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Endometritis is the leading cause of subfertility in mares and a significant challenge to equine reproduction. Unraveling uterine fluid proteome may promote advancements in the knowledge of endometritis etiopathogeneses and its diagnosis and therapeutic practices. Therefore, we aimed to characterize and compare the protein profile of the uterine fluid from healthy mares and animals diagnosed with endometritis. Mangalarga Marchador breed mares from Muriaé - Brazil were divided into control, infectious endometritis, and post-breeding endometritis groups (n = 8/ group). Uterine fluid was collected via low-volume lavage and subjected to protein identification and relative abundance counting. From the 549 proteins detected, 279 were in the uterine fluid of mares from the three experimental groups. Thirteen proteins expressed mostly in healthy mares were associated with endometrial remodeling and early embryonic development. Albumin and uteroglobin presented higher relative abundance in healthy mares and animals with infectious endometritis. Infectious endometritis exhibited proteins related to innate immune and inflammatory responses, including annexin and glutathione S-transferase, and the highest abundance of lipocalins. Fifty-five proteins detected in mares with post-breeding endometritis showed signaling pathways and biological processes related to the innate immune response. These animals also presented the highest abundance of PIGR proteins, which promote IgA transport from plasma into the endometrial mucosa. In conclusion, our results revealed distinct protein profiles from the uterine fluid of mares with infections and post-breeding endometritis. These findings provided valuable insights into the molecular alterations during the establishment and progression of endometritis, contributing to further identification of potential biomarkers., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 Elsevier B.V. All rights reserved.)

Glanders is a zoonotic disease of equids caused by the bacterium Burkholderia mallei, responsible for considerable economic loss. This study aimed to describe the clinical manifestations, pathological findings, and also bacteriological and molecular methods for agent detection in naturally infected animals (16 adult horses and one fetus) detected by serological survey from three glanders outbreaks. Of the 16 horses, 6 (37.5%) did not show clinical signs. After necropsy,samples of organs, lymph nodes, lesions and secretions were collectedfor histopathology, bacterial isolation, and PCR. The clinical and gross alterations mainly comprised nasal and respiratory forms in the three outbreaks, and less of the cutaneous form. All tested animals were positive by PCR (100%, n=17) on at least one sample. Of 121 samples analyzed 8.2% (10/121) isolated B. mallei and 41.3% (50/121) were polymerase chain reaction (PCR) positive. This work highlights the importance of combining diagnostic techniques, such as histopathology microbiological culture and PCR,to confirm cases and characterize the morbidity of glanders as well as considering seropositive animals without glanders clinical signs as potential carrier animals affecting disease control programmes., Competing Interests: Declaration of competing interest None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper., (Copyright © 2024. Published by Elsevier Inc.)

Background: Dental disease is a common but often under-recognised condition in horses, possibly due to an inability to recognise clinical signs of oral discomfort. Some dental disorders are reportedly more painful than others, but there is no current metric by which dental pain can be objectively assessed. This study aimed to determine whether a facial expression-based pain scale offered an objective and reliable method for assessing dental pain in horses. It was hypothesised that dental disorders affecting the periodontium would produce high pain scores., Methods: Twelve horses with dental disease were evaluated for pain using a numerical rating scale (NRS) and a horse grimace scale (HGS) by blinded observers using still, lateral photographs., Results: Interobserver reliability was poor across all observers when both the NRS (intraclass correlation coefficient [ICC] = 0.36) and the HGS (ICC = 0.27) were used in horses with dental disease. The highest mean scores were given for horses with equine odontoclastic tooth resorption and hypercementosis (EOTRH) and periodontal disease (PD)., Limitations: This study has a small sample size of both horses and questionnaire respondents, and the respondent demographics are not representative of the wider veterinary population Furthermore, no positive or negative controls were used for the pain scoring., Conclusions: The results of this study indicate the unreliability of tools designed for identifying acute pain for assessing chronic pain, such as dental pain. A more dental-specific ethogram is required to accurately identify dental pain in horses. Both the NRS and HGS produced the highest mean scores for EOTRH and PD, supporting existing literature that these conditions are associated with more obvious signs of pain., (© 2024 British Veterinary Association.)

Background: Pulse oximetry has not been thoroughly evaluated for assessment of oxygenation in conscious foals. Compared with invasive arterial blood sampling, it is a painless and non-invasive method for real-time monitoring of blood oxygen saturation. The aim of this prospective clinical study was to evaluate the usability, validity, and reliability of pulse oximetry at two measuring sites (lip and caudal abdominal skin fold) for blood oxygen saturation measurement in conscious foals with and without respiratory compromise. Thirty-two foals under one month of age were used. Nineteen foals had normal respiratory and cardiovascular function, and 13 had pneumonia. Pulse oximetry with a transmittance sensor was performed in triplicate on each foal's lip (n = 196 measurements) and/or skin fold (n = 338 measurements), and arterial blood sample was collected. The oxygen saturation values measured by pulse oximetry from the lip and skin fold were compared with each other (n = 58 measurement pairs) and with the calculated arterial oxygen saturation based on arterial blood samples (n = 93 measurement pairs). Furthermore, repeatability of the pulse oximetry measurements was assessed., Results: Measured blood oxygen saturation was clearly associated with the calculated saturation, but on average (± SD) it was 1.8 (± 3.3) percentage units higher from the lip and 5.7 (± 4.3) percentage units higher from the skin fold than the calculated saturation. In concurrent lip and skin fold measurements within a foal, the skin fold measurements were 2.4 (± 2.4) percentage units higher than the lip measurements. The repeatability of three pulse oximetry saturation measurement results was moderate to good and significantly improved when the measurement furthest from the middle-measured value was excluded. The most deviating measurement was often obtained first. Pulse oximetry in general was well tolerated and easy to perform, but as expected in conscious foals, movement and contact problems generated occasional technical difficulties in some individuals., Conclusions: In conscious foals, pulse oximetry with a transmittance sensor attached to the lip (but not to the skin fold) is a clinically applicable and valid method for arterial blood oxygen saturation determination. Several measurements should be obtained and outliers discarded to obtain a reliable result., Competing Interests: Declarations. Ethics approval and consent to participate: The Finnish Project Authorisation Board approved the study (licence no. ESAVI/37496/2021). Consent for publication: The owners of the foals provided a signed informed consent prior to participation in the study. Prior publication: Data have not been published previously. Competing interests: The authors declare that they have no competing interests., (© 2025. The Author(s).)

Background: Glanders and melioidosis are contagious zoonotic diseases caused by Burkholderia mallei and B. pseudomallei, respectively. Bacterial isolation and polymerase chain reaction (PCR) have been used to detect these bacteria in animals suspected of infection; however, both methods require skilled experimental techniques and expensive equipment. These obstacles make it difficult to diagnose B. mallei and B. pseudomallei infections in areas where reagents and equipment are difficult to procure. To solve this problem, we developed an easy and ready-to-use dried-format diagnostic tool based on loop-mediated isothermal amplification (LAMP) method., Results: The primer set targeting the internal transcribed spacer (ITS) region detected 10 genomic copies of B. mallei DNA and B. pseudomallei DNA using the conventional liquid LAMP method. This primer set did not detect any other Burkholderia species. Using this novel primer set, a dried-format in-house LAMP method with high sensitivity and specificity was developed. This method was used to test for the presence of B. mallei DNA in swabs collected from the nasal cavity and ulcerated skin of 19 B. mallei-infected horses and five uninfected horses and was compared with the real-time PCR method. These two tests showed 87.5% agreement for the positive samples and 100% agreement for the negative samples. This method detected all tested B. pseudomallei clinical isolates., Conclusions: We established the first dry LAMP method for the detection of B. mallei and B. pseudomallei. This study provided a simple, rapid, cost-effective, and sensitive diagnostic tool for glanders and melioidosis., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Animal Ethics Committee of the Veterinary Science and Bio-medical Research at the Mongolian University of Life Science (VSBMR23/01/21) and was carried out in accordance with the Standard Diagnosis Guide for Animal Diseases 2015 of the State Central Veterinary Laboratory, Mongolia. In accordance with the General Authority for Veterinary Services of Mongolia, no approval was required for ante-mortem sampling as it was conducted as part of standard veterinary care. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

