Equine Veterinary Journal最新文献

Background: Intra-articular (IA) corticosteroids can cause hyperinsulinemia, which can subsequently increase the risk of laminitis, particularly in horses with insulin dysregulation (ID). Sodium glucose cotransporter 2 inhibitors (SGLT2i), a drug class that is being utilised more commonly in horses with insulin dysregulation, could potentially be used to control post-IA corticosteroid hyperinsulinemia.

Objectives: To determine whether treatment with the SGLT2i drug ertugliflozin decreases hyperinsulinemia following intra-articular corticosteroid administration in metabolically normal horses.

Methods: Prospective, controlled, cross-over study design. Eight mixed-breed, metabolically normal geldings either received no treatment (CTL) or were treated with ertugliflozin (ERT) for 7 days before and 7 days after a total dose of 18 mg of IA triamcinolone acetonide (TA). Samples for resting glucose and insulin concentrations, as well as dynamic oral sugar testing (OST), were collected. Treatments were crossed over and the study repeated. Two-way, repeated measures analysis of variance was used to identify timepoint by treatment differences (p < 0.05).

Results: Insulin was significantly lower 2 days after IA TA with ERT treatment at 60 min post-OST. Resting glucose concentrations were significantly lower with ERT treatment at 8 h, 12 h, 24 h, and 48 h while resting insulin concentrations were significantly lower with ERT treatment at 12 h, 24 h, 48 h, and 72 h post-IA injection.

Main limitations: Non-insulin dysregulated horses and compounded ertugliflozin were utilised.

Conclusions: Treatment with ertugliflozin decreases glucose and insulin changes following IA corticosteroid administration in metabolically normal horses. Further investigation of this treatment strategy in insulin dysregulated horses is warranted as it may reduce hyperinsulinemia and, therefore, the risk of laminitis with IA corticosteroid administration.

Background: African horse sickness (AHS), caused by the vector-borne African horse sickness virus (AHSV), is endemic to sub-Saharan Africa and infection results in high mortality in naïve equine populations. Clinical signs include submucosal petechiae and prolonged bleeding post venepuncture indicative of hypocoagulation. Pathological activation of haemostasis may result from tissue factor expression as a result of vascular endothelial damage or dysfunction, the proposed pathologic mechanism in AHS, potentially resulting in disseminated intravascular coagulation (DIC).

Objectives: To describe haemostatic changes during experimental AHSV infection and to characterise DIC using plasma-based and viscoelastic assays.

Study design: In vivo experiments.

Methods: Four horses were experimentally infected with AHSV. Blood samples were obtained before infection, then every 24 h until humane euthanasia. Haematology and thromboelastography (TEG) were performed and prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and D-dimer concentrations, as well as activities of antithrombin (AT) and coagulation factors II, VII, VIII, X, and XII were measured.

Results: Over the disease course, TEG variables showed increased clot initiation time (R) and decreased α-angle, maximum amplitude (MA), and clot strength (G). The velocity curve showed decreased maximum rate of thrombus generation (MRTG) and thrombus generation (TG), and increased time to maximum rate of thrombus generation (TMRTG). Prothrombin time, aPTT and D-dimer concentration increased while AT activity decreased. All horses developed severe thrombocytopenia.

Conclusions: Horses experimentally infected with AHSV developed a consumptive coagulopathy with a bleeding phenotype. These findings fulfil the criteria of overt DIC characterised by procoagulant activation, inhibitor consumption and increased fibrinolytic activity.

Background: Condylar stress fracture of the third metacarpal bone (MC3) is a common catastrophic injury in Thoroughbred racehorses and is associated with parasagittal groove (PSG) subchondral osteolysis. Standing computed tomography (sCT) imaging enables sensitive identification of this fatigue-induced early subchondral bone injury (SBI), but there is no objective method for identifying racehorses at heightened risk of condylar stress fracture.

Objectives: To estimate PSG first principal strain in elite Thoroughbred racehorses that have undergone subjective risk assessment using sCT fetlock screening.

Study design: Retrospective clinical study.

Methods: We used fetlock sCT images from nine thoracic limbs from seven Thoroughbred racehorses. A tuned, validated, 3D finite element (FE) analysis was used as a virtual mechanical test to estimate PSG first principal strain in the distal MC3 from these joints. Virtual mechanical testing results were compared with a subjective clinical imaging risk assessment using a screening approach by Racing Victoria.

