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OBJECTIVE To compare results for initial body-mounted inertial sensor (BMIS) measurement of lameness in equids trotting in a straight line with definitive findings after full lameness evaluation. ANIMALS 1,224 equids. PROCEDURES Lameness measured with BMIS equipment while trotting in a straight line was classified into categories of none, forelimb only, hind limb only, and 8 patterns of combined forelimb and hind limb lameness (CFHL). Definitive findings after full lameness evaluation were established in most horses and classified into types (no lameness, forelimb- or hind limb–only lameness, CFHL, or lameness not localized to the limbs). Observed proportions of lameness type in equids with definitive findings for each initial BMIS-assessed category were compared with hypothetical expected proportions through χ2 goodness-of-fit analysis. RESULTS The most common initial BMIS-assessed lameness category was CFHL (693/1,224 [56.6%]), but this was the least common definitive finding (94/ 862 [10.9%]). The observed frequency of no lameness after full lameness evaluation was greater than expected only when initial BMIS measurements indicated no lameness. The observed frequency of forelimb-only lameness was greater than expected when initially measured as forelimb-only lameness and for CFHL categories consistent with the diagonal movement principle of compensatory lameness. Observed frequency of hind limb–only lameness was greater than expected when initially measured as hind limb–only lameness and for CFHL categories consistent with the sagittal movement principle of compensatory lameness. Equids initially assessed as having no lameness had the highest (103/112 [92%]) and those assessed as CFHL pattern 7 (forelimb with contralateral hind limb impact-only lameness) had the lowest (36/66 [55%]) rates of definitive findings. CONCLUSIONS AND CLINICAL RELEVANCE In equids, results of initial straight-line trotting evaluations with a BMIS system did not necessarily match definitive findings but may be useful in planning the remaining lameness evaluation.

Some horses increase in forelimb lameness (measured as vertical head height asymmetry, or differences in maximums and minimums of head heights [HDmax, HDmin]), after a palmar digital nerve (PDN) block. The prevalence of this finding, or what it means clinically, has not been reported in peer-reviewed literature.To estimate the prevalence of increasing head height asymmetry after a PDN block and determine if this is associated with cause of forelimb lameness.Retrospective case series.Head height asymmetry, normalised to expected vertical head displacement, from inertial-sensor data collections of all horses evaluated for forelimb lameness while trotting in a straight line at two different clinics were screened for cases that had an initial PDN block and then another more proximal block in the same limb during the same lameness evaluation. Medical records of the screened cases (n = 213) were evaluated to determine the cause of lameness. Prevalence of increasing head height asymmetry was calculated. Differences in lameness amplitude between groups of cases that remained unchanged (group 1), that increased (group 2), and that decreased (group 3) in head height asymmetry before and after the initial PDN block were compared (Kruskal-Wallis). Determination of the location of the cause of lameness and final diagnoses of cases were compared between group 1 and group 2 (chi-squared tests of independence) RESULTS: The PDN block increased head height asymmetry at a prevalence of 32.5% (95% CI = 24.5 - 41.5%) and 13.8% (95% CI = 7.3 - 22.9%), in clinic 1 and 2, respectively. Increasing head height asymmetry after an initial PDN block did not predict localisation of the cause of forelimb lameness or specific diagnosis (p = 0.1), other than indicating that it is unlikely to be in the foot (p = 0.02).Study samples consisted primarily of Warmbloods (clinic 1) and Quarter Horses (clinic 2). Analysis of blocking induced changes was limited to straight line trot only.Increasing head height asymmetry after PDN block is common during forelimb lameness evaluations. Other than indicating that the cause of lameness is more proximal in the blocked forelimb, this does not help determine the final diagnosis. This article is protected by copyright. All rights reserved.

Soluble epoxide hydrolase (sEH) inhibitors are novel anti-inflammatory and analgesic agents that could improve pain management in horses. The objective of the present study was to evaluate the anti-nociceptive effect of a single-dose intravenous administration of the sEH inhibitor trans-4-{4-[3-(4-trifluro-methoxy-phenyl)-ureido]-cyclohexyloxy}-benzoic acid (t-TUCB) using an adjustable heart bar shoe (a-HBS) model of lameness. We hypothesized that t-TUCB would improve objective and subjective lameness measures compared to the control.Reversible lameness was induced in 8 horses for 24 h using an a-HBS in a randomized, crossover design. A vehicle-control placebo (DMSO) or t-TUCB (1 mg/kg) was intravenously administered at time 0 following a baseline induced lameness evaluation. Blood was collected and lameness was objectively measured with an inertial sensor system at 0-, 1-, 3-, 6-, 12-, and 24-h time points. Front-facing videos were obtained at each time point for subjective evaluation by three blinded evaluators using a visual analog scale (VAS).Treatment with t-TUCB significantly decreased (i.e. improved) lameness compared to placebo at 1-h and compared to baseline at 1-, 3-, and 6-h following administration. Lameness significantly increased (i.e. worsened) from baseline in placebo-treated horses 12 h after administration. All horses returned to baseline soundness within 24 h of reversing lameness.Treatment with single-dose IV administration of t-TUCB improved lameness induced by the a-HSB, suggesting that t-TUCB has anti-nociceptive effects in horses.The soluble epoxide hydrolase inhibitor, t-TUCB, is a promising novel analgesic for horses.

This study has investigated the immediate effect of induced hindlimb length difference on hindlimb lameness measured as differences in minimum (Pmin) and maximum (Pmax) pelvic heights in 16 horses trotting in a straight line and lungeing on both hard and soft surfaces with body-mounted inertial sensors. Hindlimb length differences were induced by applying an Easyboot Glue-on shoe to one hindlimb. Changes in Pmin and Pmax with induced hindlimb length difference were assessed with a two-way repeated-measures ANOVA with trial (straight, lunge with inside limb elevation, lunge with outside limb elevation) and surface (hard, soft) as within-subject factors. Change in Pmin, indicating an impact-type lameness, in the hind limb with the elevation, was significant in both the straight line and while lunging on both hard and soft surfaces. Change in Pmax, indicating pushoff-type lameness, in the opposite, non-elevated hind limb, was significant when trotting in a straight line but not while lunging.