BPV1, BPV2, BPV13, and BPV14 are all genotypes of bovine delta papillomaviruses (δPV), of which the first three cause infections in horses and are associated with equine sarcoids. However, BPV14 infection has never been reported in equine species. In this study, we examined 58 fresh and thawed commercial semen samples from healthy stallions. In 34 (58.6%), bovine δPV DNA was detected and quantified using droplet digital polymerase chain reaction (ddPCR). Real time quantitative PCR (qPCR) was able to identify bovine δPV DNA in 5 samples (8.6%). Of the BPV-infected semen samples, 15 were positive for BPV2 (~ 44.1%) on ddPCR and 4 (~ 11.7%) on qPCR; 12 (~ 35.3%) for BPV14 on ddPCR and 1 (~ 3%) by qPCR; 4 (~ 11.7%) for BPV1 on ddPCR, whereas qPCR failed to reveal this infection; 3 (~ 8.8%) for BPV13 on ddPCR; and BPV13 infection was not detected by qPCR. Our study showed for the first time that BPV14 is an additional infectious agent potentially responsible for infection in horses, as its transcripts were detected and quantified in some semen samples. Large-scale BPV14 screening is necessary to provide substantial data on the molecular epidemiology for a better understanding of the geographical divergence of BPV14 prevalence in different areas and how widespread BPV14 is among equids., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: Semen samples were commercially purchased. Some additional samples were collected at the Didactic Veterinary University Hospital (DVUH) of Naples. All animal studies were approved by the Institutional Animal Care and Use Committee (Protocol PG/2024/0023599, Naples University Federico II). Permission to collect samples was obtained from the animals’ owners., (© 2025. The Author(s).)

Background: A markerless artificial intelligence (AI) system for lameness detection has recently become available but has not been extensively compared with commonly used inertial measurement unit (IMU) systems for detecting asymmetry under field conditions., Objective: Comparison of classification of asymmetric limbs under field conditions and comparison of normalised asymmetry data using a markerless AI system (SleipAI; recorded on a tripod mounted iPhone 14pro [SL]); the Equinosis Q Lameness Locator (LL); the EquiMoves (EM); and subjective evaluation (SE)., Study Design: Descriptive clinical study., Methods: Straight line trot data were collected from 52 client-owned horses in regular training. Limbs were categorised as symmetric or asymmetric. Number of analysed strides were compared with Wilcoxon's each pairs test. Inter-rater reliability in classification of asymmetric limbs was assessed with Light's Kappa. Bland Altman analysis of normalised asymmetry data was performed., Results: Data from 41 horses were included. Most horses showed mild asymmetry. The EM analysed significantly more strides than the other systems, both for forelimbs and for hindlimbs (53 ± 11 strides for both, respectively; p < 0.006). The LL analysed significantly more hindlimbs strides (45 ± 13) than the SL (27 ± 6; p < 0.001). Moderate inter-rater agreement for asymmetry classification was found between systems (k = 0.59 forelimbs; 0.44 hindlimbs); agreement decreased when including the SE. For the normalised asymmetry data, the strongest agreement was found between the two IMU systems., Main Limitations: Horses were assessed during straight-line trot only., Conclusions: The objective systems were comparable in classification of asymmetric limbs under field conditions when using defined asymmetry thresholds. Discrepancies stemmed largely from the imposed thresholds (i.e., systems largely identified same-side asymmetry). Overall, the strongest agreement was found between LL and EM. The SL analysed significantly fewer hindlimb strides than the LL and EM which could represent a limitation of the Sleip AI., (© 2024 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)

Background: Racehorses may experience exercise-induced bronchodilation or bronchoconstriction, with potential differences between healthy and asthmatic individuals., Objectives: To identify exercise-related lung function variations by oscillometry in racehorses, compare lung function between healthy and mild equine asthma (MEA) horses, assess oscillometry's potential as a predictor of racing fitness., Study Design: Prospective case-control clinical study., Methods: Fourteen Thoroughbred racehorses (5 healthy, 9 MEA) underwent a protocol including respiratory oscillometry at rest, exercise with fitness monitoring, oscillometry at 15 and 45 min post-exercise, and bronchoalveolar lavage fluid (BALf) cytology. Oscillometry parameters (resistance [Rrs] and reactance [Xrs]) were compared within and between healthy and MEA groups at different timepoints. Associations between Rrs and Xrs at rest and 15 min post-exercise and BALf cytology and fitness indices were evaluated., Results: MEA horses showed higher Rrs at 15 min post-exercise (0.6 ± 0.2 cmH 2 O/L/s) than healthy horses (0.3 ± 0.1 cmH 2 O/L/s) (p < 0.01). In healthy horses, Rrs decreased at 15 min post-exercise compared with resting values (0.5 ± 0.1 cmH 2 O/L/s) (p = 0.04). In MEA horses, oscillometry parameters did not vary with time. Post-exercise Xrs inversely correlated with total haemosiderin score (p < 0.01, r 2  = 0.51). Resting Rrs inversely correlated with speed at 200 bpm (p = 0.03, r 2  = -0.61), and Xrs with maximum heart rate (HR) during exercise (p = 0.02, r 2  = -0.62). Post-exercise Rrs inversely correlated with mean (p = 0.04, r 2  = -0.60) and maximum speed (p = 0.04, r 2  = -0.60), and HR variability (p < 0.01, r 2  = -0.74)., Main Limitations: Small sample size, oscillometry repeatability not assessed, potential interference of upper airway obstructions, external variables influencing fitness indices., Conclusions: Oscillometry identified lung function differences between healthy and MEA horses at 15 min post-exercise. Only healthy horses exhibited exercise-induced bronchodilation. Oscillometry showed potential in predicting subclinical airway obstruction., (© 2024 EVJ Ltd.)

Background: The diagnostic value of plain radiography for diagnosing synovial penetration in limb wounds near synovial structures has not been determined., Objectives: To assess diagnostic accuracy of plain radiography to identify synovial penetration in horses with traumatic limb wounds., Study Design: Retrospective case study., Methods: Case records of horses presented to the Faculty of Veterinary Medicine of Ghent University (2011-2021) with limb wounds near synovial structures were categorised in groups with and without synovial penetration using results of synovial fluid analysis and surgical findings. Plain radiographic images were evaluated retrospectively. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the total study sample and for the cases with and without use of a metallic probe in the wound during radiographic evaluation., Results: Based on the total sample of 141 horses with synovial penetration and 75 cases without synovial involvement, plain radiography presented a sensitivity of 61% (95% CI: 52%-69%), a specificity of 81% (95% CI: 70%-89%), a PPV of 86% (95% CI: 79%-90%) and a NPV of 53% (95% CI: 46%-58%). With the use of a metallic probe, a sensitivity of 54% (95% Cl: 39%-69%), a specificity of 88% (95% Cl: 64%-99%), a PPV of 93% (95% Cl: 78%-98%) and a NPV of 41% (95% Cl: 32%-49%) were obtained., Main Limitations: Sample size did not allow comparing different synovial structures. Results can be influenced by individual case characteristics., Conclusions: If findings of a series of plain radiographs suggest synovial penetration in horses with a wound near a synovial cavity, then synovial penetration is likely, but the absence of plain radiographic findings does not rule out synovial penetration. The use of a metallic probe during radiography may be helpful. However, plain radiography should be interpreted cautiously, and clinical decision making should also include other techniques., (© 2024 EVJ Ltd.)

