Objective—To assess the accuracy and reliability of a
visual method of evaluating horseshoe characteristics.
Animals—1,199 Thoroughbred racehorses.
Procedure—Characteristics of 1 forelimb horseshoe
were visually assessed on horses immediately
prior to racing by 5 field observers at 5 major
racetracks in California. Characteristics evaluated
included horseshoe type; toe grab height; and the
presence of a rim, pad, and heel traction devices.
Sensitivity and specificity for observer assessment
of horseshoe characteristics were calculated by
comparing observer assessments to a postmortem
laboratory standard for horses that died within 48
hours of a race. Intraobserver agreement was
assessed in a subset of horses by comparing horseshoe
observations made before and after the
horse's race. Interobserver agreement was evaluated
by comparing horseshoe assessment among
observers who examined the same subset of horses
prior to racing on select days.
Results—The sensitivity and specificity of this visual
method of evaluating horseshoe characteristics were
good and ranged from 0.75 to 1 and 0.67 to 1, respectively.
Agreement beyond chance (weighted kappa
values) between observers and the laboratory standard
for toe grab height was fair (0.60 to 0.62).
Intraobserver and interobserver agreements (kappa
values) were high (0.86 to 0.99 and 0.71 to 1, respectively).
Conclusions and Clinical Relevance—Visual observation
of horseshoes can be a feasible and reproducible
method for assessing horseshoe characteristics
prospectively in a large cohort of horses under
racing conditions. (Am J Vet Res 2004;65:1674–1679)
Objective—To describe forelimb horseshoe characteristics
of horses racing on dirt surfaces and determine
whether these characteristics vary with region
of California, season, horse characteristics, and race-related
Animals—5,730 Thoroughbred racehorses.
Procedure—From June 17, 2000, to June 16, 2001,
the characteristics of 1 forelimb horseshoe of horses
that raced on dirt surfaces at 5 major racetracks in
California were recorded. These characteristics included
shoe type; toe grab height; and presence of a rim,
pad, and heel traction devices (jar caulks, heel stickers,
heel blocks, and special nails). Horse and race
information was obtained from commercial records.
One race/horse was randomly selected.
Results—99% of forelimb horseshoes were aluminum
racing plates, 35% had a pad, 23% had a rim,
and 8% had a heel traction device. A toe grab was
observed on 75% of forelimb horseshoes (14% very
low [≤ 2 mm], 30% low [> 2 and ≤ 4 mm], 30% regular
[> 4 and ≤ 6 mm], and 1% high [> 6 and ≤ 8 mm]).
Forelimb horseshoe characteristics varied with region
of California, season, age and sex of the horse, race
purse and distance, and track surface condition. Loglinear
modeling revealed that all of these factors were
Conclusions and Clinical Relevance—Complex
interrelationships among forelimb horseshoe characteristics
and region, season, age and sex of the horse,
and race-related factors need to be considered when
evaluating the relationships between injury and
horseshoe characteristics in Thoroughbred racehorses.
( Am J Vet Res 2004;65:1021–1030)
Objective—To characterize biomechanical differences in gait between dogs with and without an amputated thoracic limb.
Animals—Client-owned dogs (16 thoracic-limb amputee and 24 quadruped [control] dogs).
Procedures—Dogs were trotted across 3 in-series force platforms. Spatial kinematic and kinetic data were recorded for each limb during the stance phase.
Results—Amputees had significant increases in stance duration and vertical impulse in all limbs, compared with values for control dogs. Weight distribution was significantly increased by 14% on the remaining thoracic limb and by a combined 17% on pelvic limbs in amputees. Braking ground reaction force (GRF) was significantly increased in the remaining thoracic limb and pelvic limb ipsilateral to the amputated limb. The ipsilateral pelvic limb had a significantly increased propulsive GRF. The carpus and ipsilateral hip and stifle joints had significantly greater flexion during the stance phase. The cervicothoracic vertebral region had a significantly increased overall range of motion (ROM) in both the sagittal and horizontal planes. The thoracolumbar vertebral region ROM increased significantly in the sagittal plane but decreased in the horizontal plane. The lumbosacral vertebral region had significantly greater flexion without a change in ROM.
Conclusions and Clinical Relevance—Compared with results for quadruped dogs, the vertebral column, carpus, and ipsilateral hip and stifle joints had significant biomechanical changes after amputation of a thoracic limb. The ipsilateral pelvic limb assumed dual thoracic and pelvic limb roles because the gait of a thoracic limb amputee during trotting appeared to be a mixture of various gait patterns.
Objective—To evaluate biomechanical gait adaptations in dogs after amputation of a pelvic limb.
Animals—Client-owned dogs (12 pelvic limb–amputee and 24 quadruped [control] dogs).
Procedures—Dogs were trotted across 3 in-series force platforms. Spatial kinematic and kinetic data were recorded for each limb during the stance phase.
