Objective: To investigate the network pharmacology of furosemide in horses and identify potential off-target interactions that could influence cardiac electrophysiology and arrhythmogenic risk. Procedures: Human protein targets of furosemide were predicted using SwissTargetPrediction and mapped to equine orthologs through gene name matching and UniProt verification. Molecular docking against all equine targets was performed using AutoDock Vina integrated with PrankWeb. High-affinity targets (affinity <125 µM) were subjected to protein-protein interaction network and molecular function enrichment analyses in STRING. Network enrichment analyses were performed for all targets of furosemide, its metabolites (furosemide glucuronide and saluamine), and targets shared between the parent drug and metabolites. Results: Nineteen high-affinity targets of furosemide were identified, including SLC5A2, CDK9, AURKA, MAP2K1, and multiple carbonic anhydrase isoforms. Network analysis highlighted clusters related to ion transport, kinase signalling, and zinc-dependent enzymatic activity. Carbonic anhydrase and zinc-binding functions were prominent in broader network and enrichment analyses, suggesting potential off-target effects of furosemide in cardiopulmonary tissues. Conclusions: Furosemide interacts with multiple equine proteins beyond its canonical renal target, including carbonic anhydrases and zinc-dependent enzymes. These interactions may influence cardiac acid-base homeostasis and electrophysiological stability, providing a plausible mechanism for arrhythmogenic risk and SCD in racehorses. Further in vitro and in vivo studies are warranted to validate these findings and guide safer therapeutic use in high-performance equines.

Background – Sepsis is an important cause of morbidity and mortality in foals. Early diagnosis can improve outcome but is complicated by non-specific clinical signs and delayed confirmation of infection via blood culture. Molecular assays represent a rapid and more sensitive alternative. Objectives – To evaluate and compare bacterial load and composition in blood and blood culture media of sick and healthy foals, and to compare results with traditional bacterial culture. Study design – Cross-sectional observational clinical pilot study. Methods – 13 septic foals, 10 sick non-septic and 8 healthy foals were included. Bacterial load and composition from whole blood (WB), pre-enriched blood culture media (BCM) and contamination controls were analysed by quantitative PCR and sequencing of the universal bacterial 16S rRNA marker gene. Results – Whole blood sequencing yielded more positive samples (27/31) than BCM (6/62; p<0.01). Positive blood culture and WB sequencing were comparable in only 3/12 foals. Sequencing samples were at high potential for contamination, with most samples having high relative abundances (RAs) of Paucibacter and Ralstonia. High RAs of Actinobacillus and Staphylococcus in septic foals may however suggest true pathogen detection. No significant differences in bacterial RAs, 16S rRNA gene load (qPCR), or other sequencing-based metrics were found between foal groups and between WB and contamination controls. Main limitations – Inherent inaccuracies of classification schemes for septic and sick non-septic foals, and the impact of contamination when sequencing low biomass samples. Conclusions – High-throughput sequencing represents a possible avenue for the diagnosis of bacteraemia in foals but has high potential for environmental and extraction-related contamination and cannot replace blood culture at this time. Further research to optimize detection yield and sensitivity on WB samples is warranted.

Background: Ureteral ectopia is an uncommon but clinically important congenital abnormality in horses. If left untreated it can lead to persistent dermatitis, urinary tract infections, and failure to thrive. Surgical correction is necessary, but traditional approaches have produced mixed results with high morbidity. Identification of a minimally invasive, effective technique would significantly improve prognosis. Objective: To describe the procedure and outcomes of cytstoscopic guided laser neoureterocystostomy in three fillies. Study design: Short case series. Methods: Retrospective review of three cases treated with cystoscopic guided laser neoureterocystostomy. Results: Laser neoureterocystostomy was a safe, effective, and minimally invasive treatment for ectopic ureters, with favorable short- and long-term outcomes. Main limitations: Small sample size. Conclusion: Ectopic ureters in horses can be successfully managed using minimally invasive surgical intervention.