Fungal and bacterial culture is currently the primary method for pathogen detection and identification. Next-generation sequencing is a powerful method for detecting and identifying the presence of microbial DNA in samples. We evaluated the correlation between fungal and bacterial culture with next-generation sequencing in equine uterine samples. Fungal cultures (n=63) were evaluated based on their culture results. In culture positive (n=16) samples, next-generation sequencing identified the same organism in 10 samples (62.5%), 5 samples did not identify fungal agents, and 1 sample identified other species of fungal agents. In no growth samples (n=42), next-generation sequencing did not identify fungal agents in 37 samples (88.1%), 4 samples had a potential fungal pathogen identified, and one sample identified only non-pathogenic fungal organisms. Fungal culture and next-generation sequencing had an 80% agreement and moderate correlation by Kappa coefficient (0.508). Bacterial culture (n=57) was also evaluated based on bacterial culture results. In bacterial culture Positive samples (n=32), next-generation sequencing identified the same organism in 25 (78.1%) samples, and identified different organisms from the remaining 7 samples. In bacterial no growth samples (n=14), next-generation sequencing detected bacterial presence in 5 samples, and 9 samples had no bacterial DNA identified. The agreement between bacterial culture and next-generation sequencing was 74% with a moderate correlation by Kappa coefficient (0.46). In conclusion, culture and next-generation sequencing have moderate correlation, and next-generation sequencing has the potential as a diagnostic option for enhancing pathogen detection for equine endometritis., Competing Interests: Declaration of competing interest SHC received honoraria as a speaker at a veterinary conference from MicrogenVet., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In 2018, a new virus, named equine parvovirus-hepatitis (EqPV-H), was discovered in a biologic product that had been administered to horses that subsequently developed clinical signs of equine serum hepatitis (Theiler disease). Further correlation of the virus with the disease sparked federal requirements that all equine biologics be free of EqPV-H. The initial quantitative real-time PCR (qPCR) test for EqPV-H has proved to be sensitive to co-extracted PCR inhibitors in template nucleic acids, causing false-negative results. We investigated the use of digital PCR (dPCR) as a more robust test. Examination of 227 equine biologic product lots available for purchase both before and after regulatory implementation using both detection methods indicated that dPCR is a more reliable platform. Nevertheless, use of the qPCR method for product screening had reduced the fraction of serials with EqPV-H detected from 39.6% prior to regulation to 6.8% after regulatory implementation. Adoption of dPCR testing is an opportunity to further decrease the prevalence of EqPV-H in equine biologics., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Pituitary pars intermedia dysfunction (PPID) is a neurodegenerative disease of senior horses. Loss of dopaminergic inhibition of the melanotropes of the pars intermedia leads to increased concentrations of pro-opiomelanocortin (POMC)-derived peptides. Diagnosis is challenging due to pre-analytical variables, such as sample storage, handling, and time to analysis. Our objective was to develop an ELISA for ACTH measurement, which could ultimately form the basis for a stall-side equine ACTH test. We selected 2 ACTH-specific monoclonal antibodies, CBL57 and EPR20361-248, based on the recognition of separate epitopes, strong and rapid color change, and minimal background interference, including no cross-reactivity with themselves, each other, and the test reagents. CBL57 was chosen as the detection antibody (or secondary antibody). EPR20361-248, functionalized on superparamagnetic iron oxide beads, was chosen as the capture antibody (or primary antibody) to bind ACTH in plasma. The incorporation of magnetic beads marks the initial stage in establishing a platform that could potentially be utilized in the field, similar to other stall-side tests. The concentrations of antibodies, magnetic beads, and incubation durations were optimized. Our immunoassay detected unglycosylated rat recombinant ACTH. Further studies are ongoing to optimize and validate our assay using equine plasma and serum samples., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Equine Coronavirus (ECoV) can cause gastrointestinal disease and was first described in 2000 in the USA followed by several international outbreak case reports. Disease manifestation is characterised by vague clinical signs, including mild pyrexia, lethargy and anorexia. Morbidity ranges greatly from 10% to 83%. Although uncommon, ECoV may result in death secondary to disruption to the gastrointestinal barrier causing endotoxaemia and hyperammonaemic encephalopathy. Unfortunately to date, there is no vaccine available to prevent ECoV., Case Reports: Three faecal quantitative polymerase chain reaction (qPCR)-positive ECoV cases are described that presented with mild to severe colic signs: a 2-year-old Miniature Pony gelding from South Australia, an 8-year-old Arabian Riding Pony gelding, and a 6-year-old Warmblood mare, both from Western Australia. The diagnosis was based on a positive faecal qPCR, which is currently the gold standard diagnostic tool. All horses in this case series survived after medical management. The Miniature Pony presented with anorexia and mild colic signs. On day 5, the pony revealed severe colic signs unresponsive to analgesia along with severe abdominal distension secondary to caecal distension requiring surgical intervention., Conclusion: To the authors' knowledge, this case series is the first published report of ECoV cases in Australia, and it adds both to the clinical description of the disease in horses and to the differential diagnosis list of colic signs., (© 2024 Australian Veterinary Association.)

An 8-y-old National Show Horse mare was presented for evaluation of pneumonia and laminitis. Harsh bronchovesicular sounds were auscultated throughout both lung fields, and the mare had signs of moderately painful laminitis. Thoracic ultrasonography revealed lung consolidation throughout the dorsal aspect of both lungs, and radiography revealed an extensive diffuse-to-patchy bronchointerstitial lung pattern. The mare's clinical condition rapidly deteriorated, and euthanasia was elected. On postmortem examination, the lungs, omentum, spleen, liver, adrenal glands, kidneys, and femur contained 0.5-2.5-cm, firm, tan nodules. Histologically, the lungs, spleen, liver, kidneys, adrenal glands, omentum, left eye, and femur were infiltrated by bundles and nests of pleomorphic polygonal-to-spindloid cells intermixed with frequent multinucleate cells. Lymphatic vessels in the affected tissues were frequently distended with tumor emboli. Neoplastic cells were diffusely positive for vimentin, desmin, sarcomeric actin, myoblastic differentiation protein 1, and myogenin, supportive of the diagnosis of rhabdomyosarcoma (RMS), which is a rare neoplasm in horses. Cross-striations were not evident with H&E or phosphotungstic acid-hematoxylin stains. Markedly pleomorphic neoplastic cells, multinucleate cells, and lack of cross-striations suggested the subclassification of pleomorphic RMS., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Alpha-fetoprotein (AFP) concentrations have been reported in healthy foals and proposed as a biomarker of sepsis in foals born from mares with experimentally induced placentitis. This study aimed to describe the diagnostic and prognostic value of plasma AFP in foals spontaneously affected by different diseases. The study included all foals less than 72 h old that were diagnosed with either: (1) prematurity (PRE), when born prior to 320 days of gestation with immature physical characteristics; (2) sepsis (SEP), in the presence of both positive blood culture and SIRS or (3) neonatal encephalopathy (NE), with evidence of hypoxic-ischemic injury. Data from healthy foals (H; n=20) were obtained from a previous study. Foals received a complete physical and hematochemical evaluation and blood culture sample collection at hospital admission. Forty-six foals with an average age of 16 h were enrolled and divided into: PRE group (n=7); SEP group (n=14); NE group (n=25). AFP was measured in plasma collected at admission using a commercially available immunoassay validated for horses. AFP was increased in foals in PRE, SEP and NE groups compared with healthy ones (P<0.001) but was not able to discriminate between different diseases and outcomes. Overall, AFP was negatively correlated with foal age (r=-0.6; P<0.001), foal weight (r=-0.3; P=0.048), monocytes count (r=-0.4; P=0.011) and SAA concentration (r=-0.4; P=0.011). AFP appears to be a useful but non-specific indicator of neonatal health, since it upregulates not only in the presence of SIRS and bacteremia, but also during prematurity and hypoxic-ischemic injury., Competing Interests: Declaration of competing interest None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Hydropsical conditions in domestic animals are characterized by abnormal fluid accumulation. While their complete pathophysiology remains unclear, factors such as changes in chorioallantoic membranes, placentitis, or fetal abnormalities may contribute. Hydrops present as a medical emergency that can cause complications for the mare. Early diagnosis and treatment are crucial for the mare's prognosis, as fetal survival is often poor. This report describes a case of hydroallantois in a 9-year-old pregnant Quarter mare at 271 days of gestation, leading to dystocia of a non-viable foal with multiple congenital abnormalities. Given the poor prognosis for fetal survival, transcervical gradual fluid drainage and pregnancy termination were performed. The malformed fetus was subsequently delivered and humanely euthanized. Necropsy findings revealed a schistosomus fetus with palatoschisis, a wry nose, prognathism, and unilateral ovarian agenesia. The case underscores the importance of timely intervention in managing hydroallantois. The report contributes to understanding horses' clinical presentation, diagnosis, and management of hydroallantois., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Coxofemoral dysplasia is a condition characterized by the abnormal development and flattening of the femoral head and deformities in the acetabulum, leading to joint instability. Although described in various animal species, it is uncommon and rarely reported in horses. This article presents a case of incapacitating coxofemoral dysplasia diagnosed in a four-month-old foal Mangalarga Marchador, which exhibited lameness in the hind limbs, thoracolumbar kyphosis, gluteal muscle atrophy, and pronounced sensitivity during pelvic limb flexion. The clinical diagnosis indicative of bilateral coxofemoral dysplasia was confirmed through post-mortem examination. This case report highlights the importance of awareness and monitoring for early detection of coxofemoral dysplasia in foals., Competing Interests: Declaration of competing interest None of the authors have any financial or personal relationships that could improperly influence or bias the content of the paper., (Copyright © 2024. Published by Elsevier Inc.)

