Injured Horses Research Articles

Does colonization with MRSA, ESBL - producing Enterobacteriaceae, and/or Acinetobacter baumannii - increase the risk for postoperative surgical site infection?

Evaluation of the role of indicator pathogens in equine surgical site infection (SSI) and other infection-promoting factors. Cross-sectional study. Horses presenting with an open injury or surgical colic during 1.5 years. A nasal swab and a faecal sample were collected from every patient upon admission. Furthermore, a wound swab was collected from wounds of injured horses. Details on the wounds and procedures were documented. Laparotomy incisions and injuries were monitored for signs suggesting infection. In total, 156 horses presented because of a surgical colic (n=48) or open injuries (n=108). Thirteen surgical colic patients and three injured horses did not survive beyond 24h, and four injured horses were discharged from the clinic at the day of admission. SSIs occurred in 31 (30.7%) injured horses and 11 (31.4%) horses after laparotomy. Regarding injuries, general anaesthesia increased the risk of developing a WI compared to sedation. Indicator pathogens were cultured from 29/42 SSI. In total, 10/11 infected laparotomy incisions and 19/31 injuries with SSI tested positive for multidrug-resistant pathogens (MDRPs) . Indicator pathogens were not detected at admission in any of the horses that developed incisional SSIs after laparotomy but were detected in two of the injured horses that developed SSIs. MDRPs were identified in almost 70% of the SSI. Less than 5% of the affected animals were colonized with the same pathogen before admission, indicating that colonization with MDR pathogens is only one of the crucial factors for the development of SSI. Colonization with MDRP seems not to predispose horses to MDR SSIs.

The role of DMSO and MSM in treatment of tendinopathies affection in equine: A comparative study

Superficial digital flexor tendon (SDFT) injury is a main cause of lameness in polo and racehorses inciting long-term lameness and recovery. This study aimed to compare the efficacy of topical dimethyl sulfoxide (DMSO) and Methylsulfonylmethane (MSM) on bowed tendons in horses. Ten client-owned injured horses, aged between 5-15 years with an average age of 8.5 years and weighing approximately 400-500 kg, suffering from chronic tendinitis were selected and allocated into two groups: group A (DMSO) and group B (MSM). The group A animals (n=5) were treated with 60 mL of topical 90% DMSO aqueous solution, while Group B animals (n=5) received 60 mL of topical 90% MSM aqueous solution on the bowed tendon at days 0, 7, 14, 21, 28, 35, and day 42. Clinical examinations were performed to evaluate the severity of pain and lameness grade. Ultrasound scans of the superficial digital flexor tendon were taken at days 0, 21, and day 42. Images were placed in numerical form, and the fiber alignment score of the fibers (FS) and the echogenicity score (ES) of the superficial digital flexor tendon at the maximum injury zone (MIZ) were recorded. Results showed that pain reduction and lameness significantly (P<0.05) reduced from 21d to 42d in the DMSO animals compared with the MSM animals. The echogenicity score didn’t differ between the two groups at 0d, 21d, and 42d (P>0.05) however, it was significantly declined in group A at 42d than 0d (P<0.05). Fiber alignment in group A was (P<0.01) reduced at 42d compared with group B. This study concluded that group A horses showed very effective and long-term improvements compared to the group B horses.

Artificial Microvesicles: New Perspective on Healing Tendon Wounds

Tendons have a limited capacity to repair both naturally and following clinical interventions. Damaged tissue often presents with structural and functional differences, adversely affecting animal performance, mobility, health, and welfare. Advances in cell therapies have started to overcome some of these issues, however complications such as the formation of ectopic bone remain a complication of this technique. Regenerative medicine is therefore looking toward future therapies such as the introduction of microvesicles (MVs) derived from stem cells (SCs). The aim of the present study was to assess the characteristics of artificially derived MVs, from equine mesenchymal stem cells (MSCs), when delivered to rat tendon cells in vitro and damaged tendons in vivo. The initial stages of extracting MVs from equine MSCs and identifying and characterizing the cultured tendon stem/progenitor cells (TSCs) from rat Achilles tendons were undertaken successfully. The horse MSCs and the rat tendon cells were both capable of differentiating in 3 directions: adipogenic, osteogenic, and chondrogenic pathways. The artificially derived equine MVs successfully fused with the TSC membranes, and no cytotoxic or cytostimulating effects were observed. In addition, co-cultivation of TSCs with MVs led to stimulation of cell proliferation and migration, and cytokine VEGF and fractalkine expression levels were significantly increased. These experiments are the first to show that artificially derived MVs exhibited regeneration-stimulating effects in vitro, and that fusion of cytoplasmic membranes from diploid cell lines originating from different species was possible. The experiment in vivo demonstrated the influence of MVs on synthesis of collagen I and III types in damaged tendons of rats. Explorations in vivo showed accelerated regeneration of injured tendons after introduction of the MVs into damaged areas. The results from the studies performed indicated obvious positive modifying effects following the administration of MVs. This represents the initial successful step required prior to translating this regenerative medicine technique into clinical trials, such as for tendon repair in injured horses.