Background: Streptococcus equi subspecies zooepidemicus is a highly diverse opportunistic pathogen of horses, associated with respiratory disease and endometritis. Objectives: To characterise S. zooepidemicus isolates recovered from young ponies during a natural episode of respiratory disease, and to determine if vaccination with Strangvac, a vaccine against Streptococcus equi subspecies equi, conferred cross-protection. Study design: Retrospective analysis of a double-blinded placebo-controlled study involving 32 ponies (16 vaccinates and 16 placebo controls) that experienced a natural episode of respiratory disease around the time of second vaccination. Methods: Ponies were monitored daily for clinical signs of respiratory infection. Nasopharyngeal swabs were taken from affected animals to identify equine pathogens by qPCR and culture. The genomes of 23 S. zooepidemicus isolates were sequenced. Clinical and serological differences between vaccine and placebo groups were determined. Results: The clinical samples were positive for equine herpes virus-4 or S. zooepidemicus (1/15 (7%) and 13/15 (87%), respectively). Seven different S. zooepidemicus sequence types, which encoded between four and seven of the eight antigens in Strangvac with ≥70% amino acid identity, were recovered from affected horses. The most conserved antigens were CNE, EAG, Eq5 and IdeE. The number of days that ponies had a cough were significantly associated ( p=0.005) with the vaccination status, with fewer days in the vaccinated compared to co-mingled control ponies (1.8±1.9 days vs. 3.4±3.5 days). A higher antibody titre to IdeE immediately prior to second vaccination correlated with a lower cumulative coughing score ( p=0.03). A reduced number of days with abnormal temperature correlated with increased antibody levels against Eq85 ( p=0.023-0.028). Main limitations: Small group size. Conclusions: This study provides evidence in support of a cross-protective effect of Strangvac for the reduction of clinical signs associated with natural infection with S. zooepidemicus, which correlated with the presence of higher antibody titres to IdeE and Eq85.

Background: Peri-anaesthetic hypothermia is a well-documented complication of general anaesthesia and is associated with prolonged recovery, impaired wound healing, and delayed coagulation. Fluid warmers can be used to mitigate heat loss, but there is little evidence supporting their effectiveness in equine anaesthesia. Objectives: To determine whether administration of warmed intravenous fluids attenuates heat loss during general anaesthesia in horses. Study design: Prospective, randomized, crossover study. Methods: Six healthy adult horses were anesthetized twice and administered intravenous fluids with the HOTLINE (R) Blood and Fluid Warmer either activated or inactivated. Core body temperature was recorded at four anatomic sites (rectum, nasopharynx, pulmonary artery, and urinary bladder), and fluid temperature was measured in the fluid bag, proximal to the warmer, and distal to the warmer. Linear mixed-effects models evaluated the effects of warmer status, time, measurement site, and ambient temperature, including relevant interactions, with random intercepts for horse. Results: Overall core body temperature differed statistically but not clinically meaningfully between warmer conditions; however, warmed fluid administration significantly reduced the rate of temperature decline (time × warmer interaction, β = 0.0033°C/min, SE = 0.001, p = 0.0004). Fluid temperature distal to the warmer increased substantially with warmer activation, and ambient temperature strongly influenced fluid temperature (χ 2 = 634.2, p < 0.0001). Main limitations: Small sample size; environmental variability; no surgical procedure. Conclusions: Although warmed intravenous fluids did not increase core temperature, they significantly attenuated intra-anaesthetic heat loss. The HOTLINE (R) Blood and Fluid Warmer increased delivered fluid temperature and provided a modest but measurable protective effect against hypothermia. These findings are the first to demonstrate that warmed fluid administration can slow heat loss in horses under general anaesthesia.

