The deciduous hoof capsule (Capsula ungulae decidua) of the equine fetus and newborn foal

The term Eponychium is used to describe the deciduous hoof capsule in veterinary-medical and embryological literature. In other aspects of veterinary medicine, the term is generally reserved for the perioplic corium of the permanent hoof. In order to clarify this double usage, the structure and origin of the hoof epidermis from 10 equine fetus at different stages of development and 4 newborn foals were investigated and described using light microscopical techniques. Epidermal tubules and lamellae are already present in the non-cornified fetal hoof epidermis. These structures, along with the formation of a white line, allow this epidermis to be divided into the same segments as are commonly used when referring to the permanent hoof. The greatest part of the deciduous hoof epidermis consists of the sole and frog, with significant portions forming in the coronary corium and that of the hoof wall as well. The perioplic corium only makes up insignificant portions of the fetal hoof capsule, however. Between the second half of the gestation period and birth, this deciduous (primary) hoof capsule is continually being replaced from below by newly-forming, cornified permanent hoof capsule. On the basis of its structure and origin, we therefore suggest that the term "deciduous hoof capsule (Capsula ungulae decidua)" be used as a replacement for the word "Eponychium" when referring to the primary hoof epidermis.     

A singular case of traumatic total hoof capsule avulsion

Total, full thickness hoof wall avulsion is rare in horses. Sometimes complications such as fracture of the distal phalanx, osteomyelitis, septic arthritis and degenerative joint disease have been reported. Limiting motion at the affected site and hoof stabilisation are essential to obtain a good hoof regeneration. This case report reviews the clinical features including diagnostic techniques (radiographic examination and venography) of a Quarter Horse filly presented with a complete and full‐thickness traumatic hoof capsule avulsion complicated by an open fracture of the third phalanx. A transfixation casting technique was performed followed after one month by 2 short limb casts applied for 2 months each. Twenty‐four months after trauma the foot had completely regrown. The dorsal aspect of the hoof wall appears to be remarkably shorter compared to the heels. From a radiographic viewpoint, the lateral aspect of the left hind foot shows diffuse bone remodelling and a deformed distal phalanx.     

The effect of hoof trimming on radiographic measurements of the front feet of normal Warmblood horses

The understanding of the normal position of the third phalanx (P3) and the distal sesamoid bone in relation to the size and shape of the hoof capsule in sound horses is helpful in the diagnosis of equine foot lameness. Some measurements on radiographs used to define the position of the pedal bone within the hoof capsule are significantly influenced by hoof trimming and the height of the withers. In this study, the front hooves of 40 Warmblood horses were radiographed twice, eight weeks apart, both before and after their hooves were trimmed by an experienced farrier. Using the software programme Metron PX, 22 parameters on the lateromedial view and 16 parameters on the dorsopalmar view were measured and the effect of hoof trimming and height of the withers were calculated, respectively. Some of the hoof parameters showed mild positive correlation with the height of the withers. In 70% of the horses the left hoof capsule and P3 were significantly larger than the right. Hoof trimming had a remarkable influence on hoof conformation, especially for parameters in the toe region. Of all the measurements that describe the position of the third phalanx (P3) in relation to the hoof capsule, the distances between the distal tip of P3 to the solar surface of the foot, P3 to the tip of the toe and P3 to the point of break-over showed the greatest differences before and after trimming. The database of the present study can be used by farriers and veterinarians as a guideline for routine and corrective shoeing of Warmblood horses.     

