Equine Veterinary Journal最新文献

Background: A proportion of senior horses (≥15 years of age) are still used for competition. Information about this particular group of horses is currently sparse.

Objectives: To provide an overview of the demographics, management and health of competing U.S. senior horses (≥15 years of age).

Study design: Online survey.

Methods: Descriptive and inferential (Kruskal-Wallis test) analysis of 246 surveys from owners of U.S.-resident senior horses used for competition. Confidence intervals were calculated for prevalence estimates of clinical signs and medical conditions.

Results: Competing senior horses were mainly kept at their owners' own facility, with owners making all management decisions (52.2%). In terms of housing, competing senior horses were most frequently kept in a stall but with ≥12 h a day on pasture. Competing seniors were predominantly 15-20 years of age (73.4%), were geldings (69.5%) and were Quarter Horses (33.5%). About one-half competed/trained for competition at a medium level. Three percent competed at the highest (e.g., international) level. The most common discipline was dressage (32.0%). Stiffness/reduced leg-joint flexibility was the most common owner-reported clinical sign (29.2%; 95% CI: 23.5-35.6) and osteoarthritis was the most common owner-reported veterinary-diagnosed medical condition (32.6%; 95% CI: 26.8-39.0), followed by gastric ulcers (8.0%; 95% CI: 5.1-12.3) and lameness (7.6%; 95% CI: 4.8-11.8). Nearly one-half (43.3%) indicated that their competing senior horse had no veterinary-diagnosed medical condition at the time of the survey.

Main limitations: Potential recall, response and sampling bias.

Conclusions: Although few horses over 20 years of age were used in competition, senior horses (≥15 years of age) competed up to the highest level (e.g., internationally) in some disciplines. Competing senior horses were affected by medical conditions commonly reported in the general senior horse population (e.g., osteoarthritis and lameness) and younger competing horses (e.g., gastric ulcers and lameness), potentially increasing the complexity of their management.

Background: In anaesthetised horses, bradycardia secondary to high vagal tone can reduce cardiac output and blood pressure. The use of anticholinergics in horses is limited due to concerns about ileus and abdominal discomfort. This retrospective study sought to determine the prevalence of post-operative abdominal discomfort in healthy horses that received atropine under isoflurane anaesthesia.

Study design: A retrospective evaluation of 222 general anaesthesia events between January 2019 and December 2019 was undertaken.

Methods: One hundred and eleven horses that received atropine were identified, and 111 case match controls that did not receive atropine were also selected. Information gathered from the medical records included signalment, anaesthetic drugs, surgical procedures, duration of anaesthesia and surgery, dobutamine and atropine administration, and the occurrence of abdominal discomfort for 24 h after anaesthesia. After initial data analysis, a second cohort of records was assessed separately. The horses in this group were castrated under general anaesthesia (with or without atropine; n = 68). Logistic regression models and Fisher's exact tests were used to look for factors contributing to abdominal discomfort post-anaesthesia. The significance level was set to 5% (p < 0.05).

Results: Atropine administration was not associated with the development of post-anaesthetic abdominal discomfort (OR = 2.121, 95% CI [0.767, 5.869]; p = 0.2). Overall, 18/222 (8.1%) incidences of abdominal discomfort were identified. All incidents occurred in colts undergoing castration. In a separate analysis of only horses anaesthetised for castration, atropine was associated with developing abdominal discomfort (OR = 3.143, 95% CI [1.082, 9.132]; p = 0.04).

Discussion: Atropine was not associated with post-operative abdominal discomfort except in colts undergoing castration. All episodes of discomfort were mild and resolved with minimal intervention. The potential impact of insufficient analgesia in horses undergoing castration is a confounding factor and requires prospective investigation.

Conclusion: Overall, atropine at a dose of 0.006 mg/kg IV appears to be a safe method to treat bradycardia in otherwise healthy horses anaesthetised for orthopaedic and upper airway procedures. Further work is required to determine if atropine is safe for colts undergoing castration.

Background: Affordable particulate matter (PM) monitors suitable for use on horses will facilitate the evaluation of PM mitigation methods and improve the management of equine asthma.

Objective: Calibrate a real-time wearable PM monitor (Black Beauty [BB]) and compare the PM exposures of horses fed dry or soaked hay.