Background: Insulin dysregulation (ID) in horses is characterized by insulin resistance and exaggerated insulin responses, yet the underlying endocrine mechanisms remain incompletely understood. In humans, α-cell dysfunction, characterized by exaggerated glucagon secretion, contributes to metabolic disease; however, the role of pancreatic α-cell function in equine ID has not previously been investigated. Objectives: To determine whether horses with moderate to severe ID exhibit α-cell dysfunction, assessed by fasting and postprandial glucagon concentrations and postprandial suppression of glucagon secretion, compared with horses with normal insulin regulation (NIR). Study Design: Cross-sectional experimental study. Methods: Insulin dysregulated horses (n = 19) and NIR horses (n = 19) underwent a 180-minute seven-sampled oral sugar test. Plasma glucose, insulin, and glucagon concentrations were measured at baseline and every 30-minute for 180 minutes postprandially. Fasting glucagon concentrations (Fasting GLUCAGON), total area under the curve for glucagon (AUC GLUCAGON) and postprandial suppression of glucagon secretion were used as primary outcomes. Results: Horses with ID exhibited higher geometric mean (95% confidence interval) values compared to NIR horses for the α-cell dysfunction indices Fasting GLUCAGON (10.3 (8.0 – 13.4) vs 4.1 (3.5 – 4.8) pmol/L, P < 0.0001) and AUC GLUCAGON (1351.5 (1016.1 – 1797.7) vs 624.7 (529.8 – 736.6) pmol/L x min, P < 0.0001). Geometric least squares mean (95% confidence interval) glucagon concentrations were higher (P = 0.01) at 180 minutes after oral sugar administration in ID horses (6.3 (5.0 – 8.0) pmol/L) compared with baseline concentrations in NIR horses (4.1 (3.3 – 5.2) pmol/L), indicating impaired postprandial glucagon suppression in the ID group. Main Limitations: Cross-sectional design and unmatched groups limit causal inference. Conclusions: Horses with moderate to severe ID exhibit marked α-cell dysfunction characterized by fasting and postprandial hyperglucagonemia and impaired postprandial suppression of glucagon secretion. These findings identify α-cell dysregulation as a novel component of equine ID.

Background: Equine Grass Sickness (EGS) is a devastating polyneuropathy linked to grazing. While a causative neurotoxin is suspected, the environmental conditions facilitating its production or ingestion remain unknown. Objectives: To determine if atmospheric ”Saddle Points”—regions of low wind speed created by converging air flows—are spatially and temporally correlated with EGS onset, and to analyse the particulate matter (PM) fractionation within these zones. Study Design: Retrospective case-control study. Methods: EGS cases (n=48) from 2025 were matched with 48 location-controlled sites. Atmospheric data (Copernicus ERA5/CAMS) were used to identify Saddle Points characterized by wind speeds <0.8 m s -1 and convergence of wind vectors. We analysed the ratio of fine (PM2.5) to coarse (PM10) particulates to assess sedimentation. Association was measured using Odds Ratios (OR) with 95% Confidence Intervals (CI). Results: EGS locations were significantly more associated with Saddle Point events compared to controls. The strongest association was found 90 days prior to clinical presentation within a 20 km radius (OR 10.45, 95% CI 2.24–48.85; P=0.0004). These atmospheric events exhibited a significantly elevated PM2.5/PM10 ratio (0.88) compared to background levels (0.68) (P < 0.001), indicative of coarse particle sedimentation. Main Limitations: Small sample size (n=48) results in wide confidence intervals, indicating uncertainty regarding the precise magnitude of risk. The retrospective nature limits causal inference, and the biological content of the particulate matter remains uncharacterised. Conclusions: Atmospheric Saddle Points are significantly correlated with EGS cases with a 2-3 month lag time. The demonstrated fractionation of particulates suggests these zones may facilitate the localized deposition of environmental agents.