Serum Phosphorylated Neurofilament Heavy Subunit Levels and its Association with the Risk for Catastrophic Injury in Thoroughbred Racehorses

Neurofilaments are structural proteins that are concentrated in the body and axons of neurons. Damage to the neurons or axons as a result of trauma or infectious diseases leads to the release of neurofilaments into blood and cerebrospinal fluid (CSF). This case-control study was carried out to compare serum levels of phosphorylated neurofilament heavy chain (pNF-H) between clinically healthy Thoroughbred (TB) horses and TB horses that suffered catastrophic musculoskeletal injuries (cMSI), and to investigate the correlation between putative risk factors and serum concentrations of pNF-H in injured horses. Blood samples were collected from clinically healthy horses and from horses that suffered cMSI. The concentration of pNF-H in serum samples was determined using the Phosphorylated Neurofilament H Sandwich enzyme-linked immunosorbent assay kit. A total of 343 horses were enrolled in the study (148 cases and 195 controls). The median serum concentration of pNF-H for controls was 0.0 ng/ml and for cases was 0.07 ng/ml. No significant difference was observed between the 2 groups in racing. The number of lifetime starts was correlated with serum pNF-H concentration in case horses. The serum concentration of pNF-H was higher in case horses that experienced cMSI while training than while racing. The number of lifetime starts is a proxy measure for several risk factors related to cumulative exercise load during the career of racehorses. Measurement of serum concentrations of pNF-H in TB racehorses does not support the hypothesis that subclinical neurologic injury or conditions are associated with catastrophic injury of TB racehorses.

Effect of lactic acid addition to equine whole blood on platelet aggregation measured by impedance aggregometry

Acidemia in sick or injured horses is often due to lactic acid accumulation. Alterations in platelet function and hemostasis are among numerous deleterious effects caused by decreased physiologic pH. We aimed to evaluate the effect of hyperlactatemia and resultant acidemia on platelet aggregation in equine whole blood using impedance aggregometry. Platelet aggregation was measured using the Multiplate analyzer in whole blood from 34 healthy horses at baseline and after in vitro addition of lactic acid to adjust the pH. Platelet aggregation of each sample was quantified by the area under the curve measurement reported by the Multiplate system. The association between platelet aggregation and pH was analyzed using a linear mixed-effects model. The association of baseline platelet aggregation with hematocrits (Hcts), white blood cell (WBC) counts, and platelet counts was evaluated using Pearson's correlations. There was a significant association between acidemia and decreased platelet aggregation. No significant correlations were detected between platelet aggregation and Hct, WBC count, or platelet count. Platelet aggregation measured in healthy horses using the Multiplate analyzer showed substantial variation between animals. Acidemia caused by the addition of lactic acid to equine whole blood was associated with a mild though statistically significant decrease in platelet aggregation. In conjunction with other factors, this change may contribute to morbidity-related disorders of hemostasis, although its precise clinical relevance is uncertain.

Using Short Term of High Power Laser Therapy in Horse's Tendon Injuries.

High-power laser therapy has been used as a treatment to cure sports injuries; however, there are no controlled standardized studies on its efficacy. Moreover, high-power laser therapy has been applied for the sport horses field. This study aimed to investigate whether high-power laser therapy can cure tendon disorders and reduce the pain in tendon lesions in injured horses and also to examine the effect of laser therapy on injured horses. This retroactive experiential clinical research was performed on50 racing horses between 5 and 15 years old. They were diagnosed with neither superficial digital flexor tendon nor deep digital flexor tendon injuries of the suspensory ligament on either hind or front limbs and were medicated with a high-power laser. The high-power laser was used with a maximum output power of 15000 MW and therapeutic effects were assessed using lameness graded and ultrasound the day after laser therapy (week 2) and 4weeks later (week 6). Results showed that laser treatment was effective and uncomplicated in all injured horses. In addition, significant improvement was observed in ultrasound scores and lameness following high-power laser treatment. There was a progressive correlation between the improvement of lameness and the following parameters; returning tendon survival, normality of tendon tissue and functions in rest, trot, or competition after treatment. According to the results, laser treatment is a good way to eliminate the complications caused by tendon damage.