Serum protein electrophoresis (SPE) is widely used to evaluate protein changes associated with several pathologies, aiming to assist clinical diagnosis. This study determines, for the first time, SPE profile changes in West Nile virus-naturally infected horses. Sixty horses with different clinical and infection status (encephalitis, asymptomatic infection, and immunologically naïve) were included. Total protein concentrations were determined via an automated biuret method and SPE was performed using a cellulose acetate membrane-based automated system. Statistical analysis revealed significantly higher total protein between both infected horse groups (encephalitis, asymptomatic) and naïve controls. Horses with encephalitis had higher globulin and α2-globulin levels than the other two groups (asymptomatic, naïve), along with lower albumin percentage and albumin-to-globulin ratio. Furthermore, γ-globulin levels were significantly higher in asymptomatically infected compared to control horses. These findings highlight the diagnostic value of SPE profile determination, assisting the clinicians, and providing the grounds for further research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background/objectives: The aim was to compare ophthalmic diagnoses made by veterinarians to a deep learning (artificial intelligence) software tool which was developed to aid in the diagnosis of equine ophthalmic diseases. As equine ophthalmology is a very specialised field in equine medicine, the tool may be able to help in diagnosing equine ophthalmic emergencies such as uveitis., Study Design: In silico tool development and assessment of diagnostic performance., Methods: A deep learning tool which was developed and trained for classification of equine ophthalmic diseases was tested with 40 photographs displaying various equine ophthalmic diseases. The same data set was shown to different groups of veterinarians (equine, small animal, mixed practice, other) using an opinion poll to compare the results and evaluate the performance of the programme. Convolutional Neural Networks (CNN) were trained on 2346 photographs of equine eyes, which were augmented to 9384 images. Two hundred and sixty-one separate unmodified images were used to evaluate the trained network. The trained deep learning tool was used on 40 photographs of equine eyes (10 healthy, 12 uveitis, 18 other diseases). An opinion poll was used to evaluate the diagnostic performance of 148 veterinarians in comparison to the software tool., Results: The probability for the correct answer was 93% for the AI programme. Equine veterinarians answered correctly in 76%, whereas other veterinarians reached 67% probability for the correct diagnosis., Main Limitations: Diagnosis was solely based on images of equine eyes without the possibility to evaluate the inner eye., Conclusions: The deep learning tool proved to be at least equivalent to veterinarians in assessing ophthalmic diseases in photographs. We therefore conclude that the software tool may be useful in detecting potential emergency cases. In this context, blindness in horses may be prevented as the horse can receive accurate treatment or can be sent to an equine hospital. Furthermore, the tool gives less experienced veterinarians the opportunity to differentiate between uveitis and other ocular anterior segment disease and to support them in their decision-making regarding treatment., (© 2024 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)

The control of equine respiratory infections is a biosecurity challenge. Respiratory viruses are often rapidly detected using quantitative polymerase chain reaction (qPCR) on nasal swabs. In the past, some laboratories developed handmade techniques to increase the amount of nasal secretions collected, without comparing them with nasal swabs when qPCR replaced the use of viral culture. The objectives of this study were to compare nasal swabs and handmade foam cubes for i) the detection of a common equine herpesvirus (EHV-5) by qPCR, and ii) their tolerability. Forty-five polyester swabs and foam cubes were used to sample 9 horses 5 times. These were then analyzed by qPCR for EHV-5. Agreement of qPCR results (positive, suspect, negative) was assessed using the intraclass correlation (ICC) and the avoidance scores were compared using a proportional odds mixed model. The ICC showed moderate agreement (0.61, P < 0.001). Twenty-seven percent of the samples were positive or suspect with either swabs or foam cubes, whereas 18% were strictly positive with swabs and 11% with foam cubes. Avoidance scores were not statistically different. Both methods have an acceptable agreement. Handmade foam cubes did not provide additional diagnostic value compared to polyester swabs, which is the method presently recommended., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Background: Evaluating antibody titers for Sarcocystis neurona for the diagnosis of equine protozoal myeloencephalitis from serum samples is a common practice. However, ensuring timely and proper refrigeration is not always possible., Objectives: To evaluate immunofluorescent antibody (IFA) titers for S. neurona from serum samples stored at room temperature and 4°C., Samples: Twenty-two serum samples., Methods: Prospective longitudinal study. Two serum aliquots of 1 mL each were stored at room temperature (20-23.3°C) and 4°C. The unrefrigerated aliquot was immediately tested for IFA titers. Both aliquots were retested on Days 5 and 10 after collection. A paired t test was used to compare IFA titers at different time points., Results: There was no significant difference between IFA titers from baseline with those stored at room temperature at Days 5 (P = .741, 95% CI [-56.83, 78.65]), 10 (P = .677, 95% CI [-50.01, 75.46]), and between 5 and 10 days (P = 0.949, 95% CI [-57.50, 61.14]). There was no significant difference from baseline with those stored at 4°C for Days 5 (P = .964, 95% CI [-81.81, 85.45]), 10 (P = 0.573, 95% CI [-109.4, 62.15]), and between 5 and 10 days (P = .5, 95% CI [-102.6, 51.67]). There was no statistical difference between samples stored at room temperature and 4°C (P = .688, CI [-55.51, 37.33]) on Days 5 and 10 (P = .104, CI [-80.8, 8.07])., Conclusions and Clinical Importance: Immunofluorescent antibody test titers for S. neurona are stable for up to 10 days at room temperature and 4°C., (© 2024 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Strongylus vulgaris, a devastating parasitic nematode in equids, causes life-threatening verminous aneurysms that are challenging to diagnose early. This study pioneered integrating nanotechnology into an indirect enzyme-linked immunosorbent assay (i-ELISA) system to enhance the sensitivity and specificity for detecting S. vulgaris larval antigens in equine serum samples, with PCR confirmation of the species. A conventional i-ELISA and an innovative nano-based ELISA were developed using excretory-secretory antigens from adult S. vulgaris worms. The nano-ELISA incorporated gold nanoparticles (17.4-41.4 nm) conjugated with detection antibodies, enabling remarkable signal amplification. Of the 120 examined equines, 100 (83.33%) were positive for S. vulgaris infection. A conventional i-ELISA and an innovative nano-ELISA incorporating 17.4-41.4 nm gold nanoparticles were optimized using S. vulgaris excretory-secretory antigens. Both assays demonstrated high specificity, with no cross-reactivity against sera from animals infected with other helminth parasites. Remarkably, optical density (OD) readings from both i-ELISAs exhibited a positive quantitative correlation with infection intensity. The i-ELISA OD ranged from 0.45-0.74 (G3), 0.75-0.94 (G2), to 0.95-2.5 (G1). The nano-ELISA showed enhanced signal amplification, with OD ranging from 0.40-0.84 (G3), 0.85-0.99 (G2), to 1.0-3.5 (G1). This nanotechnology-amplified ELISA opens new, highly sensitive, and specific techniques for parasitic diagnosis in equine medicine. Its superior performance, facilitated by signal-amplifying gold nanoparticles, illuminates nanotechnology's potential in revolutionizing parasitological diagnostics for enhanced animal health and welfare management., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Animal Care and Use Committee of Cairo University and performed in accordance with the “Guidelines for Experimental Animals as well as collection of samples; of the Faculty of Veterinary Medicine, Cairo University, Egypt with the code: Vet CU 25122023848. All the methods were carried out in accordance with the relevant guidelines and regulations of the use and handling of the animals and we take a permission from our university for sampling. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Diagnosis of equine Lyme borreliosis (LB), an infection caused by members of the Borrelia burgdorferi sensu lato complex (Bbsl), is challenging due to the nonspecific clinical signs of the disease and due to the variety of non-standardized serological tests. Specific vaccine-induced antibodies against LB, providing an effective protection against the infection, complicate the issue further. The standard for the detection of specific antibodies against Bbsl is a two-tier test system based on an enzyme-linked immunosorbent assay (ELISA) or indirect fluorescent antibody test (IFA) for antibody screening combined with a qualitative, highly specific immunoassay (e. g. line immunoassay (LIA)) for confirmation. In this study, three LIAs available for detection of antibodies in equine serum samples were evaluated and compared. A total of 393 serum samples of 131 horses with known serostatus were used. It included groups of non-vaccinated horses, immunized horses (vaccinations against LB on days 0 and 14), and horses that had received an initial immunization plus an additional booster on day 180. Sera were collected on days 0, 135 and 210 of the study. Results were compared considering the tests' sensitivity, specificity, diagnostic outcome, and the operability of each test. Agreements of the diagnostic results among the LIAs were calculated for overall test results and single antigen-antibody-complex signal results. They are presented as inter-rater agreement and statistic reliability, represented by the Fleiss' kappa coefficient. Agreement scores ranged from poor to moderate depending on group and time-point of blood sample collection. Depending on LIA used, deficiencies were observed in the form of non-sufficient sensitivity of antigen signals on the LIA strips (especially for outer surface protein A (OspA) or variable major protein like sequence expressed (VlsE)) or as an inappropriate test interpretation of the OspA signal. Operability of the three LIAs was equally user-friendly with minor variations. In two LIAs, test-evaluation was simplified by a supplied scanner and evaluation software. To improve functionality of available LIAs for equine serum samples it is advisable to adjust sensitivity and specificity of single test antigen signals and establish appropriate evaluation protocols., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Broeckl et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: To describe indications for and demonstrate the technique to perform a transtracheal aspirate in horses. Transtracheal aspirate is indicated to collect samples for cytology and bacteriologic culture in cases of suspected pneumonia or other lower respiratory tract disease., Animals: 1 healthy university-owned horse was used for demonstration purposes. Images of clinical case samples from the University of Illinois Veterinary Teaching Hospital are shown., Methods: The horse is restrained and sedated with detomidine or xylazine to facilitate restraint and butorphanol to minimize coughing. The ventral neck is clipped and aseptically prepared. The site of planned puncture proximal to the bifurcation of the sternocephalicus is anesthetized with lidocaine. Two to three 30-mL syringes are filled with saline aseptically. A stab incision is made with a No. 15 blade to the depth of the trachea. The trocar is advanced between tracheal rings on midline, the stylet removed, and the aspiration catheter advanced through the trocar to the level of the proximal horizontal trachea. Sterile saline (30 mL) is infused rapidly, and suction is applied to the syringe while slowly withdrawing the catheter until fluid is retrieved. The catheter and trocar are withdrawn and the puncture site covered with antimicrobial ointment or a light bandage., Results: Samples are collected in a plain tube for bacteriologic culture and EDTA for cytology. The visual appearance of purulent effluent confirms severe pneumonia., Clinical Relevance: Transtracheal aspirate is minimally invasive and simple to perform with available kits. Samples provide valuable information to guide treatment decisions and selection of antimicrobials for horses with suspected lower respiratory tract disease.

