Changes in aspects of hoof and distal limb conformation in foals by radiographic evaluation

This study investigated age-related radiographic changes in the distal parts of the forelimbs by radiographic evaluation and identified the radiographic changes associated with diseases specific to foals. The hoof angle (HA), distal phalanx angle (P3A), distal phalanx palmer angle (P3PA), distal interphalangeal joint angle (DIPJA), and metacarpophalangeal joint angle (MPJA) on lateromedial radiographs of forelimbs were measured on the day after birth (Day 1); at 1, 2, 4, 6, and 8 weeks of age; and then at monthly intervals until 12 months of age. HA and P3A significantly increased from 1 day to 4 weeks and 4 weeks to 3 months of age. The P3PA increased dramatically from 1 day to 1 week, 1 week to 2 weeks, and 2 weeks to 8 weeks of age, and then decreased after 3 months of age. DIPJA significantly decreased from 1 day to 2 weeks of age before increasing from 3 to 5 months of age. MPJA increased with age until 4 weeks, slightly decreased from 2 to 4 months of age, and then gradually decreased from 4 to 6 months of age. The findings indicate that foals' forelimbs typically show flexion of the fetlock and a broken backward hoof-pastern axis just after birth, an upright fetlock until 4 months of age, and a change to a mature conformation after 6 months of age. Physiological variants were correlated with the occurrence of common foal diseases during the radiographic evaluation periods.

A prospective cohort study examining the association of claw anatomy and sole temperature with the development of claw horn disruption lesions in dairy cattle

Foot characteristics have been linked to the development of sole lesions (sole hemorrhage and sole ulcers) and white line lesions, also known as claw horn disruption lesions (CHDL). The objective of this study was to examine the association of claw anatomy and sole temperature with the development of CHDL. A cohort of 2,352 cows was prospectively enrolled from 4 UK farms and assessed at 3 time points: before calving (T1-precalving), immediately after calving (T2-calving), and in early lactation. At each time point body condition score was recorded, a thermography image of each foot was taken for sole temperature measurement, the presence of CHDL was assessed by veterinary surgeons, and an ultrasound image was taken to retrospectively measure the digital cushion and sole horn thickness. Additionally, at the postcalving time point, foot angle and heel depth were recorded. Four multivariable logistic regression models were fit to separately examine the relationship of precalving and postcalving explanatory variables with the development of either white line lesions or sole lesions. Explanatory variables tested included digital cushion thickness, sole horn thickness, sole temperature, foot angle, and heel depth. Farm, parity, body condition score, and presence of lesion at the time of measurement were also included in the models. A thicker digital cushion shortly after calving was associated with decreased odds of cows developing sole lesions during early lactation (odds ratio [OR]: 0.74, 95% confidence interval [CI]: 0.65-0.84). No association was found between digital cushion thickness and development of white line lesions. Sole temperature after calving was associated with increased odds of the development of sole lesions (OR: 1.03, 95% CI: 1.02-1.05), and sole temperature before and after calving was associated with the development of white line lesions (T1-precalving OR: 1.04, 95% CI: 1.01-1.07; T2-calving OR: 0.96, 95% CI: 0.93-0.99). Neither foot angle nor heel depth was associated with the development of either lesion type. However, an increased sole horn thickness after calving reduced the odds of cows developing sole lesions during early lactation (OR: 0.88, 95% CI: 0.83-0.93), highlighting the importance of maintaining adequate sole horn when foot trimming. Before calving, animals with a lesion at the time of measurement and a thicker sole were more likely to develop a sole lesion (OR: 1.23, 95% CI: 1.09-1.40), compared with those without a sole lesion. The results presented here suggest that white line and sole lesions may have differing etiopathogenesis. Results also confirm the association between the thickness of the digital cushion and the development of sole lesions, highlight the association between sole horn thickness and sole lesions, and challenge the potential importance of foot angle and heel depth in the development of CHDL.

An abattoir study of the prevalence of foot lesions and claw measurements in water buffalo in Egypt

BACKGROUND

Lameness has been associated with compromised animal welfare and reduced productivity in dairy cattle herds worldwide. However, little is known about the prevalence of claw lesions in the dairy buffalo population in Egypt. Furthermore, the optimum measurements for claw trimming in buffalo are unknown. A cross-sectional cadaver study was conducted where 135 pair buffalo hind feet were collected from 4 slaughterhouses and examined for the presence of claw lesions. The proportion and associated 95% confidence interval (CI) of each type of lesion were calculated. A separate set of healthy claws (n = 26) underwent ultrasonography (US) and computed tomography (CT). The agreement between US and CT measurements was assessed using Passing-Bablok regression and intraclass correlation coefficient. The CT measurements were used to calculate trimming recommendations.

RESULTS

At least one lesion was identified in 242 claws (89.6%, 95% CI = 85.4-93.0). In healthy claws, poor to moderate agreement was identified between US and CT measurements which could be due a sample size of the study. The average ± standard deviation (SD) minimum recommended external wall length of the lateral and medial claws in heifers was 7.1 ± 0.36 cm and 7.5 ± 0.35 cm, respectively. The average ± SD minimum recommended external wall length in buffaloes over five years of age was 8.2 ± 0.27 cm and 8.4 ± 0.39 cm for the lateral and medial claws, respectively.

CONCLUSIONS

The study found a high prevalence of claw lesions in buffalo in Egypt, the clinical significance of which requires further elucidation. Recommended measurements will help guide claw trimming in buffalo to minimise lesions.

Radiographic analysis of the dorsal hoof wall thickness in clinically normal draft horses

OBJECTIVE

To evaluate the radiographic thickness of the dorsal hoof wall in normal draft horse feet.

