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Abstract

Objective—To characterize medial femoral condyle (MFC) morphometrics and subchondral bone density patterns in Thoroughbred racehorses and to determine whether these variables differ between left and right limbs.

Sample—Stifle joints harvested from 6 Thoroughbred racehorses euthanized for reasons other than hind limb lameness.

Procedures—The distal portion of the left and right femurs of each cadaver was scanned via CT. Hounsfield units were converted to dipotassium phosphate equivalent densities through use of a phantom on each specimen. Medial femoral condyle width, length, height, and curvature; subchondral bone plate densities; and subchondral trabecular bone densities were analyzed in multiple sections in 5 frontal planes and 3 sagittal planes and were compared between left and right MFCs.

Results—MFC width, length, and height did not differ between left and right limbs. Regions of interest in the right caudoaxial subchondral bone plate and subchondral trabecular bone were significantly denser than their corresponding left regions of interest in the frontal and sagittal planes. A concavity in the otherwise convex articular surface of the cranial aspect of the MFC was identified in 11 of 12 specimens.

Conclusions and Clinical Relevance—A disparity was identified between left and right subchondral bone density patterns at the caudoaxial aspect of the MFC, which could be attributable to the repetitive asymmetric cyclic loading that North American Thoroughbred racehorses undergo as they race in a counterclockwise direction. The uneven region at the cranial aspect of the MFC could be associated with the development of subchondral bone cysts in horses.

Full access
in American Journal of Veterinary Research

OBJECTIVE

To report history, physical examination findings, clinicopathologic abnormalities, treatments, and outcomes of dogs with confirmed α-amanitin toxicosis resulting from ingestion of α-amanitin–containing mushrooms, and to report whether any differences were significant between survivors and nonsurvivors.

ANIMALS

59 dogs.

PROCEDURES

Medical records of all dogs with confirmed α-amanitin toxicosis presented to a northern California emergency and specialty veterinary hospital between January 2006 and July 2019 were reviewed for signalment; body weight; history; physical examination findings including rectal temperature at presentation; results of serum biochemical analyses, coagulation tests, and a test for the detection of α-amanitin in urine; treatments; and outcomes. Differences for each were compared between survivors and nonsurvivors.

RESULTS

Among the 59 dogs, 36 were < 1 year of age; 56 had variable clinical signs that included vomiting, diarrhea, anorexia, and weakness or lethargy; and 22 had rectal temperatures > 39.2°C (102.5°F) at presentation. Cases were seen throughout the calendar year. At presentation, alanine aminotransferase activity was mildly to markedly increased in 97% of dogs, hypoglycemia was noted in 78%, and coagulation times were prolonged in 91%. Most dogs that rapidly decompensated died; however, 13 dogs survived to hospital discharge and completely recovered.

CONCLUSIONS AND CLINICAL RELEVANCE

Ability to recognize dogs with α-amanitin toxicosis on the basis of clinical signs, physical examination findings, and clinicopathologic test results is essential because mushroom ingestion is rarely observed and immediate treatment is necessary. Dogs that have marked hypoglycemia or coagulopathy may have a poor prognosis.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate a Markov-chain model for the development of forelimb injuries in Thoroughbreds and to use the model to determine effects of reducing sprint distance on incidence of metacarpal condylar fracture (CDY) and severe suspensory apparatus injury (SSAI).

Sample Population—Weekly exercise and injury data for 122 Thoroughbreds during racing or training.

Procedure—Weekly data were used to construct a Markov-chain model with 5 states (uninjured [UNINJ], palpable suspensory apparatus injury [PSAI], SSAI, CDY, and lost to follow-up [LOST]). Transition probabilities between UNINJ and PSAI were estimated as a function of weekly sprint distance by use of linear regression analysis. The model was used to predict distributions of annual CDY and SSAI incidences in southern California racehorses and was validated by using CDY incidence reported by racetrack practitioners. The model was modified by reducing the number of sprint distances that were > 6 furlongs (> 1.20 km) by 20%, and CDY and SSAI incidences were compared with those generated by the baseline model.

Results—The model accurately fit development of injuries in the sample population but overestimated development of injuries in the southern California racehorse population. Development of and recovery from PSAI were correlated with distance run at high speeds. Reducing by 20% the number of sprints run at distances > 6 furlongs significantly reduced modeled annual CDY and SSAI incidence by 9%.