A Static Bioimpedance and Dynamic Acoustic Myography Preliminary Assessment of Low Frequency Therapeutic Ultrasound Treatment of the Shoulder Muscle Trapezius: An Equine Study

Background: In horses, therapeutic ultrasound has been shown to be beneficial for suspensory ligament injuries, and more generally to stimulate tissue repair and reduce localized pain. However, it has yet to be examined in relation to soft tissue injuries sustained during competition or in connection with rider/saddle interactions. Aim: The aim of the present study was to examine the efficacy of topical low-frequency therapeutic ultrasound on the shoulder muscles of injured horses. Methods: Muscle mass and cellular health was assessed for M. trapezius using non-invasive multi-frequency bioimpedance, and dynamic improvements in M. trapezius and M. latissimus dorsi were examined using acoustic myography (AMG). A total of 8 injured horses (painful to palpation and atrophied) were treated using an EQ Pro Therapy unit, following a set protocol that comprised treatment every other day for 10 treatments. Pre-treatment values were then compared with post-treatment measurements (1 & 6 months later). Results: The mfBIA results for M. trapezius showed a significant improvement (P 0.05) of EQ Pro Therapy treatment for the membrane capacitance (Mc) and phase angle (PA) parameters when comparing the Pre vs Post 1 and Post 1 vs Post 2 measurements. Similar improvements were seen for the AMG measurements for M. trapezius and M. latissimus dorsi where statistically significant improvements in the muscle efficiency (E-score) and temporal summation (T-score) as well as the spatial summation (S-score) and mean of the ST-scores were noted (P 0.05 to P 0.01). Conclusion: The present findings suggest that EQ Pro Therapy treatment is efficacious in terms of equine cases involving soft tissue shoulder muscle injuries (painful to palpation and atrophied). The main improvements noted were not only increased muscle mass and cellular health but also improved force production, better coordination, and lateral balance, which persisted for at least six months after treatment.

Racing performance after surgical repair of medial condylar fracture of the third metacarpal/metatarsal bone in thoroughbred racehorses.

To report the performance of thoroughbred racehorses after surgical repair of a medial condylar fracture of the third metacarpal/metatarsal bone. Retrospective cohort study. Forty-three horses surgically treated for medial condylar fractures, 30 with previous racing experience, 13 without previous racing experience (nonexperienced). Medical records (2009-2017) were reviewed for signalment, radiographic fracture characteristics, repair technique, and postoperative morbidity and mortality. Each experienced horse was matched with two horses randomly selected from its most recent race to serve as healthy controls. Racing performance parameters (race rating, competitive level, speed rating, performance index) and career racing statistics were compared with multiple regression models between injured experienced horses and controls. The career racing statistics for nonexperienced horses were evaluated. Reasons for nonreturn to racing were obtained. The median duration of follow-up was 6 years (minimum 2, maximum 10). Twenty-one of 43 (49%) horses raced again as well as 18 of 30 (60%) experienced horses and three of 13 (23%) nonexperienced horses. Experienced horses were five times more likely than nonexperienced horses to return to racing (95% confidence interval = 0.07-0.58, P = .003). Higher preoperative racing performance parameters were associated with return to racing. Racing performance parameters were lower after the date of fracture in injured horses compared with controls. Experienced horses were more likely to return to racing after medial condylar fracture repair, although their performance was generally lower than that of comparably uninjured horses. Owners should be aware that horses with medial condylar fractures likely will race at a lower level than their uninjured peers.