Background: Thoracolumbar flexion–extension range of motion (FE ROM) in horses is difficult to assess reliably using subjective evaluation. A handheld, smartphone-based markerless computer vision system (Anonymised, RH) may enable objective field-based assessment but requires validation against an established optical motion capture reference system (Qualisys®; QS). Objectives: To compare the accuracy and precision of RH relative to QS for measuring FE ROM in horses trotting on a straight-line and on a circle. Study Design: Cross-sectional comparative validation study of a markerless computer vision algorithm. Methods: Fifty-nine horses were recorded trotting on a straight-line; 23 of these were also recorded on a circle. Data were collected simultaneously using RH and QS, with a marker light used for temporal synchronisation. Anatomical landmarks at the withers, mid-back, and croup were used to calculate the flexion–extension angle at the mid-back. FE ROM was derived at the stride-level as the difference between stride-specific maxima and minima. Agreement between RH and QS was analysed separately for straight-line and circular trot at stride- and trial-levels using mean signed error (MSE), mean absolute error (MAE), and Bland–Altman limits of agreement (LoA). Results: On the straight-line, stride-level MSE was −0.08°, MAE 0.96°, and LoA −2.49° to 2.32°. Trial-level agreement improved, with MSE −0.13°, MAE 0.44°, and LoA −1.22° to 0.94°. On the circle, stride-level MSE was −0.71°, MAE 1.14°, and LoA −3.17° to 1.74°. At the trial-level, variability was reduced (MSE −0.62°, MAE 0.78°, LoA −2.18° to 0.93°). Overall agreement was lower on the circle than on the straight-line. Conclusions: Stride-level agreement between RH and QS was influenced by expected stride-to-stride variability, particularly during circular exercise, while trial-level agreement was improved. RH enables objective assessment of FE ROM under field conditions.

Background: The number of new veterinary graduates entering equine practice continues to decline, and more than half leave the field within five years. Understanding the perspectives of veterinary students is critical for developing interventions that promote retention and long-term career satisfaction in equine medicine. Objective: To explore what factors influence veterinary student interest in and commitment to equine practice using the Conservation of Resources (COR) Theory as a guiding framework. Study design: Qualitative descriptive study using semi-structured student focus groups. Methods: Eighteen veterinary students who have considered or are actively pursuing equine medicine were recruited via snowball and convenience sampling to participate in virtual focus groups. Discussions were transcribed and analyzed using Delve, where they were then coded in the context of the COR Theory. A card sorting activity was used to rank the four resource domains in the COR Theory (condition, object, energy, and personal resources). Results: Students emphasized the importance of structured mentorship, supportive work environments, and work-life balance. Barriers included concerns about gender bias, compensation, student debt, and unrealistic client expectations. Personal passion for equine medicine and positive early experiences with horses were key motivators for pursuing the field. Main limitations: The study sample may not represent the diversity of veterinary student experiences across regions or schools. Conclusions: Veterinary students interested in equine practice face challenges related to work-life balance, mentorship, financial viability, and inclusivity. Despite these barriers, many students remain motivated by a desire to contribute something meaningful to the field and by positive early experiences with horses. Creating structured mentorship, increasing inclusivity in equine medicine, and addressing workload and compensation concerns may improve student retention and career satisfaction in equine practice.

Background: Antimicrobial resistance is a global challenge, according to the Centers for Disease Control and Prevention (CDC), it affects more than 2 million people through infections caused by multidrug-resistant bacteria. Furthermore, estimates suggest that if the necessary measures to control resistant microorganisms are not taken, deaths could rise to 10 million per year by 2050. The contribution of veterinary medicine to mitigating this problem is substantial. Objectives: The aim of this study was to characterize phenotypic and genotypic antibiotic resistance profile of strains isolated from horses with sepsis that were unresponsive to antibiotic treatment, from an equine production. Study design: descriptive, observational, and cross-sectional Methods: The phenotypic profile of the isolated strains was characterized using the disk diffusion method, while the genotypic profile was determined by polymerase chain reaction (PCR) to detect resistance-associated genes, employing previously reported primers for β-lactams; blaTEM1, sulphonamides; sul1, sul2, phenicoles; cat1 & cmlA, tetracyclines; tetA & tetB, aminoglycosides; strA, aadA2 & aac(60), fluoroquinolones; qnrA, qnrB & qnrS1. Results: In nine of the 33 isolates, an association between genotype and phenotype was detected; however, in the remaining 24 isolates, despite the presence of resistance in disk diffusion tests, no resistance-associated genes were amplified. Main Limitation: The lack of primers for searching for other genes associated with resistance limits the evidence of other resistance mechanisms in the isolates. Conclusion: It is one of the first studies to describe the presence of bacteria involved in sepsis cases with their resistance-associated genes.