Results—Pelvic limb amputees had increased peak braking forces in the contralateral thoracic limb and increased propulsive forces and impulses in both the ipsilateral thoracic limb and remaining pelvic limb. Time to peak braking force was significantly decreased, and time to peak propulsive force was significantly increased in all remaining limbs in amputees. Amputees had an increase in range of motion at the tarsal joint of the remaining pelvic limb, compared with results for the control dogs. Amputees had increased vertebral range of motion at T1 and T13 and increased vertebral extension at L7 within the sagittal plane. In the horizontal plane, amputees had increased lateral bending toward the remaining pelvic limb, which resulted in a laterally deviated gait pattern.
Conclusions and Clinical Relevance—Pelvic limb amputees adjusted to loss of a limb through increased range of motion at the tarsal joint, increased range of motion in the cervicothoracic and thoracolumbar vertebral regions, and extension of the lumbosacral vertebral region, compared with results for the control dogs. Amputees alternated between a laterally deviated gait when the pelvic limb was in propulsion and a regular cranially oriented gait pattern when either forelimb was in propulsion with horizontal rotation around L7.
Objective—To compare temperature readings from an implantable percutaneous thermal sensing microchip with temperature readings from a digital rectal thermometer, to identify factors that affect microchip readings, and to estimate the sensitivity and specificity of the microchip for fever detection.
Animals—52 Welsh pony foals that were 6 to 10 months old and 30 Quarter Horses that were 2 years old.
Procedures—Data were collected in summer, winter, and fall in groups 1 (n = 23 ponies), 2 (29 ponies), and 3 (30 Quarter Horses), respectively. Temperature readings from a digital rectal thermometer and a percutaneous thermal sensing microchip as well as ambient temperature were recorded daily for 17, 23, and 19 days in groups 1 through 3, respectively. Effects of ambient temperature and rectal temperature on thermal sensor readings were estimated. Sensitivity and specificity of the thermal sensor for detection of fever (rectal temperature, ≥ 38.9°C [102°F]) were estimated separately for data collection at ambient temperatures ≤ 15.6°C (60°F) and > 15.6°C.
Results—Mean ambient temperatures were 29.0°C (84.2°F), −2.7°C (27.1°F), and 10.4°C (50.8°F) for groups 1 through 3, respectively. Thermal sensor readings varied with ambient temperature and rectal temperature. Rectal temperatures ranged from 36.2° to 41.7°C (97.2° to 107°F), whereas thermal sensor temperature readings ranged from 23.9° (75°F) to 42.2°C (75° to 108°F). Sensitivity for fever detection was 87.4%, 53.3%, and 58.3% in groups 1 to 3, respectively.
Conclusions and Clinical Relevance—The thermal sensor appeared to have potential use for initial screening of body temperature in equids at ambient temperatures > 15.6°C.
Objective—To develop a questionnaire for self-assessment of biosecurity practices at equine boarding facilities and to evaluate infectious disease control practices in these facilities in Colorado.
Sample Population—64 equine boarding facilities in Colorado.
Procedures—Survey questions were rated according to importance for prevention and containment of equine infectious diseases. Point values (range, 0 to 20) were assigned for possible responses, with greater values given for optimal infection control methods. Questionnaires were mailed to equine boarding facilities in Colorado advertised on the World Wide Web. Survey responses were compared with assessments made by a member of the research team during visits to 30 randomly selected facilities. Agreement among results was analyzed via a kappa test and rated as poor, fair, moderate, substantial, or nearly perfect.
Results—Survey responses were received for 64 of 163 (39%) equine boarding facilities. Scores ranged from 106 to 402 points (maximum possible score, 418). Most facilities received better scores for movement and housing of equids than for other sections of the survey. Respondents at 24 of 48 (50%) facilities that routinely received new equids reported isolation of new arrivals. Agreement between self-assessment by survey respondents and evaluation by a member of the research team was determined to be fair to substantial.
Conclusions and Clinical Relevance—Most equine boarding facilities have opportunities to improve measures for prevention or containment of contagious diseases (eg, isolation of newly arrived equids and use of written health management protocols). Most self-assessments of infection control practices were accurate.
Objective—To evaluate effects of toe grabs, exercise
intensity, and distance traveled as risk factors for subclinical
to mild suspensory apparatus injury (SMSAI)
in Thoroughbred racehorses and to compare incidence
of severe musculoskeletal injury (MSI) in horses
with and without SMSAI.
Design—Nested case-control study.
Animals—219 Thoroughbred racehorses racing or in
Procedure—Racehorses were examined weekly for
90 days to determine incidence of suspensory ligament
injury and monitor horseshoe characteristics.
Every horse's exercise speeds and distances were
recorded daily. Conditional logistic regression was
used to compare exposure variables between incident
case (n = 25) and selected control (125) horses.
Survival analysis was used to compare time to MSI
for horses with (n = 41) and without (76) SMSAI.