Comparison of Two Methods for Presurgical Disinfection of the Equine Hoof

OBJECTIVES: To determine for equine hooves the normal resident aerobic bacterial population and the efficacy of 2 methods of disinfection. Study Design-Measurement of total bacterial, gram-positive bacterial, and gram-negative bacterial surface populations from the frog, sole, and hoof wall after each step of 2 different preoperative surgical disinfection techniques. ANIMALS: Six adult horses. METHODS: Hoof wall, sole, and frog samples were collected for quantitative bacteriology before, during, and after 2 multistep antiseptic preparation techniques: Method A-6-minute scrub with povidone-iodine soap, followed by 24-hour submersion in povidone-iodine solution-soaked cotton; and Method B-initial removal of superficial layer of hoof capsule before completing Method A disinfection procedures. RESULTS: Removal of the superficial hoof layer, application of the povidone iodine scrub, and completion of the povidone-iodine soak all significantly (P < .0008) decreased total bacterial numbers. Method B had significantly lower bacterial counts than method A at each consecutive step. Final total bacterial counts remained greater than 10(5) bacteria per gram of tissue regardless of preparation method. CONCLUSIONS: The hoof surface hosts a broad spectrum of aerobic gram-positive and -negative bacteria, many of which are potential pathogens. Bacterial numbers can be significantly reduced by removal of the superficial hoof surface, by application of a povidone-iodine scrub, and by use of a 24-hour povidone-iodine soak. However, bacterial populations >10(5) g per tissue persist after these disinfection procedures. CLINICAL RELEVANCE: Regardless of the preparation methods used in this study, bacterial populations capable of inducing wound infection remain on the hoof capsule.     

White line disease: A review (1998–2018)

White line disease (WLD) is a significant pathological condition that affects the equine hoof. White line disease continues to frustrate veterinarians and farriers due to the diversity regarding the aetiology, diagnosis and especially treatment. Furthermore, WLD lacks a definitive definition as the disease becomes apparent only when the hoof wall is compromised with an extensive separation, a hoof capsule distortion is present or when lameness exists. Clinical signs can range from a minor hoof wall separation to an extensive disruption of the external laminar bond resulting in displacement of the distal phalanx within the hoof capsule. There has been a myriad of treatments and topical preparations proposed for treating WLD, but most remain controversial with few having any scientific documentation or evidence of efficacy. This review of WLD is based on the sparse information available in the veterinary literature, the large number of WLD cases treated successfully in the authors’ combined practices using conventional farriery and the relevant questions that hopefully can be answered in the future.     

Quantitative morphology of the equine laminar junction in relation to capsule shape in the forehoof of Standardbreds and Thoroughbreds

REASONS FOR PERFORMING STUDY: Differences in hoof morphology have largely been underappreciated in the literature until recently, and it is these that hold the key to interpreting functional adaptation in the hoof. HYPOTHESES: Primary laminar morphology correlates with hoof capsule shape; and breeds with different hoof shapes and loadings show different patterns of correlation. METHODS: Seventeen measurements of capsule shape and 3 of primary epidermal laminae (PEL) morphology (spacing, orientation and curvature) were made on right and left front hooves from 27 Standardbred and 25 Thoroughbred horses, and tested for breed differences. Three laminar variables (spacing, orientation and curvature) were measured on each hoof for samples of 25 PEL in 5 circumferential and 4 proximodistal locations. Pairwise correlations of capsular and laminar measurements were compared within breeds. Significant correlations were mapped onto the 20 sampling sites. RESULTS: Capsule shape differed significantly between breeds in 7 measurements and in a multivariate test. Between breeds, PEL differed in orientation and spacing primarily at the medial quarters and heels, and in curvature at both quarters (P<0.05). Significant correlations between several pairs of capsule and laminar variables were found at sample locations that differed markedly between breeds. CONCLUSIONS: Laminar morphology, hoof capsule shape and correlations between them differ between Standardbreds and Thoroughbreds. These results support the concept that remodelling of PEL is, at least in part, stimulated and directed by varying stress or strain levels in the laminar junction. POTENTIAL RELEVANCE: Understanding the biological responses of hoof tissues to stress should add to the ability to prevent lameness involving the hoof and maintain its health.     

Fenestration of the abaxial hoof wall and implantation of gentamicin-impregnated collagen sponges for the treatment of septic arthritis of the distal interphalangeal joint in cattle.