Equine granulocytic anaplasmosis (EGA) is a tick-borne disease caused by Anaplasma ( A .) phagocytophilum . In Central, Northern, Western, and Eastern Europe, ticks of the Ixodes ( I .) ricinus / I. persulcatus complex, in Germany mainly I. ricinus , are considered as vectors. Ixodes ricinus ticks show peaks of activity during the spring and summer months, particularly April to July. Changing climatic conditions, however, have meanwhile led to a year-round risk of tick exposure and thus infections with A. phagocytophilum . The presented case report underlines the seasonal peak phase of the infection risk in that the presentation of the horse to the veterinarian occurred in June. Additionally, clinical signs - including fever - are mostly unspecific and thrombocytopenia represents the most significant hematological abnormality. Direct and indirect detection methods are available for the diagnosis of an infection or contact with the pathogen. A positive PCR confirms an acute infection, as in the presented case, while positive antibody levels indicate contact with the pathogen in the (recent) past. Additionally, inclusion bodies, so called morulae, may be detected rapidly and inexpensively in smears derived from the peripheral blood and are predominantly found in neutrophilic granulocytes, less frequently in eosinophilic granulocytes. However, microscopy has a lower sensitivity compared to PCR-testing. In the presented case, morulae could not be detected in EDTA blood despite positive PCR. Antibiotics with intracellular activity, such as oxytetracycline and/or doxycycline are the treatment of choice and, as in the described case, often result in rapid clinical improvement in horses suffering from EGA. The elimination of the pathogen should be confirmed by PCR-testing 5-8 days after the completion of the antibiotic therapy. Whether and how long antibodies against A. phagocytophilum could possibly be protective against reinfection remains unknown. In humans, A. phagocytophilum is classified as an emerging pathogen of increasing clinical importance in the northern hemisphere., Competing Interests: Carla Wiebke Axt, Torsten J. Naucke und Ingo Schäfer sind Angestellte der Laboklin GmbH & Co. KG. Elisabeth Müller ist Geschäftsführerin der Laboklin GmbH & Co. KG. Christina Strube hat für diagnostische und (veterinär-)pharmazeutische Unternehmen Vorträge gehalten sowie diese beraten und in der Vergangenheit wie auch gegenwärtig wissenschaftlich zusammengearbeitet. Andrea Springer und Arno Besse deklarieren keinen potenziellen Interessenkonflikt., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