In this issue of Vet Record , Starke and Oosterlinck present a summary of the results of a study (p 63)showing that visual gait assessment is unreliable for differentiating sound and mildly lame horses, especially with hindlimb lameness.1 They also found experience or confidence in one’s ability to detect lameness did not improve reliability. This is another study concluding that subjective evaluation for lameness in horses is not a standard of practice that we should be satisfied with.2-7 As an equine practitioner who has been evaluating horses with lameness for over 35 years, I find this a hard pill to swallow. I believe I was mentored well over the years, by seasoned lameness evaluators, and that I know how to detect and assess lameness in the horse. Yet, reflecting on the number of times I’ve been challenged on my lameness assessments and then proven wrong by observant colleagues, interns and residents and even, occasionally, good veterinary students, I understand, believe, and accept Starke and Oosterlinck’s results. If you don’t have the opportunity (some would say curse) of evidence-based assessment or other experts looking over your shoulder keeping you honest, you begin to think you are right all the time, eventually perceiving yourself as becoming gifted in a skill that is difficult to explain. This is …

Power system fault detection has been an import area of study for power distribution networks. The power transmission systems often operate in the kV range with significant current flowing through the lines. A single fault, even lasting for a fraction of a second, can cause huge losses and manufacturing downtime for industrial applications. In this research, we develop an approach to detect, classify, and localize different types of phase-to-ground and phase-to-phase faults in three-phase power transmission systems based on discrete wavelet transform (DWT) and artificial neural networks (ANN). The multi-resolution property of wavelet transform provides a suitable tool to analyze the irregular transient changes in voltage or current signals in the network when fault occurs. An artificial neural network is employed to discriminate the types of fault based on features extracted by DWT. Computer simulation results show that this method can effectively identify various faults in a typical three-phase transmission line in power grid.

OBJECTIVE To evaluate head, pelvic, and limb movement to detect lameness in galloping horses. ANIMALS 12 Thoroughbreds. PROCEDURES Movement data were collected with inertial sensors mounted on the head, pelvis, and limbs of horses trotting and galloping in a straight line before and after induction of forelimb and hind limb lameness by use of sole pressure. Successful induction of lameness was determined by measurement of asymmetric vertical head and pelvic movement during trotting. Differences in gallop strides before and after induction of lameness were evaluated with paired-sample statistical analysis and neural network training and testing. Variables included maximum, minimum, range, and time indices of vertical head and pelvic acceleration, head rotation in the sagittal plane, pelvic rotation in the frontal plane, limb contact intervals, stride durations, and limb lead preference. Difference between median standardized gallop strides for each limb lead before and after induction of lameness was calculated as the sum of squared differences at each time index and assessed with a 2-way ANOVA. RESULTS Head and pelvic acceleration and rotation, limb timing, stride duration measurements, and limb lead preference during galloping were not significantly different before and after induction of lameness in the forelimb or hind limb. Differences between limb leads before induction of lameness were similar to or greater than differences within limb leads before and after lameness induction. CONCLUSIONS AND CLINICAL RELEVANCE Galloping horses maintained asymmetry of head, pelvic, and limb motion between limb leads that was unrelated to lameness.

OBJECTIVE To investigate associations between inertial sensor and stationary force plate measurements of hind limb lameness in horses. ANIMALS 21 adult horses with no lameness or with mild hind limb lameness. PROCEDURES Horses were instrumented with inertial sensors and evaluated for lameness with a stationary force plate while trotting in a straight line. Inertial sensor–derived measurements of maximum and minimum pelvic height differences between right and left halves of the stride were compared with vertical and horizontal ground reaction forces (GRFs). Stepwise linear regression was performed to investigate the strength of association between inertial sensor measurements of hind limb lameness and amplitude, impulse, and time indices of important events in the vertical and horizontal GRF patterns. RESULTS Difference in minimum pelvic position was moderately (Ra2 = 0.60) associated with the difference in peak vertical GRF but had little association with any horizontal GRF measurements. Difference in maximum pelvic position was strongly (Ra2 = 0.77) associated with a transfer of vertical to horizontal ground reaction impulse in the second half of the stance but was not associated with difference in peak vertical GRF. CONCLUSIONS AND CLINICAL RELEVANCE Inertial sensor–derived measurements of asymmetric pelvic fall (difference in minimum pelvic position) indicated a decrease in vertical GRF, but similar measurements of asymmetric pelvis rise (difference in maximum pelvic position) indicated a transfer of vertical to horizontal force impulse in the second half of the stance. Evaluation of both pelvic rise and fall may be important when assessing hind limb lameness in horses.

Summary Reasons for performing study Fibrotic myopathy can cause incapacitating gait abnormalities. Transection of the fibrotic mass followed by early post operative exercise is the best treatment for fibrotic myopathy. A laser may be used to transect the fibrotic mass. Assessment of the effectiveness of therapies for fibrotic myopathy has been limited to subjective evaluation. Objectives To objectively assess gait abnormalities associated with fibrotic myopathy before and after laser fibrotomy followed by early post operative exercise. Methods Kinematic evaluation of horses with fibrotic myopathy walking and trotting on a treadmill was used to investigate hindfeet trajectories (n = 8) and lameness (n = 5) before and after laser fibrotomy. Hoof flight trajectory length (HFTL), relative protraction length (%PL), maximum hoof height during swing (MXHH), hoof height at end of protraction (HHpro) and retraction (HHret) were measured and differences between fibrotic myopathy affected and nonaffected limbs were calculated. Lameness was quantified by measuring maximum and minimum pelvic height differences between right and left halves of the stride. Results Before surgery the foot of the fibrotic myopathy affected limb had abnormal trajectories characterised as increased HFTL, MXHH and HHpro and decreased %PL and HHret and the 5 horses objectively evaluated for lameness were lame in the fibrotic myopathy affected limb. Immediately after surgery the difference between affected and nonaffected limbs decreased for HFTL, %PL and HHpro. Six to 11 weeks after surgery, the HFTL difference increased but was still smaller than before surgery, which was interpreted as partial recurrence of the gait abnormality; all horses objectively evaluated for lameness were either improved (n = 1) or not lame (n = 4) in the previously affected, operated limb. Conclusions Fibrotic myopathy affects the foot flight and leads to asymmetric vertical excursion of the pelvis. Laser fibrotomy followed by early post operative exercise can minimise these abnormalities. Potential relevance Laser fibrotomy combined with early post operative exercise is a viable therapy for fibrotic myopathy.