A novel surgical approach to the distal interphalangeal joint of cattle, through the abaxial hoof wall, for the treatment of septic arthritis is described. In seven cattle a rectangular piece of horn (15 x 40 mm) was excised from the abaxial hoof wall and the joint was lavaged with Ringer's solution. Infected and/or necrotic tissue was removed from the joint and gentamicin-impregnated collagen sponges were introduced. The piece of horn was reattached, a rubber block was glued to the contralateral claw, and a bandage applied. Aftercare consisted of changes of bandage, systemic administration of antimicrobial drugs and box rest. At follow-up, six of the cattle were sound but one cow which had been slaughtered five months after surgery had remained slightly lame.     

The effect of frog pressure and downward vertical load on hoof wall weight-bearing and third phalanx displacement in the horse--an in vitro study

A shoe was designed to combine the advantages of a reverse shoe and an adjustable heart bar shoe in the treatment of chronic laminitis. This reverse even frog pressure (REFP) shoe applies pressure uniformly over a large area of the frog solar surface. Pressure is applied vertically upward parallel to the solar surface of the frog and can be increased or decreased as required. Five clinically healthy horses were humanely euthanased and their dismembered forelimbs used in an in vitro study. Frog pressure was measured by strain gauges applied to the ground surface of the carrying tab portion of the shoe. A linear variable distance transducer (LVDT) was inserted into a hole drilled in the dorsal hoof wall. The LVDT measured movement of the third phalanx (P3) in a dorsopalmar plane relative to the dorsal hoof wall. The vertical component of hoof wall compression was measured by means of unidirectional strain gauges attached to the toe, quarter and heel of the medial hoof wall of each specimen. The entire limb was mounted vertically in a tensile testing machine and submitted to vertical downward compressive forces of 0 to 2,500 N at a rate of 5 cm/minute. The effects of increasing frog pressure on hoof wall weight-bearing and third phalanx movement within the hoof were determined. Each specimen was tested with the shoe under the following conditions: zero frog pressure; frog pressure used to treat clinical cases of chronic laminitis (7 N-cm); frog pressure clinically painful to the horse as determined prior to euthanasia; frog pressure just alleviating this pain. The specimens were also tested after shoe removal. Total weight-bearing on the hoof wall at zero frog pressure was used as the basis for comparison. Pain-causing and pain-alleviating frog pressures decreased total weight-bearing on the hoof wall (P < 0.05). Frog pressure of 7 N-cm had no statistically significant effect on hoof wall weight-bearing although there was a trend for it to decrease as load increased. Before loading, the pain-causing and pain-alleviating frog pressures resulted in a palmar movement of P3 relative to the dorsal hoof wall compared to the position of P3 at zero frog pressure (P < 0.05). This difference remained statistically significant up to 1300 N load. At higher loads, the position of P3 did not differ significantly for the different frog pressures applied. It is concluded that increased frogpressure using the REFP shoe decreases total hoof wall weight-bearing and causes palmar movement of P3 at low weight-bearing loads. Without a shoe the toe and quarter hoof wall compression remained more constant and less in magnitude, than with a shoe.     

Hoof capsule distortion: understanding the mechanisms as a basis for rational management.

Understanding the basic mechanisms of hoof capsule distortion enables the clinician to unravel the sometimes complex mix of abnormalities, identify early warning signs, and manage existing problems more effectively. Distortion of the hoof capsule can often seem like a complicated puzzle by the time the veterinarian is called to examine the lame horse. Evaluating each of the components of the hoof capsule, both individually and as an integrated unit, allows the clinician to tease apart the tangle of primary and secondary problems and come up with effective options for countering or attenuating the forces responsible for the distortion. Using high-quality radiography and developing an eye for detail regarding the physical and radiographic characteristics of the foot allow the clinician to identify subtle abnormalities, thereby averting a clinical problem or addressing the problem while it is still reversible. With existing problems, developing these skills enhances the clinician's ability to interpret the degree of damage accurately and to devise mechanical solutions that create an environment in which healing and restoration of function are maximized.     

