Equine Veterinary Journal最新文献

Background: Remifentanil and xylazine are used as continuous infusions to facilitate standing surgery in horses. Their use for this purpose has not been reported in donkeys.

Objectives: To evaluate the behavioural, sedative, and cardiorespiratory effects of continuous intravenous infusion of remifentanil and xylazine in donkeys.

Study design: Non-blinded in vivo experiments.

Methods: Ten donkeys were sedated with an intravenous bolus of xylazine (0.8 mg/kg). After 3 min, continuous infusions of xylazine (0.65 mg/kg/h) and remifentanil (6 μg/kg/h) were administered for 60 min. Cardiorespiratory physiological parameters, rectal temperature, gastrointestinal motility, and sedation and ataxia scores were evaluated by a simple descriptive scale at M0 (baseline) and every 5 min, up to M60 (60 min), with scores 0-3. Head height concerning the ground was also evaluated. Dunnett and Friedman statistical tests (p < 0.05) were used.

Results: Heart rate (p = 0.049) and respiratory rate (p = 0.001) decreased significantly at M10 and M5, respectively, compared to M0. There was a significant decrease in systolic (p = 0.04), mean (p = 0.02), and diastolic (p = 0.03) blood pressure at M15 compared to M0. The capillary refill time at M20 was statistically different (p = 0.001) from M0. The head height in relation to the ground reduced significantly from M5 (p = 0.001) to M60. Satisfactory sedation was obtained from M15 to M60. After stopping the infusion, all donkeys recovered successfully (7.1 ± 2.4 min). No adverse effects were observed during and after the infusion.

Main limitations: No painful stimulus or surgical procedure was performed.

Conclusions: Combining remifentanil and xylazine at the doses used caused adequate sedation and short recovery time. Remifentanil did not cause excitation in the donkeys. Future studies are necessary to test the protocol with painful stimuli.

Background: Race-related injuries in horse racing, especially those requiring extended recovery, are a welfare concern and threaten the sport's social licence. Previous studies predominantly report on fatalities; however, serious non-fatal musculoskeletal injuries often end horses' racing careers or have a high recurrence risk. No recent studies have described or quantified long-term injuries (LTIs) in racing Thoroughbreds, which is essential to inform targeted risk prevention strategies.

Objectives: To describe the types, frequencies and incidences of LTIs in British jump racing.

Study design: Retrospective cohort.

Methods: Analyses included all starts made in British hurdle and steeplechase races between 1 May 2018 and 30 April 2024. An LTI was defined as any non-fatal musculoskeletal injury incurred during racing, following which the horse had a minimum 90-day break from racing. LTIs were described by clinical diagnosis(es), body region(s) and anatomical structure(s) affected. Incidence per 1000 starts was calculated overall, by race type and year. Stratified incidence rates were calculated for selected injury types by age, sex, season, going and faller status.

Results: There were 918 LTIs recorded in 898 horses. The overall incidence of LTIs was 5.5 per 1000 jump starts (95% CI 5.2-5.9), with 5.2 per 1000 hurdle starts (95% CI 4.8-5.7) and 6.0 per 1000 steeplechase starts (95% CI 5.4-6.7). Tendon and ligament injuries (TLIs) were the most common, accounting for 72.9% of LTIs in hurdle starts and 70.6% in steeplechase starts. Firmer going, summer and falling in a race were associated with a higher LTI incidence.

Main limitations: Classification of LTIs commonly relied upon presumptive diagnoses.

Conclusions: The incidence of LTIs was higher in steeplechase than hurdle starts, and TLIs are an important cause of morbidity in British jump racehorses. This study provides a benchmark for ongoing LTI surveillance in jump racing, against which to monitor the effects of future interventions.

Background: Non-linear equine electrocardiography (ECG) analysis is an actively developing study area which has the potential to lead to novel, artificial intelligence-based diagnostic tools in equine cardiology. As more ECG recording devices are becoming available, there is a need to ensure results are interchangeable regardless of the equipment used to record the equine ECG.

Objectives: To evaluate the agreement of ECG complexity values obtained using the Televet™ and Equimetre™ systems.

Study design: Cross-sectional clinical.

Methods: ECGs were recorded using two devices simultaneously from 37 healthy Thoroughbred horses during routine training. An automated algorithm extracting the ECG segments of acceptable quality extracted 60-second strips with a stable heart rate in the range 30-100 beats per minute. Threshold-crossing, beat detection, and feature detection coarse-graining algorithms were used to annotate the ECG for complexity analysis. Complexity values were corrected to the heart rate using data from 37 horses, and inter-device agreement was evaluated using Bland-Altman plots and Student's t-test using ECG data from 28 horses that provided sufficient data from both devices.