ANIMALS

33 adult draft horses with no history of laminitis, no clinically obvious lameness, and visibly unremarkable front feet were included.

METHODS

This was a prospective, descriptive study of clinically normal draft horses' front feet. Lateromedial radiographs were acquired of the front feet. A ratio of the dorsal hoof wall thickness to the length of the distal phalanx (DHWP3 ratio) was calculated.

RESULTS

The dorsal hoof wall thickness to length of the distal phalanx was calculated as 0.33 ± 0.03 (range of 0.28 to 0.39) in this population of draft horses.

CLINICAL RELEVANCE

With very few exceptions, the heterogeneous population of draft horses evaluated in this study had a DHWP3 ratio greater than previously published values in lighter breeds (< 0.30).

Hoof Unevenness in Juvenile Quarter Horses During First 6 Months of Training

The role of hoof morphology is increasingly recognized as a factor associated with lameness incidence in performance horses. The primary objective was to evaluate effect of training initiation on hoof unevenness in Quarter Horses (n = 42; 29 2-year-olds, 13 3-year-olds) over 6-months (m) in training (m0, m2, m4, and m6). Horses were objectively assessed for lameness (inertial sensor system) and photographs and radiographs of feet were taken. Hoof measurements were taken (palmar/plantar angles, frog base width/length, toe length/angle, heel length/angle, heel/foot width, wall height/angle), and analyzed with regards to laterality. Front and hindfoot pairs were determined even if toe angles were within 1.5°. Statistical analyses were performed (Fisher's exact test, mixed-model linear regression, P < .05). There were no differences in distal phalanx palmar/plantar angle between lame/nonlame forelimbs (P = .54) or hindlimbs (P = .20). Unevenness between front feet was seen in toe angle m6 (P < .001), heel length m6 (P = .01) and heel angle over time (P = .006). Unevenness between hind feet was seen at m6 in toe angle (P < .001), heel length (P = .009) and heel angle (P = .02). Lameness incidence did not differ between even and uneven footed horses in forelimbs (P = .64) or hindlimbs (P = .09). In uneven feet, there was no difference in lameness between high versus low foot in forelimbs (P = .34) or hindlimbs (P = .29). Limitations include lack of control group not entering training, lack of consistency in timing data collection to previous trimming, and small sample size. In summary, differences in foot measurements and laterality were noted over time following training initiation in juvenile Western performance horses.

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.

Synchrotron CT of an equine digit at the Australian Synchrotron Imaging and Medical Beamline

Laminitis is an extremely painful and debilitating condition of horses that can affect their athletic ability and even quality of life. The current gold standard for assessment of laminar tissue is histology, which is the only modality that enables detailed visualization of the lamina. Histology requires dissection of the hoof and therefore can only represent one specific time point. The superior spatial and contrast resolution of synchrotron computed tomography (sCT), when compared with readily available imaging modalities, such as radiographs and conventional CT, provides an opportunity for detailed studies of the lamina without the need for hoof dissection and histological assessment. If the resolution of histology can be matched or even approached, dynamic events, such as laminar blood flow, could also be studied on the microscopic tissue level. To investigate this possible application of sCT further, two objectives are presented: (i) to develop a protocol for sCT of an equine digit using cadaver limbs and (ii) to apply the imaging protocol established during (i) for sCT imaging of the vasculature within the foot using an ex vivo perfusion system to deliver the vascular contrast. The hypotheses were that sCT would allow sufficient resolution for detailed visualization to the level of the secondary lamellae and associated capillaries within the equine digit. Synchrotron CT enabled good visualization of the primary lamellae (average length 3.6 mm) and the ex vivo perfusion system was able to deliver vascular contrast agent to the vessels of the lamina. The individual secondary lamellae (average length 0.142 mm) could not be seen in detail, although differentiation between primary and secondary lamellae was achieved. This approaches, but does not yet reach, the current gold standard, histology, for assessment of the lamellae; however, with further refinement of this imaging technique, improved resolution may be accomplished in future studies.

Ultrasonographic alterations of bovine claws sole soft tissues associated with claw horn disruption lesions, body condition score and locomotion score in Holstein dairy cows

Claw Horn Disruption Lesions (CHDL) negatively affect the sole soft tissue structures located beneath the sole horn. The aim of the present study was to investigate the effect of CHDL on sole soft tissues by ultrasound means, correlating Body condition score (BCS), locomotion score and CHDL with ultrasonography evaluations of sole soft tissues in Holstein dairy cows. 100 Holstein dairy cows were enrolled in the study. BCS and locomotion score were assessed and functional trimming was performed on all animals. 84 healthy claws and 174 claws with solely one CHDL per claw were evaluated both clinically and with ultrasound, and CHDL were identified and recorded. Sole soft tissues thickness (mm) and echogenicity was determined, and ultrasonographic alterations, related to CHDL presence, where measured long their vertical (L1) and horizontal (L2) axis. Statistically significant (P < .001) differences were found in echogenicity between healthy claws and all the affected ones, with the healthy ones being mainly anechoic. Statistically significant (P < .001) differences were found for vertical (L1) and horizontal (L2) axis measures between the diverse CHDL, confirming ultrasonography as a useful tool to distinguish lesions and their extension by measuring L1 and L2. BCS had an influence both on sole soft tissues ultrasonographic appearance and on CHDL insurgency. These results confirm ultrasonography as a reliable tool for detecting an increase in sole soft tissues echogenicity, that was seen to occur with CHDL insurgency, and in determining lesion extension.