Microtomographic Parameters and Nanoindentation of the Hoof of Girolando Cattle

The aim of this study was to describe the microstructure of the pigmented and depigmented hoof capsule of Girolando cattle by bi‐ and tridimensional microtomography and nanoindentation, analysing the possible relation between these findings and the susceptibility of such animals to podal diseases. To carry out the microtomography and the nanoindentation, duplicated samples were collected from the dorsal wall, abaxial wall and pre‐bulbar sole of the hoof capsule. Material collection was performed in 40 medial digits of thoracic limbs and 40 lateral digits of pelvic limbs. The bidimensional microtomography showed that the dorsal wall of the thoracic and pelvic limbs presented higher density, followed by the abaxial wall, and finally by the sole, with the lowest density. Moreover, the hoof capsule of cows of Girolando breed is a compact, non‐porous material, and constituted by extratubular and intratubular keratin. By the tridimensional microtomography, it was possible to measure the angles of the corneal tubules in relation to the periople and the claws in the different regions of the hoof capsule, which were 90° for the dorsal wall, 55° for the abaxial wall and 70° for the sole. The tridimensional microtomography also showed corneal tubules of different diameters: 17, 51, 85, 119 and 153 μm. The nanoindentation test, when performed in different regions of the hoof capsule, did not reveal significant difference of Vickers hardness in the evaluated areas. However, we verified a larger elastic module of these regions on the transversal cut of the corneal tubules compared to the longitudinal cut.     

The Long-Term Results of Glue-on Shoes on Dorsal Hoof Wall Distortion

Every equine hoof has a certain amount of distortion. This presents in various forms: flares, dished toes, under-run heels, and cracks. Several farrier texts anecdotally suggest a correlation between hoof capsule distortion and lameness. The goal of this study was to evaluate the effects of the Sigafoos Series I glue-on shoe on hoof capsule distortion, and specifically, the effect on dorsal wall deviation. Measurements of the hoof were made using the Metron hoof evaluating system by Eponatech. Comparisons were made of the following values: dorsal length, hoof angle, dorsal wall deviation, hairline angle, hairline deviation, heel/toe height, heel height, heel angle, and support length. The study group consisted of front feet of horses shod exclusively in the Sigafoos glue-on shoe for a period of 1 year, and the control group consisted of 133 front feet from horses using nailed on shoes for a similar period and with a musculoskeletal complaint. The results indicate a 48% reduction in dorsal wall deviation for the study group. This finding supports the use of this glue-on shoe as beneficial with the goal to reduce capsular distortion of the dorsal wall.     

Breakover of the hoof and its effect on stuctures and forces within the foot

The location of the breakover of the hoof capsule can be positioned through shoe placement, shoe shape, or trimming on barefoot horses. Placing the breakover in relation to the tip of PIII is a more dependable location than placing breakover guided only by visual evaluation of the hoof capsule. The hoof-pastern axis and the position of the navicular bone will be affected by the distance from the apex of the frog to breakover. The resulting decrease in strain of the deep digital flexor tendon while standing and during movement will decrease inflammation and disease in the equine digit.     

局部静脉灌注技术在野生动物疾病治疗中的应用

局部静脉灌注最早用于局部灌注麻醉药物进行一些简单的局部外科手术,随后作为一种治疗骨关节感染的技术,近年逐渐应用于野生动物蹄部感染疾病的治疗中。该文对昆明动物园饲养的1只川金丝猴脚部感染的治疗过程进行分析总结,展望局部静脉灌注抗生素在野生动物外伤感染中的应用前景,也为野生动物的关节、骨髓以及局部组织感染类疾病提供新的治疗思路。     

Clinical Outcome of 14 Obese,Laminitic Horses Managed with the Same Rehabilitation Protocol