Results: MC3 condyles with PSG SBI consistently and significantly displayed increased levels of first principal strain throughout the PSG. We found focal strain concentrations associated with the SBI location compared to condyles with no evidence of PSG SBI. Diagnosis of SBI with PSG focal osteolysis, FE-predicted strain elevation, and clinical imaging risk assessment were concordant with R² = 0.62.

Main limitations: The sample size was small, and our virtual mechanical testing protocol does not account for whole-joint physiology.

Conclusions: Risk assessment through sCT screening is an established approach to injury prevention in racing Thoroughbreds. Concordance of a current clinical imaging risk assessment approach by Racing Victoria with objective FE analysis of principal strain in sites of PSG SBI in the present study suggests 3D FE analysis using a validated pipeline has potential as a new approach for routine assessment of risk of MC3 condylar stress fracture in Thoroughbred racehorses once computational pipeline automation yields a clinically relevant analysis time.

Background: A handheld smartphone-based computer vision algorithm (RealHorse® [RH]) offers accessible alternatives for equine gait analysis but requires validation against a gold-standard three-dimensional multicamera optical motion capture system (Qualisys® [QS]).

Objectives: To evaluate the accuracy and precision of RH in measuring vertical displacement signals (VDS) at the eye, withers, back and croup in horses trotting on a straight line and on a circle.

Study design: Cross-sectional comparative validation study of a markerless computer vision algorithm.

Methods: Fifty-nine horses were recorded while trotting on a straight line and 24 were lunged on a circle. RH detected two-dimensional anatomical keypoints on each frame, which were used to estimate a dynamic groundline and compute ground relative VDS with stride-based difference in maxima (Maxdiff) and minima (Mindiff). QS provided synchronous ground-relative VDS reference values. Agreement was evaluated using mean signed error, mean absolute error and Bland-Altman analysis.

Results: On the straight line (n = 2620 strides), the pooled stride-level MAE for Maxdiff and Mindiff was 3.8 mm. Keypoint-specific errors were 5.1 mm (eye), 4.3 mm (withers) and 3.0 mm (croup). On the circle (n = 2419 strides), pooled stride-level error increased to 5.5 mm. Trial-level analysis (n = 58 trials) showed much lower errors: 1.4 mm for both eye and withers and 1.1 mm for croup. On the circle (n = 24 trials), trial-level errors were higher, with 2.8 mm for the eye, 1.8 mm for the withers and 3.3 mm for the croup. The back keypoint consistently showed the lowest errors across both stride and trial levels.

Main limitations: RH measurements of the croup Mindiff during circling resulted in higher values and showed the largest error.

Conclusions: RH measured vertical displacement of all keypoints with high accuracy and precision (trial-level MAE 1.1-1.4 mm straight, 1.8-3.3 mm circle), supporting its use for equine gait analysis.

Background: Current treatment options for equine gastric ulcer syndrome (EGUS), such as omeprazole-a proton pump inhibitor (PPI)-have notable limitations, including the need for administration on an empty stomach. Potassium-competitive acid blockers (P-CABs), such as vonoprazan, are a newer class of acid suppressants that offer several advantages over PPIs in humans and may provide similar benefits in horses.

Objectives: To describe the pharmacokinetics and effect of a single oral dose of vonoprazan on intragastric pH in horses. We hypothesised that vonoprazan would follow linear kinetics across the doses studied and effectively increase intragastric pH.

Study design: Prospective, randomised four-way balanced crossover study.

Methods: Six horses received vonoprazan (0.5 and 1 mg/kg), omeprazole (4 mg/kg) and water (60 mL). Blood samples were collected prior to and up to 72 h post-administration. Plasma vonoprazan concentrations were measured using liquid chromatography-tandem mass spectrometry, and non-compartmental and compartmental pharmacokinetic analyses were performed. Intragastric pH was continuously recorded 12 h before and 24 h after each treatment. The percentage of time pH remained above 4 was compared among treatments.

