Equine Veterinary Journal最新文献

Background: Assessment of equine metabolic and locomotory responses to quantified levels of physical exercise is needed to support the creation of tailored protocols for optimal training adaptation. The locomotory response to exercise in horses is not fully understood.

Objectives: To investigate the effect of a standardised exercise test (SET) on upper-body and limb kinematics and stride-to-stride variability in Standardbred Warmblood trotters.

Study design: Experimental repeated-measures field study.

Methods: Thirteen Standardbred trotters, equipped with nine inertial measurement units (IMUs), performed an incremental SET on an oval track. Heart rate and lactate data were collected to identify internal workload. Two 30-s segments of jog on the straight (at the beginning and at the end of the SET) were used for statistical analysis of the effect of the SET on locomotion parameters.

Results: Upper-body kinematics revealed a decrease in head and withers range of motion (ROM; -12.3 mm; p = 0.04 and -8.5 mm; p = 0.01, respectively). Front limb sagittal ROM (16.1°; p = 0.001) increased explained by increased maximal protraction and retraction (6.9°, p = 0.002 and 9.1°, p = 0.002, respectively). Stride-to-stride variability (i.e., coefficient of variation) was reduced for stride duration (-0.7%; p = 0.01), front limb sagittal ROM (-7.3%; p = 0.04), front limb maximal protraction (-6.9%; p = 0.01) and maximal retraction (-7.4%; p = 0.03). No effects were found on sagittal hindlimb angles and none of the absolute asymmetry parameters changed (p > 0.05).

Main limitations: Horses were of different ages and training statuses, and full orthopaedic examinations were not performed.

Conclusions: Several kinematic parameters were affected by the SET. Head and withers ROM were reduced, while front limb sagittal ROM increased. Stride-to-stride variability showed a decrease. The results indicate that exercise in Standardbred trotters produces both a metabolic and locomotory response. Additionally, these findings highlight the efficacy of IMUs as a non-invasive tool for detecting exercise-induced changes in limb and upper-body kinematics.

Background: Airway dysfunction in severe equine asthma (SEA) often results in early retirement or euthanasia of affected horses. Exercise-induced bronchodilation occurs in horses with SEA after intense treadmill exercise, but the effects of a lighter, field-applicable, training regimen remain largely unexplored.

Objectives: To evaluate the impact of submaximal aerobic exercise on airway obstruction during exacerbation of SEA.

Study design: The preliminary phase explored the effects of a 25-min standardised exercise on the lung function of eight SEA horses. As notable bronchodilation occurred, the results were confirmed in a randomised controlled crossover protocol comparing the effect of the same standardised exercise on lung function with that of an equal duration turnout.

Methods: Lung function was assessed by standard lung mechanics before and 15 min after the interventions (turnout and walk/trot lungeing exercise). To compare exercise-induced bronchodilation with that of a potent bronchodilator in the main study, salbutamol was administered after the turnout intervention only, and lung function was measured again 5 min later. Data were analysed with t tests, Wilcoxon tests, and mixed-effects models.

Results: In the preliminary phase, exercise led to a mean 50% reduction in pulmonary resistance. This was confirmed in the main study, where pulmonary resistance decreased from 2.6 (2.1-3.3) to 1.3 cm (0.8-2.2) H₂O/L/s after exercise (p = 0.006), whereas it remained unchanged after the turnout intervention. Following salbutamol administration after the turnout, lung function was comparable to that of the lunged horses, suggesting that the extent of exercise-induced bronchodilation was similar to that achieved with a β2-adrenergic agonist.

Main limitations: The small number of aged horses, the lack of blinding, and the focus on the short-term effects of exercise restrict the generalisability of the results.

Conclusions: The rapid and potent bronchodilation achieved through brief aerobic exercise supports the investigation of a training program's impact on the management of SEA.

Background: Computer vision-based algorithms offer accessible alternatives for equine gait analysis but require thorough assessment under diverse conditions.

Objectives: To evaluate a proprietary vision-based algorithm's reliability in measuring vertical displacement signals (VDS) at the eye, withers and croup, alongside groundline estimation, for horses trotting on straight lines and circles under field conditions.

Study design: Cross-sectional comparative study evaluating agreement, variability and reliability of a markerless computer vision algorithm.

Methods: We obtained 67 handheld iPhone recordings from 37 horses. A vision-based algorithm and independent manual annotation produced 2D anatomical keypoints on all frames of the recordings, which were processed to estimate a groundline and compute VDS and stride-based maxima (Maxdiff) and minima (Mindiff) vertical differences. Mean signed error (MSE), mean absolute error (MAE) and Bland-Altman plots were used to compare detected and annotated data.

Results: The frame level vertical keypoint accuracy was 4.5 mm (eye), 5.5 mm (croup) and 11.8 mm (withers), and the manual annotation error was averaged at 2.7 mm. At the stride level (n = 1556), the overall mean absolute errors (MAEs) for both Maxdiff and Mindiff were 4.3 mm. The eye keypoint exhibited the lowest errors (2.9 mm Maxdiff, 3.0 mm Mindiff), while the withers error was 5.5 mm for both Maxdiff and Mindiff, and the croup showed 4.3 mm (Maxdiff) and 4.4 mm (Mindiff). Trial-level (n = 67) analysis, with below optimal number of strides per trial in this study, revealed lower overall absolute differences (Eye: 2.3 mm, Withers: 3.7 mm, Croup: 2.7 mm), indicating consistent performance across multiple strides. Subjective lameness scoring aligned with objective measures with some variation.

Main limitations: Groundline estimation accuracy was stress-tested on treadmill data in another study. Further clinical comparison with established gait analysis systems is recommended.

Conclusions: The algorithm robustly measured vertical displacements under varied conditions.