Revisiting predictive biomarkers of musculoskeletal injury in thoroughbred racehorses: longitudinal study in polish population

BackgroundHigh prevalence of musculoskeletal disorders in racehorses and its impact on horse welfare and racing economics call for improved measures of injury diagnosis and prevention. Serum biomarkers of bone and cartilage metabolism have previously shown promise in prediction of musculoskeletal injuries in horses. This study aimed to re-evaluate usability of the predictive serum biomarkers identified in North American Thoroughbred racehorses in a geographically distinct group of Polish Thoroughbreds.ResultsSerum concentrations of bone and cartilage biomarkers: osteocalcin, c-terminal telopeptide of type I collagen, total glycosaminoglycans (GAG), chondroitin sulfate epitope and c-propeptide of type II procollagen (CPII) were evaluated in the beginning and the next 3 months of one racing season in a cohort of twenty-six 2-year-old Polish racehorses. Exit criteria were diagnosis of musculoskeletal injury, leading to > 5 days off training (n = 8), or completion of 3 study months with no training interruptions (n = 18). Normalized results and matching archival data from 35 2-year-old North American racehorses was used for logistic regression analysis to identify universal predictors of injury. Mean GAG and CPII levels were lower in injured group comparing to control, which is consistent with previous findings in racehorses. These biomarkers were also identified as predictors of injury in the mixed population model. Population origin had no significant effect on predictive value of evaluated biomarkers (Wald test p = 0.137). Decreased osteocalcin and increased c-terminal telopeptide of type I collagen levels in injured horses comparing to controls were specific for Polish population and signalized disruption in bone turnover homeostasis.ConclusionsChanges in serum GAG and CPII in racehorses at risk of injury appear to be similar across distinct populations while dynamics of serum bone marker is more population-specific.

Radiographic Comparison of Carpal Morphometry in Thoroughbred and Standardbred Race horses

Carpal conformation is thought to contribute to the frequency of carpal pathology so non-invasive measurement of carpal morphometry would be useful to identify joints at risk. However, there are scant radiographic morphometrical details for the carpals of Thoroughbred (TB) and Standardbred (SB) racehorses even though these breeds differ in the incidence of carpal damage. This study aimed to identify morphometrical similarities and differences in carpal conformation in TB and SB. Thirty carpal dorsopalmar radiographs (DP) were collected from 15 TB and 15 SB. All DP radiographs were at zero degrees or within the acceptable range of rotation. Twelve carpal radiographic parameters were selected and measured on each radiograph. Statistical analysis found significant differences in four carpal parameters. These parameters revealed that the middle carpal joint in SB was significantly more angled distomedially whereas the radial distal metaphysis showed a greater distolateral inclination in TB. The radiocarpal and the carpometacarpal articulations exhibited common features in the two groups of horses. These carpal traits in TB and SB highlight their potential association with loading distribution and pathology. Measuring carpi from untrained and injured horses is necessary to establish breed specific features for the ideal carpal conformation in each of these breeds.

Replacing injured horses, cross-dressing and dust: modernist circus technologies in Asia

Horse performers were replaced by machines demonstrating the wonders of electricity and cinema on the third circus tour of Asia by the well-known equestrian, Clarke family in 1915. Circus was part of the wider economic shift away from equine capital. The analysis considers leading horse acts in early modernist circus and their continuing popularity with the multi-racial Asian audiences, in relation to technological change and the socio-economic legacies of European colonial dominance in Asia. Four out of six horses died on the Clarke’s first tour of colonial Asia, an exceptionally high mortality rate and three died on the second tour, and this article argues that a high rate of horse injury and mortality complicates a claim that the shift to scientific display in the 1915 entertainment was simply reflecting progressive modernisation or the shortage of horses at the beginning of World War One. While the 2015 replacement of horses provides a literal demonstration of the scientific shift from horse power to electric power during the modernist (anthropocene) era, it additionally prefigures the displacement of the live animal with filmed imagery in entertainment. International ship travel continued to hold considerable physical risk for the horse performers, which meant it posed economic risks for the circus aesthetic.

Prevalence and risk factors for overweight horses at premises in Sweden assessed using official animal welfare control data.