Results: For 0.5 and 1 mg/kg vonoprazan, respectively, C_max was 23.7 ± 14.0 and 55.8 ± 18.1 ng/mL (mean ± SD); T_max was 0.875 (0.25-3.0) and 0.625 (0.08-1.0) h (median and range); and terminal half-life was 6.12 ± 1.65 and 6.29 ± 1.86 h (mean ± SD). At 1 mg/kg, vonoprazan significantly increased the percentage of time pH >4 compared to pre-treatment (91.85% vs. 85.5%; p = 0.007) and placebo (90.28 ± 5.6% vs. 5.68 ± 39%; p = 0.021).

Main limitation: Small sample size which may impact clinical applicability of observed changes and potential variability in pH probe positioning.

Conclusion: Vonoprazan was well tolerated and effectively increased and maintained intragastric pH above 4 at the 1 mg/kg dose in horses.

Background: Bodyweight, age and breed influence the echocardiographic assessment of foals. There are no echocardiographic studies in Standardbred neonatal foals.

Objectives: To describe echocardiographic values for selected variables, evaluate intra- and inter-observer variability and assess cardiac changes in the first 5 days of life in healthy Standardbred neonatal foals.

Study design: Prospective observational study.

Methods: Fifty-six healthy Standardbred neonatal foals were examined by transthoracic echocardiography using standard right parasternal and subcostal views at three time points: in the first 48 h (T1), between 49 and 96 h (T2), and 97 and 144 h (T3) after birth. Descriptive statistics, variability analysis and linear mixed models assessed age-related changes in cardiac parameters. Intra/inter-observer variability was assessed using intraclass correlation coefficients (ICC).

Results: A total of 114 echocardiographic examinations were performed. Intra-observer agreement was excellent for most variables, while inter-observer agreement was excellent in approximately half. An increase in end-diastolic left ventricular internal diameter (T1: 5.3 ± 0.6 cm; T3: 5.6 ± 0.8 cm; p < 0.01), left atrial diameter in the four-chamber view (T1: 5.8 ± 0.6 cm; T3: 6.0 ± 0.6 cm; p = 0.01), end-diastolic aortic sinus diameter in the left ventricular outflow tract view (T1: 3.0 ± 0.3 cm; T3: 3.2 ± 0.3 cm; p < 0.01) and peak velocity of the transmitral E wave (T1: 0.8 ± 0.1 m/s; T3: 0.9 ± 0.1 m/s; p < 0.01) were observed over time. Additionally, a gradual decrease in the end-diastolic pulmonary diameter at the sinus (T1: 2.8 ± 0.3 cm; T3: 2.5 ± 0.3 cm; p < 0.01) and at the valve (T1: 2.6 ± 0.3 cm; T3: 2.5 ± 0.4 cm; p = 0.03) levels was noted.

Main limitations: Some variables have fewer individuals; coefficients of variation are moderate to high for some variables.

Conclusions: Changes in echocardiographic variables in a healthy Standardbred neonatal foal population reflect a physiological adaptation of the cardiorespiratory system from foetal to extrauterine life. These observations can be used as a reference in the assessment of neonatal foals of similar age and weight.

Background: Abdominal ultrasound is widely used to evaluate the intestinal tract of horses. Despite being a routine examination, there is limited data on the reliability of this diagnostic procedure.

Objectives: To investigate intra- and inter-rater reliability of ultrasonographic intestinal wall thickness measurements in healthy horses. A second aim was to assess variance within repeated measurements to determine threshold values that distinguish whether differences between repeated examinations are true findings versus solely due to measurement variation.

Study design: In vivo reliability study.

Method: Eight healthy horses (7 Standardbreds, 1 Warmblood) were ultrasonographically examined in six intestinal regions: duodenum, right dorsal colon (RDC), right ventral colon (RVC), caecum, jejunum and left ventral colon (LVC). In each horse, triplicate measurements of intestinal wall thickness were performed by three sonographers on three consecutive days. Intra-class correlation coefficient (ICC) was calculated to assess intra- and inter-rater reliability.

Results: Intra-rater ICC was <0.5 for all regions except the duodenum (0.52). Inter-rater ICC was <0.5 for duodenum, caecum and jejunum and between 0.5 and 0.75 for RDC, RVC and LVC. The standard deviation of repeated measurements was low (0.33-0.45 mm). Across all regions, 95% (±2 SD) of all reported measurements were within a 1 mm range.

