Objective—To determine kinematic changes to the hoof of horses at a walk after induction of unilateral, weight-bearing forelimb lameness and to determine whether hoof kinematics return to prelameness (baseline) values after perineural anesthesia.
Animals—6 clinically normal Quarter Horses.
Procedures—For each horse, a sole-pressure model was used to induce 3 grades of lameness in the right forelimb, after which perineural anesthesia was administered to eliminate lameness. Optical kinematics were obtained for both forelimbs with the horse walking before (baseline) and after induction of each grade of lameness and after perineural anesthesia. Linear acceleration profiles were used to identify hoof events, and each stride was divided into hoof-contact, break-over, initial-swing, terminal-swing, and total-swing segments. Kinematic variables were compared within and between limbs for each segment by use of mixed repeated-measures ANOVA.
Results—During the hoof-contact and terminal-swing segments, the hoof of the left (nonlame) forelimb had greater sagittal-plane orientation than did the hoof of the right (lame) forelimb. For the lame limb following lameness induction, the break-over duration and maximum cranial acceleration were increased from baseline. After perineural anesthesia, break-over duration for the lame limb returned to a value similar to that at baseline, and orientation of the hoof during the terminal-swing segment did not differ between the lame and nonlame limbs.
Conclusions and Clinical Relevance—Subclinical unilateral forelimb lameness resulted in significant alterations to hoof kinematics in horses that are walking, and the use of hoof kinematics may be beneficial for the detection of subclinical lameness in horses.
Objective—To determine kinematic changes to the hoof of horses at a trot after induction of unilateral, weight-bearing forelimb lameness and to determine whether hoof kinematics return to prelameness values after perineural anesthesia.
Animals—6 clinically normal Quarter Horses.
Procedures—For each horse, a sole-pressure model was used to induce 3 grades (grades 1, 2, and 3) of lameness in the right forelimb, after which perineural anesthesia was administered to alleviate lameness. Optical kinematics were obtained for both forelimbs with the horse trotting before (baseline) and after induction of each grade of lameness and after perineural anesthesia. Hoof events were identified with linear acceleration profiles, and each stride was divided into hoof-contact, break-over, initial-swing, terminal-swing, and total-swing segments. For each segment, kinematic variables were compared within and between limbs by use of mixed repeated-measures ANOVA.
Results—During hoof-contact, the left (nonlame) forelimb hoof had greater heel-down orientation than did the right (lame) forelimb hoof, and during break-over, the nonlame hoof went through a larger range of motion than did the lame hoof. Maximum cranial acceleration during break-over for the lame hoof was greater, compared with that at baseline or for the nonlame hoof. Following perineural anesthesia, the sagittal plane orientation of the hoof during hoof-contact did not vary between the lame and nonlame limbs; however, interlimb differences in maximum cranial acceleration and angular range of motion during break-over remained.
Conclusions and Clinical Relevance—Results suggested that hoof kinematics may be useful for detection of unilateral, weight-bearing forelimb lameness in horses that are trotting.
Objective—To determine intralimb orientation changes with an inertial measurement unit (IMU) in hooves of horses at a walk and trot after induction of weight-bearing single forelimb lameness and to determine whether hoof orientations are similar to baseline values following perineural anesthesia.
Animals—6 clinically normal horses.
Procedures—3-D hoof orientations were determined with an IMU mounted on the right forelimb hoof during baseline conditions, during 3 grades of lameness (induced by application of pressure to the sole), and after perineural anesthesia. Linear acceleration profiles were used to segment the stride into hoof breakover, stance, initial swing, terminal swing, and total swing phases. Intralimb data comparisons were made for each stride segment. A repeated-measures mixed-model ANOVA was used for data analysis.
Results—Lameness resulted in significant changes in hoof orientation in all planes of rotation. A significant increase in external rotation and abduction and a significant decrease in sagittal plane rotation of the hoof were detected at hoof breakover during lameness conditions. For sagittal plane orientation data, the SDs determined following perineural anesthesia were higher than the SDs for baseline and lameness conditions.
Conclusions and Clinical Relevance—Results of this study indicated the IMU could be used to detect 3-D hoof orientation changes following induction of mild lameness at a walk and trot. An increase in data variability for a sagittal orientation may be useful for assessment of local anesthesia for hooves. The IMU should be further evaluated for use in clinical evaluation of forelimb lameness in horses.
Objective—To determine the epidemiologic plausibility
of a sylvatic transmission cycle for Neospora caninum
between wild canids and beef cattle.
Design—Spatial analysis study.
Animals—1,009 weaned beef steers from 94 beef
herds in Texas.
Procedure—Calves were grouped on the basis of
seroprevalence for N caninum and ecologic region in
Texas. The Morans I test was used to evaluate spatial
interdependence for adjusted seroprevalence by ecologic
region. Cattle density (Number of cattle/259 km2
[Number of cattle/100 mile2] of each ecologic region)
and abundance indices for gray foxes and coyotes
(Number of animals/161 spotlight-transect [census] km
[Number of animals/100 census miles] of each ecologic
region) were used as covariates in spatial regression
models, with adjusted seroprevalence as the outcome
variable. A geographic information system (GIS) that
used similar covariate information for each county was
used to validate spatial regression models.
Results—Spatial interdependence was not detected
for ecologic regions. Three spatial regression models
were tested. Each model contained a variable for cattle
density for the ecologic regions. Results for the 3
models revealed that seroprevalence was associated
with cattle density and abundances of gray foxes, coyotes,
or both. Abundances of gray foxes and coyotes
were collinear. Results of a GIS-generated model validated
these spatial models.
Conclusions and Clinical Relevance—In Texas, beef
cattle are at increased risk of exposure to N caninum
as a result of the abundance of wild canids and the
density of beef cattle. It is plausible that a sylvatic
transmission cycle for neosporosis exists. (J Am Vet
Med Assoc 2000;217:1361–1365)