsule, corium, and soft tissues was performed while submerging the claws in a water bath. Macroscopic measurements were taken after cutting of the claws axially. These values were compared statistically. According to the macroscopic measurements, the mean thickness ± standard deviation (SD) of the capsule for dorsal wall and sole was 6.2 ± 0.1 and 9.5 ± 0.4 mm, respectively. The thickness of the corium and soft tissues for dorsal wall and sole was 4.5 ± 0.1 and 5.3 ± 0.1 mm, respectively. Ultrasonographically, the mean thickness ± SD of the capsule for dorsal wall and sole was 4.7 ± 0.1 and 7.8 ± 0.3 mm, respectively. The thickness of the corium and soft tissues for dorsal wall and sole was 4.3 ± 0.1 and 5.9 ± 0.2 mm, respectively. Findings demonstrated that ultrasonography can be reliably to measure of the thickness of the hoof capsule, corium, and soft tissue in bovine claw.     

Suspensory structures and supporting tissues of the third phalanx of cows and their relevance to the development of typical sole ulcers (Rusterholz ulcers)

The mural suspensory apparatus of third phalanx and its supportive heel cushion were examined in 19 cows with an ulcer at the 'typical' site (Rusterholz ulcer) to gain information on the pathogenesis of sole and heel ulcers. The claws of 17 healthy controls were used for comparison. The left hind claws, frozen at -20 degrees C, were sectioned in one longitudinal and four transverse planes with a band saw. The thickness of the subcutaneous tissue, the corium and the extent of displacement of the third phalanx were measured at defined sites on these sections. In addition, the suspensory apparatus, the tissue layer connecting the third phalanx to the dorsal wall of the horn capsule, was examined histologically. There was a direct relationship between the displacement of the third phalanx and ulceration of the sole or heel; in all the ulcerated claws the third phalanx had dropped and the corium and the subcutis under the bone were thinner than in the controls. The supportive cushions of the cows with ulcers contained less fat tissue. There was no histological evidence of damage to the epidermis or the corioepidermal junction in the ulcerated claws nor were the lamellae elongated. Similarly, there were no morphological changes in the connective tissue layer, the submural dermis.     

Measurements of forelimb claw dimensions in cows using a standardised sole thickness: a post-mortem study

Measurements of both front feet of slaughtered German Simmental cattle (17 heifers, 13 cows) were carried out to document the normal shape and size of the forelimb claws and to gain information about function and possible predisposition to disease. Only clinically normal feet were examined, and a standardised sole thickness of 5mm at the tip and 8mm in the heel region in both claws was established as a reference. The dorsal wall length, dorsal wall angle, heel length, height and width, sole and claw length and claw width, sole circumference and sole area were measured. After removal of the horn capsules, measurements of values at the level of the corium were carried out. The lateral front claws were wider and the medial claws longer than their partner claws. Overall, the sole surface areas and circumferences of the paired claws were similar, but were statistically larger in the medial claws. The front claws were characterised by long and high heel bulbs, and had a toe length:heel bulb length ratio of approximately 1.6:1. These properties, together with the musculo-tendinous attachment of the limbs to the trunk, are believed to provide better protection for the forelimb claws when standing or walking on hard surfaces. Functional mechanical relief of the medial front claws is probably best achieved by pairing the soles of the foot to the same level, which usually entails reduction of the lateral claw. For German Simmental cattle, a dorsal wall length of 75mm can be used as a guideline when trimming front and hind feet.     

Laminitis-like changes in the claws of feedlot cattle

The purpose of this study was to observe and quantitate changes in the claws of two groups of feedlot cattle (calves and backgrounded yearlings) fed diets that varied in energy (73.5 or 78.5% TDN) and crude protein (11, 13, 15, 16, 17, or 19%) content. At slaughter, the thickness of sole horn and the prevalence of toe and heel hemorrhages were greater in calves than in yearlings (p<0.02). Feeding the high-energy ration increased the prevalence of toe and heel hemorrhages in calves (p<0.02) and heel hemorrhages in yearlings (p<0.02). In yearlings, rotation of the distal phalanx and ridging of the dorsal wall of the claw were the most prominent pathological features. Osteopathy of the apex of the distal phalanx occurred more frequently in calves than in yearlings (p<0.01). This study suggests that intensive feeding of beef cattle before they reach 14 months of age has a deleterious effect on digital health.     