Complete ostectomy of middle phalanx and partial ostectomy of proximal phalanx in a Brown Swiss calf for treatment of purulent arthritis of the proximal interphalangeal joint and adjacent severe osteomyelitis

A five month old Brown Swiss heifer calf (212 kg body mass) with severe left hind limb lameness, caused by a wound of the lateral digit was referred to the veterinary teaching hospital. The calf showed a score 4 of 5 lameness on the left hind limb. A scarified skin lesion with a fistula formation and purulent exudate was observed at the level of the proximal interphalangeal joint (PIJ) of the lateral digit of the left hind. The PIJ region and the lateral digit were severely swollen and painful. Ultrasonography showed a moderate anechoic effusion of the lateral digital flexor tendon sheet (DFTS) and a severe heterogeneous hypoechoic effusion with some small hyperechoic areas of the plantar and dorsal pouch of the PIJ. In addition, a highly irregular contour of the dorsal and abaxial surface of the phalanx media (P2) and the distal aspect of the proximal phalanx (P1) were imaged. Based on physical examination and ultrasonographic findings, the diagnosis was chronic purulent arthritis of the PIJ, osteitis of P2 and the distal end of P1 with suspected adjacent osteomyelitis. Complete ostectomy of P2 and ostectomy of the distal part of the P1 of the lateral digit was performed with an oscillating saw through the extended debrided wound. The lameness improved subsequently and 21 days post-surgery the calf was discharged from the clinic without lameness, and with a wooden block attached to the healthy claw. A year later the heifer was pregnant and still in the herd, during this period it did not exhibit lameness. The described surgical technique resulted in an excellent long-term outcome and may be considered in cases of severe purulent joint infection of the PIJ with osteolytic processes in adjacent bones, as a digit salvage procedure especially for young cattle.

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.

Effects of egg-bar shoes on the 3-dimensional kinematics of the distal forelimb in horses walking on a sand track

REASONS FOR PERFORMING STUDY

Understanding of the biomechanical effects of egg-bar shoes remains incomplete because kinematic studies are usually performed on hard tracks and with skin markers that do not measure the actual 3-dimensional (3D) movements of the 3 digital joints.

OBJECTIVE

To quantify the effects of egg-bar shoes on the 3D kinematics of the distal forelimb in horses walking on a sand track.

METHODS

Four healthy horses were equipped with ultrasonic markers fixed surgically to the 4 distal segments of the left forelimb. The 3D movements of these segments were recorded while the horses were walking on a sand track. Rotations of the digital joints were calculated by use of a joint coordinate system. Data obtained with egg-bar shoes were compared to those obtained with standard shoes. Mean differences were expressed in a 0.95 confidence interval.

RESULTS

With egg-bar shoes, the initial sinking of the heels into the ground during landing was reduced and the heels were raised by up to 5.1 degrees (3.5-6.7 degrees) compared to standard shoes at mid-stance. Concurrently, maximal flexion of the distal (DIPJ) and proximal (PIPJ) interphalangeal joints was increased by up to 3.2 degrees (2.2-4.2 degrees) and 1.8 degrees (1.1-2.5 degrees), respectively, at the beginning of the stance phase. At heel-off, extension of the DIPJ was reduced by 3.8 degrees (2.6-5.0 degrees). In extrasagittal planes of movement, egg-bar shoes prevented sinking of the medial quarter into the ground which led to a slight decrease of DIPJ medial rotation and lateromotion.

CONCLUSIONS

Egg-bar shoes prevent the heels and, to a lesser extent, the medial side of the hoof from sinking into the ground on a sand track. They contribute to a decrease of DIPJ maximal extension at heel-off and to hoof stabilisation in the transversal plane.

POTENTIAL RELEVANCE

Such quantitative results support the clinical indications of egg-bar shoes.

Effects of 6° elevation of the heels on 3D kinematics of the distal portion of the forelimb in the walking horse

REASONS FOR PERFORMING STUDY

Understanding of the biomechanical effects of heel elevation remains incomplete because in vivo studies performed with skin markers do not measure the actual movements of the 3 digital joints.

OBJECTIVE

To quantify the effects of 6 degree heel wedge on the 3-dimensional movements of the 4 distal segments of the forelimb in the walking horse.

METHODS

Four healthy horses were used. Kinematics of the distal segments was measured invasively with a system based on ultrasonic triangulation. Three-dimensional rotations of the digital joints were calculated by use of a 'joint coordinate system' (JCS). Data obtained with heel wedges were compared to those obtained with standard shoes during the stance phase of the stride.

RESULTS

Heel wedges significantly increased maximal flexion of the proximal (PIPJ) and distal (DIPJ) interphalangeal joints and maximal extension (mean +/- s.d. +0.8 +/- 0.3 degrees) of the metacarpophalangeal joint (MPJ). Extension of the PIPJ and DIPJ was decreased at heel-off. Few effects were observed in extrasagittal planes of movement.

CONCLUSIONS

Heel wedges affect the sagittal plane kinematics of the 3 digital joints.

POTENTIAL RELEVANCE

Controversial effects previously observed on the MPJ may be explained by the substantial involvement of the PIPJ, which was wrongly neglected in previous studies performed on the moving horse.

Endotoxin-induced digital vasoconstriction in horses: associated changes in plasma concentrations of vasoconstrictor mediators

REASONS FOR PERFORMING STUDY

Lipopolysaccharide (LPS) infusion reduces digital perfusion, but the mediators responsible remain undetermined.

OBJECTIVES

To identify vasoconstrictor mediators released following LPS infusion and relate their appearance in plasma to digital blood flow alterations.

METHODS

Blood flow in the lateral digital vessels of 6 Thoroughbred horses, following a 30 min infusion of LPS (E. coli 055:B5; 30 ng/kg), was measured using Doppler ultrasonography. Concomitant measurements of hoof wall and coronary band surface temperatures (HWST and CBST) were made. Serial blood samples were collected and plasma LPS, tumour necrosis factor alpha (TNFalpha), 5-HT, thromboxane B2 (TxB2) and endothelin measured.