There are a number of unusual tumors in the horse. Gross tumor characteristics, anatomical location, and signalment may assist with identification. Clinical pathology is often unrewarding with non-specific findings, while fine needle aspirates may not obtain sufficient tissue material to confirm a diagnosis. Although regular staining of biopsy material may be sufficient, immunohistochemistry markers may be required, especially in less differentiated tumors. The prognosis is dependent on the type, location, tumor size as well as on metastatic spread. A selection of unusual and rare tumors that the clinician is more likely to encounter is discussed., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Neoplasia has been reported to involve the majority of the urinary system of the horse, with tumors affecting the kidneys and bladder most comprehensively described. Primary tumors of the external genitalia are relatively common in the horse and are easily identified on clinical examination while primary tumors of the upper urogenital tract are uncommon. This article will highlight the common tumors, their clinical presentations, and discuss potential medical and surgical treatment options available. The less common neoplasms will be mentioned but not discussed in depth., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Cancer is disease of the genome. The Hallmarks of cancer are a way of thinking of cancer to help rationalize what occurs in this disease process. A solid tumor is a complex of normal and neoplastic cells, arising through an evolutionary process to survive and grow. By understanding how normal cellular mechanisms are subverted to promote cancer we can refine our approach to improve outcomes. It gives us opportunities to prevent some cancers and allowing earlier diagnosis. We can refine conventional diagnostic tools and give more accurate prognoses. It offers novel targets to improve treatment of cancers, allowing personalized medicine., Competing Interests: Disclosure There are no affiliations other than I (S. Murphy) work for the University of Edinburgh., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This article reviews the different types of equine non-neoplastic and neoplastic oral and sinonasal tumors and describes their known prevalence and general characteristics. The clinical and ancillary diagnostic findings (primarily radiography and endoscopy, and increasingly computed tomography) for each type of growth that can aid diagnosis are described. Most lesions require a histopathological confirmation of the diagnosed growth. The possible treatments and prognosis for these growths are briefly described., Competing Interests: Disclosure The author has nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Uroperitoneum is a typical disease in newborn foals. It occurs rarely but regularly. The aim of the present study is to present clinical signs, laboratory findings and prognosis of foals with uroperitoneum., Material and Methods: Medical records of 33 foals suffering from uroperitoneum that were treated between 2006 and June 2018 were reviewed retrospectively., Results: The incidence was 2.3% based of all presented foals during the first 14 days of life in the investigation period. Colts (78.8%) were significant more often affected (p=0,012) than fillies (21.2%). Common clinical signs were disturbed general condition (79.3%), tachypnea (74.1%), tachycardia (71.4%), distended abdomen (79.2%), highly turgid abdomen (60%) respectively tense abdomen (32%) and straining to urinate (46.7%). The mean age at time of diagnosis was 4.3±3.4 days (median: 3 days, range:<1 to 14 days). 26 foals were treated surgically. 16 foals survived (61.5%). Common laboratory findings at the time of diagnosis were hypochloridemia (91.2%), increased creatinine concentration (77.8%), hyperkaliemia (74.2%) and hyponatriemia (71%). 6 foals developed recurrence of the uroperitoneum. Five foals underwent a second laparotomy, 4 of these survived. The mean duration of hospitalization of healthy discharged foals was 11.6±3.7 days (median: 11 days). Follow-up data was obtained through owner contact for discharged 12 foals six months or longer following surgery (6 months to 9 years). 91.7% of these were alive and none of them developed medical issues in the urinary tract as sequela to surgery of the uroperitoneum., Conclusion and Clinical Relevance: The short-term prognosis of uroperitoneum is good when it is recognized and treated early and no or only few concomitant diseases are present. Performing repeated postoperative follow-up sonography examinations is recommended in order to recognize a recurrence of the uroperitoneum early-on. The further long-term prognosis is very good., Competing Interests: Die Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Lymphoma and myeloproliferative diseases in horses are relatively uncommon. The clinical signs, prognosis, and treatment options depend upon the anatomic location and subtype. Significant gaps in knowledge remain regarding prevalence, pathogenesis of different subtypes, antemortem diagnostic tests, response to treatment, and standardized treatment protocols. However, treatment options are available, accessible on the farm, and could improve quality of life and prolong survival., Competing Interests: Disclosure The authors declare no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This article discusses the reported paraneoplastic syndromes (PNSs) in horses, including the possible pathogenesis, diagnostic methods, and any treatment options. The more commonly reported PNSs in horses include cancer anorexia and cachexia, fever and increased acute phase protein concentrations, and hypercalcemia and monoclonal gammopathy. As these conditions can often be more commonly diagnosed in non-neoplastic conditions, the diagnosis of a PNS and the accompanying neoplasia can be challenging. As signs of a PNS may precede signs of the underlying neoplasia, it is important that the clinician be aware of the possible presence of a PNS., Competing Interests: Disclosure The author has no conflicts to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Lymphoma is the most common tumor of hematopoietic origin in horses. The course of the disease and clinical signs vary greatly, depending on tumor location and extent. The aim of this report is to describe the occurrence of T-cell-rich oral large B-cell lymphoma with marked local infiltration in a 25-year-old Crioula mare. The mare showed an increase in volume on the right side of its face, dyspnea, anorexia, and progressive weight loss. The clinical assessment showed that the lesion was located in the rostral and caudal sinuses and was markedly invasive to adjacent structures. The autopsy revealed a yellow mass with a soft to firm consistency, infiltrating multiple bones in the skull, and extensively invading the hard palate and masseter muscle. Histologically the mass comprised an undifferentiated malignant neoplasm characterized by a densely cellular neoplasm composed of large CD20 + neoplastic B-lymphocytes admixed with sheets of small, CD3 + reactive T-lymphocytes supported by delicate fibrovascular stroma leading to the diagnosis of oral T-cell-rich large B-cell lymphoma., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Thoracic neoplasia often presents with generalized and nonspecific clinical signs and should be considered as a differential especially when patients are nonresponsive to therapeutic intervention for more common differential diagnoses of respiratory disease (such as equine asthma) and where there is evidence thoracic and/or abdominal effusion upon examination. Antemortem diagnosis can be challenging and working closely with a pathologist to differentiate the respective neoplasia is helpful. Early recognition and appropriate management of thoracic neoplasia are vital for patient welfare as rapid disease progression can be relatively quick, and/or the relatively advanced stage of disease in which these patients frequently present., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Gastrointestinal neoplasia is uncommon in horses. Clinical signs can be vague and advanced testing, including biopsy, exploratory surgery, and/or advanced imaging may be required for diagnosis. Prognosis varies by location, organ involved and is frequently poor to grave., Competing Interests: Disclosure No conflicts of interest to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The diagnosis of neoplasia in the horse is both simple and extremely challenging, depending on the type of neoplasm and its location. Obtaining an accurate diagnosis of a neoplastic condition is key to formulating an appropriate treatment plan if possible or developing a palliative plan if curative treatment options do not exist. A combination of historical features, clinical examination findings, and diagnostic testing typically allow a working diagnosis of neoplasia to be made, with a definitive diagnosis requiring the identification of neoplastic cells in a sample or tissue., Competing Interests: Disclosure No conflicts of interest of funding declared by either author., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Due to concerns about disagreement between veterinarians when grading resting laryngeal function (LF), a diagnostic decision tree (DDT) has been developed by codifying the Havemeyer grading system and objectively defining certain terms to remove ambiguity. Videoendoscopic examinations of the equine larynx that had previously been assigned a unanimous LF grade by 3 experienced observers were used to develop the DDT and determine the cut-off values. The DDT is a flow chart consisting of a series of dichotomous (yes/no) decisions, to dictate the order of decision making and direct the observer down a pathway towards the most appropriate LF grade. To use the DDT, the observer must know the frame rate of the video and use frame-by-frame video playback when reviewing the videos. The first decision involves determining if full left arytenoid cartilage (LAC) abduction is achieved (≤ grade III.1), or not achieved (> grade III.1). Maintained full LAC abduction (≤ grade II.2) is defined as maintenance of full abduction for ≥ 0.2 seconds. Full LAC abduction that is achieved but not maintained (grade III.1) is defined as maintenance of full abduction for < 0.2 seconds. Arytenoid abductor deficit is categorized into left arytenoid abduction ≥45° from vertical midline (grade III.2) and <45° abduction (grade III.3). The DDT could be used as a first step towards computer assisted laryngeal function grading., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Surveillance of Strongylus vulgaris and other Strongylus spp. in equids is important for targeted intervention in parasite control, requiring reliable routine diagnostic methods., Objectives: Comparing morphological examination and PCR analyses of larval cultures to identify Strongylus spp. species based on German diagnostic samples from 2018., Study Design: Method comparison., Methods: During the routine diagnostic investigations, in total 712 strongyle-egg positive equine faecal samples were cultured. Third-stage larvae (L3) were morphologically differentiated. For molecular validation, samples were examined using S. vulgaris real-time PCR and Strongylus edentatus/Strongylus equinus/Strongylus asini high-resolution melting PCRs., Results: Based on 28S rRNA PCR, 594 samples positive for nematode DNA were included in the study. The inter-rater reliability to compare morphological and molecular species identification was fair for Strongylus spp. without species identification and for S. edentatus, slight for S. equinus and poor for S. vulgaris. The frequency based on morphological and molecular data in this study were for S. vulgaris 0% and 0.8%, respectively, for S. edentatus 0.3% and 1.5%, respectively, and for S. equinus 2.0% and 0.2%, respectively. Based on molecular analyses, one sample obtained from a domestic horse contained S. asini DNA, which was confirmed by sequencing., Main Limitations: For many samples, no or only incomplete data regarding clinical history, the exact geographical location and whether samples were obtained on individual or farm level, were available., Conclusions: Results of morphological and molecular examination methods of strongyle L3 from equine samples can differ substantially. Further evaluation of these methods is required to provide reliable and cost-effective methods of screening equine parasites. Further studies using approaches suitable to detect S. asini are needed to evaluate its clinical and epidemiological relevance., (© 2024 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)

Background: Paroxysmal atrial fibrillation (pAF) occurs sporadically and can impair athletic performance. Gold standard for diagnosis is surface electrocardiography (ECG), however, this requires AF to be sustained. Implantable loop recorders (ILRs) are routinely used for AF detection in human medicine. While ILR placement has been studied in horses, its AF detection performance is unknown., Objectives: (I) Validation of ILRs for AF detection in horses. (II) Determining pAF incidence using ILRs and estimate the positive predictive value (PPV)., Study Design: (I) Experimental study; (II) Longitudinal observational study., Methods: (I) Implantation of ILRs in 15 horses with AF and 13 horses in sinus rhythm. Holter ECGs were recorded at: 1, 4, 8, 12 and 16 weeks of AF. The ILR ECGs were compared with surface ECGs to assess diagnostic sensitivity and specificity. (II) Eighty horses (43 Warmbloods, 37 Standardbreds) with ILRs were monitored for 367 days [IQR 208-621]., Results: (I) ILRs detected AF on all recording days, in horses with AF, with a sensitivity of 66.1% (95% CI: 65.8-66.5) and a specificity of 99.99% (95% CI: 99.97-99.99). The sensitivity remained consistent across all time points. (II) The incidence of pAF was 6.3% (5/80). In horses with pAF, the PPV ranged from 8% to 87%. Increased body condition score (BCS > 6/9) was associated with an increased number of false positive episodes (p = 0.005)., Main Limitations: (I) Horses were stabled during the ECG recordings, and AF was induced, rather than naturally occurring pAF. (II) Integrated algorithm in this ILR is optimised for AF detection in humans using remote monitors. Additionally, sensing is affected by motion artefacts., Conclusion: The ILR reliably detected AF in resting horses, particularly in horses with normal BCS (6/9). The ILR proved useful to detect pAF and is recommended alongside Holter monitoring for diagnostic workup of horses with suspected pAF., (© 2024 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)