A specific method of rehabilitation was used to manage obese horses with laminitis, and clinical outcome was evaluated after 5 to 20 months. Clinical data from 14 similar laminitis cases were statistically analyzed to evaluate response to rehabilitation. Data were analyzed using repeated measures or logistic regression methodologies. Each horse presented as obese and laminitic with no history of a systemic inflammatory disease. The rehabilitation method emphasized a mineral-balanced, low nonstructural carbohydrate diet; daily exercise; hoof trimming that minimized hoof wall loading; and sole protection in the form of rubber hoof boots and/or hoof casts. Distal phalanx alignment within the hoof capsule was significantly improved, and hoof wall thickness was significantly decreased (P < .0001) following treatment. Solar depth was significantly increased (P < .0015). Reduction of palmar angle measurements was detected in acutely and chronically affected horses. This treatment effect was statistically greater for horses with chronic laminitis than for horses with acute laminitis (P interaction < .0001). Horses were 5.5 times more likely to be sound post-treatment than before treatment. Daily exercise, dietary modification, and removal of ground reaction force from the hoof wall were foci of the rehabilitation program. Hoof care and husbandry as applied to these horses may be an effective method of rehabilitation of horses from obesity-associated laminitis.     

Density and morphologic features of primary epidermal laminae in the feet of three-year-old racing Quarter Horses

OBJECTIVE: To quantify the density of primary epidermal laminae (PELs) around the solar circumference and evaluate the relationship between regional PEL density and hoof capsule morphology in horses. SAMPLE POPULATION: Forefeet from nine 3-year-old Quarter Horse cadavers. PROCEDURES: Data pertaining to gross features of hoof morphology and PEL variables, including number, density, and distribution patterns around the perimeter of the hoof wall and number of bar PELs, were collected. Tissues of the laminar junction were examined histologically. RESULTS: No significant differences were found between left and right forefeet with respect to gross hoof morphologic measurements. Mean +/- SD number of PELs, including those at the bars of the hoof, was 551 +/- 30. Primary epidermal laminar density in the toe was significantly higher, compared with that in the quarter and heel regions, and was higher on the lateral aspect of the foot, compared with the medial aspect. Feet were significantly wider on the lateral aspect of the foot, compared with the medial aspect, as measured across the widest point of the solar surface. Histologic examination revealed atypical laminar morphology at the toe. CONCLUSIONS AND CLINICAL RELEVANCE: Variations were detected in PEL density and morphology around the solar circumference of hooves from 3-year-old racing Quarter Horses. A better understanding of relationships between laminar density, laminar morphology, and gross morphology of the hoof capsule in different populations of horses may aid practitioners in diagnosis and treatment of disease involving the hoof wall in horses.     

An investigation of the relationships between angles and shapes of the hoof capsule and the distal phalanx

Reasons for performing study: There is little scientific evidence to support the premise that poor foot conformation predisposes to foot pain and lameness. Objectives: To determine relationships between external characteristics of the hoof capsule and angles of the distal phalanx; to determine variability in shape of the distal phalanx; and to investigate association between distal phalanx angles and the injury causing lameness. Materials and methods: Feet were documented photographically and radiographically. Linear and angle measurements were obtained for the hoof capsule and distal phalanx and compared statistically. Horses were categorised according to injury group, and angles and linear ratios were compared between groups. Results: There was modest correlation between hoof wall and heel angles and angles of the distal phalanx. There was variation in shape of the distal phalanx. There was no significant association between injury type and angles of the distal phalanx, although there was a trend for the angle of the dorsal aspect of the distal phalanx with the horizontal to be smaller in horses with injuries of the podotrochlear apparatus or deep digital flexor tendon compared with other groups. Conclusions: There are variations in shape of the distal phalanx largely due to differences in orientation of the concave solar border and the solar border to the horizontal. Variations in shape of the distal phalanx were not accurately correlated with external characteristics of the hoof capsule. There were weak associations between injury groups and angles of the distal phalanx. Clinical relevance: Further work is required to elucidate risk factors for foot‐related lameness.     

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.     

