Equine Veterinary Journal最新文献

Background: Musculoskeletal injuries (MSI) are a major concern in the horse racing industry, often leading to career-ending outcomes. Contributing factors include conformation, limb and joint defects, hoof structure, age, and hard track surfaces.

Objectives: This study aimed to evaluate the distribution of MSI in Thoroughbred and Arabian racehorses during racing and training, categorised by breed and track surface.

Study design: Retrospective cohort study.

Methods: The data from 2018 to 2023 were collected at the Turkish Jockey Club's Şirinyer Hippodrome (38°23'03.7″ N 27°09'01.0″ E), covering 553 MSI cases. The distribution of MSI, categorised by track surface and race/training, was evaluated using a 2 × 3 Pearson chi-square analysis and a post hoc Z-test. MSI occurrences during racing and training were examined based on breed and track surface by gender, age, category, location, and impact on the horses' racing career, was calculated using descriptive statistical indicators such as frequency and percentage.

Results: The majority of MSI occurred between June and September, the summer and dry period in the northern hemisphere. The 553 MSI cases included 45.3% fractures, 40.3% tendon injuries, 9.8% bone fissure. Distribution of MSI occurring during races and training according to track surface in Thoroughbred and Arabian horses had significant differences (p < 0.0001). Among Thoroughbreds, injuries were most common at 2- and 3-year-old, while in Arabians, they were most frequent at 3- and 4-year-old. The highest prevalence of MSI occurred in the forelimbs during racing, affecting 91.3% of Thoroughbreds and 92.7% of Arabians, with a particular focus on the carpal joint and its distal structures. MSI ended the racing careers of 66.3% of Thoroughbreds and 46.4% of Arabians.

Main limitations: This study relied on routinely recorded hospital data.

Conclusions: Fractures predominated in Thoroughbreds, particularly on dirt tracks, while tendon injuries were common in Arabians across both surfaces. Findings indicate the need to improve track maintenance and training practices to support racehorse welfare and longevity.

Background: Obesity has been associated with human obstructive sleep apnoea and canine brachycephalic obstructive airway syndrome. The effect of body condition score (BCS) on structures of the oropharynx, nasopharynx and upper airway of the horse has not been investigated.

Objectives: To investigate the effect of BCS on tongue measurements, soft palate angle and basihyoid depth in horses.

Study design: Retrospective, analytical, cross-sectional.

Methods: Computed tomographic (CT) images of the head of 58 horses were assessed. DICOM viewing software was used to measure head length, basihyoid-skin depth, soft palate angle (SPA), midline tongue area, dorsoventral height (DVH) of the tongue in two locations and head angle. BCS were assigned during CT examinations. Associations between measurements were tested and following initial calculations, further associations with tongue measurements as a ratio of head length were assessed.

Results: For initial measurements, 44 horses met the inclusion criteria. Addition of head length ratios to tongue measurements resulted in 24 of 44 horses meeting the inclusion criteria for the second set of calculations. Increased BCS led to an increased mean SPA (mean difference = 2.56 ${}^{°}$ ; p = 0.02) and increased median basihyoid depth (mean difference = 0.246 cm; p = 0.006). Following adjustments made for the effect of head length on tongue measures, significant correlation was identified between SPA and tongue area (Spearman's r = 0.544; p = 0.007); SPA and DVH of the tongue at the level of the hard palate (Spearman's r = 0.562; p = 0.004) and SPA and DVH of the tongue at the lingual process of the basihyoid bone (Spearman's r = 0.690; p < 0.001). No significant correlation was identified between variables and sex.

Main limitations: The sample size was small and the effect of breed on measures was not studied. Measurements were acquired on a single sagittal CT plane. The investigator collecting CT measures was not blinded to BCS. All horses were sedated for the CT procedure which may have affected measures obtained.

Conclusions: Increased BCS increases SPA and basihyoid bone depth. Increases in tongue size measurements increase SPA. Results from this study warrant further investigation into the clinical significance of the effects of BCS on the upper airways of the horse.

Biological variation in laboratory results refers to physiological fluctuations that occur around a homeostatic setpoint (HSP) for various laboratory measurands. Assessment of biological variation includes determining individual variation (CV_I), group variation (CV_G), and analytical variation (CV_A). Reference change value (RCV) is an objective tool for an evidence-based approach to interpret data by assessing the significance of consecutive results in an individual for the diagnosis, prognosis, and monitoring of disease. The individualised reference intervals (iRI) are derived from the determination of the HSP for an individual and the RCV. Evaluation of dispersion (DI) of results around any numerical result, reference interval limit, or recommended cut-off value can help define grey zones in clinical data interpretation. The Index of Individuality (II), which compares the amount of biological variation in a group (CV_G) relative to the amount of biological variation in an individual (CV_I), is useful to determine if 95% population-based or iRI would be more valuable to detect a significant change in a measurand. The critical number of specimens provides confidence in a defined probability needed for the estimation of the HSP for laboratory measurands. Biological variation data may help support or disprove empirically derived or consensus-derived interpretation recommendations. Biological variation data has the potential to improve the diagnostic accuracy of clinical laboratory testing. Examples of these applications are included.

Background: In orthograde endodontic treatments, different methods are available to debride the pulp canals of endodontically compromised equine cheek teeth, but their efficacy is unknown.

Objectives: To explore and compare the efficacy and anatomical changes caused by manual versus reciprocating filing techniques in equine cheek teeth, to explore the presence of instrumentation mishaps described in human dentistry and to explore anatomical complexities of the pulp cavity that often remain uninstrumented using microcomputed tomography (μCT).