Study design: Laboratory calibration; complete cross-over feed trial.

Methods: Side-by-side sampling with BB monitors and tapered element oscillating microbalances (TEOMs) was performed under varying concentrations of PM from alfalfa hay. Linear regression was used to derive a calibration formula for each unit based on TEOM PM measurements. Precision was evaluated by calculating the coefficient of variation and pairwise correlation coefficients between three BB monitors. PM exposure was measured at the breathing zone of 10 horses for 8 h after they were fed dry or soaked hay. Repeated measures generalised linear models were constructed to determine the effect of hay treatment and measurement duration (initial 20-min vs. 8-h) upon exposure to PM with diameters smaller than or equal to 10 μm (PM₁₀) and 2.5 μm (PM_2.5).

Results: BB monitor PM_2.5 and PM₁₀ measurements were linearly correlated with TEOM data (coefficient of determination r² > 0.85 and r² > 0.90 respectively), but underestimated PM_2.5 mass concentrations by a factor of 4 and PM₁₀ concentrations by a factor of 44. Measures from the three BB monitors had a coefficient of variation <15% and pairwise r > 0.98. Feeding soaked hay significantly reduced average PM_2.5 exposures (20-min: dry: 160 μg/m³, soaked: 53 μg/m³, p < 0.0001; 8-h: dry: 76 μg/m³, soaked: 31 μg/m³, p = 0.0008) and PM10 exposures (20-min: dry: 2829 μg/m³, soaked: 970 μg/m³, p < 0.0001; 8-h: dry: 1581 μg/m³, soaked: 488 μg/m³, p = 0.008).

Main limitations: No health outcome measures were collected.

Conclusions: With appropriate corrections, the BB monitor can be used to estimate horse PM exposure. While 20-min measurements yielded higher estimates of exposure than 8-h measurements, both intervals demonstrate that soaking hay reduces PM exposures by more than 50%.

Background: Equine post-operative morbidity represents a significant concern for both veterinary surgeons and horse owners.

Objectives: To estimate the prevalence of post-operative complications in horses after elective/non-abdominal surgery or colic surgery.

Study design: Systematic review.

Methods: A database search identified eligible studies which reported the prevalence of equine post-operative complications published as a full paper in English in a peer-reviewed journal between 2000 and 2023. Studies were evaluated using the JBI Critical Appraisal Checklist for Prevalence Studies and GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework. Data for the most commonly reported complications were analysed using Chi-squared analysis of weighted means to answer 13 PICO (Population, Intervention, Comparator and Outcomes) questions.

Results: Sixty-seven studies met inclusion criteria. Data for eight post-operative morbidities (colic, surgical site complications, myopathy/neuropathy, laminitis, diarrhoea/colitis, fever/pyrexia, jugular thrombophlebitis/thrombosis, respiratory complications) were sufficient to allow statistical analyses. The weighted mean of the overall proportion of post-operative complications after elective/non-abdominal surgery is 17.48% (95% confidence interval [95% CI]: 13.20-22.92), significantly increasing to 55.62% (95% CI: 45.79-65.03) after colic surgery (odds ratio [OR] 6.63; 95% CI: 5.83-7.56; p < 0.001). The most commonly reported morbidity was post-operative colic, with a weighted mean prevalence of 7.45% (95% CI: 4.83-11.76) after elective/non-abdominal surgery, significantly rising to 26.46% (95% CI: 19.11-35.97) after colic surgery (OR 4.11; 95% CI: 3.60-4.71; p < 0.001). The weighted mean prevalence of surgical site complications, laminitis, diarrhoea/colitis, fever/pyrexia, jugular thrombophlebitis/thrombosis and respiratory complications were significantly higher after colic surgery compared with elective/non-abdominal surgery. Myopathy/neuropathy was the only morbidity where prevalence was not different between groups (OR 1.86; 95% CI: 0.86-4.16; p = 0.16).

Main limitations: The majority of studies were retrospective. Morbidity definitions, data collection periods, follow-up time and methods varied between studies.

Conclusions: Based on current evidence, the prevalence of post-operative colic, surgical site complications, laminitis, diarrhoea/colitis, fever/pyrexia, jugular thrombophlebitis/thrombosis and respiratory complications is significantly higher after colic surgery compared with elective/non-abdominal surgery under general anaesthesia.