BackgroundThere are Swedish animal welfare regulations concerning the body condition of horses and general advice on keeping horses including that horses should be fed so that they do not become over- or underweight relative to their use. Compliance is assessed by official animal welfare inspectors. The objective of this study was to determine whether the national animal welfare control database could be used to estimate the prevalence and risk factors for overweight horses in Sweden. The official animal welfare control checklist for horses contains 45 checkpoints (CP) of which CP-8 pertains to the acceptability of the horses’ body condition including whether they were under- or overweight. Prevalence of non-compliance with CP-8, with 95 % confidence intervals (CI), were calculated for the years 2010–2013. Associations between risk factors and non-compliance for overweight body condition were estimated using logistic regression and expressed as odds ratios (OR) with 95 % CIs.ResultsOf 7870 premises with registered horses that were inspected against CP-8, a total of 63 premises had non-compliant inspections due to overweight horses (0.80 %; CI 0.62, 1.02 %). In multivariable analyses, premises that were non-compliant with requirements for the care of sick or injured horses (OR 3.52; CI 1.51, 8.22) or with the requirements for feeding a balanced high-quality diet (OR 5.15; CI 2.49, 10.67) had greater odds of having overweight horses. Premises that also kept other species for meat production were more likely to have overweight horses (OR 2.12; CI 1.18, 3.81) whereas professional horse establishments were less likely (OR 0.09; 0.01, 0.64). Overweight horses were more likely in summer compared to winter (OR 2.18; CI 1.02, 4.70). Premises in regions of Sweden with more horses in relation to the human population were less likely to have overweight horses (OR 0.97; CI 0.95, 1.00).ConclusionsOfficial animal welfare control data may be used to monitor the premises prevalence of overweight horses in Sweden. Strategies to reduce the prevalence of overweight horses should focus on education about equine care and nutrition, especially summer grazing.Electronic supplementary materialThe online version of this article (doi:10.1186/s13028-016-0242-3) contains supplementary material, which is available to authorized users.

Regional Limb Perfusion Of The Equine Distal Limb With Stem Cells: Lessons Learned From In Vivo Tracking Of Tc99m-HMPAO Labeled Cells

Regional Limb Perfusion Of The Equine Distal Limb With Stem Cells: Lessons Learned From In Vivo Tracking Of Tc99m-HMPAO Labeled Cells

384 ISOLATION OF MESENCHYMAL STEM CELLS FROM WHARTON'S JELLY, CORD BLOOD, AND AMNIOTIC FLUID IN THE HORSE

The effect of orthopedic injuries on the health of racehorse and racing financials can be dramatic. Bearing this in mind, there is naturally a great interest in new possible treatments for orthopedic injuries. In this study we evaluated equine amniotic fluid (AF), cord blood (CB), and Wharton’s jelly (WJ) as alternative sources of primitive, multipotent stem cells. All chemicals were obtained from Sigma-Aldrich (St. Louis, MO, USA) unless otherwise stated. Samples were recovered at labor from 7 standardbred mares with ages between 6 and 15 years. Wharton’s jelly was incubated with collagenasis at 37°C for at least 2 hr. The resulting cell suspension was centrifuged, and the cell pellet was resuspended in culture medium (DMEM and TCM-199, 1:1) plus 10% FBS (GIBCO®, Invitrogen Corporation, Carlsbad, CA, USA), 100 IU mL-1 penicillin, and 100 μg mL-1 streptomycin). Amniotic fluid and CB were diluted 1:1 in PBS medium supplemented with antibiotic solution and centrifuged for 15 min at 300 x g. The pellet was resuspended in 5 mL of culture medium, placed on 5 mL of 70% Percoll solution, and centrifuged at 1200 x g for 30 min. The interface layer was then aspirated and resuspended in culture medium. All the cell lineages were washed seeded into 25 cm2 flasks and cultured in a 5% CO2 incubator at 38.5°C. Medium was refreshed after 48 h and then twice a week. Adherent fibroblast-like cells were tested for their differentiation potential at passage 3. Chondrogenic differentiation was performed using a micromass culture technique, whereas osteogenic differentiation was induced in monolayer culture (Mizuno H and Hyakusoku H 2003 J. Nippon Med. Sch. 70, 300-306). Evidence for differentiation was made via morphological, biochemical, and cytological evaluations. Sample volume was 15-55 mL for AF, 10-60 mL for CB, and 5-12.6 g for WJ. In 4 out of 6 (66.7%) AF, 5 out of 5 (100%) CB, and 6 out of 7 (85.7%) WJ samples, colonies with the classical mesenchymal stem cell (MSC) morphology of adherent fibroblastoid spindle-shaped cells growing in a monolayer were observed. Undifferentiated cells have been passaged up to 8 times, population-doubling times (DT) were calculated for a subset of cell passages, and data were analyzed by ANOVA (Statistica for Windows, Stat Soft Inc., Tulsa, OK, USA). In all samples, there were no significant differences (P &gt; 0.05) between DT of all passages. The DT was greater (P &lt; 0.05) forCB (2.6 ± 1.3 d) than for AF (2.1 ± 0.8 d) and WJ (1.9 ± 0.5 d). By passage 8, the cells had undergone 39.1 ± 1.2 cell-doubling numbers in AF, 35.1 ± 2.7 in CB, and 37.4 ± 2.0 in WJ. A spheroid structure and positive Alcian blue staining of matrix glycosaminoglycans illustrated chondrogenesis. Cellular morphology and positive von Kossa staining, as well as alkaline phosphatase activity, confirmed osteogenesis. Based on the results obtained, WJ, CB, and for the first time in the horse, AF represent alternative sources of stem cells. Their differentiation into osteocytes and chondrocytes demonstrated that equine MSC from these samples can be induced to form multiple cell types, which underlies their value for regenerative medicine in injured horses.