Background: Compensatory vertical head and pelvis movement asymmetry may occur in trotting horses with a primary cause of lameness in one end of the body due to the weight shifting between limbs, leading to apparent combined forelimb and hindlimb lameness (CFHL). Little is known about CFHL patterns observed with body-mounted inertial sensors (BMIS) and regardless of their underlying mechanisms, compensatory and secondary lameness may complicate the definitive identification of the primary causes of lameness., Objective: Determine associations between vertical pelvic movement asymmetry and location of primary lameness in ipsilateral CFHL cases where hindlimb lameness is solely impact or push-off type., Study Design: Retrospective cohort., Methods: From a body-mounted inertial sensor (BMIS) evaluated equine lameness database, we identified cases with a consistent, low-variability ipsilateral impact (IpI) or ipsilateral pushoff (IpP) hindlimb lameness in a straight-line trot and that had definitive diagnoses. Cases were categorised by lameness location to the limb(s), diagnosis, and ratio of the amplitude of forelimb to hindlimb lameness (Fore a /Hind a ). Differences in the numbers of IpI and IpP cases in these categories were analysed with chi-square tests, effect sizes, and odds ratios., Results: Among the 2375 total lameness cases screened, 49 IpI and 36 IpP cases met the criteria for consistency, low variability, and definitive diagnosis. IpI cases were more likely than IpP cases to have forelimb-only lameness causes when Fore a /Hind a  >1 (OR = 43, 95% CI = 2.3-798). IpP cases were more likely than IpI cases to have hindlimb-only causes at both Fore a /Hind a  >1.0 (OR = 20, 95% CI = 2.2-200) and <1.0 (OR = 14, 95% CI = 2.9-66.7). Compared with IpI, IpP cases were more frequently diagnosed with tendon, suspensory ligament, or high-motion joint disorders in hindlimbs (OR = 3.6, 95% CI = 1.1-12.3) and less with unknown causes (OR = 13.2, 95% CI = 3.2-75.2). In IpI cases, positive forelimb regional anaesthesia often reduced hindlimb lameness, whereas in IpP cases, positive hindlimb regional anaesthesia typically lessened forelimb lameness., Main Limitations: Most cases were Quarter Horses. The likelihood of location and cause of lameness may be different for other breeds., Conclusions: The type of pelvic movement asymmetry observed in IpI and IpP cases is linked to the location and underlying cause of the primary lameness., (© 2024 EVJ Ltd.)

Smartphone-based technology is increasingly used in veterinary medicine as a complementary tool for cardiac auscultation and ECG recording. This prospective observational study evaluates a digital stethoscope (DS) that consists of simultaneous phonocardiographic and one-lead ECG recording (dECG) in adult horses, comparing it with auscultation using a conventional stethoscope (CS) and reference base-apex ECG (rECG). A total of 104 horses underwent cardiac auscultation using CSs and DSs to detect arrhythmias and murmurs. Audio and dECG were acquired using the DS. The rECG tracings were also recorded. All ECG tracings were blindly evaluated for interpretability, measurements, and diagnosis. The Shapiro-Wilk test was used to assess the data distribution. Weighted Cohen's κ and Bland Altman plot analysis were applied to verify the agreement between reference vs. smartphone-based methods. Almost perfect agreement was found in detecting murmurs and/or arrhythmias between auscultation with the CS and DS, and between CS auscultation and re-listening to DS audio. Perfect agreement was observed between re-listening to DS audio and DS auscultation and in detecting murmur timing between CS and DS auscultation. Almost perfect agreement was found between rECG and dECG in detecting bradycardia, tachycardia, or normal heart rate (HR) and for P-wave polarity. The lack of variability with both methods for QRS polarity prevented statistical analyses from being performed. Fair agreement was found in the assessment of the presence of artifact. In conclusion, the DS reliably detected heart murmurs and arrhythmias through direct auscultation and re-listening to recordings, and accurately evaluated HR, wave and interval measurements, P-wave and QRS-complex polarities in adult horses., Competing Interests: Declarations. Ethics approval: The experiments were conducted following the Guide for the Care and Use of Animals in Research and Teaching, after the approval of the Ethic Committee of the University of Pisa (OPBA n. 53/2020). Consent to participate: All authors consent to participation in this publication. Consent to publish: All authors consent to publication of the manuscript. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Objective: To establish the reference interval (RI) of fecal calprotectin (fCP) and fCP:protein ratio in the feces of healthy horses and demonstrate preliminary clinical utility for the quantification of intestinal inflammation., Methods: Feces were collected from healthy horses (n = 103) and horses with colic (n = 15) or colitis (n = 13). Feces were suspended in buffer to create fecal supernatant. Fecal calprotectin concentration was determined by ELISA, fecal total protein concentration was determined by bicinchoninic acid assay, and the fCP:protein ratio was calculated. Reference intervals for fCP and fCP:protein ratio were calculated from healthy horses. Descriptive and inferential statistics were performed to evaluate associations between fCP concentration and fCP:protein ratio with group and other clinical features. The study period was from September 20, 2023, through April 20, 2024., Results: The RI for fCP was 0.056 to 0.278 μg/mL; 4 of 13 colitis cases had fCP above the RI. The RI for fCP:protein was 6.6 X 10-6 to 4.9 X 10-5; 5 of 13 colitis cases and 2 of 15 colic cases had fCP:protein above the RI. Horses with colitis had significantly greater fCP (median [quartile 1, quartile 3], 0.234 [0.194, 0.279] μg/mL) than healthy horses (0.196 [0.138, 0.220] μg/mL) or colic cases (0.189 [0.164, 0.215] μg/mL). There was a greater difference in fCP:protein ratio between colitis cases (4.31 X 10-5 [3.19 X 10-5, 6.23 X 10-5]) and both healthy horses (2.19 X 10-5 [1.58 X 10-5, 2.88 X 10-5]) and colic cases (1.52 X 10-5 [1.22 X 10-5, 3.56 X 10-5])., Conclusions: Both fCP and fCP:protein ratio were increased in horses in colitis; additional work is needed to establish clinical utility., Clinical Relevance: There are few reliable diagnostic modalities for inflammation of the equine large colon. With additional development of a clinically applicable test and validation in larger population, fecal calprotectin may facilitate noninvasive quantification of intestinal inflammation in horses.

Animal owners may increasingly rely on large language models for gathering animal health information alongside internet sources in the future. This study therefore aims to provide initial results on the accuracy of ChatGPT-4o in triage and tentative diagnostics, using horses as a case study. Ten test vignettes were used to prompt situation assessments from the tool, which were then compared to original assessments made by a veterinary specialist for horses. The most probable diagnosis suggested by ChatGPT-4o was found to be quite accurate in most cases, with the urgency to contact a veterinarian sometimes assessed as higher than necessary. When provided with all relevant information, the tool does not seem to compromise horse health by recommending excessively long waiting times, although there is still potential for improving the relief of veterinarians' workload.

Decreasing speed and stride length over successive races have been shown to be associated with musculoskeletal injury (MSI) in racehorses, demonstrating the potential for early detection of MSI through longitudinal monitoring of changes in stride characteristics. A machine learning (ML) approach for early detection of MSI, enforced rest, and retirement events using this same horse-level, race-level, and stride characteristic data across all race sectionals was investigated. A CatBoost model using features from the two races prior to an event had the highest classification performance (sensitivity score for MSI, enforced rest and retirement equal to 0.00, 0.58, 0.76, respectively and balanced accuracy score corresponding to 0.44), with scores decreasing for models incorporating windows that included additional races further from the event. Feature importance analysis of ML models demonstrated that retirement was predicted by older age, poor performance, and longer racing career, enforced rest was predicted by younger age and better performance, but was less likely to occur when the stride length is increasing, and MSI predicted by increased number of starters, greater variation in speed and lower percentage of career time at rest. A relatively low classification performance highlights the difficulties in discerning MSI from alternate events using ML. Improved data recording through more thorough assessment and annotation of adverse events is expected to improve the predictability of MSI., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical animal research: Data were sourced from existing collections of data and involved no direct work with animals. The Animal Ethics Committee at the University of Melbourne Faculty of Veterinary and Agricultural Science gave an exemption for formal ethics approval., (© 2024. The Author(s).)