Background: Computed tomography (CT) is increasingly used for metacarpo/tarsophalangeal or fetlock joint (MC/TPJ) evaluation in Thoroughbred racehorses. CT features and lesion prevalence in competing Thoroughbreds are unknown.

Objectives: To identify standing CT features within the MC/TPJ of elite Thoroughbred staying racehorses.

Study design: Retrospective cohort study.

Methods: Computed tomography scans of the MC/TPJ were performed as part of pre-race screening for fracture risk and graded for CT features. Descriptive statistics and univariable logistic regression models were generated to investigate associations with presence of palmar osteochondral disease (POD), parasagittal groove subchondral lysis and fissure.

Results: A total of 406 limbs from 86 horses were scanned; 72 horses were scanned once, 12 horses were scanned twice, and two horses scanned three times. POD was common, being present in 74/86 (86.0%, 95% CI 76.9-92.6) horses and in 231/342 (67.5%, 95% CI 62.3-72.5) limbs on first scan. POD was associated with more career race starts (p = 0.05) but fewer placings per start (p = 0.008). Parasagittal groove (PSG) lysis, previously associated with condylar fracture, was observed in 16/86 (18.6%; 95% CI 11.0-28.4) horses and 20/342 (5.8%; 95% CI 3.6-8.9) limbs on the first scan, whereas fissures in this region, which are not associated with fracture, were observed in 41/86 (47.7%; 95% CI 36.8-58.7) horses and 65/342 (19.0%; 95% CI 15.0-23.6) limbs. Osteoarthritis of the fetlock joint was uncommon.

Main limitations: Horses travelling from overseas had undergone prior screening of their fetlock joints, predominantly with MRI, likely reducing the prevalence of pathology in these horses.

Conclusions: POD is common in elite staying Thoroughbred racehorses, however, negatively impacts performance. The prevalence of PSG lysis supports the use of CT screening of high-risk populations of Thoroughbred racehorses in fracture risk management. Further work is required to determine if these findings are applicable more generally to other racing Thoroughbreds.

Background: Several induction quality scoring systems (IQSS) have been described to evaluate drugs and risk factors of this anaesthetic period in horses, but no attempts to compare their reliability have been performed.

Objectives: To elucidate the reliability of three IQSS: the visual analogue scale (VAS), a simple descriptive scale (SDS), and a composite grading scale (CGS) proposed by the authors.

Study design: Reliability study.

Methods: Eight randomly selected video-recorded anaesthetic inductions from horses that underwent general anaesthesia were evaluated twice by four blinded evaluators with experience in equine anaesthesia, with a 1-month interval between assessments using the three aforementioned IQSS. A total of 64 evaluations per scale were generated. To assess reliability, intra- and inter-rater intraclass correlation coefficient (ICC), and their 95% confidence intervals (CI) were calculated based on a mean rating (k = 4), absolute agreement, 2-way random-effects model.

Results: The inter-rater agreement was classified as moderate to good inter-rater reliability for all the scales, with the highest ICC found for the VAS (0.74 ± 0.11), followed by the CGS and the SDS (0.65 ± 0.22 and 0.63 ± 0.21, respectively). Intra-rater agreement results demonstrated very good reliability for both VAS and SDS (0.82 ± 0.08; 0.81 ± 0.18, respectively) and excellent reliability for the CGS (0.91 ± 0.08).

Main limitations: The use of video-recordings instead of in situ evaluations, as the absence of audio may affect the assessment. Additionally, these findings are applicable only when free inductions are evaluated.

Conclusions: The VAS and the novel CGS are reliable IQSS in horses, as are the widely used SDS. As the SDS are inconsistent across the literature, the VAS would be advised if multiple evaluators assess induction quality for research purposes, whereas the CGS would be selected for studies involving a single observer. We suggest routine inclusion of the VAS in the evaluation of the anaesthetic induction in horses.

Background: Obstruction by strangulating lipoma (SLO) is one of the most common causes of small intestinal strangulation in horses and is fatal without surgery. Current knowledge of risk factors for SLO is limited to horse signalment features. To date, other risk factors have not been investigated.

Objectives: To investigate horse- and management-level risk factors for SLO using a population of healthy horses as controls.

Study design: Matched, case-control study.

Methods: A prospective, international multicentre study was conducted in the UK and USA between January 2022 and May 2024. Cases were horses with SLO confirmed at exploratory laparotomy at the four participating hospitals. Three controls per case were randomly selected, matched on clinic and time. Conditional logistic regression was used to identify associations between variables and the risk of SLO.

Results: Data from 55 SLO cases (UK, n = 42; USA, n = 13) and 167 matched controls were analysed. In a final multivariable model, increased age (odds ratio [OR]: 1.15; 95% confidence intervals [95% CI]: 1.04-1.28; p = 0.008) and particular breeds (Pony, Welsh Section D/Cob, American Quarter Horse/American Paint Horse/Appaloosa/Arabian) were at increased risk of SLO (OR: 1.53; 95% CI: 1.10-2.15; p = 0.012). SLO was more likely in horses with a prior history of laminitis (OR: 10.94; 95% CI: 2.21-54.13; p = 0.003) or increased stabling in the previous 4 weeks (OR: 6.79; 95% CI: 1.96-23.54; p = 0.003). Management strategies to maintain optimal weight and address equine metabolic syndrome were protective (OR: 0.19, 95% CI: 0.39-0.94; p = 0.041).

Main limitations: Potential for selection and recall bias by horse owners.

Conclusions: This study adds to knowledge of the epidemiology of SLO and has identified new risk factors which may be modifiable. Strategies to prevent endocrine-associated laminitis, including weight management in high-risk groups, should be considered to minimise SLO risk.