Conclusions and Clinical Relevance—Reducing the number of sprints at distances > 6 furlongs, particularly among horses with PSAI, reduces risk of CDY and SSAI. (Am J Vet Res 2003;64:328–337)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine incidences and underlying causes of fatal intestinal inflammatory lesions (FIILs) and demographic characteristics of affected equids necropsied at any of the California Animal Health and Food Safety Laboratory facilities between January 1, 1990, and April 16, 2013.

ANIMALS

710 equids with FIILs, including colitis, duodenitis, enteritis, enterocolitis, enteropathy, enterotyphlitis, gastritis, gastroenteritis, ileitis, jejunitis, typhlitis, or typhlocolitis, alone or in combination.

PROCEDURES

The medical records were reviewed, and data collected included animal age, sex, geographic origin, necropsy submission date, and breed, purpose, or characteristic of use. Descriptive statistics were compiled and reported as numbers and percentages.

RESULTS

Colitis (323/710 [45.5%]), enteritis (146/710 [20.6%]), and typhlocolitis (138/710 [19.4%]) were the most common FIILs, and the underlying cause of most FIILs was categorized as either undetermined (465/710 [65.5%]) or bacterial (167/710 [23.5%]). The most common bacteria responsible for FIILs were Clostridium spp and Salmonella spp.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that the underlying cause for most FIILs could not be identified; however, when it was identified, it was most commonly bacterial and typically Clostridium spp or Salmonella spp, which could be useful information for practitioners when evaluating and managing horses and other equids with intestinal distress. In addition, results underscored the need for improved diagnostic procedures and strategies to determine underlying causes of FIILs in equids. Knowledge of the most common FIILs and their underlying causes may help in diagnosing and mitigating intestinal disease in equids.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess individual and combined associations of high-speed exercise and horseshoe characteristics with risk of forelimb proximal sesamoid bone fractures and proximal sesamoid bone midbody fractures in Thoroughbred racehorses.

Animals—269 deceased Thoroughbred racehorses.

Procedures—A case-control study design was used to compare 121 horses with a fracture of at least 1 of 4 forelimb proximal sesamoid bones (75 horses had a midbody fracture) and 148 horses without a forelimb proximal sesamoid bone fracture. Univariable and multivariable logistic regression analyses were used to evaluate potential risk factors for association with proximal sesamoid bone fracture.

Results—Compared with horses that died without proximal sesamoid bone fractures, horses that died with proximal sesamoid bone fractures were more likely to be sexually intact males, spend more time in active trainingand racing, complete more events, train and race longer since their last layup, have higher exercise intensities during the 12 months prior to death, and have greater cumulative distances for their career. Horses with proximal sesamoid bone midbody fractures were more likely to be sexually intact males, train and race longer since their last layup, and have higher exercise intensities during the 12 months prior to death.

Conclusions and Clinical Relevance—Limitingexercise intensity and the continuous time spent in activity duringa horse's career may decrease the frequency of forelimb proximal sesamoid bone fractures in Thoroughbred horses.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate veterinarian-client communication and veterinarian and client satisfaction with veterinary visits before and after veterinarians underwent a 6-month communication skills training program in a practice setting.

DESIGN Case-based pretest-posttest intervention study.

SAMPLE 1 purposely selected companion-animal practice.

PROCEDURES The practice team (3 veterinarians, 5 veterinary technicians, 1 receptionist, and 1 office manager) participated in a 6-month educational program (intervention) that included interactive communication modules, individual coaching, and a communication laboratory. For each of the veterinarians, 6 appointments were video recorded and 30 additional clients completed a visit satisfaction survey both before and after the intervention. The Roter interaction analysis system was used to analyze the video-recorded appointments.

RESULTS After the intervention, appointments were 5.4 minutes longer and veterinarians asked 60% fewer closed-ended lifestyle-social questions, provided 1.4 times as much biomedically related client education, and used 1.5 and 1.25 times as much facilitative and emotional rapport communication, respectively, compared with before the intervention. Clients provided veterinarians with 1.3 times as much biomedically related information and engaged in twice as much social conversation. After the intervention, veterinarians perceived their clients as complaining less and being more personable and trusting, and clients felt more involved in the appointment and reported that the veterinarian expressed greater interest in their opinion.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the intervention resulted in veterinarians who spent more time educating and building rapport with their clients and facilitating client input in an unhurried environment, which enhanced overall veterinarian visit satisfaction and various aspects of client visit satisfaction.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess concurrently the effects of moderate ligamentous suspensory apparatus injury (MLSAI), racing-speed exercise, and horseshoe characteristics on risk of catastrophic suspensory apparatus failure (SAF) or metacarpal condylar fracture (CDY) in forelimbs of racehorses.