Vascular hamartoma is an abnormal development of endothelial tissue that rarely affects horses. Histopathological examination remains the gold standard for definitive diagnosis, yet the presence of abnormal vascular structures must be carefully differentiated from other vascular anomalies and neoplasms. This report describes two cases of vascular proliferation affecting the skin on the lateral side over the left tarsus and the dorsolateral region over the fetlock joint of two fillies. The clinical history, presentation, and radiographic and sonographic findings in both patients suggested a neoplasm of unknown origin. Surgical excision of the mass was successfully performed in both patients. In one patient, a second surgery was performed six months after the first surgery because of the recurrence of the mass. Histopathological examination revealed a disorganized proliferation of well-differentiated, tortuous, and varied-sized blood vessels hemmed in myxoid tissue with abundant fibrocollagenous bands. Immunohistochemical examination of the endothelium markers factor VIII and ERG revealed positive staining of the mass samples in both cases, confirming their vascular origin. The combination of these markers was effective, providing a reliable option for differentiating vascular proliferation in horses. To the best of the author's knowledge, this is the first report applying the ERG endothelial marker to horse vascular malformations., Competing Interests: Declarations Competing interests The authors declare no competing interests. Ethical approval The study described in this manuscript involved the use of non-experimental horses. The owners have provided consent for veterinary clinical care for the individual patient at the São Paulo State University —School of Veterinary Medicine and Animal Science (FMVZ/UNESP), Botucatu, Brazil, and for the publication of their pet’s data. Therefore, ethical approval from a committee was not specifically required for publication., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Current methods for obtaining fecal egg counts in horses are often inaccurate and variable depending on the analyst's skill and experience. Automated digital scanning of fecal sample slides integrated with analysis by an artificial intelligence (AI) algorithm is a viable, emerging alternative that can mitigate operator variation compared to conventional methods in companion animal fecal parasite diagnostics. Vetscan Imagyst is a novel fecal parasite detection system that uploads the scanned image to the cloud where proprietary software analyzes captured images for diagnostic recognition by a deep learning, object detection AI algorithm. The study describes the use and validation of Vetscan Imagyst in equine parasitology., Methods: The primary objective of the study was to evaluate the performance of the Vetscan Imagyst system in terms of diagnostic sensitivity and specificity in testing equine fecal samples (n = 108) for ova from two parasites that commonly infect horses, strongyles and Parascaris spp., compared to reference assays performed by expert parasitologists using a Mini-FLOTAC technique. Two different fecal flotation solutions were used to prepare the sample slides, NaNO 3 and Sheather's sugar solution., Results: Diagnostic sensitivity of the Vetscan Imagyst algorithm for strongyles versus the manual reference test was 99.2% for samples prepared with NaNO 3 solution and 100.0% for samples prepared with Sheather's sugar solution. Sensitivity for Parascaris spp. was 88.9% and 99.9%, respectively, for samples prepared with NaNO 3 and Sheather's sugar solutions. Diagnostic specificity for strongyles was 91.4% and 99.9%, respectively, for samples prepared with NaNO 3 and Sheather's sugar solutions. Specificity for Parascaris spp. was 93.6% and 99.9%, respectively, for samples prepared with NaNO 3 and Sheather's sugar solutions. Lin's concordance correlation coefficients for VETSCAN IMAGYST eggs per gram counts versus those determined by the expert parasitologist were 0.924-0.978 for strongyles and 0.944-0.955 for Parascaris spp., depending on the flotation solution., Conclusions: Sensitivity and specificity results for detecting strongyles and Parascaris spp. in equine fecal samples showed that Vetscan Imagyst can consistently provide diagnostic accuracy equivalent to manual evaluations by skilled parasitologists. As an automated method driven by a deep learning AI algorithm, VETSCAN IMAGYST has the potential to avoid variations in analyst characteristics, thus providing more consistent results in a timely manner, in either clinical or laboratory settings., Competing Interests: Declarations Ethics approval and consent to participate No IACUC or IRB approval was needed for this study design, in accordance with Texas Tech University’s IACUC policies. They were consulted in regard to this study and set up. Consent for publication All authors consent to publication in Parasites and Vectors. Competing interests Ashley Steuer is now employed by Zois, however, at the time of study design and conduct, was under the employ of Texas Tech University., (© 2024. The Author(s).)

The aim of this study was to determine whether horses exhibiting unilateral hindlimb lameness unload (rest) the lame limb more than the contralateral limb. The resting/unloading of the hindlimbs and the time spent lying down were measured using accelerometers. Ten non-lame horses and 20 lame horses were recruited for participation and monitored for 11 h overnight with accelerometers (MSR145, sampling rate: 1 Hz, and measuring range: ±15 g) attached to the lateral metatarsal and metacarpal regions of each limb. Metatarsal and metacarpal orientation were used to determine whether the limb was unloaded (rested) or loaded, respectively, or whether the horses were lying down. The relation of resting time between non-lame and lame limbs (non-lame/lame: 0.85 ± 1.2) of the lame horses differed significantly ( p = 0.035) from that of the non-lame horses (right/left: 1.08 ± 0.47). Non-lame horses rested their hindlimbs evenly (left: 15 ± 10%; right: 17 ± 16%). Horses with unilateral hindlimb lameness unloaded the lame limb longer (lame limb: 61.8 ± 25.3%, non-lame limb: 38.2 ± 25.3%) than their contralateral limb. The lame horses (13 ± 11%) lay down longer ( p = 0.012) than the non-lame horses (3 ± 6%). The degree of lameness determined by the participating veterinarians (Vet Score) (r = -0.691, p < 0.01) and the asymmetry evaluated by the lameness locator (ALL) (r = -0.426, p = 0.019) correlated with the resting ratio (rest time ratio). Both factors were also correlated with the time spent lying down (Vet Score (r = 0.364, p = 0.048) and the ALL (r = 0.398, p = 0.03)). The ALL and VET Score were significantly correlated (r = 0.557, p = 0.01). The results of this study provide a good baseline for future research into how individual resting patterns may help to detect pain.

A 4.5-month-old Standardbred colt presented for neck swelling and fever. Endoscopy and contrast radiography identified a full thickness esophageal perforation. Surgical intervention with fasciotomies and placement of an esophageal feeding tube was elected. Intensive postoperative treatment was carried out with broad-spectrum antibiotics, gastroprotectants and probiotics, calculated feeding plan, esophagostomy and fasciotomy site lavages, care, and cleaning. Complications included recurrent bilateral pneumothorax and development of an incomplete fistula at the esophagostomy site following removal of the feeding tube, necessitating primary closure. One year following presentation, the colt appears to have made a full recovery with an excellent body and muscle condition score and undergoing athletic training. Anticipated price of sale as a yearling was achieved. This study highlights a viable treatment route for youngstock with esophageal perforation that necessitate an esophagostomy. Despite intensive dietary needs of growing foals, appropriate nutritional requirements and normal growth rates can be achieved in such cases., Competing Interests: Declaration of competing interest There are no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

A 16-year-old horse, 400 kg, male, Quarter horse gelding was examined for a cardiac murmur that had not been previously heard. Physical examination revealed a regularly irregular pulse and a grade III/VI, decrescendo, diastolic murmur with a point of maximum intensity over the left heart base. Base-apex standard electrocardiographic examination at rest showed sinus rhythm with second-degree atrio-ventricular blocks. Echocardiography identified the presence of four aortic valve cusps, two equal larger and two unequal smaller cusps. Color flow Doppler examination showed a diastolic regurgitant jet emerging from the central region of closed aortic valve. Based on clinical and echocardiographic findings a diagnosis of mild to moderate aortic valve insufficiency secondary to quadricuspid aortic valve was made. This report describes a rare congenital heart defect that can be detected by transthoracic echocardiography in the horse., Competing Interests: Declaration of competing interest All authors declare that there is no conflicts of interest., (Copyright © 2024. Published by Elsevier Inc.)

Chlamydia abortus is a reported cause of infertility and endometritis in sheep, cattle, and pigs; however, the association between uterine disease and C. abortus is poorly understood in horses. Recently, a high prevalence of C. abortus in equine aborted chorioallantoises was reported in horses in western Canada. Based on this high prevalence, investigation into the effects of C. abortus on infertility and endometritis in western Canadian mares is prudent. We examined 98 formalin-fixed, paraffin-embedded endometrial biopsies from western Canada submitted between 2014 and 2022 using a Chlamydia -specific 16S rRNA PCR test; 40 samples tested positive for Chlamydia on PCR, and 28 were sequenced as C. abortus . The C. abortus -positive cases were primarily associated with a history of failure to conceive, early embryonic loss, or abortion. Our findings suggest that C. abortus may be a cause of conception failure and abortion in horses in western Canada., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.