RESULTS

Plasma LPS concentrations reached a maximum of 13.2 pg/ml during the infusion, followed by an increase in plasma TNFalpha concentration. Digital arterial and venous blood flow decreased by 43 and 63%, respectively; HWST and CBST similarly decreased. Systemic blood pressure remained unaltered. Plasma concentrations of TxB2 and 5-HT increased, coinciding with the onset of digital hypoperfusion. Plasma endothelin concentrations remained unchanged.

CONCLUSIONS

The temporal relationship between the onset of digital hypoperfusion and increases in plasma 5-HT and TxB2 concentrations is consistent with these platelet-derived mediators being associated with LPS-induced laminitis.

POTENTIAL RELEVANCE

These experimental data support the use of anti-platelet therapy in the prevention of laminitis associated with endotoxaemic conditions.

Three-dimensional kinematics of the distal forelimb in horses trotting on a treadmill and effects of elevation of heel and toe

REASONS FOR PERFORMING STUDY

Comprehensive understanding of the 3-dimensional (3D) kinematics of the distal forelimb and precise knowledge of alterations induced by dorsopalmar foot imbalance remains incomplete because in vivo studies performed with skin markers do not measure the actual movements of the 3 digital joints.

OBJECTIVE

To quantify the effects of 6 degree heel or toe wedges on the 3D movements of the 4 distal segments of the forelimb in horses trotting on a treadmill.

METHODS

Three healthy horses were equipped with ultrasonic markers fixed surgically to the 4 distal segments of the left forelimb. The 3D movements of these segments were recorded while horses were trotting on a treadmill. Rotations of the digital joints were calculated by use of a joint coordinate system. Data obtained with 6 degree heel or toe wedges were compared to those obtained with flat standard shoes.

RESULTS

Use of heel wedges significantly increased maximal flexion and decreased maximal extension of the proximal (PIPJ) and distal (DIPJ) interphalangeal joints. Inverse effects (except for PIPJ maximal extension) were observed with the toe wedges. In both cases, neither flexion-extension of the metacarpophalangeal joint nor extrasagittal motions of the digital joints were statistically different between conditions.

CONCLUSIONS

At a slow trot on a treadmill, heel and toe wedges affect the sagittal plane kinematics of the interphalangeal joints.

POTENTIAL RELEVANCE

Better understanding of the actual effects of toe and heel wedges on the 3D kinematics of the 3 digital joints may help to improve clinical use of sagittal alteration of hoof balance in the treatment of distal forelimb injuries.

The effects of vasoactive amines found in the equine hindgut on digital blood flow in the normal horse

REASONS FOR PERFORMING STUDY

Disturbances of digital blood flow are thought to be fundamental to the pathophysiology of acute laminitis. However, factors linking the initiating events in the equine hindgut with these disturbances in the foot remain to be determined.

HYPOTHESIS

Amine compounds, formed by bacteria in the equine hindgut, have digital vasoconstrictor effects in vivo.

METHODS

Tryptamine (1.6 microg/kg/min) and phenylethylamine (2.13 microg/kg/min) were infused i.v. into standing nonsedated horses. Digital blood flow was measured by Doppler ultrasound and foot surface temperature was monitored. Plasma 5-hydroxytryptamine (5-HT) concentrations were measured by HPLC.

RESULTS

Tryptamine and phenylethylamine infusions had no effect on systemic arterial blood pressure or heart rate, but caused significant decreases in digital arterial blood flow (mean +/- s.e. 29.2 +/- 8.5 and 18.4 +/- 6.8%, respectively). Both amines also caused decreases in dorsal hoof wall temperature (0.6 +/- 0.1 and 0.5 +/- 0.1 degrees C for tryptamine and phenylethylamine, respectively) and concomitant increases in plasma 5-HT concentration.

CONCLUSIONS

Tryptamine and phenylethylamine caused reduction of digital blood flow, effects which may have been mediated, in part, via displacement of 5-HT from platelets.

POTENTIAL RELEVANCE

Amine compounds occurring in the equine hindgut, if released into the circulation following carbohydrate overload, could contribute to selective digital vasoconstriction. Further work in ponies and horses, with naturally occurring laminitis, is necessary to determine whether amines represent a therapeutic target in this disease.

Radiographic evolution of the forelimb digit in Ardenner horses from weaning to 28 months of age and its clinical significance

Ossification of collateral cartilages is a common radiographic finding in draught horses and indication of a high frequency of interphalangeal osteo-arthropathy have been found in Ardenner horses. This study first aimed at following the evolution of the digits of the forelimbs on radiographic images in a group of 32 Ardenner horses from weaning to 852 +/- 19 days and, secondly, at evaluating the clinical significance of the observed radiographic changes. At 250 +/- 21 days, only 23% of the horses presented a small separate ossification centre of collateral cartilages above the level of the distal sesamoid bone or at the level of the proximal half of the middle phalanx. At 852 +/- 19 days, 100% of the horses presented an ossification of collateral cartilages but at different stages and grades. The presence and the extent of the ossification of the lateral cartilages were not significantly associated with lameness. Phalanges changes appeared at the average age of 1 year and they were represented by entheseophytes on the dorsal surface of the middle and distal phalanges. The frequency of affected horses increased with age as well as the size of the entheseophytes. This may reflect mechanical stresses applied to the interphalangeal joints. A significant association with the presence of lameness was pointed out. The presence and the severity of phalanges changes could be of importance, in combination with a clinical examination, in improving the selection of horses able to assume work and/or leisure activities.

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.