Summary Reasons for performing study: Subjective evaluation of mild lameness has been shown to have poor interobserver reliability. Traditional methods of objective lameness evaluation require specialised conditions and equipment. Wireless inertial sensor systems have been developed to allow for simple, rapid, objective lameness detection in horses trotted over ground. Objective: The purpose of this study was to compare the sensitivities of an inertial sensor system and subjective evaluation performed by experienced equine practitioners at detecting lameness in horses. We hypothesised that the inertial sensor system would identify lameness at a lower level of sole pressure than a consensus of 3 experienced equine veterinarians. Methods: Fifteen horses were fitted with special shoes that allowed for lameness induction via sole pressure. Horses were simultaneously evaluated by 3 equine veterinarians and a wireless inertial sensor system. Horses were subjected to multiple trials: 1) before inserting the screw; 2) after inserting the screw to just touch the sole; and 3) after tightening the screw in half turn increments. The number of screw turns required for lameness identification in the correct limb by the inertial sensors and by consensus of 3 equine veterinarians was compared using the Wilcoxon test. Results: The inertial sensor system selected the limb with the induced lameness after fewer screw turns than did the 3 veterinarians (P

Summary Reasons for performing study: Previous studies have suggested that agreement between equine veterinarians subjectively evaluating lameness in horses is low. These studies were limited to small numbers of horses, evaluating movement on the treadmill or to evaluating previously-recorded videotape. Objectives: To estimate agreement between equine practitioners performing lameness evaluations in horses in the live, over ground setting. Methods: 131 mature horses were evaluated for lameness by 2–5 clinicians (mean 3.2) with a weighted-average of 18.7 years of experience. Clinicians graded each limb using the AAEP lameness scale by first watching the horse trot in a straight line only and then after full lameness evaluation. Agreement was estimated by calculation of Fleiss' (κ). Evaluators agreed if they picked the same limb as lame or not lame regardless of the severity of perceived lameness. Results: After only evaluating the horse trot in a straight line clinicians agreed whether a limb was lame or not 76.6% of the time (κ= 0.44). After full lameness evaluation clinicians agreed whether a limb was lame or not 72.9% of the time (κ= 0.45). Agreement on forelimb lameness was slightly higher than on hindlimb lameness. When the mean AAEP lameness score was >1.5 clinicians agreed whether or not a limb was lame 93.1% of the time (κ= 0.86), but when the mean score was ≤1.5 they agreed 61.9% (κ= 0.23) of the time. When given the task of picking whether or not the horse was lame and picking the worst limb after full lameness evaluation, clinicians agreed 51.6% (κ= 0.37) of the time. Conclusions: For horses with mild lameness subjective evaluation of lameness is not very reliable. Potential relevance: A search for and the development of more objective and reliable methods of lameness evaluation is justified and should be encouraged and supported.

OBJECTIVE To test the hypothesis that botulinum toxin type A (BoNT-A) can attenuate lameness associated with acute synovitis in an equine model. DESIGN Four horses 2-6 yrs of age with clinically normal carpi were studied for 15 days. Kinematic gait analysis and clinical measures of lameness were conducted before and after experimental interventions. Horses were randomly assigned to either placebo (saline) or treatment (BoNT-A) groups. On day 0 of the intervention, 50 units of BoNT-A or an equivalent volume of saline (0.09%) was given into the middle carpal joints. On day 14, acute synovitis was induced with intra-articular injection of recombinant equine interleukin-1 beta (IL-1 beta) 100 ng. Synovial fluid, clinical evaluation of lameness, and kinematic gait analysis were evaluated on day 15. RESULTS Synovitis was observed on histology and cytology in all horses after IL-1 beta, indicating acute suppurative inflammation. In the BoNT-A group, one horse developed lameness, whereas the other demonstrated no change in baseline gait evaluation. No adverse effects were observed in joints injected with BoNT-A or with saline alone. CONCLUSIONS Our findings support the idea that BoNT-A can attenuate lameness in an equine model of acute synovitis. Our findings further suggest that BoNT-A might be a potential new treatment for painful arthritis; this warrants further study.

Kinematic and kinetic gait analysis potentially offers veterinarians an objective method of determining equine limb lameness. Subjective analyses have been shown to be somewhat flawed, and there does not seem to be a high degree of intraobserver agreement when evaluating individual horses. In addition, recognition of the compensatory effects of primary lameness may be helpful for the practicing equine veterinarian.

Objective— To determine if intravenous lidocaine is useful and safe as a treatment for equine ileus. Study Design— Prospective double-blinded placebo-controlled trial. Study Population— Horses (n=32) with a diagnosis of postoperative ileus (POI) or enteritis and that had refluxed >20 L or had been refluxing for >24 hours. Methods— Refluxing horses were administered lidocaine (1.3 mg/kg intravenously [IV] as a bolus followed by a 0.05 mg/kg/min infusion) or saline (0.9% NaCl) solution placebo for 24 hours. Variables evaluated included volume and duration of reflux, time to 1st fecal passage, signs of pain, analgesic use, heart rate and arrhythmias, respiratory rate, temperature, days of hospitalization, outcome (survival to discharge), and complications. Results— Of the lidocaine-treated horses, 65% (11/17) stopped refluxing within 30 hours (mean±SD, 15.2±2.4 hours) whereas 27% (4/15) of the saline-treated horses stopped within 30 hours. Fecal passage was significantly correlated with response to treatment; horses that responded to lidocaine passed feces within 16 hours of starting the infusion. Compared with placebo treatment, lidocaine treatment resulted in shorter hospitalization time for survivors, equivalent survival to discharge, no clinically significant changes in physical or laboratory variables, and no difference in the rate of incisional infections, jugular thrombosis, laminitis, or diarrhea. Muscle fasciculations occurred in 3 lidocaine-treated horses (18%). Conclusion— IV lidocaine significantly improved the clinical course in refluxing horses with minimal side effects. Clinical Relevance— At the infusion rate studied, IV lidocaine is safe and should be considered for the treatment of equine ileus.

Objective—To determine whether a shoe with an axialcontoured lateral branch would induce greater lateral roll of the forelimb hoof during the time between heel and toe lift-off at end of the stance phase (breakover). Animals—10 adult horses. Procedure—A gyroscopic transducer was placed on the hoof of the right forelimb and connected to a transmitter. Data on hoof angular velocity were collected as each horse walked and trotted on a treadmill before (treatment 1, no trim–no shoe) and after 2 treatments by a farrier (treatment 2, trim–standard shoe; and treatment 3, trim–contoured shoe). Data were converted to hoof angles by mathematical integration. Breakover duration was divided into 4 segments, and hoof angles in 3 planes (pitch, roll, and yaw) were calculated at the end of each segment. Multivariable ANOVA was performed to detect differences among treatments and gaits. Results—Trimming and shoeing with a shoe with contoured lateral branches induced greater mean lateral roll to the hoof of 3.2° and 2.5° during the first half of breakover when trotting, compared with values for no trim–no shoe and trim–standard shoe, respectively. This effect dissipated during the second half of breakover. When horses walked, lateral roll during breakover was not significantly enhanced by use of this shoe. Conclusions and Clinical Relevance—A shoe with an axial-contoured lateral branch induced greater lateral roll during breakover in trotting horses, but change in orientation of the hoof was small and limited to the first half of breakover. (Am J Vet Res 2005;66:2046–2054)