A method of biomechanical testing the suspensory apparatus of the third phalanx in cattle: a technical note

There are a number of differences between the claws of the front and hind limbs in cattle concerning macroscopic shape, chemical and physical properties of claw horn and epidemiological data. Front claws have superior data in almost every respect. Virtually no information is available on the mechanical stability of the suspensory apparatus of the third phalanx. It was the objective of this study to develop a method to measure the maximum strength (N/mm2) of the suspensory apparatus of the bovine distal phalanx. This apparatus includes all layers of tissue such as bone, corium, corioepidermal junction and wall horn. The feet of 13 clinically healthy beef bulls were collected from the local abattoir. Testing was performed in three locations of the wall segment (dorsal, abaxial, axial) in a material testing machine. The corium and the corioepidermal junction were set under increasing tension until failure occurred. Maximum stress was recorded. The values ranged between 2.47-3.13 N/mm2 (dorsal), 4.08-4.87 N/mm2 (abaxial) and 2.27-2.66 N/mm2 (axial). No differences could be validated statistically between front and hind claws and between lateral and medial claws respectively. Abaxial ultimate stress values were significantly higher than dorsal and axial ones. Between the two a statistical difference could not be validated. Most of the specimens (57.1%) were torn apart at the corioepidermal junction, almost a quarter of the samples (27.6%) were to a degree disrupted at the corioepidermal junction and to a certain extent in the deeper layers of the corium. A few samples showed disruption within the horn (11.5%) or at the attachment of the third phalanx (3.8%). Biomechanical features of the experimental set-up are discussed. The biological significance of these findings is that the body weight and the additional dynamic loading is predominantly taken over by the abaxial part of the claw, while the dorsal and axial aspects are less loaded.     

A macroscopic study of the vascular system of the bovine hind limb claw

The vascular organisation of the hind limb claws from clinically normal cattle was studied using plastic corrosion casts. The proper digital artery ran dorsodistally within the interdigital space and gave off a bulbar branch to the bulb, a plantar branch to the axial aspect of the wall and sole, and a coronary artery to the coronary margin and proximal wall. The artery entered the distal phalanx at the axial foramen, coursed through the nutrient canal as the terminal arch, and emerged at the abaxial foramen to anastomose with branches of the bulbar artery. During its interosseous course, the terminal branch gave off 6-8 primary branches which provided the arterial supply to the coronary margin, axial and abaxial wall, white zone and sole. The dorsal proper digital vein and axial and abaxial proper plantar digital veins drained all venous blood from the claw. Each of these large veins arose from numerous smaller veins which joined to form the venous networks of the coronary margin, wall, sole and bulb. A large arched vein passed through the coronary cushion and formed a connection between the superficial coronary venous plexus and the intra-osseous plexus of the distal phalanx. The axial and abaxial proper plantar digital veins were connected by a vessel through the bulbar cushion. At the same level, the axial proper plantar digital veins of the lateral and medial claw were connected to each other by a large vessel through the interdigital space, situated just proximal to the distal interdigital ligaments. This resulted in the presence of a complete distal venous arch along the plantar aspects of both claws. The parietal collecting veins drained most of the venous blood from the sole, white zone and wall, and connected directly to the venous plexuses of the coronary margin and bulb. Valves occurred commonly in medium and larger calibre veins throughout the claw.     

Modulus of elasticity and dry-matter content of bovine claw horn affected by the changes of chronic laminitis

The mechanical properties of horn samples from 22 hind claws with chronic laminitis were determined in adult Austrian Fleckvieh cows. The resistance to deformation was quantified as the modulus of elasticity (E). Tension tests revealed mean E values of 520MPa for the dorsal wall, 243MPa for the abaxial wall, 339MPa for the axial wall and 97MPa for the sole. E tended to be lower in laminitic horn than in sound horn in all segments tested, with the difference being largest in the abaxial wall. The mean dry-matter content (DMC) of the laminitic claws was 75.8% in the dorsal wall, 75.86% in the abaxial wall, 71.15% in the axial wall and 69.28% in the sole. These values are generally comparable to those for sound claws except in the axial wall. Further, E and DMC were only correlated in the axial wall. Chronic laminitis leads to a low resistance of claw horn to mechanical insults in the dorsal wall, abaxial wall and sole, and to the loss of a correlation between the E and DMC in these segments. The reason for these alterations is therefore not increased ingress of moisture, but must be due to changes in the microstructure, biochemical components and/or horn formation by the diseased dermis.     

Measurement of the thickness of the corium and subcutaneous tissue of the hind claws of dairy cattle by ultrasound

The thickness of the subsolar soft tissue layer (dermis and subcutaneous tissue) of the hind lateral and medial claws of 23 Holstein dairy cattle was measured by ultrasound imaging. The results showed that on average the subsolar soft tissue layer of the lateral hind claw was significantly thicker (4.29 mm) than that of the medial hind claw (3.92 mm).     