Background: The equine roundworm Parascaris spp. commonly infects foals, and high burdens can cause fatal small intestinal impactions. Progressive anthelmintic resistance challenges infection control, posing a risk for an increase of Parascaris spp. related disease in juvenile horses. Objectives: To investigate Parascaris-related surgical intestinal lesions, with special emphasis on ascarid impactions, in Scandinavia by exploring (1) disease occurrence and (2) short-term survival rates after laparotomy in affected foals and yearlings. Methods: A retrospective clinical record search was conducted at six Scandinavian equine hospitals during a 7-15-year period. Horses older than one month but less than two years of age that had been surgically treated for colic were included. Age, breed, surgical diagnosis, presence of Parascaris spp. infection, immediate anthelmintic history and short-term survival, defined as survival to hospital discharge, were recorded. Results: A total of 233 records were included. Fourteen foals were diagnosed with ascarid impaction at laparotomy, with an occurrence of 6.0% (14/233), encompassing 11.4% of surgical small intestinal lesions (14/123). The occurrence of ascarid impaction in horses younger than one year of age was 9.7% (13/134). Six foals with ascarid impaction had been treated with an anthelmintic drug within two days of presentation. Four foals with ascarid impaction survived to discharge. Overall occurrence of Parascaris-associated intestinal lesions, including impactions, was 13.7% (32/233), encompassing 26.0% (32/123) of all small intestinal abnormalities, and with a short-term survival rate of 38% (12/32). Main limitations: Due to the retrospective study design, hospital-dependent variations could not be controlled. No previous data was available to compare disease occurrence. Conclusion: Parascaris spp. related disease in juvenile horses comprises a substantial portion of small intestinal surgical lesions with a poor prognosis for survival. With the appearance of multi-drug-resistant parasite populations, this emphasises the importance of developing management practices to reduce parasite infection burdens.

Background: The proportion of geriatric horses is increasing in Germany necessitating a deeper understanding of health and management demands. Objectives: To gain insights into the aging horse population in Germany to improve the corresponding management of geriatric horses, with particular attention to diseases, vaccination, worming, dental checks and hoof care. Study design: Cross-sectional online survey. Methods: Descriptive and inferential analysis of 923 questionnaires from owners of geriatric horses (≥20 years of age). Results: 919 horses aged 20 to 39 years (25.7 ± 3.96 years) were assigned to the following age groups: 20–24 years (42.2%, n = 388), 25–29 years (38.1%, n = 350), and ≥30 years (19.7%, n = 181). The most prevalent diseases observed were orthopaedic (66.7%, n = 580), dental (57.2%, n = 497), skin (35.9%, n = 289), cardiovascular (32.7%, n = 255), gastrointestinal diseases (32.3%, n = 257) and reduced mobility (65.9%, n = 602). Comorbidity (68.2%, n = 629) was significantly associated with age ( p < 0.001). Horses aged 20–24 years showed lower odds than horses aged 25–29 years (Odds Ratio (OR) [95% Confidence Interval (CI)] = 0.53 [0.36-0.76]) and ≥30 years (OR [95% CI] = 0.36 [0.22-0.60]). The vaccination rate was 85.0% ( n = 783). Most horses (89.3%, n = 818) had their hooves trimmed every six to eight weeks. The majority of horses were wormed multiple times per year (69.1%, n = 637) followed by a selective strategy (25.4%, n = 234). Dental check-ups were performed annually for most horses (71.2%, n = 653). Main limitations: Data were owner-reported, free-text responses required categorisation and the online survey may have caused selection bias. Conclusions: This study contributes data on geriatric horses in Germany, highlighting significant age-related increases in disease prevalence and comorbidity and emphasizing key management aspects such as dental care, vaccination and worming.