Objective—To compare a sensor-based accelerometer-gyroscopic (A-G) system with a video-based motion analysis system (VMAS) technique for detection and quantification of lameness in horses. Animals—8 adult horses. Procedure—2 horses were evaluated once, 2 had navicular disease and were evaluated before and after nerve blocks, and 4 had 2 levels of shoe-induced lameness, alternatively, in each of 4 limbs. Horses were instrumented with an accelerometer transducer on the head and pelvis, a gyroscopic transducer on the right forelimb and hind feet, and a receiver-transmitter. Signals from the A-G system were collected simultaneously with those from the VMAS for collection of head, pelvis, and right feet positions with horses trotting on a treadmill. Lameness was detected with an algorithm that quantified lameness as asymmetry of head and pelvic movements. Comparisons between the A-G and VMAS systems were made by use of correlation and agreement (κ value) analyses. Results—Correlation between the A-G and VMAS systems for quantification of lameness was linear and high ( r 2 = 0.9544 and 0.8235 for forelimb and hind limb, respectively). Quantification of hind limb lameness with the A-G system was higher than measured via VMAS. Agreement between the 2 methods for detection of lameness was excellent (κ = 0.76) for the forelimb and good (κ = 0.56) for the hind limb. Conclusions and Clinical Relevance—The A-G system detected and quantified forelimb and hind limb lameness in horses trotting on the treadmill. Because the data are collected wirelessly, this system might be used to objectively evaluate lameness in the field. ( Am J Vet Res 2004;65:665–670)

Objective—To investigate continuous wavelet transformation and neural network classification of gait data for detecting forelimb lameness in horses. Animals—12 adult horses with mild forelimb lameness. Procedure—Position of the head and right forelimb foot, metacarpophalangeal (ie, fetlock), carpal, and elbow joints was determined by use of kinematic analysis before and after palmar digital nerve blocks. We obtained 8 recordings from horses without lameness, 8 with right forelimb lameness, and 8 with left forelimb lameness. Vertical and horizontal position of the head and vertical position of the foot, fetlock, carpal, and elbow joints were processed by continuous wavelet transformation. Feature vectors were created from the transformed signals and a neural network trained with data from 6 horses, which was then tested on the remaining 2 horses for each category until each horse was used twice for training and testing. Correct classification percentage (CCP) was calculated for each combination of gait signals tested. Results—Wavelet-transformed vertical position of the head and right forelimb foot had greater CCP (85%) than untransformed data (21%). Adding data from the fetlock, carpal, or elbow joints did not improve CCP over that for the head and foot alone. Conclusions and Clinical Relevance—Wavelet transformation of gait data extracts information that is important for the detection and differentiation of forelimb lameness of horses. All of the necessary information to detect lameness and differentiate the side of lameness can be obtained by observation of vertical head movement in concert with movement of the foot of 1 forelimb. (Am J Vet Res 2003;64:1376–1381)

Objective—To determine significant molecular and cellular factors responsible for differences in secondintention healing in thoracic and metacarpal wounds of horses. Animals—6 adult mixed-breed horses. Procedure—A full-thickness skin wound on the metacarpus and another such wound on the pectoral region were created, photographed, and measured, and tissue was harvested from these sites weekly for 4 weeks. Gene expression of type-I collagen, transforming growth factor (TGF)-β1, matrix metalloproteinase (MMP)-1, and tissue inhibitor of metalloproteinase (TIMP)-1 were determined by quantitative in situ hybridization. Myofibroblasts were detected by immunohistochemical labeling with α-smooth muscle actin (α-SMA). Collagen accumulation was detected by use of picrosirius red staining. Tissue morphology was examined by use of H&E staining. Results—Unlike thoracic wounds, forelimb wounds enlarged during the first 2 weeks. Myofibroblasts, detected by week 1, remained abundant with superior organization in thoracic wounds. Type-I collagen mRNA accumulated progressively in both wounds. More type-I collagen and TGF-β1 mRNA were seen in forelimb wounds. Volume of MMP-1 mRNA decreased from day 0 in both wounds. By week 3, TIMP-1 mRNA concentration was greater in thoracic wounds. Conclusions and Clinical Relevance—Greater collagen synthesis in metacarpal than thoracic wounds was documented by increased concentrations of myofibroblasts, type-I collagen mRNA, TGF-β1 mRNA, and decreased collagen degradation (ie, MMP-1). Imbalanced collagen synthesis and degradation likely correlate with development of exuberant granulation tissue, delaying healing in wounds of the distal portions of the limbs. Factors that inhibit collagen synthesis or stimulate collagenase may provide treatment options for horses with exuberant granulation tissue. (Am J Vet Res 2002;63:1564–1570)

Objective—To identify hind limb and pelvic kinematic variables that change in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and after subsequent intra-articular administration of anesthetic. Animals—8 clinically normal adult horses. Procedure—Kinematic measurements were made before and after transient endotoxin-induced lameness of the distal intertarsal and tarsometatarsal joints and after intra-articular administration of anesthetic. Fourteen displacement and joint angle (metatarsophalangeal [fetlock] and tarsal joints) measurements were made on the right hind limb, sacrum, and the right and left tubera coxae. Kinematic measurements were compared by general linear models, using a repeated measures ANOVA. Post hoc multiple comparisons between treatments were evaluated with a Fisher least squared difference test at α = 0.05. Results—After lameness induction, fetlock and tarsal joint extension during stance decreased, fetlock joint flexion and hoof height during swing increased, limb protraction decreased, and vertical excursion of the tubera coxae became more asymmetric. After intra-articular administration of anesthetic, limb protraction returned to the degree seen before lameness, and vertical excursion of the tubera coxae became more symmetric. Conclusions and Clinical Relevance—Increased length of hind limb protraction and symmetry of tubera coxae vertical excursion are sensitive indicators of improvement in tarsal joint lameness. When evaluating changes in tarsal joint lameness, evaluating the horse from the side (to assess limb protraction) is as important as evaluating from the rear (to assess pelvic symmetry). (Am J Vet Res 2000;61:1031–1036)

Objective— To determine if there is a difference in in vitro growth of fibroblasts isolated from the trunk and distal aspect of the limb of horses and ponies. To determine the effects of a corticosteroid and monokine on in vitro growth of fibroblasts isolated from the trunk and distal aspect of the limb of horses and ponies. Study Design— Growth of fibroblasts from tissues harvested from the trunk and limb were compared from horse and pony samples grown in control media and control media with triamcinolone or monokine added. Animals or Sample Population— Dermal and subcutaneous tissue from 22 horses and 17 ponies of various ages and breeds. Methods— Fibroblast growth was assessed by tritiated thymidine uptake using standard cell culture techniques. The effect of a monokine or triamcinolone plus control media were compared with control media for fibroblast growth. Results— Fibroblast growth from tissues isolated from the horse limb was significantly less than growth from the horse trunk and the limb and trunk of ponies. Monokine was more effective than triamcinolone in suppressing fibroblast growth from tissues isolated from the trunk and limb in both horses and ponies. Conclusions— There are growth differences in fibroblasts isolated from the limb of horses compared with those isolated from the trunk and from the limb and trunk of ponies. Clinical Relevance— The difference in fibroblast growth from tissues isolated from the trunk and limb of horses and ponies may provide evidence for the difference reported in the healing characteristics of limb wounds in horses and ponies. Influencing fibroblast growth may provide a key to controlling the development of exuberant granulation tissue in horses and ponies.