Complete and partial hoof wall resection for keratoma removal: post operative complications and final outcome in 26 horses (1994-2004)

REASONS FOR PERFORMING STUDY

There are no data on the frequency of post operative complications following keratoma removal, such as recurrence, hoof wall instability and excessive granulation tissue formation, or their relation to the method of surgical removal.

OBJECTIVE

To identify important factors in the outcome for horses undergoing surgical removal of a keratoma and compare the post operative complications encountered following keratoma removal by complete hoof wall resection (CR) and partial hoof wall resection (PR).

HYPOTHESIS

Horses undergoing PR would have fewer post operative complications and would return to work more quickly than those undergoing CR.

METHODS

A retrospective review of medical records from one equine hospital identified 26 horses that underwent removal of a keratoma by CR or PR. Clinical, radiological and surgical findings and outcome were analysed.

RESULTS

Common clinical signs included lameness and the presence of a subsolar abscess. Fourteen horses underwent CR and 12 PR. The complication rate following CR (71%) was significantly lower than that following PR (25%) (P<0.01). Complications encountered included excess granulation tissue formation, hoof crack formation and keratoma recurrence at the surgical site. The time taken to return to full work post operatively was significantly shorter in horses undergoing PR compared to CR (P<0.01). All horses, except one, returned to their previous exercise level.

CONCLUSIONS

PR resulted in fewer post operative complications and a more rapid return to athletic activity than CR.

POTENTIAL RELEVANCE

Although the overall complication rate for CR was higher than for PR, the overall prognosis for return to soundness and the previous performance level is very good.

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).

Ultrasonography of the solar aspect of the distal phalanx in the horse

Ultrasonographic examinations were performed on the solar aspect of the distal phalanx of 10 feet of five normal live horses (Group 1), 22 feet of seven normal cadavers (Group 2), and nine feet of five horses with pathology of the dorsal solar aspect of the distal phalanx (Group 3). Lateromedial radiographs of the distal phalanx were made in all groups, and in Group 2, digits were sagitally sectioned after imaging. The ultrasonographic and radiographic appearance of the sagittal solar aspect of the distal phalanx was described. Measurements of the distance between the sole and the distal tip of the distal phalanx (A), the solar aspect of the apex of the frog and the distal phalanx (B), and the body of the frog's surface and flexor surface of the distal sesamoid bone (C) were made ultrasonographically, radiographically, and on the sectioned cadaver specimens. There was no statistical difference between the radiographic, ultrasonographic, and direct cadaver measurements in A and C. In B, there was a statistical difference between the radiographic, ultrasonographic, and cadaver measurements-most likely as a result of the difference in trimming of the frog apex. Ultrasonographic and radiographic examination of the nine feet of the five horses in Group 3 were performed and the abnormalities described. Color flow and power Doppler ultrasonography were performed on the normal sagittal solar distal phalanx, on the impar distal sesamoidean ligament, and at the insertion of the deep digital flexor tendon on the facies flexoria of the distal phalanx. Power Doppler in these horses showed blood flow at 0.16-0.48 kHz at the tip of the distal phalanx and at 0.16 kHz at the deep digital flexor tendon insertion and in the impar distal sesamoidean ligament. Using color flow Doppler in normal horses mean blood flows ranged from 1.8 to 5.4 cm/s at the tip of the distal phalanx and 1.8-2.0 cm/s at the deep digital flexor tendon insertion and in the impar distal sesamoidean ligament.

Moisture Content, Thickness, and Lesions of Sole Horn Associated with Thin Soles in Dairy Cattle

Thin soles and resulting lameness are often associated with increased culling rates in large dairy operations. The moisture content of the sole horn may cause the horn to be softer, thus predisposing it to an increased rate of wear. For that reason, the first objective of this study was to determine the moisture content of the sole horn of thin-soled cows. The second objective was to document physical changes of the claw associated with thin soles. Twenty-six adult Holstein cows showing signs of thin soles, and 16 normal cows were used in the study. Selection criteria for thin-soled cows included a dorsal wall length of less than 7.5 cm and the following clinical signs: painful gait, arched back, and specific leg lameness. Sixteen normal adult cows with dorsal wall length in excess of 7.5 cm were randomly selected. For thin-soled cows, the moisture contents of sole horn were 37.1 +/- 0.7% for front claws and 40.5 +/- 0.7% for rear claws. These values were significantly different from each other. Moisture contents of sole horn from normal cows were 31.08 +/- 0.93% for front claws and 33.1 +/- 0.9% for rear claws, which were significantly different from each other and different from thin-soled cows. Rear claws had higher moisture contents than front claws. Mean sole horn thickness was 4.23 +/- 0.18 mm for the rear lateral claws and 5.15 +/- 0.18 mm for the rear medial claws. The average dorsal wall lengths were 66.8 +/- 3.94 mm for rear lateral claws and 69.1 +/- 7.25 mm for rear medial claws. Thirty percent of rear feet with thin soles had pathological claw horn lesions including sole/white line separation (72%) and sole ulcers (28%). Of the affected claws, 13% had more than one lesion. Seventy-seven percent of claw lesions occurred in the lateral claw.

Chronic laminitis: current treatment strategies

Laminitis is divided into four different phases: developmental, acute, subacute, and chronic. The focus of this article is on treating the laminitic horse after the cessation of therapy for the acute phase, that is, usually 2 to 4 weeks after the onset of clinical signs.

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.

Radiographic imaging of the equine foot

Radiographic examination of the equine foot can provide the veterinarian and farrier with a wealth of information. Positioning and selection of exposure factors are of central importance if one is to produce radiographs of maximum diagnostic value.

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.