Results—The best-fitting logistic model for the data
included age (< 5 vs ≥ 5 years old), toe grab height the
week of injury (none vs very low, low, regular, or
Quarter Horse height), and weekly distance the week
preceding injury (miles). Although the 95% confidence
intervals for all odds ratios included 1, the odds
for SMSAI appeared to increase with the presence of
a toe grab, higher weekly distance, and age ≥ 5 years.
Horses that had SMSAI were significantly more likely
to have a severe MSI or severe suspensory apparatus
injury than were horses that did not.
Conclusions and Clinical Relevance—Results suggest
that pre-existing SMSAI is associated with development
of severe MSI and severe suspensory apparatus
injury. Modifying training intensity and toe grab
height for horses with SMSAI may decrease the incidence
of severe MSI. (J Am Vet Med Assoc 2001;
Objective—To characterize direct and indirect contacts among livestock operations in Colorado and Kansas.
Design—Cross-sectional quarterly survey.
Sample—532 livestock producers.
Procedures—Livestock producers in Colorado and Kansas were recruited by various means to participate in the survey, which was sent out via email or postal mail once quarterly (in March, June, September, and December) throughout 2011. Data were entered into an electronic record, and descriptive statistics were summarized.
Results—Large swine operations moving animals to other large swine operations had the highest outgoing direct contact rates (range, 5.9 to 24.53/quarter), followed by dairy operations moving cattle to auction or other dairy operations (range, 2.6 to 10.34/quarter). Incoming direct contact rates for most quarters were highest for large feedlots (range, 0 to 11.56/quarter) and dairies (range, 3.90 to 5.78/quarter). For large feedlots, mean total indirect contacts through feed trucks, livestock haulers, and manure haulers each exceeded 725 for the year. Dairy operations had a mean of 434.25 indirect contacts from milk trucks and 282.25 from manure haulers for the year.
Conclusions and Clinical Relevance—High direct contact rates detected among large swine operations may suggest a risk for direct disease transmission within the integrated swine system. Indirect contacts as well as incoming direct contacts may put large feedlots at substantial risk for disease introduction. These data can be useful for establishing and evaluating policy and biosecurity guidelines for livestock producers in the central United States. The results may be used to inform efforts to model transmission and control of infectious diseases such as foot-and-mouth disease in this region.
Objective—To describe the prevalence of West Nile virus (WNV) infection and evaluate factors associated with positive IgM capture ELISA results in equids with clinical signs compatible with WNV infection.
Design—Retrospective case series.
Sample Population—Laboratory submission forms from 1,104 equids tested for WNV in Colorado in 2003.
Procedures—Submission forms accompanying samples submitted for detection of WNV via IgM capture ELISA were obtained from the Colorado state veterinarian and diagnostic laboratories performing the tests. Data on signalment, clinical signs, history of vaccination against WNV, and assay results were collected from laboratory submission forms. Equids with clinical signs compatible with WNV infection in which IgM capture ELISA results were positive were considered as case equids.
Results—1,104 equids were tested for WNV; 1,017 (92.1%) had clinical signs compatible with WNV infection. Among equids with clinical signs compatible with WNV infection, the odds of testing positive for WNV via IgM capture ELISA were lower in males and in vaccinated equids and higher in equids with moderate and severe illness, compared with females, unvaccinated equids, and equids with mild illness.
Conclusions and Clinical Relevance—Among equids with clinical signs compatible with WNV infection, vaccination against WNV, severity of clinical signs, duration of illness, and region in Colorado were associated with increased risk of having a positive IgM capture ELISA result.
Objective—To determine the distribution for limbs and bones in horses with fractures of the proximal sesamoid bones and relationships with findings on palmarodorsal radiographic images.
Sample Population—Proximal sesamoid bones obtained from both forelimbs of cadavers of 328 racing Thoroughbreds.
Procedure—Osteophytes; large vascular channels; and fracture location, orientation, configuration, and margin distinctness were categorized by use of high-detail contact palmarodorsal radiographs. Distributions of findings were determined. Relationships between radiographic findings and fracture characteristics were examined by use of χ2 and logistic regression techniques.
Results—Fractures were detected in 136 (41.5%) horses. Biaxial fractures were evident in 109 (80%) horses with a fracture. Osteophytes and large vascular channels were evident in 266 (81%) and 325 (99%) horses, respectively. Medial bones typically had complete transverse or split transverse simple fractures, indistinct fracture margins, > 1 vascular channel that was > 1 mm in width, and osteophytes in abaxial wing and basilar middle or basilar abaxial locations. Lateral bones typically had an oblique fracture and distinct fracture margins. Odds of proximal sesamoid bone fracture were approximately 2 to 5 times higher in bones without radiographic evidence of osteophytes or large vascular channels, respectively.
Conclusions and Clinical Relevance—Biaxial fractures of proximal sesamoid bones were common in cadavers of racing Thoroughbreds. Differences between medial and lateral bones for characteristics associated with fracture may relate to differences in fracture pathogeneses for these bones. Osteophytes and vascular channels were common findings; however, fractures were less likely to occur in bones with these features.