Background: Vaccination guidelines for foals against C. tetani vary, and existing evidence is outdated or lacks statistical power to assess foal immune responses, maternal antibody interference, or individual variation. Objectives: To quantify antibody responses after tetanus vaccination in foals and explore associations with passively transferred tetanus antibodies. Study design: Longitudinal prospective cohort study. Methods: Sixty-two Warmblood foals from a single stud farm were randomly assigned to two vaccination groups. Group 1 (n=32) received tetanus-influenza (ProteqFlu®-Te) and equine herpesvirus (Equip® EHV1,4) vaccines at day 180 (d180) and d220 of life. Group 2 (n=30) received an additional influenza and EHV1/4 vaccination at d150, followed by the same protocol as Group 1. Serum samples collected at 19 time points from birth to d360 were analysed using a fluorescent bead-based Tetanus Multiplex assay to quantify total and isotype-specific anti-tetanus antibodies. Results: No differences were observed between vaccination groups, allowing combined analysis of all foals (n=62). Passively transferred anti-tetanus antibodies declined from d15 and reached minimal concentrations by d180 (P < 0.0001). Vaccination on d180 and d220 induced an antibody increase by d230 (P < 0.0001), followed by a decline to below pre-vaccination levels by d360. No correlations were observed between maternally derived antibody concentrations (d5) and the vaccine-induced response on d230 (rsp = –0.36), or between pre-vaccination levels (d180) and d230 (rsp = –0.16). IgG1 contributed most to the initial vaccine-induced response, whereas IgM concentrations remained unaffected. Considerable inter-individual variability was observed, with approximately half of the foals showing low responsiveness. Main limitations: A single vaccine formulation and tetanus immunisation schedule were explored. Conclusions: Vaccination of mares during late gestation effectively transfers protective anti-tetanus antibodies to foals. The variability in foal responses and rapid post-vaccination antibody decline suggest that tetanus vaccination schedules for foals, including booster timing, may require optimisation to ensure early-life protection.

Background: Flysheet use is common without any published scientific evidence to justify their use. Objectives: To demonstrate the effectiveness of flysheets at reducing fly avoidance behaviors and measure changes in body temperature, heart rate, or cortisol levels. Study design: 10-week alternating crossover design Methods: 6 horses were divided into two groups. Flysheets were alternated between groups weekly for 10 weeks. Fly avoidance behaviors were recorded for 30-minutes once weekly. Cortisol samples were collected before flysheet application or removal, and again 10 minutes later. Star-Oddi data loggers recorded heartrate and temperature every 15 minutes throughout the study period. Results: Flysheet use significantly reduced fly avoidance behaviors. Mean head tosses decreased from 12.17 (95% CI: 17.58–6.76) to 2.33 (95% CI: 0.64–4.02) (p<0.0001), and tail swishing fell from 214.67 (95% CI: 131.06-298.28) to 52.54 (95% CI: 11.17-93.92) (p<0.0001). Mean baseline cortisol levels were lowest without flysheets (2.92, 95% CI: 2.35-3.48 μg/dL), though no time effect was detected (p>0.05). Body temperatures differed by group: Group A had higher mean temperature with flysheets ON (35.85°C, 95% CI: 35.77–35.93) vs. OFF (35.53°C, 95% CI: 35.44–35.62, p<0.0001), whereas Group B had lower mean temperature with flysheets ON (36.42°C, 95% CI: 36.34–36.51) vs. OFF (36.70°C, 95% CI: 36.61–36.79, p<0.0001). Heart rate was significantly higher with flysheets ON (+6.3 bpm, 95% CI: +4.9 to +7.7, p<0.0001). Main limitations: Sample size was small, and one horse was removed from the study due to an unrelated condition. Star-Oddi devices were rejected by two horses creating gaps in data collection. Conclusions: Flysheets effectively reduced insect avoidance behaviors but were associated with increased heart rate and group-dependent effects on body temperature, suggesting a potential thermal or physiologic cost. Flysheet use may improve horse comfort during insect season, but heat load and physiologic stress should be monitored.