Nonsteroidal anti‐inflammatory agents and musculoskeletal injuries in Thoroughbred racehorses in Kentucky

Injuries sustained by horses during racing have been considered as an unavoidable part of horse racing. Many factors may be associated with the musculoskeletal injuries of Thoroughbred race horses. This study surveyed the amounts of nonsteroidal anti-inflammatory agents (NSAIDs) in injured horse's biological system (plasma) at Kentucky racetracks from January 1, 1995 through December 31, 1996. During that period, there were 84 catastrophic cases (euthanized horses) and 126 noncatastrophic cases. Plasma concentrations of NSAIDs were determined by High Performance Liquid Chromatography in injured and control horses. The possible role of anti-inflammatory agents in musculoskeletal injuries of Thoroughbred race horses was investigated by comparing the apparent concentrations of NSAIDs in injured horses to concentrations in control horses. The plasma concentrations of phenylbutazone and flunixin were higher in injured horses than in control horses. Most injured and control horses did not have a detectable level of naproxen in their plasma samples. Further studies must be carried out to determine whether horses with higher plasma concentrations of NSAIDs have an altered risk of musculoskeletal injuries compared with other horses.

Regulatory considerations related to stem cell treatment in horses

Vet Med Today: Veterinary Medicine and the Law 1657 H owners, veterinarians, and the equine industry in general are constantly searching for new and more effective treatments for injured horses. Stem cell treatment may offer such an alternative to current treatments, and initial reports suggest that stem cell treatment may be effective for a variety of injuries, including tendon and ligament injuries, in horses and may shorten recovery times and reduce the overall risk of further injury. Not surprisingly, therefore, the use of stem cell treatment in horses has gained considerable ground in recent years. To date, neither the US FDA nor the USDA, the federal agencies responsible for regulation of veterinary treatments and products containing cellular and tissue material, has promulgated regulations specifically governing the practice of veterinary stem cell treatment in the United States. Nevertheless, current laws do provide these agencies the authority to exercise regulatory control over stem cell treatment, and it is possible to predict how equine stem cell treatment might be regulated in the future on the basis of how the FDA currently regulates human cellular and tissue products and veterinary drugs and how the FDA and USDA currently regulate veterinary biologics. The present article provides a brief overview of equine stem cell treatment, offers thoughts on how the practice may be federally regulated in the future, and analyzes the potential impact of such regulations on practicing veterinarians.

Equine umbilical cord blood contains a population of stem cells that express Oct4 and differentiate into mesodermal and endodermal cell types

Mesenchymal stem cells (MSCs) offer promise as therapeutic aids in the repair of tendon, ligament, and bone damage suffered by sport horses. The objective of the study was to identify and characterize stem-like cells from newborn foal umbilical cord blood (UCB). UCB was collected and MSC isolated using human reagents. The cells exhibit a fibroblast-like morphology and express the stem cell markers Oct4, SSEA-1, Tra1-60 and Tra1-81. Culture of the cells in tissue-specific differentiation media leads to the formation of cell types characteristic of mesodermal and endodermal origins. Chondrogenic differentiation reveals proteoglycan and glycosaminoglycan synthesis as measured histochemically and Sox9 and collagen 2A1 gene transcription. Osteocytes capable of mineral deposition, osteonectin and Runx2 transcription were evident. Hepatogenic cells formed from UCBs express albumin and cytokeratin 18. Multinucleated myofibers that express desmin were observed indicating partial differentiation into mature muscle cells. Interestingly, conventional human protocols for UCB differentiation into adipocytes were unsuccessful in foal UCB and adult horse adipose-derived MSC. These results demonstrate that equine UCB can be induced to form multiple cell types that underlie their value for regenerative medicine in injured horses. In addition, this work suggests that subtle differences exist between equine and human UCB stem cells.