The bovine digital cushion--a descriptive anatomical study

The properties of the suspensory and supporting structures of the bovine claw are of particular importance in the pathogenesis of claw lesions since both must function optimally to prevent soft tissue compression and trauma. An essential component is the shock-absorbing digital cushion situated under the distal phalanx. The sound claws of 54 slaughtered cows were dissected. The digital cushion consisted of three parallel pads--axial, middle and abaxial--that ran longitudinally from the heel and underneath the distal phalanx with numerous transverse finger-shaped branches that connected the axial and abaxial pads cranial to the flexor process of the distal phalanx. The middle fat pad frequently ended just at the apical end of the flexor process of the distal phalanx, which may result in an inferior cushioning effect under the distal phalanx and increase the likelihood of ulcers. There were differences in the structure of the digital cushion with age and loose connective tissue in heifers' pads was first replaced by fat which, after the third lactation, was gradually supplanted by collagenous connective tissue.     

The hardness of horn in different segments of the bovine claw

Hardness of bovine hoof horn was tested as ball indentation hardness and as shore D hardness post mortem in different segments of the hoof wall, in the sole and the hard bulb of sound claws of 10 Austrian Holstein Friesian cows. Both methods of hardness determination showed corresponding results, with shore D hardness between 52.2 and 63.9 hardness units (hu) and ball indentation hardness between 11.2 N/mm2 and 24.3 N/mm2. Bovine hoof horn becomes significantly softer from the coronary band towards the weight bearing border (vertical decrease) and from the dorsal wall towards the heel (horizontal decrease). Decreasing hardness was associated with decreasing dry matter content. Measurements of the claw capsule showed thickness of the hoof wall increasing from the coronary border towards the sole. In dorsopalmar/-plantar direction, bovine hoof wall at the weight bearing border decreases towards the heel.     

The segmental organization and horny structure of the claw of the dog]

This study classifies the segments of the dog claw and presents a new conception to define crown and wall segments that deviates from the common statements in literature. The perioplic segment extends along the internal surface of the claw fold (vallum). The crown segment lies in the unguicular groove, and there in a semicircular zone. In the crown segment there is development of horn tubuli, but these lose their tubular structure before they have reached the top of the claw. The wall segment, adjacent distally, comprises a dorsal ridge, and lateral surfaces proximally and distally which are all marked by superficial lamellar-shaped surface configurations. The sole segment shows desquamative soft horn and is situated between the free margin of the wall segment palmar/plantar to the unguicular process. The new conception of homology of dog claw distinguishes between main and secondary criteria. The main criterion is the epidermal and dermal configuration. Secondary criteria are the typical horn products (for example perioplic horn) and dimension, shape and topography of segments. The sterile/fertile-bed theory, which was believed to be the determining factor for the classification of the dog claw, is neither the proper method to define the individual segments nor to judge the rate of cornification.     

Effects of supplementing pregnant heifers with methionine or melatonin on the anatomy and other characteristics of their lateral hind claws

Three groups of four primiparous Holstein-Friesian heifers were fed throughout pregnancy either a control diet or that diet supplemented with either 5 to 6 g per day of rumen-protected intestinally available methionine or 25 mg melatonin. They were euthanased three days after calving. The dietary supplements had no effect on the impression hardness or the concentrations of cysteine and methionine in samples of claw horn collected from a range of sites, or on the areas of erosion in the sole and heel. Significant differences were recorded for the hardness of the horn in the order wall >sole >heel. These differences were associated with higher concentrations of cysteine and lower concentrations of methionine in samples of horn from the dorsal wall than in samples from the prebulbar region of the sole. There were no significant differences attributable to the dietary supplements in the soft tissue anatomy of the solear dermis and epidermis.     

A finite element model of the bovine claw under static load for evaluation of different flooring conditions