An investigation of the shape of the hoof capsule in hindlimbs,its relationship with the orientation of the distal phalanx and comparison with forelimb hoof capsule conformation

There is limited information documenting hind foot conformation. The objectives of the study were to describe the shape of the hoof capsule of hindlimbs from the lateral aspect in horses of variable breeds, and, within horses, to compare the conformation of the hoof capsule of forelimbs and hindlimbs and determine the orientation of the distal phalanx within the hoof capsule in hindlimbs. Lateral photographs of the fore and hind feet (n = 225) and lateromedial radiographs of the hind feet (n = 29) were obtained. Differences among breed and shoeing status groups were assessed using multivariable mixed-effects linear regression models. Angular parameters and ratios of linear measurements were compared between fore and hind feet; angular radiological variables and photographic parameters of the hind feet were compared. The mean dorsal hoof wall angle for hind feet (50.9°±3.7°) was smaller than forefeet (51.8°±3.9°) (P = 0.04). The mean heel angles for hind feet (36.4°±9.6°) were smaller than forefeet (40.1°±9.3°; P < 0.001). Dorsal hoof wall (P < 0.001) and heel (P = 0.002) angles were larger in unshod than shod feet. In the hind feet, the dorsal hoof wall was parallel to the dorsal aspect of the distal phalanx. The median angle of the distal phalanx to the horizontal (angle S) was 0.6° (interquartile range: −1.4, 2.3°). There was a positive relationship between angle S and the hoof wall angle (W); each 1° increase in angle S was associated with 0.6° increase in angle W (P < 0.001). Angle S was also positively associated with photographic heel angle; each degree increase in the angle S was associated with 1.8° increase in the heel angle (P < 0.001). It was concluded that the angle of the distal phalanx to the horizontal in hindlimbs is smaller than published values for forelimbs. The orientation of the distal phalanx in hindlimbs is correlated with external characteristics of the hoof capsule.     

Microstructure and Hardness of Buffalo's Hoofs

The aim of this study was to describe the microstructure of hoof capsules of the buffalo. In addition, the study emphasized the morphometric aspects of the horn tubules, the Vickers nanohardness of the dorsal and abaxial walls and sole of the digits of the thoracic and pelvic limbs of the buffalo. The abaxial wall in the thoracic and pelvic digits showed larger diameter of the horn tubules when compared to all dorsal wall and sole. In addition, the abaxial wall of the thoracic digits showed larger diameter of the horn tubules when compared with the pelvic digits. According to the three‐dimensional microtomography, the dorsal wall was higher in density compared with the abaxial wall. The latter exhibited an intermediate density, while the sole showed the lowest density. The Vickers nanohardness test showed that there was no difference in hardness and resistance between the experienced regions. However, the elastic modulus was greater on the transversal section of the hoof capsule. In conclusion, the results of the current study show that modern technologies such as microtomography and subsequent imaging can be used to investigate details of the basic morphology in different regions of the buffalo's hoof.     

Evaluation of a standardised radiographic technique of the equine hoof

Radiography of the equine hoof is often used to obtain a diagnosis. Quantitative interpretation, especially for research purposes requires high quality and accuracy of radiographs. The purpose of this study was to describe and evaluate a radiographic technique for the lateromedial (LM) and the dorsopalmar (DP) view of the equine hoof. Ten radiographs for each view from one cadaver limb and from both front feet in a standing horse were taken in order to assess repeatability of the radiographic technique. The method requires easy to use adjustable and portable equipment and strictly defined external radio opaque markers on the hoof capsule. The digitalised radiographs were processed and analysed with the software package Metron PX, measuring 13 parameters in the LM view and 10 parameters in the DP view, respectively. Results show that with few exceptions measurements of these parameters revealed a coefficient of variation that was smaller than 0.05. It was concluded that this easy to use standardised radiographic technique ensures excellent accuracy and repeatability for both the LM and DP view. Hence, this method provides an adequate tool for quantitative assessment of the equine hoof, inter- and intraindividually.