Association of high-speed exercise with racing injury in Thoroughbreds

To determine the association between high-speed exercise and risk of injury while racing among Thoroughbreds in Kentucky. Matched case-control study. 206 Thoroughbreds that sustained a musculoskeletal injury while racing and 412 Thoroughbreds that were not injured during the same races. Data regarding official timed workouts and races and the Beyer's numbers for the 3 races before the race during which injury occurred were extracted from past performance charts and compared between injured horses and control horses. For injured horses, cumulative distance of high-speed exercise during the 1- and 2-month periods prior to the race in which injury occurred was significantly less than that of control horses; for either period, a difference of 10 furlongs was associated with approximately 2-fold greater risk of injury. Beyer's numbers were significantly higher for injured horses than for control horses. These effects remained significant after adjusting for age and results of prerace physical inspection. In Kentucky, injured horses had significantly less cumulative high-speed exercise than did control horses during the 1- and 2-month periods prior to the race in which injury occurred. These results differ from those observed in California. The association of injury with cumulative high-speed exercise appears to vary among regions in the United States.

Frequency of musculoskeletal injuries and risk factors associated with injuries incurred in Quarter Horses during races

Objective To determine the frequency and anatomic location of musculoskeletal injuries incurred by Quarter Horses during races and to compare data from injured horses and matched control horses. Design Matched case-control study. Animals 97 Quarter Horses that sustained a musculoskeletal injury during races and 291 horses from the same races that were not injured. Procedure Data examined included racing history, race-entrant characteristics, racing events determined by analysis of videotapes of races, and, when performed, results of prerace physical inspections. Data for injured horses were compared with data for control horses, using conditional logistic regression. Results Incidence of a catastrophic injury among Quarter Horses during races was approximately 0.8/1,000 race starts, whereas incidence of musculoskeletal injury during racing was approximately 2.2/1,000 race starts. Odds of musculoskeletal injury were approximately 8 times greater among horses assessed to be at increased risk of injury on the basis of results of prerace physical inspection than for horses not considered to be at increased risk of injury. Evidence was lacking that 2-year-old horses were at increased risk of injury or that sex influenced the risk of injury among Quarter Horses during races. Conclusions and Clinical Relevance Incidence of racing injury among Quarter Horses appears to be lower than that observed among Thoroughbreds. Regulatory veterinarians can identify horses at increased risk of injury on the basis of prerace physical inspection, indicating that these inspections could be used to reduce the risk of injury during races. (J Am Vet Med Assoc 1999;215:662–669)

Racing-related factors and results of prerace physical inspection and their association with musculoskeletal injuries incurred in Thoroughbreds during races

Objective— To describe and compare data from Thoroughbreds that sustained musculoskeletal injuries while racing with data from matched control horses. Design— Matched case-control study. Animals— 216 Thoroughbreds that sustained a musculoskeletal injury while racing and 532 horses from the same races that were not injured. Procedure— Data regarding racing history, race-entrant characteristics, racing events determined by analysis of videotapes of races, and results of prerace physical inspections were determined for all horses. Injured horses were compared with control horses by using conditional logistic regression. Results— Results of prerace inspection by regulatory veterinarians were significantly associated with injury. Odds of musculoskeletal injury, injury of the suspensory apparatus of the forellmb, and injury of the tendon of the superficial digital flexor muscle of the forelimb were 5.5 to 13.5 times greater among horses assessed to be at increased risk of injury by regulatory veterinarians on the basis of results of prerace inspection than for horses not considered to be at increased risk of injury. Odds of an abnormal finding in the suspensory ligament during prerace inspection were 3.4 times greater among horses that injured the suspensory apparatus than among control horses, and odds of an abnormal finding in the tendon of the superficial digital flexor muscle during prerace inspection were 15 times greater among horses that njured the tendon than among control horses. Clinical Implications— Regulatory veterinarians can identify horses during prerace physical inspection that have an increased risk of injury during races. Prerace physical inspections could be used to reduce the risk of injury to Thoroughbreds during races. (J Am Vet Med Assoc 1997;211:454–463)