AIM: To create a computer-based finite element (FE) model of the bovine claw and to use finite element analysis (FEA) to estimate stress and deformation of a physiologically-shaped model claw under static load, to visualise potential material weakness and to evaluate the effect of different flooring conditions. METHODS: Model geometry was derived using digitalised images from a recently trimmed, sound, hind claw from a 4-year-old Austrian Fleckvieh cow. Material properties of bovine claw horn were defined from preliminary investigations and recently established material data, using a modulus of elasticity from 200 to 600 N/mm2. Meshing of the model was performed with 42,127 elements based on 116,141 nodes. Loading of the model was defined at 756 N per claw on a hard and soft surface. RESULTS: The FE model of the bovine claw under a load of 756 N showed only minimal deformation, most of which took place at the axial wall. Highest stresses were evident in the proximal axial wall, the outer edge of the weight-bearing surface and under the heels. The claw-floor contact image showed a pressure distribution resembling the distal rim of the claw wall. On the hard surface, the maximum stresses were three times higher than those on the soft surface. CONCLUSIONS AND CLINICAL RELEVANCE: FEA allowed visualisation of the effects that loading on different floor surfaces have on the biomechanics of the claw. Uneven preparation of the claw sole resulted in high stresses at and close to irregularities of the sole. Consequences were more severe on harder flooring. The model supports the hypothesis that mechanical factors play a substantial role in the pathogenesis of claw lesions.     

Clinical study of toe ulcer and necrosis of the apex of the distal phalanx in 53 cattle

Clinical signs, causative factors, radiographic findings, type and duration of treatment or reason for killing were evaluated in 53 cattle (mean age: 5.3 years) suffering from toe ulcer and/or apical pedal bone necrosis. A total of 78 claws were affected. Four cattle suffered from a toe ulcer in one claw, 35 cattle showed osteolysis of the apex of the distal phalanx in a single claw and 14 cattle in two or three claws per cow. Overtrimming by means of a grinding disc and/or perforation of the sole was diagnosed as the major cause in 27 cattle (49%), laminitis in 30.2% and traumatic injuries in 11.3%. Radiography revealed a varying degree of osteolysis involving up to two-thirds of the pedal bone. Twenty-one cattle (39.6%) showing multiple toe disorders or involvement of one single claw with concurrent internal diseases were destroyed. In 23 cattle, the osteolytic bone was resected using a bone curette or hammer and chisel. Of these, the treatment was successful in 20 animals. The healing period ranged from 16-60 days when one claw was affected and from 43-53 days when two claws were affected. In five cattle, the digit was amputated.     

Association of claw disorders with claw horn colour in norwegian red cattle - a cross-sectional study of 2607 cows from 112 herds

Claw disorders cause problems in dairy cattle all over the world. Nutrition, feeding, environment, claw trimming routines, hormonal changes related to calving and genetics are among the factors which influence the pathogenesis. The colour of the claw horn (pigmentation) has been suggested to play a role. The aim of this study was to investigate if there were any associations between the colour of the sole horn and claw disorders detected at claw trimming. Altogether, 2607 cows on 112 farms were claw trimmed once and the colour (dark, mixed or light) of the right lateral hind claw and hind claw disorders were recorded by 13 trained claw trimmers. The data were analysed using logistic regression models with logit link function, binomial distribution and herd and claw trimmer as repeated effects, with herd nested within claw trimmer. Haemorrhages of the sole (HS) and white line (HWL) were more frequently found in light than in dark claws (OR = 2.61 and 2.34, respectively). Both HS (OR = 1.43) and corkscrewed claws (OR = 1.84) were slightly more prevalent among cows which had claws with mixed colour versus dark claws. There were no significant associations of other claw disorders with claw horn colour.     

A finite element model of the bovine claw under static load for evaluation of different flooring conditions

AIM: To create a computer-based finite element (FE) model of the bovine claw and to use finite element analysis (FEA) to estimate stress and deformation of a physiologically-shaped model claw under static load, to visualise potential material weakness and to evaluate the effect of different flooring conditions.

METHODS: Model geometry was derived using digitalised images from a recently trimmed, sound, hind claw from a 4-year-old Austrian Fleckvieh cow. Material properties of bovine claw horn were defined from preliminary investigations and recently established material data, using a modulus of elasticity from 200 to 600 N/mm² . Meshing of the model was performed with 42,127 elements based on 116,141 nodes. Loading of the model was defined at 756 N per claw on a hard and soft surface.

RESULTS: The FE model of the bovine claw under a load of 756 N showed only minimal deformation, most of which took place at the axial wall. Highest stresses were evident in the proximal axial wall, the outer edge of the weight-bearing surface and under the heels. The claw-floor contact image showed a pressure distribution resembling the distal rim of the claw wall. On the hard surface, the maximum stresses were three times higher than those on the soft surface.

CONCLUSIONS AND CLINICAL RELEVANCE: FEA allowed visualisation of the effects that loading on different floor surfaces have on the biomechanics of the claw. Uneven preparation of the claw sole resulted in high stresses at and close to irregularities of the sole. Consequences were more severe on harder flooring. The model supports the hypothesis that mechanical factors play a substantial role in the pathogenesis of claw lesions.