Main limitations: Homogenous study group and use of healthy horses may limit generalisability to clinical populations.

Conclusions: Ultrasonographic measurements of intestinal wall thickness show limited consistency but low absolute variation. Differences of less than 1 mm fall within expected repeated measurement variability. This study supports the use of repeated ultrasonographic intestinal wall thickness measurements in clinical practice and provides a practical cut-off value of 1 mm to differentiate expected variability within and between observers from true changes in intestinal wall thickness.

Background: The number of horses with equine squamous gastric disease (ESGD) and equine gastric glandular disease (EGGD) recurrence when pharmacological treatment is discontinued is high.

Objective: To examine if a commercially available nutraceutical compound containing lecithin, pectin, and meadowsweet could prevent recurrence of both ESGD and EGGD after omeprazole treatment, evaluated by repeated gastroscopic examinations and saliva biomarkers.

Study design: Blinded, randomised, placebo-controlled clinical trial.

Methods: Thirty horses of mixed breeds and sex with a recent diagnosis and treatment of both ESGD and EGGD were included and randomly assigned to a placebo or a nutraceutical group. The horses received 10 mL per 100 kg bodyweight (bwt) of either nutraceutical or placebo orally for the 4-8-week duration of the study and were kept in their home environment and trained as normal. Gastroscopic grading of ESGD and EGGD and saliva were obtained at the initial diagnosis, as well as before and after the trial. Salivary biomarkers were measured by automated chemistry analysers using commercial kits. Due to the non-normal distribution of data, Friedman tests with Wilcoxon post hoc tests were applied to assess changes over time within groups, Mann-Whitney U tests were performed to evaluate difference between groups.

Results: Regardless of nutraceutical or placebo assignment, only five horses remained ulcer free after the trial. The nutraceutical was not found to be better than placebo for preventing gastric disease recurrence when evaluated by gastroscopy scores. At the time of the last gastroscopy, the nutraceutical group had lower salivary ADA and higher bicarbonate concentrations compared to the placebo group.

Main limitations: Salivary biomarkers need further validation.

Conclusion: Although addition of the nutraceutical did not have a significant effect in preventing ESGD or EGGD recurrence, it produced changes in salivary biomarkers suggesting a potential improvement in gastric mucosal health.

Background: Racehorses undergo profound physiological changes with training and competition, but current biomarkers inadequately capture the complex molecular dynamics of exercise. This study aimed to identify novel plasma biomarkers of training adaptation and peak load using high-throughput proteomics.

Objectives: We hypothesised that systematic training and racing induce distinct plasma proteomic signatures, enabling the discovery of candidate biomarkers linked to training status, oxidative stress, inflammation and metabolic remodelling.

Study design: In vivo longitudinal study.

Methods: Forty-nine Arabian and Thoroughbred racehorses underwent standardised high-intensity training. Plasma samples were collected at rest, immediately post-exercise and after recovery during three phases: initial training (T1), mid-season conditioning (T2) and race-phase (R). In total, 314 samples were analysed using tandem mass tags based quantitative proteomics and Orbitrap mass spectrometry. Protein abundance changes were assessed with multiple-testing correction (q < 0.05), and pathway enrichment was performed using STRING and ShinyGO.

Results: Proteomic responses differed by phase. T1 showed broad activation of inflammatory (S100A8/A9), antioxidant (superoxide dismutase 1, catalase) and metabolic proteins (glucose-6-phosphate dehydrogenase, phosphoglycerate kinase 1). T2 displayed a more refined profile with remodelling and redox regulators (decorin, thymosin β4, glutathione S-transferase). Racing elicited the strongest response, with over 100 up-regulated proteins linked to energy metabolism, oxidative defense and cytoskeletal adaptation. Several proteins: including S100A8, thymosin β4, prothymosin-α, cofilin-1 and lipocalins, were consistently modulated across phases, highlighting their biomarker potential.

Main limitations: Breed imbalance and incomplete follow-up sampling may affect generalisability. Validation in larger, diverse cohorts with targeted assays is required.

Conclusions: This study identifies a panel of promising plasma proteins as candidate biomarkers of exercise adaptation and overload in racehorses. These findings may support improved monitoring of performance, training load and early detection of overtraining in equine athletes.