A radiographic technique to assess the longitudinal balance in front hooves

The aim of this study was to validate a radiographic technique to measure objectively the longitudinal hoof balance in the horse. Ten left third phalanges (P3) obtained from front hooves and 19 left front hooves were used in order to assess the reliability of the radiographic technique and to identify any effect of rotation or alignment of specimens or distance between the X-ray machine and the radiographic cassette, in measuring P3s structures and balance related parameters. A rotational support was made to hold specimens in order to standardise some of the conditions of X-raying. The main axis of the frog was used as a marker for the sagittal plane of P3. Results showed that single radiographic measurements could have wide limits of agreement with actual measurements of the hoof (gold standard values). In order to limit errors we suggest the use of a combination instead of single parameters to assess balance. Rotation of the hoof is also to be controlled when a measurement of angles is needed. The radiographic technique used in this study can be used to objecticely measure balance parameters considered important in order to assess hoof balance.

A description of the motion of the navicular bone during in vitro vertical loading of the equine forelimb

Motion of the navicular bone might play a role in the development of navicular disease in horses but is difficult to asses. In the present study, 3-dimensional motion of this bone was determined using roentgen stereophotogrammetric analysis. Tantalum pellets were inserted, in vitro, in the bones of 6 forelimbs of mature Shetland ponies and kinematics were measured during vertical loading up to 2 kN. The motions of the navicular bone and coffin joint were limited to flexion/extension, there were no substantial out-of-plane motions. There was only little flexion between the navicular bone and the coffin bone, which was correlated (r = 0.66) with coffin joint flexion. There was substantial flexion between the navicular bone and the short pastern, which was highly correlated with coffin joint flexion (r = 0.97). We conclude that the navicular bone, generally, follows the coffin bone during coffin joint flexion, although there are small but consistent motions between the navicular bone and the coffin bone. These motions might play a role in the development of navicular disease in horses.

Subjective and quantitative scintigraphic assessment of the equine foot and its relationship with foot pain

It was hypothesised that in solar bone images of the front feet of clinically normal horses, or horses with lameness unrelated to the front feet, there would be less than a 10% difference in the ratio of uptake of radiopharmaceutical in either the region of the navicular bone, or the region of insertion of the deep digital flexor tendon (DDFT), compared to the peripheral regions of the distal phalanx. Nuclear scintigraphic examination of the front feet of 15 Grand Prix show jumping horses, all of which were free from detectable lameness, was performed using dorsal, lateral and solar images. The results were compared with the examinations of 53 horses with primary foot pain, 21 with foot pain accompanying another more severe cause of lameness and 49 with lameness or poor performance unrelated to foot pain. None of the horses with foot pain had radiological changes compatible with navicular disease. All the images were evaluated subjectively. The solar views were assessed quantitatively using regions of interest around the navicular bone, the region of insertion of the deep digital flexor tendon and the toe, medial and lateral aspects of the distal phalanx. In 97% of the feet of normal showjumpers, there was <10% variance of uptake of the radiopharmaceutical in the navicular bone, the region of insertion of the DDFT and the peripheral regions of the distal phalanx. There was a significant difference in uptake of radiopharmaceutical in the region of the navicular bone in horses with foot pain compared to normal horses. There was a large incidence of false positive results related to the region of insertion of the DDFT. Lateral pool phase images appeared more sensitive in identifying potentially important DDFT lesions. There was a good correlation between a positive response to intra-articular analgesia of the distal interphalangeal joint and intrathecal analgesia of the navicular bursa and increased uptake of radiopharmaceutical in the region of the navicular bone in the horses with primary foot pain. It is concluded that quantitative scintigraphic assessment of bone phase images of the foot, in combination with local analgesic techniques, can be helpful in the identification of the potential source of pain causing lameness related to the foot, but false positive results can occur, especially in horses with low heel conformation.

Doppler sonographic measurements of arterial blood flow and their repeatability in the equine foot during weight bearing and non-weight bearing

In six normal adult horses, pulsed-wave Doppler sonographic inspections were made of the left and right lateral palmar proper digital artery (LPPDA) of each thoracic limb. Using a two-period, crossover design with repeated measures, each LPPDA was inspected on four occasions throughout the day over a 7 hour period and, on each occasion, with the limb weight bearing and non-weight bearing. In comparison with the observations made during weight bearing, there were significant increases (P<0.001) in blood-flow velocities when the limb was non-weight bearing. There was no relationship between blood velocities and the time of day, the order in which the inspections were made, resting heart rate, age of the horse, or hoof angle. In both weight bearing and nonweight bearing, the Doppler waveform demonstrated a systolic peak followed by at least two diastolic peaks and an end diastolic plateau. Horses that moved least during sonographic inspections had the lowest co-efficients variation.

Morphology of the laminar junction in relation to the shape of the hoof capsule and distal phalanx in adult horses (Equus caballus)

The purpose was to investigate whether differences in equine hoof shape, which are inferred to alter foot function, are accompanied by differences in morphology of the laminar junction. Ten fore feet from adult horses were segregated into normal and low-angle groups, depending on the dorsal angle of the hoof wall. Twenty measurements of external hoof shape and four of the enclosed distal phalanx were tested for differences between groups, and for intragroup correlations. Three measurements of laminar morphology (spacing, orientation and degree of bend) were recorded for samples of up to 50 primary epidermal laminae at each of 20 sample sites. Sites were distributed over the foot in 5 circumferential columns and 4 proximodistal rows. Intergroup differences were investigated, as were correlations among sample sites of the laminar variables with the shape measurements. Results show differences in hoof shape between groups (but not bone shape) and laminar morphology. Six shape measurements are significantly different between groups: dorsal angle, medial and lateral angles, lateral sole width, solar circumference, and dorsal length. In the normal group, shape measurements show patterns of correlation among regions of the hoof, and between hoof and bone measurements. In the low-angle group, shape correlations occur largely within one region of the hoof (the heels) and in the bone measurements. Laminar spacing tends to be nonsignificantly greater in the low-angle group, while variances for laminar spacing and orientation are significantly greater in this group. Laminar spacing correlates with bone width and coronary circumference (CC) of the hoof in the normal group, but only with CC in the low-angle group. When taken as a whole, and interpreted in light of a model of foot mechanical function, the results appear to indicate a deterioration in structural coherence of the foot in the low-angle group.