Objective This study compared the mechanical properties of the normal intact suspensory apparatus and two methods of fixation for repair of transverse, midbody fractures of the proximal sesamoid bones of adult horses: transfixation wiring (TW) and screws placed in lag fashion (LS). Study Design An in vitro, paired study using equine cadaver limbs mounted in a loading apparatus was used to test the mechanical properties of TW and LS. Animal or Sample Population Seventeen paired (13 repaired, 4 normal) equine cadaver limbs consisting of the suspensory apparatus third metacarpal bone, and first and second phalanges. Methods The two methods of repair and normal intact specimens were evaluated in single cycle-to-failure loading. Yield failure was defined to occur at the first notable discontinuity (>50 N) in the load-displacement curve, the first visible failure as evident on the videotape, or a change in the slope of the moment-fetlock angle curve. Ultimate failure was defined to occur at the highest load resisted by the specimen. Corresponding resultant force and force per kg of body weight on the suspensory apparatus, fetlock joint moment, and angle of fetlock dorsiflexion were calculated by use of specimen dimensions and applied load. These were compared along with specimen stiffness, and ram displacement. Results Load on the suspensory apparatus, load on the suspensory apparatus per kg of body weight, moment, applied load, and angle of fetlock dorsiflexion at yield failure were significantly greater for the TW-repaired than for the LS-repaired specimens. A 3 to 5 mm gap was observed before yield failure in most TW-repaired osteotomies. Conclusions Transfixation wiring provided greater strength to yield failure than screws placed in lag fashion in single cycle load-to-failure mechanical testing of repaired transverse osteotomized specimens of the medial proximal forelimb sesamoid bone. Clinical Relevance Our study indicates the initial strength of repair is greater following transfixation wiring than for lag screw fixation. Knowledge of the mechanical properties of these methods of fixation should aid the surgeon contemplating repair of mid-body fractures of the proximal sesamoid bones.

Summary We retrospectively evaluated the medical records and obtained follow-up information for nine horses which had been treated for cecocolic intussusception (CCI) between January 1982 and April 1998. During the 16-year study period, CCI was diagnosed in nine of 748 horses in which exploratory celiotomy was undertaken for abdominal pain, representing an incidence of 1.2%. Most affected horses (78%) were less than four years of age (median age was 12 months, age range was five months to 15 years). Cecocolic intussusception affected male horses (78%) more commonly than female horses. The most common clinical presentation was abdominal pain of a severe, acute nature or milder but recurrent signs of abdominal pain persisting in spite of conservative treatment for several days. Correction of CCI by either simple reduction or reduction followed by partial typhlectomy was successful if compromise of the intestine by devitalization and adhesion formation was not found at surgery. Definitive diagnosis of CCI necessitates exploratory celiotomy, although an ultrasonographic examination of the abdomen may confirm the diagnosis in some cases. When recognized early during the course of disease, surgical correction of CCI is associated with a favorable outcome; of the eight horses which underwent surgery in our series, five horses (63%) survived surgical correction of CCI. Handling of compromised gut during reduction of CCI necessitates extreme caution because the risk of intestinal tearing is quite high.

Summary The effects of balancing the foot and shoeing (B&S) on the kinematics of five Quarter Horses with navicular disease were evaluated using computerized gait analysis. Kinematic measurements of the right forelimb and head were made before and after palmar digital nerve block (PDNB) and before and after B&S of the forelimb feet. Carpal and fetlock joint angle, foot displacement, and temporal gait measurements were made for at least five strides in each horse trotting on a treadmill. Kinematic measurements were compared before and after PDNB and before and after B&S by analysis of variance with an α=0.05. The most significant kinematic changes seen after PDNB were in the vertical head movement parameters studied. Total vertical head excursion and measures of head height asymmetry between right and left forelimb stance phases decreased after PDNB. After B&S mean carpal flexion and maximum hoof height during the swing phase of the stride increased, but none of the head movement parameters significantly changed. Results of this study indicate that the ability of treadmill kinematic gait analysis to evaluate for improvement in lameness by monitoring vertical head movement parameters is not significantly affected in horses with navicular disease three weeks after balancing and shoeing the forelimb feet.

SummaryLong oblique diaphyseal osteotomies were created in 14 pairs of femurs from cadaver foals less than six months of age. One bone from each pair was repaired using two dynamic compression plates (DP), and the other was repaired using a dynamic compression plate with cable cerclage (CC). Seven pairs were tested in compression and seven pairs in craniolateral-caudomedial (CrL-CdM) three-point bending.A difference was not found in mean (± SD) breaking strength in compression between the DP (7257.19 ± 2004.08 N) and CC (7761.41 ± 2552.91 N) techniques. Nor was there a difference in mean stiffness in compression between the DP (2533.83 ± 1777.38 N/mm) and CC (3177.98 ± 1694.70 N/mm) techniques. There was no difference in mean stiffness in three-point bending between the DP (244.60 ± 60.80 N/mm) and CC (195.50 ± 80.90 N/mm) techniques. The mean bending breaking strength and bending moment for the DP technique (2839.36 ± 199.46 N and 124,932.00 ± 8776.38 N mm) was significantly (P = 0.02) greater than the CC technique (1940.39 ± 732.80 N and 85,377.72 ± 32243.34 N mm).The CC system was inferior to the DP technique in CrL-CdM three-point bending strength and moment, but provided equal bending stiffness and equal compressive strength and stiffness.The use of compression plating with cable cerclage was compared to double plating for repair of long oblique osteotomies in foal femurs. The repairs were tested in compression and 3-point bending. The compression plate with cable cerclage was inferior to double plating in bending strength and moment, but provided equal compressive strength and stiffness.