Study design: Ex-vivo randomised experiments.

Methods: Twenty-two extracted healthy equine cheek teeth were randomised into two groups: debridement with nickel-titanium (Ni-Ti) manual H-files and debridement with Ni-Ti reciprocating K-files. All canals of all teeth were instrumented by a single clinician and μCT scans made before and after instrumentation were digitally analysed to compare the change in pulp volume, loss of dental material, percentages of instrumented pulp canal wall at three levels, instrumentation times and instrumentation mishaps between both techniques. The data were analysed using either an Independent samples T-test or Mann-Whitney U-test with p < 0.05 denoting a statistically significant difference.

Results: The use of reciprocating files resulted in a statistically significant advantage at apical levels when it comes to the percentage of instrumented root canal surface (p < 0.01; reciprocating mean 12% ± 6; manual mean 3% ± 3). No other significant differences were found between the methods. Instrumentation mishaps were detected in this study and were equally distributed between the two groups. Frequently uninstrumented regions consisted of intercanal communications, root canal branches, narrow corners of pulp canals and branches of pulp horns.

Main limitations: Convenience sample, use of healthy cheek teeth, ex vivo debridement.

Conclusions: The debridement efficacy in equine cheek teeth is generally poor with a slight apical advantage using reciprocating instruments. Instrumentation mishaps should be kept in mind when performing endodontic procedures in the equine patient.

Background: Noseband adjustment should avoid discomfort and allow some jaw movement.

Objectives: To determine pressure beneath a cavesson noseband at five tightness levels during standing and chewing. It was hypothesised that increased noseband tightness is associated with increases in nasal and mandibular pressures while standing and chewing, accompanied by increases in eye temperature and blink rate.

Study design: Experimental.

Methods: Eight highly-trained dressage horses wore a snaffle bridle with their own bit. Pressure mats over the nasal bones and beneath the mandibular rami recorded sub-noseband pressures (50 Hz) for five tightness levels (2.0, 1.5, 1.0, 0.5, 0.0 finger-equivalents from loosest to tightest) measured using a taper gauge during quiet standing and chewing a treat. Eye temperature and blink rate were recorded synchronously. Data were analysed using Friedmans two-way ANOVA with Wilcoxon post hoc tests and Bonferroni adjustment for repeated measures. Significance level p ≤ 0.01.

Results: During standing, total force increased from (mean ± SD) 5.8 ± 4.4 N (nasal) and 12.3 ± 8.2 N (mandibular) at 2.0 finger-equivalents to 45.1 ± 24.9 N (nasal) and 70.7 ± 25.7 N (mandibular) at 0.0-finger-equivalents. Forces and pressures were higher on the mandibles than nasal bones although differences did not always reach statistical significance. Horses willingly ingested and chewed a treat at all noseband tightness levels generating forces ~100 N and pressure >40 kPa without increases in eye temperature or blink rate that would suggest discomfort. Post hoc tests indicated significantly higher pressure for 0.0 finger-equivalents than 2.0 finger-equivalents (p < 0.01).

Main limitations: Small sample size. Nosebands always tested from loosest to tightest.

Conclusions: Mandibular pressure exceeded nasal pressure and values at both sites increased with noseband tightness. Horses accepted high noseband pressures when chewing a treat with a cavesson adjusted from 0.0 to 2.0 finger-equivalents. Blink rate and eye temperature suggest horses were not distressed when chewing at 2.0 to 0.0 finger-equivalents tightness.

Background: The British horseracing industry is committed to reducing equine fatalities in jump racing. Race-related fatalities are a major welfare concern and threaten the sport's social licence to operate.

Objectives: To describe the risk of, and determine risk factors for, fatality in British jump racing.

Study design: Retrospective cohort.

Methods: Analyses included all starts made in British jump races between January 2010 and April 2023. Available information for each horse, race, racecourse, trainer and jockey was collated and combined with details of all fatalities recorded by official veterinary officers in a central database. A fatality was defined as any post-start veterinary event that resulted in the sudden death or euthanasia of a horse within 48 h of racing. Risk factors (n = 101) were evaluated using mixed-effects logistic regression. Data for steeplechase and hurdle starts were analysed separately.

Results: The overall fatality rate was 5.9 per 1000 steeplechase starts (n = 836/141 922; 95% CI 5.5-6.3) and 4.5 per 1000 hurdle starts (n = 1096/242 486; 95% CI 4.3-4.8). In both race types, fallers (steeplechase: OR 28.7, 95% CI 23.0-35.8; hurdle: OR 41.4, 95% CI 32.9-52.0) and older horses (steeplechase: OR 1.1 per extra year, 95% CI 1.1-1.2; hurdle: OR 1.2 per extra year, 95% CI 1.1-1.2) had higher odds of fatality. In steeplechase racing, starts made in summer (OR 1.2, 95% CI 1.0-1.5) and by non-GB trained horses (OR 2.0, 95% CI 1.4-3.0) experienced higher fatality odds. In hurdling, maiden races (OR 1.3, 95% CI 1.0-1.6) were at higher odds of fatality. In both race types, softer going decreased the odds of fatality. Approximately half of the unexplained variation in fatality odds was attributable to horse.

Main limitations: Analysis was restricted to routinely recorded race-day factors and performance history.

Conclusions: Reducing the risk of falling and racing on softer ground could substantially decrease fatalities in jump racing.