Radiographic interpretation of normal skeletal variations and pseudolesions in the equine foot

Effective radiographic interpretation requires a veterinarian who is knowledgeable of equine limb anatomy and the various principles that affect the resulting image. The normal and its variations must be recognized and understood before the abnormal can be confidently identified as pathologic. Proper patient positioning and sound radiographic technique are mandatory if reliable diagnostic radiographs are to be produced. This review emphasizes equine foot radiographic variations of normal and pseudolesions that occur with commonly used radiographic views performed in equine practice.

Effects of heel and toe elevation upon the digital joint angles in the standing horse

Five sound mature horses, age 8-14 years, with toe angles 45.5-55.0 degrees were placed on a specially designed platform with only the left forelimb weightbearing, which allowed the successive production of 7 different conditions of foot orientation: neutral position (N), 5, 10, 15 degrees heel (H5, H10, H15) and toe (T5, T10, T15) elevation, performed according to 2 different sequences. For each condition, 2 lateromedial radiographs were taken to evaluate the metacarpophalangeal joint (MPJ) and both interphalangeal joint (PIPJ and DIPJ) angles, respectively. In addition, two-dimensional (2-D) kinematic recordings, using reflective skin markers placed laterally on the left forelimb joints, were performed. The value of each joint angle (JA) and its angular variation to N (AV) were considered for statistical analysis. For all JA and their AV determined radiographically, the condition effect was significant and the sequence did not influence the differences between conditions. The relationships between the JA and the conditions (in the sequence: T15, T10, T5, N, H5, H10, H15) were overall linear for the 3 joints. The maximal range T15-H15 was mean +/- s.d. 6.9 +/- 2.0 degrees for MPJ (dorsal angle decrease), 7.3 +/- 1.0 degrees and 29.5 +/- 1.8 degrees for PIPJ and DIPJ (palmar angle decrease), respectively. Contrary to JA and in spite of large variations in hoof conformation, AV did not show any significant horse effect. Wide differences were observed between the digital JA measured radiographically and from kinematics, which could be related to cutaneous displacement. Heel elevation induced elbow flexion, whereas a slight extension was observed with toe elevation. These movements, even slight (mean elbow angle amplitude: 3.6 +/- 1.3 degrees), may have consequences upon flexor tendon tension.

Ultrasonographic characterization of ovarian events and fetal gestational parameters in two southern black rhinoceros (Diceros bicornis minor) and correlation to fecal progesterone

A tremendous potential exists for the application of transrectal ultrasonography as a tool to enhance the captive management of endangered species. Reproductive study of two southern black rhinoceros (Diceros bicornis minor) females was performed daily to every other day for a approximately 60 day period to document ovarian changes, and three times weekly in early pregnancy to once monthly in late pregnancy in order to characterize changes in fetal parameters throughout gestation. All ovarian and fetal anatomical structures were measured in millimeters. The mean (+/- SD) length of the estrous cycle or interovulatory period was 26 +/- 1.4 days (n=2 cycles). Follicular growth rate of a dominant follicle was approximately 3 mm/day once the follicle reached 35 mm in diameter. Ovulation was observed to occur at a mean (+/- SD) follicular diameter of 49.5 +/- 2.6 mm (n=4) and within 48 to 72 h after observed estrus (n=2). Large ovarian structures [mean (+/- SD) diameter of 71.7 +/- 2.9 mm; n=3], considered analogous to equine anovulatory hemorrhagic follicles, were observed to form in the winter months and suggest seasonal periods of reduced fertility. Fecal progesterone assays confirmed ultrasonographic events. Although preliminary, the results of fetal sexing are presented and compared to the horse. Our data indicate that fetal eye or fetal foot diameter measurements can be used to accurately predict gestational age from about 2 months to term, providing useful information to managers of both captive and wild rhino populations. The ability to identify and quickly release animals in late term pregnancy in the wild and thereby reduce-abortions and neonatal mortalities in holding bomas is one potential practical conservation benefit of the fetal age predictive models.

Laminitis in a mature elk hind (Cervus elaphus)

Laminitis should be considered as a differential diagnosis in elk presenting with shifting leg lameness, reluctance to move, recumbency and hoof wall ridging. Eliminating the underlying cause and corrective trimming lead to a good prognosis for recovery.

Diagnosis and treatment of a fractured third phalanx in a Masai giraffe (Giraffe camelopardalis tippelskirchi)

A 10-yr-old male Masai giraffe (Giraffe camelopardalis tippelskirchi) presented with acute right forelimb lameness. Radiographs revealed a fracture of the medial claw of the distal phalanx penetrating into the distal interphalangeal joint. The giraffe was sedated while it was standing in a chute, and a wooden "hoof block" was applied to the lateral claw of the same limb. The animal was no longer lame 3 days after the procedure. Subsequent treatments included vitamin E, phenylbutazone, and glycosaminoglycans. For 7 wk it was maintained in a small holding yard on packed sand during the day and on deep sand during the night. The hoof block slowly wore down, and at 7 wk, it was placed back on concrete in the evening. At 8 wk, the block had completely worn off and the animal was no longer lame, but radiographs indicated minimal fracture healing. Radiographs performed at 7 mo indicated that there was still a radiolucent zone at the fracture line but calcification was evident at the margins of the fracture.