Objective—To compare data obtained with an inertial sensor system with results of subjective lameness examinations performed by 3 experienced equine veterinarians for evaluation of lameness in horses. Animals—106 horses. Procedures—Horses were evaluated for lameness with a body-mounted inertial sensor system during trotting in a straight line and via subjective evaluation by 3 experienced equine practitioners who performed complete lameness examinations including lunging in a circle and limb flexion tests. Agreement among evaluators regarding results of subjective evaluations and correlations and agreements between various inertial sensor measures and results of subjective lameness evaluations were determined via calculation of Fleiss’ κ statistic, regression analysis, and calculation of 95% prediction intervals. Results—Evaluators agreed on classification of horses into 3 mutually exclusive lameness categories (right limb lameness severity greater than left limb lameness severity, left limb lameness severity greater than right limb lameness severity, or equal right and left limb lameness severity) for 58.8% (κ = 0.37) and 54.7% (κ = 0.31) of horses for forelimb and hind limb lameness, respectively. All inertial sensor measures for forelimb and hind limb lameness were positively and significantly correlated with results of subjective evaluations. Agreement between inertial sensors measures and results of subjective evaluations was fair to moderate for forelimb lameness and slight to fair for hind limb lameness. Conclusions and Clinical Relevance—Results of lameness evaluation of horses with an inertial sensor system and via subjective lameness examinations were significantly correlated but did not have strong agreement. Inertial sensor-based evaluation may augment but not replace subjective lameness examination of horses.

Objective—To assess the analytic sensitivity of an inertial sensor system for detection of the more severely affected forelimb in horses with bilateral lameness. Animals—18 adult horses with forelimb lameness. Procedures—Horses were fitted with inertial sensors and evaluated for lameness with a stationary force plate as they were trotted in a straight line. Inertial sensor-derived measurements for vertical head movement asymmetry (HMA) and vector sum (VS) of maximum and minimum head height differences between right and left halves of the stride were used to predict differences in mean peak vertical force (PVF) as a percentage of body weight between the right and left forelimbs. Repeatability was compared by calculation of the intraclass correlation coefficient (ICC) for each variable. Correct classification percentages for the lamer forelimb were determined by use of a stationary force plate as the standard. Results—SEs of the prediction of difference in PVF between the right and left forelimbs from HMA and VS were 6.1% and 5.2%, respectively. Head movement asymmetry (ICC, 0.72) was less repeatable than PVF (ICC, 0.86) and VS (ICC, 0.84). Associations were positive and significant between HMA (R2 = 0.73) and VS (R2 = 0.81) and the difference in PVF between the right and left forelimbs. Correct classification percentages for HMA and VS for detecting the lamer forelimb were 83.3% and 77.8%, respectively. Conclusions and Clinical Relevance—Results suggested that an inertial sensor system to measure vertical asymmetry (HMA and VS) due to forelimb lameness in horses trotting in a straight line has adequate analytic sensitivity for clinical use. Additional studies are required to assess specificity of the system.

Signs of mild colic, intermittent lethargy, and weight loss of 6 weeks' duration in a 2-year-old Quarter Horse gelding were attributed to persimmon (Diospyros virginiana) phytobezoar formation. Diagnosis of the phytobezoar was facilitated by gastric endoscopy. Signs of gastrointestinal tract obstruction were associated with a large phytobezoar in the lumen of the stomach, gastric ulceration, and obstruction of the small intestine (as a consequence of fragmentation of the primary bezoar). Conservative treatment, using mineral oil and dioctyl sodium sulfosuccinate, was unsuccessful. A celiotomy was performed, and gastric impaction and partial obstruction of the small intestine associated with phytobezoar formation and fragmentation were identified. The horse made a complete recovery following removal of all phytobezoars. Persimmon phytobezoar should be considered in the fall and winter as a possible cause of lethargy, colic, and weight loss in horses allowed access to persimmon fruit.

Objective—To determine the effectiveness of administering multiple doses of phenylbutazone alone or a combination of phenylbutazone and flunixin meglumine to alleviate lameness in horses. Animals—29 adult horses with naturally occurring forelimb and hind limb lameness. Procedures—Lameness evaluations were performed by use of kinematic evaluation while horses were trotting on a treadmill. Lameness evaluations were performed before and 12 hours after administration of 2 nonsteroidal anti-inflammatory drug (NSAID) treatment regimens. Phenylbutazone paste was administered at approximately 2.2 mg/kg, PO, every 12 hours for 5 days, or phenylbutazone paste was administered at approximately 2.2 mg/kg, PO, every 12 hours for 5 days in combination with flunixin meglumine administered at 1.1 mg/kg, IV, every 12 hours for 5 days. Results—Alleviation of lameness was greater after administration of the combination of NSAIDs than after oral administration of phenylbutazone alone. Improvement in horses after a combination of NSAIDs did not completely mask lameness. Five horses did not improve after either NSAID treatment regimen. All posttreatment plasma concentrations of NSAIDs were less than those currently allowed by the United States Equestrian Federation Inc for a single NSAID. One horse administered the combination NSAID regimen died of acute necrotizing colitis during the study. Conclusions and Clinical Relevance—Administration of a combination of NSAIDs at the dosages and intervals used in the study reported here alleviated the lameness condition more effectively than did oral administration of phenylbutazone alone. This may attract use of combinations of NSAIDs to increase performance despite potential toxic adverse effects.

Objective— To determine normal cartilage stiffness values in different weight-bearing and non-weight-bearing areas of 3 different equine joints, and to evaluate the relationship between cartilage stiffness and glycosaminoglycan (GAG) and collagen content. Study Design— Compressive stiffness of the articular cartilage was measured in 8 horse cadaver femoropatellar (FP), tarsocrural (TC), and metatarsophalangeal (MT) joints. Gross evaluation, collagen content, GAG content, and histologic appearance were assessed for each measurement location. Animals— Eight equine cadavers (4 intact females, 4 castrated males; 7 Quarter Horse or Quarter Horse type, 1 Arabian; aged 4–12 years, weighing 400–550 kg) Methods— The articular surfaces of 8 equine cadaver FP, TC, and MT joints were grossly evaluated for signs of articular cartilage pathology. Stiffness at preselected sites (FP joint—6 sites; TC joint—3 sites; MT joint—4 sites) was determined using an arthroscopic indentation instrument. Biochemical composition (collagen, GAG content) and histologic evaluation (modified Mankin score) were assessed for each measurement site. Results— All cartilage from all sites evaluated was determined to be normal based on macroscopic and histologic assessments. No significant correlation between Mankin scores and cartilage stiffness values was observed. Site differences in cartilage stiffness were measured in all 3 joints (P 0.622, r2>0.387). Conclusion— Relative cartilage stiffness values measured in healthy equine joints are site dependent and can be measured using an indentation device intended for arthroscopic application. Clinical Relevance— An indentation instrument provided an objective means of determining relative compressive stiffness of articular cartilage. Further research needs to be performed to confirm the site and joint differences observed in this study in clinically normal horses and to determine if the tester can be used clinically to predict articular cartilage pathology.