Results: The results of complexity analysis obtained with beat detection coarse-graining were independent of the device used at all heart rates. The results obtained with feature detection for heart rates below 75 beats per minute (bpm) and with threshold crossing for heart rates above 75 bpm were significantly different.

Main limitations: The study relied on convenience sampling, and data analysis was constrained by the availability of ECG data in the heart rate range of interest.

Conclusions: The accurate comparison of ECG complexity analysis results requires consideration of differences between recording devices, heart rates and ECG coarse-graining techniques.

Background: Subjective lameness evaluations are critical components of equine musculoskeletal health assessments. Objective approaches can supplement diagnosis and may be preferred for specific cases and scientific purposes.

Objectives: Evaluate agreements between subjective evaluation of two veterinarians and standard clinical interpretations from outputs of an AI-based smartphone application (Sleip; AI-SPA), the inertial measurement unit (IMU) system Equinosis Q Lameness Locator (LL), and the IMU system Equisym (ES).

Study design: In vivo experiment.

Methods: Twenty-five research horses (10-30 years) were evaluated on a straight-line trot. Limbs were independently graded and converted to an ordinal scale that, for objective systems, were converted from system-specific data outputs. Default settings and outputs for AI-SPA and LL were utilised to grade lameness while a manual process was developed for the ES. Pairwise agreement was calculated via weighted Cohen's κ, and agreement across rater types was calculated via Gwet's Agreement Coefficient 2 (GA2).

Results: Objective evaluator agreement (GA2 = 0.84, 95% Confidence Interval (CI): 0.77-0.91) was higher than subjective evaluator agreement (GA2 = 0.73, 95% CI: 0.63-0.83) across all limbs. For all five evaluators/systems, overall forelimb agreement (GA2 = 0.82, 95% CI: 0.69-0.95) was greater than overall hindlimb agreement (GA2 = 0.73, 95% CI: 0.59-0.87). Pairwise agreement scores between the objective systems were often higher than those involving veterinary evaluators. The ES system often produced the highest agreement when compared with each rater individually.

Main limitations: Horses were evaluated on a straight line only. Lameness diagnosis was limited to visual observation. Outcomes for each horse's four limbs were considered independent measurements.

Conclusions: This work highlights the utility of commercially available objective evaluation systems, including the more recent ES system. Hindlimb asymmetries had lower agreement regardless of evaluator type. Objective systems had higher agreements when compared with subjective straight-line veterinary examination. The ability to uniformly assess asymmetries may assist diagnosis when compared with subjective evaluation alone.

Background: High recurrence rates after atrial fibrillation (AF) treatment may be driven by myocardial changes induced by the arrhythmia itself. Understanding the molecular mechanisms behind these changes is crucial for developing targeted therapies and improving outcomes.

Objectives: To characterise the cardiac transcriptome of healthy horses and explore transcriptional changes associated with persistent AF (naturally occurring and tachypacing-induced).

Study design: Case-control study.

Methods: RNA-sequencing was performed on atrial and ventricular tissue samples collected from six horses with naturally occurring persistent AF (lasting 2-12 weeks) and six healthy controls. Differential gene expression and pathway enrichment analyses were conducted to identify chamber-specific differences and molecular pathways associated with AF. Findings were integrated with proteomic data and compared with transcriptional changes in a separate cohort of 10 horses with tachypacing-induced AF. Atrial metabolic remodelling was further investigated by evaluating the activity of AMP-activated protein kinase (AMPK), a central metabolic regulator and measuring local glycogen content.

Results: The transcriptomes of the four heart chambers had distinct molecular identities. Expression of ion channels and genes encoding calcium handling proteins was largely similar to humans, despite important differences in the ventricular expression of repolarising potassium channels. Persistent AF was associated with minimal ion channel changes but significant upregulation of metabolic, fibrotic and myofibrillar pathways. Metabolic remodeling included upregulation of fatty acid and glycolytic pathways, increased glycogen content in the left atrium and preserved AMPK activity in the right atrium. Transcriptomic profiles of naturally occurring persistent AF correlated well with those of tachypacing-induced AF.

Main limitations: The study cannot distinguish changes predisposing to AF from those caused by it.

Conclusion: Persistent AF was associated with changes in metabolic and fibrotic pathways in the atria, with minimal ion channel remodeling. Targeting these pathways, rather than focusing solely on the electrical disturbance, may improve treatment outcomes in equine AF.