Use of radiography, computed tomography and magnetic resonance imaging for evaluation of navicular syndrome in the horse

Radiographic evaluation of navicular syndrome is problematic because of its inconsistent correlation with clinical signs. Scintigraphy often yields false positive and false negative results and diagnostic ultrasound is of limited value. Therefore, we assessed the use of computed tomography and magnetic resonance imaging in a horse with clinical and radiographic signs of navicular syndrome. Cadaver specimens were examined with spiral computed tomographic and high-field magnetic resonance scanners and images were correlated with pathologic findings. Radiographic changes consisted of bony remodeling, which included altered synovial fossae, increased medullary opacity, cyst formation and shape change. These osseous changes were more striking and more numerous on computed tomographic and magnetic resonance images. They were most clearly defined with computed tomography. Many osseous changes seen with computed tomography and magnetic resonance imaging were not radiographically evident. Histologically confirmed soft tissue alterations of the deep digital flexor tendon, impar ligament and marrow were identified with magnetic resonance imaging, but not with conventional radiography. Because of their multiplanar capability and tomographic nature, computed tomography and magnetic resonance imaging surpass conventional radiography for navicular imaging, facilitating earlier, more accurate diagnosis. Current advances in imaging technology should make these imaging modalities available to equine practitioners in the future.

[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.

Radiological measurements from the feet of normal horses with relevance to laminitis

Lateromedial radiographic projections were made from the feet of 25 normal horses and 3 angles and 3 distances were measured. From these, normal ranges of calculated variables were obtained. The width and length of each foot and the height of the horse at the withers was also measured. In view of its possible importance in clinical laminitis, particular attention was paid to 'founder' distance (D). This is the vertical distance between the proximal limit of the dorsal hoof wall and the proximal limit of the extensor process of the distal phalanx. There were significant differences between breeds in D (P<0.05) and in wall thickness (P<0.01). Further studies investigated the effects of time, differing radiographic projections and different operators on D. D did not alter significantly (P>0.05) over a 6 week study period. It was concluded that errors due to radiographic beam obliquity were not of practical importance. Errors in measuring D between operators can be minimised by use of a standard radiographic technique. Although there was some variation in the value of D measured over time and with different operators, which could make the interpretation of early or subtle changes difficult, measurement variation was not considered to interfere with the assessment of large changes associated with severe laminitis.

Factors involved in the prognosis of equine laminitis in the UK

The significance of clinical and radiological parameters as prognostic indicators for laminitis, 'founder' and 'sinking syndrome' was studied using case records of 216 horses and ponies. Five animals were destroyed without treatment and were not included in the results of the study. One hundred and sixty-two (77%) animals returned to athletic soundness; 7 animals (3%) did not regain full athletic function, 42 animals (20%) died or were destroyed. Cases were assigned to 4 groups on the basis of initial clinical examination alone. These groups were laminitis, acute founder, 'sinker' and chronic founder. This grouping was found in itself to be the most important prognostic parameter which was studied. Stepwise regression analysis of the data from animals by group indicated that the radiological measurement of founder distance, was the most significant radiological prognostic measurement for acute founder cases. Less significant prognostic parameters were the severity of lameness, rotation angles, the presence of solar prolapse, and the number of feet affected. The height of the animal at the withers was not significantly related to outcome. The prognosis for horses was not significantly different from that for ponies.

Clinical presentation, diagnosis, and prognosis of chronic laminitis

This article focuses on the initial assessment of the horse affected with chronic laminitis. Variations in the clinical presentation and primary considerations in making a differential diagnosis are included. The elements of a clinical history essential to sound, therapeutic management, and prognosis are summarized. The physical and radiographic assessment of the digital lesions and diagnostic approaches to the common systemic aspects of the disease are presented and discussed.

Detection of a radiographically occult fracture of the lateral palmar process of the distal phalanx in a horse using computed tomography

A horse with a suspected injury of the distal phalanx was examined using radiography at day two and 19 after the onset of the lameness, with no definite diagnosis. Using computed tomography an incomplete fracture of the lateral wing of the distal phalanx was diagnosed at day 25. Based on computed tomography it was determined that the fracture probably did not enter the joint or involve the palmar cortex throughout its length which were of prognostic importance. The day following the CT examination a new oblique radiographic projection was made. In this radiography which was based on, and never would have been attempted without, the information about the geometric pattern of the fracture achieved by CT examination, a radiolucent area indicative of a wing fracture was seen. This report emphasizes the value of computed tomography in diagnosing a geometric complicated nonarticular oblique fracture of the palmar process of the pedal bone in a horse.

Ultrasonographic imaging and thickness measurement of the sole horn and the underlying soft tissue layer in bovine claws

Ultrasonographic imaging and thickness measurements of sole horn and underlying soft tissue layer were evaluated in 100 bovine claw specimens. The claws were trimmed and examined in longitudinal planes using a 7.5 MHz linear transducer. The sole horn, underlying soft tissue layer 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. The best imaging of these structures was achieved in claws with less than 10 mm sole horn thickness and soft sole horn. Imaging of the dorsal wall structures was more difficult. In each claw, B- and A-mode measurements of horn thickness of sole and dorsal wall and distance from outer claw surface to distal phalanx surface were made at three marked points on the weightbearing surface and at one point on the dorsal wall. In 10 claws, CT-images were taken and the horn density was determined. All claws were then frozen, transected and anatomical reference measurements were made after thawing. Statistical correlation coefficients of 0.88 and higher were found for B-mode ultrasonographic and anatomical measurements of sole horn thickness. A-mode proved not to be useful for the sole horn thickness measurement. B-mode ultrasonography was carried out successfully in the claws of five living cattle.

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.