Objective—To determine the prevalence of pedunculated lipomas and identify risk factors affecting postoperative complications and survival in horses at a veterinary teaching hospital undergoing surgery for colic caused by pedunculated lipomas. Design—Retrospective study. Animals—102 horses with a diagnosis of pedunculated lipoma. Procedure—Age, breed, weight, and sex of horses with pedunculated lipomas were compared with the total equine hospital population and the population of horses admitted for abdominal surgery during the same period. Follow-up information was obtained by reevaluation or contact with owners via telephone or written request. Results—Prevalence of pedunculated lipomas as a reason for abdominal surgery in horses, compared with the population of horses with and without lipomas admitted for abdominal surgery, was 10%. Castrated male Saddlebred and Arabian horses > 14 years old were identified as being at risk for developing pedunculated lipomas. Postoperative complications were detected in 72% of horses with pedunculated lipomas. Variables associated with low survival rates included surgery before 1992, heart rate > 80 beats/min, abnormal color of abdominal fluid, pale mucous membranes, surgery requiring intestinal resection, and inability to attain a mean arterial pressure ≥ 100 mm Hg. Horses undergoing surgery from 1992 to 1996, weighing < 409 kg (900 lb), or requiring jejunojejunal anastomosis had a high survival rate. Conclusions and Clinical Relevance—Although many of the variables reflected the health of the horse at the time of surgery, results may help veterinarians recognize risk factors associated with development of pedunculated lipomas and better predict the outcome of horses undergoing surgery for colic caused by pedunculated lipomas. (J Am Vet Med Assoc2005; 226:1529–1537)

SummaryReasons for performing study: Subjective neurologicalevaluation in horses is prone to bias. An objective method ofspinal ataxia detection is not subject to these limitations andcould be of use in equine practice and research.Hypothesis : Kinematic data in the walking horse candifferentiate normal and spinal ataxic horses.Methods : Twelve normal and 12 spinal ataxic horses wereevaluated by kinematic analysis walking on a treadmill.Each body position signal was reduced to a scalarmeasure ofuncertainty then fuzzy clustered into normal or ataxicgroups. Correct classification percentage (CCP) was thencalculated using membership values of each horse in the 2 groups. Subsequently, a guided search for measurecombinations with high CCPwas performed.Results : Eight measures of body position resulted in CCP ! 70%.Several combinations of 4Ð5 measures resulted in 100% CCP.All combinations with 100% CCPcould be obtained with onebody marker on the back measuring vertical and horizontalmovement and one body marker each on the right fore- andhindlimb measuring vertical movement.Conclusions and potential relevance: Kinematic gait analysisusing simple body marker combinations can be usedobjectively to detect spinal ataxia in horses.IntroductionSpinal ataxia is a significant problem for horses in North America,with diverse aetiology. In cases of mild to moderate severity,spinal ataxia may be suspected by the veterinarian initially fromowner complaints that their horse is weak or unable to perform.Spinal ataxia can then be determined more definitively after asubjective neurological examination. During this, the horseOsability to move and resist movement during and after a number ofdifferent manipulations and manoeuvres by the examiner isassessed and graded. The accuracy of the neurologicalexamination is limited by its subjective nature and the experientialbias of the examiner (Mackay 1997).Further diagnostic tests ranging from contrast myelograpy to avariety of spinal fluid analyses can be performed to help confirmthe existence of spinal ataxia by finding a plausible aetiology, aswell as to guide appropriate medical or surgical treatment.However, these techniques, although generally expensive andsomewhat invasive, are not very sensitive or accurate and a largepercentage of equine spinal ataxia cases remain without a specificdiagnosis. Because of this tendency for failure to find a specificdiagnosis, it is difficult for an equine practitioner to recommendthese more in-depth neurological diagnostic tests, especially if thehorse has mild, equivocal clinical signs.Clinical signs of many neurological dysfunctions have beenquantified in man and other animals by a variety of procedures,many using some form of computer-assisted kinematic analysis ofbody movements (Davis et al.2000). Kinematic evaluation ofspinal ataxia in horses has not previously been reported. Thepurpose of this study was to establish an objective, kinematicspinal ataxia detection system for use in horses.Materials and methodsT wenty-four mature horses were selected; 12 normal and 12 with spinal ataxia (Table 1). The normal horses were selectedfrom the University of Missouri teaching herd. Horses with spinalataxia were donated to the University of Missouri VeterinaryT eaching Hospital by clients after presentation for evaluation ofneurological dysfunction. All horses in the spinal ataxia groupunderwent neurological evaluation by 3 independent, experiencedexaminers and were accepted into the study if 2 or more examinersgave neurological scores of at least grade 1 . Ataxia was scored ona scale of 0Ð5+, modified from Mayhew et al. (1978), with 0 beingnormal and 5 recumbent. Since all horses were evaluated whilewalking on a treadmill, no horses affected with spinal ataxia of aseverity that prevented them from easily loading onto and off andsafely walking on the treadmill could be used in the study.All horses were trained over 3 days to load onto and walk onthe treadmill (Sato Equine Treadmill)

Objective—To evaluate pelvic movement over a large number of strides in sound horses and in horses with induced hind limb lameness by applying methods to the pelvis that have been described for evaluating vertical head movement in horses with induced forelimb lameness. Animals—17 adult horses. Procedure—Horses were filmed while trotting on a treadmill before and after induction of transient mild and moderate hind limb lamenesses. Vertical pelvic movement was measured by a signal decomposition method. The vertical pelvic signal was decomposed into a periodic component (A1) that occurred at half the stride frequency (representing vertical pelvic movement caused by lameness) and another periodic component (A2) that occurred at stride frequency (representing normal vertical pelvic movement of a trotting horse). Vertical pelvic and foot positions were correlated for each stride to compare the difference between the minimum and maximum heights of the pelvis during and after stance of the right hind limb to the minimum and maximum heights of the pelvis during and after stance of the left hind limb. Results—Maximum pelvic height difference and lameness amplitude (A1) differed significantly between sound and mild or moderate hind limb lameness conditions. Mean A1 value for vertical pelvic movement in sound horses was less than that previously reported for vertical head movement. Conclusions and Clinical Relevance—Pelvic height differences and signal decomposition of pelvic movement can be used to objectively evaluate hind limb lameness in horses over a large number of strides in clinical and research settings. (Am J Vet Res 2004;65: 741–747)

This paper discusses the use of combined uncertainty methods in the computation of wavelets that best represent horse gait signals. Combined uncertainty computes a composite of two types of uncertainties, fuzzy and probabilistic. First, we introduce fuzzy uncertainty properties and classes. Next, the gait analysis problem is discussed in the context of correctly classifying wavelet-transformed sound gait from lame horse gait signals. Continuous wavelets are selected using generalized information theory-related concepts that are enhanced through the application of uncertainty management models. Our experimental results show that models developed by maximizing combined uncertainty produce better results, in terms of neural network correct classification percentage, compared to those computed using only fuzzy uncertainty.