Sample population—Cadavers of 301 Thoroughbred racehorses (108 with SAF, 33 with CDY, and 160 control horses).

Procedure—A cross-sectional epidemiologic study was used to describe distributions and relationships between MLSAI, exercise, and horseshoe variables. Logistic regression was used to assess potential risk factors for developing SAF and CDY.

Results—Exercise variables were more highly associated with age than height of a steel bar affixed to the ground surface of the front of a horseshoe (ie, toe grab) or sex. Marginal associations were detected between MLSAI and age and height of toe grab. Higher risk for developing SAF was associated with MLSAI, use of a pad on a horseshoe, longer interval since last period of ≥ 60 days without a race or timed workout (ie, layup), 2 to 5 career races, and higher intensity of recent exercise. Higher risk for developing CDY was associated with MLSAI, male horses, age between 2 and 5 years, higher intensity of recent exercise, and longer interval since layup.

Conclusions and Clinical Relevance—Recognition of MLSAI and rehabilitation of affected horses should reduce incidence of SAF and CDY. Horses in long-term continuous training with recent high-intensity exercise are at greater risk for injury. Use of pads in horseshoes was associated with SAF, although the relationship may not be causal. (Am J Vet Res 2004;65:1508–1517).

Full access
in American Journal of Veterinary Research

Abstract

Objective—To measure passive spinal movements induced during dorsoventral mobilization and evaluate effects of induced pain and spinal manipulative therapy (SMT) on passive vertebral mobility in standing horses.

Animals—10 healthy adult horses.

Procedures—Baseline vertical displacements, applied force, stiffness, and frequency of the oscillations were measured during dorsoventral spinal mobilization at 5 thoracolumbar intervertebral sites. As a model for back pain, fixation pins were temporarily implanted into the dorsal spinous processes of adjacent vertebrae at 2 of the intervertebral sites. Vertebral variables were recorded again after pin placement and treadmill locomotion. In a random-ized crossover study, horses were allocated to control and treatment interventions, separated by a 7-day washout period.The SMT consisted of high-velocity, low-amplitude thrusts applied to the 3 non–pin-placement sites. Control horses received no treatment.

Results—The amplitudes of vertical displacement increased from cranial to caudal in the thoracolumbar portion of the vertebral column. Pin implantation caused no immediate changes at adjacent intervertebral sites, but treadmill exercise caused reductions in most variables. The SMT induced a 15% increase in displacement and a 20% increase in applied force, compared with control measurements.

Conclusions and Clinical Relevance—The passive vertical mobility of the trunk varied from cranial to caudal. At most sites, SMT increased the amplitudes of dorsoventral displacement and applied force, indicative of increased vertebral flexibility and increased tolerance to pressure in the thoracolumbar portion of the vertebral column.

Full access
in American Journal of Veterinary Research

Abstract

Objectives—To establish reference mechanical nociceptive threshold (MNT) values of the equine thoracic limb and to assess the use of MNT values to detect pain associated with induced osteoarthritis in the middle carpal joint.

Animals—24 adult horses.

Procedures—MNT values were evoked by a pressure algometer at 17 sites within each thoracic limb during 2 baseline sessions conducted an average of 5 days apart. Effects of age, sex, weight, and wither height on MNT values were assessed separately for each site. Tolerance of horses to the procedure was graded subjectively and correlated with MNT values. Synovitis and osteoarthritis were induced arthroscopically in the middle carpal joint of 1 randomly selected thoracic limb. The opposite limb served as a sham-operated control limb. Mechanical nociceptive threshold values were recorded weekly and correlated with clinical, radiographic, and necropsy scores measured over 10 weeks. Lower MNT values corresponded with increased pain, whereas higher MNT values indicated reduced pain.

Results—A gradual increase in MNT values was detected from proximal-to-distal sites of the thoracic limbs. High MNT values were recorded for geldings and tall horses. In general, tolerance to procedure scores was positively correlated with overall pooled MNT values within each thoracic limb. From 2 to 6 weeks after surgery, the osteoarthritic limb had significantly reduced MNT values within the carpal region. The osteoarthritic limb also had significant changes in clinical examination, radiographic, and necropsy scores, which were poorly correlated with MNT values.

Conclusions and Clinical Relevance—Pressure algometry provided objective assessment of nociception of the thoracic limb; however, MNT values were poorly correlated with clinical variables used to assess osteoarthritis.

Full access
in American Journal of Veterinary Research

Abstract

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)

Full access
in American Journal of Veterinary Research