Background: Endometritis is the leading cause of subfertility in horses, and it is a clinical problem where historically antibiotics have not always been used with prudent justification. Because of this, alternative therapies to treat endometritis are necessary for the rational use of antibiotics.

Objectives: To assess the in vitro antimicrobial activity of non-traditional therapies commonly used in clinical practice against microorganisms causing infectious endometritis in mares.

Study design: In vitro experiments.

Methods: A microdilution technique was performed to determine the minimum inhibitory concentrations (MIC) of 50%, 90% and 100% of microorganisms and the percentage of inhibition (PI) of each therapy against each microorganism (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Candida sp.). The MIC 50% and 90% were determined using non-linear regression, while MIC 100% was assessed using the resazurin dye technique. The serial PI was evaluated for each therapy using a spectrophotometer.

Results: All the therapies demonstrated a PI higher than positive controls for all microorganisms (p < 0.05); however, the only therapies that presented MIC 100 values were hydrogen peroxide and platelet-rich and -poor plasma.

Main limitations: In vivo, safety and treatment efficacy were not tested.

Conclusion: Hydrogen peroxide and platelet-rich and -poor plasma might be alternatives to traditional therapies for endometritis to support a reduction in antibiotic use.

Sustained atrial tachycardia at an atrial rate of 191/min on the surface ECG was detected in a 6-year-old Warmblood mare. The vectorcardiogram obtained from a 12-lead ECG suggested a caudo-dorsal right atrial origin of the arrhythmia. Impedance-based three-dimensional electro-anatomical mapping, using the EnSite™ Precision Cardiac Mapping System revealed a clockwise macro-reentry around a line of conduction block in the caudomedial right atrium. Ten radiofrequency applications were applied to isolate the caudal vena cava myocardial sleeves at a power of 35 W and mean contact force of 14 ± 3 g until a lesion size index of 6 was reached. Sinus rhythm was restored at the first energy application. Successful isolation was confirmed by demonstrating entrance and exit block. Holter monitoring 5 days post-ablation revealed no abnormalities. To date, 9 months after treatment, no recurrence has been observed. The use of lesion size index-guided ablation and isolation of the arrhythmogenic substrate in the caudal vena cava may minimise the risk of recurrence.

Background: Data on equine thoracic pathology hardly exist in breeds other than Thoroughbreds.

Objectives: To describe pathological changes of the osseous thoracic vertebral column in Warmblood horses, Shetland ponies and Konik horses, and to compare prevalence and severity.

Study design: Descriptive post-mortem study.

Methods: Computed tomography was used to examine the thoracic vertebral column of 34 Warmblood horses, 28 Shetland ponies, and 18 Konik horses. Osteoarthritis (OA), periarticular osteolysis, osseous cyst-like lesions and fragments of articular processes (APJs), costovertebral and costotransverse joints, soft tissue mineralisation surrounding these joints, intervertebral disc (IVD) mineralisation, impingement of spinous processes (SPs) and spondylosis were scored.

Results: APJ aplasia (98%; 58/59) occurred in 14 Shetland ponies. OA predominated in Warmblood horses across all joints (45% vs. 29 and 32%, p < 0.001). OA and periarticular osteolysis were found in particular in the costotransverse joints (p < 0.001) across all breeds. Warmblood and Konik horses had more and severe soft tissue mineralisation than Shetland ponies (2.3%, score 1.5 and 3.2%, score 1.3, respectively, vs. 0.3%, score 0.9, p < 0.01). Mid location was most often affected with highest severity score (4.2%, 1.5, p < 0.001). Konik horses displayed the highest IVD mineralisation (20%, p < 0.001), which notably increased with age (p < 0.001) compared with Warmblood horses (4.5%) and Shetland ponies (1.1%). SPs impingement was absent in Shetland ponies, and most prevalent in Warmblood horses (11.2%, p < 0.001) compared with Konik horses (2.2%). Osseous cyst-like lesions, fragments and spondylosis were minimal in all breeds and nearly absent in Shetland ponies.

Main limitations: Clinical histories and macroscopic and histologic examinations were unavailable.