Video-based kinematic analysis of gait in horses is accurate for quantification of lameness and reliable for identification of the affected limb. Algorithms for the measurement of the vertical head and pelvic displacement and phase correlation with vertical displacement of one forelimb and hindlimb foot have been developed for this purpose. However, because of camera field-of-view limitations, video-based analysis of gait can only be reliably accomplished with the horse constrained to move on a treadmill. This paper describes the use of 2 single-axis accelerometers and 2 gyroscopic transducers as a measurement system for the identification and quantification of forelimb and hindlimb lameness in horses. Vertical head and pelvic acceleration are converted to displacement, lameness is quantified from previously developed algorithms, and affected limb is determined by correlation of head and pelvic signals with gyroscopic signals from the right forelimb and hindlimb feet. Signals from the 4 transducers are telemeterized at 200 Hz and collected to a receiver connected to a lap top computer, freeing the horse from the constraints of a treadmill laboratory setting. In this paper we describe the reliability of this new accelerometer-based system in horses with induced lameness while trotting on a treadmill and freely outside overground.

Summary In horses at a trot, the head moves up and down twice in one stride. In horses with unilateral forelimb lameness this movement is asymmetric. Computer-assisted kinematic analysis of vertical head movement can be used to quantify objectively lameness in horses in clinical trials. However, in mild lameness, absolute measurements of vertical head height may not be sensitive enough to detect small differences in lameness, and extraneous head movement by the horse due to curiosity, excitement or nervousness interferes with the accurate measurement of vertical head movement asymmetry. We describe a simple, signal-decompensation method of evaluating vertical head movement using a model of induced mild foot lameness in 9 horses. The technique assumes that the vertical head movement pattern can be broken down into 3 components; the vertical head movement caused by forelimb lameness (A1), the amplitude of the natural biphasic vertical head movement (A2) and extraneous head movement. Extraneous head movement is mathematically removed from the vertical head movement pat tern. A1 and A2 are then calculated. After induction of lameness, mean A1 increased by 1.63 cm (range 0.10–3.33 cm, P = 0.005). Mean A2 did not significantly change after lameness induction. Error in reproduction of the original head movement pattern was 0.3–0.5%. We calculated that a hypothetical clinical trial would require 12 subjects for testing to be 80% certain that this difference would be successfully detected using this method of lameness evaluation.

Objective—To determine whether kinematic changes induced by heel pressure in horses differ from those induced by toe pressure. Animals—10 adult Quarter Horses. Procedure—A shoe that applied pressure on the cuneus ungulae (frog) or on the toe was used. Kinematic analyses were performed before and after 2 levels of frog pressure and after 1 level of toe pressure. Values for stride displacement and time and joint angles were determined from horses trotting on a treadmill. Results—The first level of frog pressure caused decreases in metacarpophalangeal (fetlock) joint extension during stance and increases in head vertical movement and asymmetry. The second level of frog pressure caused these changes but also caused decreases in stride duration and carpal joint extension during stance as well as increases in relative stance duration. Toe pressure caused changes in these same variables but also caused maximum extension of the fetlock joint to occur before midstance, maximum hoof height to be closer to midswing, and forelimb protraction to increase. Conclusion and Clinical Relevance—Decreased fetlock joint extension during stance and increased head vertical movement and asymmetry are sensitive indicators of forelimb lameness. Decreased stride duration, increased relative stance duration, and decreased carpal joint extension during stance are general but insensitive indicators of forelimb lameness. Increased forelimb protraction, hoof flight pattern with maximum hoof height near midswing, and maximum fetlock joint extension in cranial stance may be specific indicators of lameness in the toe region. Observation of forelimb movement may enable clinicians to differentiate lameness of the heel from lameness of the toe. (Am J Vet Res 2000;61:612-619)

Figure 2. Liver; equine fetus. Note loss of hepatic cords filled with blood (arrow), vascular thrombosis (t), and inflammatory cell infiltration. HE. Bar = 100 μm. access to the fetus and allantochorion by invading the cervical opening, rather than by a systemic infection of the mare. In sheep, this infection is spread by fecal contamination. Moist soil conditions and concentrated fecal contamination were the source of infection in sheep. Acknowledgements. The investigation reported in this paper (94-4-240) is published by permission of the Dean and Director of the Kentucky Agriculture Experiment Station and College of Agriculture, University of Kentucky (Lexington, KY 40546-4076). We thank Ms. E. T. Napier for histologic preparation.

complex. Proc Annu MeetUS Anim Health Assoc 66:498-501.3. Jensen R, Lauerman LH, Braddy PM, et al.: 1980, Laryngealcontact ulcers in feedlot cattle. Vet Pathol 17:667-671.4. Jensen R, Lauerman LH, England JJ, et al.:1981, Laryngealdiphtheria and papillomatosis in feedlot cattle. Vet Pathol 18:143-150.5. Kersting K, Thompson J: 1989, Tracheal collapse and stenosisof calves. Proc Am Assoc Bovine Pract 22: 18.6. Minnigerode B, Richter HG: 1987, Pathophysiology of subtra-cheal stenosis in childhood. Prog Pediatr Surg 21:1-7.7. Panciera RJ, Williams DE: 1981, Tracheal edema (honker)syndrome of feeder cattle. In: Current veterinary therapy-foodanimal practice, ed. Howard JL, p. 800. WB Saunders Co.,Philadelphia, PA.8. Pearson BW: 1976, Trachea: tracheal stenosis. In: Scientificfoundations of otolaryngology, ed. Hinchcliffe R, Harrison D,pp. 919-933. Year Book Medical Publishers, Chicago, IL.9. Sasaki CT, Horiuchi M, Koss N: 1979, Tracheostomy-relatedsubglottic stenosis: bacteriologic pathogenesis. Laryngoscope 89:857-865.10. Shaw RR, Paulson DL, Kee JL: 1961, Traumatic tracheal rup-ture. J Thorac Cardiovasc Surg 42:281.11. Squire R, Brodsky L, Rossman J: 1990, The role of infectionin the pathogenesis of acquired tracheal stenosis. Laryngoscope100:765-770.12. Vestweber JB, Leipold HW: 1984, Tracheal collapse in threecalves. J Am Vet Med Assoc 184:735-736.J Vet Diagn Invest 5:451453 (1993)