Conclusions: Distinct breed differences exist in prevalence and severity of thoracic vertebral column osseous pathologies. Costotransverse joint pathology is more common than APJ pathology in all breeds. Warmblood horses are prone to OA, spondylosis and SPs impingement; Konik horses exhibit significant IVD mineralisation, and Shetland ponies demonstrate a high prevalence of APJ aplasia. Periarticular osteolysis, osseous cyst-like lesions, fragments and soft tissue mineralisation are notably low in Shetland ponies.

Background: Computed tomography (CT) of the axial skeleton is increasing across many equine hospitals. CT of the pelvis and caudal spine in a large group of clinical cases has not been reported previously.

Objective: To describe the pathological lesions identified in the caudal spine/pelvis in horses and ponies undergoing CT spine of this region.

Study design: A retrospective case series.

Methods: Horses with CT imaging of the caudal spine/pelvis were included. Horses aged under 6 months and those with CT examinations performed post-mortem were excluded.

Results: Fifty-six horses met the inclusion criteria. Ages ranged from 8 months to 20 years and bodyweights from 85 to 680 kg (mean 488 kg). Horses presented predominantly for lameness (30/56) and poor performance (18/56). Osseous pathology was identified in 41/56 horses; including osteoarthritis of the sacroiliac joint(s) (n: 28), pathology of the intervertebral disc joint(s) (n: 12), pelvic fractures (n: 9), osteoarthritis of the coxofemoral joint(s) (n: 8), ventral spondylosis (n: 6), acetabular rim fracture (n: 2), dislocation of coxofemoral joint(s) (n: 2), and dorsal dermal sinus of the sacrum (n: 1).

Main limitations: The relationship between CT imaging findings and clinical signs in horses remains unclear. Further work is required to describe the relationship between congenital, developmental, and acquired changes in the caudal spine and pelvis, and clinical signs.

Conclusions: CT of the caudal spine and pelvis can be utilised in horses and ponies for diagnosing a range of clinical disorders that may be causing 'lumbosacroiliac pain', poor performance, hindlimb lameness, and stiffness. The pathologies we observed were diverse and many patients had multiple lesions.

Background: Foal immunity relies heavily on the absorption of colostrum immunoglobulins; thus, colostrum evaluation is used to predict the transfer of passive immunity (TPI), and its conductivity is associated with TPI in cattle. Leading up to and at parturition, a reduction in colostrum pH and conductivity is thought to be necessary for TPI; however, this remains to be determined.

Objectives: To assess conductivity, pH, and Brix refractometer index of colostrum to predict the TPI in foals.

Study design: Field study.

Methods: The colostrum of 241 mares was assessed for conductivity, pH, and Brix index using handheld devices immediately after parturition. Twenty-hour postpartum foals had complete blood cell count and plasma IgG concentrations assessed. Foals were split in complete versus incomplete TPI (i.e., IgG ≥8 g/L vs. <8 g/L). Mare (breed, duration of pregnancy, parity, and age), foal (sex), and colostrum (conductivity, pH, and Brix index) data were computed to assess factors affecting TPI. Multivariate regression and receiver operating characteristic (ROC) curves were employed for analysis.

Results: Complete TPI was achieved in 89.4% of foals. The ROC TPI values were conductivity ≤5 mS/cm (AUC = 0.68), Brix ≥23.4% (AUC = 0.70), and pH ≤6.4 units (AUC = 0.73). The odds ratio for TPI in 24 h post-partum was 6.1 (2.1-17.1, 95% CI) for conductivity, 3.2 (1.2-9.3, 95% CI) for pH, and 4.5 (1.5-12.7, 95% CI) for Brix index. Sensitivity and specificity of 93% (88-96 95% CI), 56% (44-7, 95% CI), 92% (87-96, 95% CI), 28% (14-47, 95% CI), 94% (88-97, 95% CI) and 18% (14-47, 95% CI) for conductivity, Brix and pH, respectively.

Main limitations: Low incidence of incomplete TPI.

Conclusions: Conductivity, pH and Brix are strong predictors of foals that succeed in the transfer of passive immunity; however, all three presented low to moderate specificity. The established cutoff values obtained herein can be used on-field by other foaling programs. All three handheld devices used in the study are inexpensive and ready to use on-farm.