Background: Musculoskeletal injuries are a major welfare and economic challenge in racehorses, with stress-related bone injuries contributing substantially to training interruption and catastrophic failure. Advanced imaging can detect early skeletal pathology but access is limited, creating a need for scalable indicators of bone health. Serum bone turnover markers may provide early signals of injury-related remodelling but require validation against objective imaging. Objectives: To determine whether serum osteocalcin (OC) and C-terminal telopeptides of type I collagen (CTX), individually or as the CTX/OC ratio, are associated with scintigraphic abnormalities, discriminate lame from clinically sound racehorses, and provide short-term predictive information for adverse outcomes. Study design: Prospective observational study with case–control comparisons. Methods: Ninety-six racehorses were enrolled, 48 lame horses referred for scintigraphy and 48 clinically sound controls. Serum OC and CTX were measured by ELISA concurrent with 99mTc-labelled bisphosphonate administration. Scans were classified as no abnormality detected (NAD), moderately positive (mPOS), or strongly positive (sPOS). Group comparisons,logistic regression, and receiver operating characteristic (ROC) analyses were performed. Short-term (28-day) outcomes were assessed in controls. Results: Mean OC was higher in lame than control horses (1.32 vs 0.39 ng/mL; P = 0.007), whereas CTX did not differ. Across all horses, OC was lower values in NAD horses (0.36 95% CI 0.02–0.71) than in mPOS (1.48,1.12–1.84) and sPOS (1.43,0.88–1.99;P < 0.0001). The CTX/OC ratio differed between NAD and positive scans (11.4 vs 6.0; P = 0.029). In injured horses, OC predicted injury (odds ratio ≈ 11.6, 95% CI 3.17–65.06; AUC = 0.75). CTX predicted short-term adverse outcomes in controls (odds ratio 2.21 per ng/mL; AUC = 0.76). Main limitations: Short follow-up duration, potential workload-related confounding at sampling and reliance on owner-reported outcomes. Conclusions: Serum OC is a robust indicator of scintigraphic bone pathology, while CTX is a potential predictor of short-term adverse outcomes.

Background: Working horses remain essential for rural livelihoods in Chile and across Latin America. However, housing and management conditions in these systems are poorly characterized, underscoring the need for standardized welfare assessments to generate evidence and guide targeted improvements. Objective: To estimate the prevalence of abnormal behaviours in rural working horses and to examine associations with management and housing related factors. Study Design: A descriptive, cross-sectional, non-experimental study design was employed in a rural area of the Papudo commune, Valparaíso Region, Chile. A total of 77 working horses were evaluated using the Animal Welfare Indicators protocol. To analyze the relationship between behavioral abnormalities, management practices, and housing factors, a multivariable logistic regression model was applied. Results: Most horses had good body condition (67.53%, n = 53) and a low prevalence of health problems (5.19%, n = 4); however, hoof-related disorders were common (41.56%, n = 32). Housing conditions were frequently inadequate (77.92%, n = 60), with insufficient bedding in 53.25% (n = 41) and dirty bedding in 59.74% (n = 51). Only 20.78% (n = 16) of horses performed daily exercise. Overall, 29.87% (n = 23) exhibited abnormal behaviours, most commonly wood chewing (12.99%), crib-biting (10.39%), and windsucking (6.49%). Absent or inadequate bedding was associated with markedly increased odds of abnormal behaviours (OR = 5.31; p = 0.034), whereas longer daily exercise duration was protective (OR = 0.626; p = 0.007). Main Limitations: Single rural area of Chile. Several management variables (e.g., daily time out of the stall) relied on the owner report. Conclusion: A substantial proportion of rural working horses displayed abnormal behaviours. Suboptimal bedding provision and limited time out of the stall were the main modifiable factors associated with these behaviours, highlighting practical opportunities for welfare improvement in Chilean working horse systems.

Background: Associations between suspensory ligament branch (SLB) desmopathy and proximal sesamoid bone (PSB) osteopathy have been investigated using ultrasonography and radiography but not standing magnetic resonance imaging (MRI). Objectives: To investigate the distribution of and relationship between SLB desmopathy and PSB osteopathy using standing MRI in racing Thoroughbreds. Study design: Retrospective analytical case control study. Methods: Standing MRI studies of the metacarpophalangeal region from sixty-eight racing Thoroughbreds (132 limbs) were blindly and independently evaluated by two board-certified equine specialists (surgeon and radiologist). SLB cross-sectional area (CSA) was recorded and SLB desmopathy and PSB osteopathy were graded. Data were analyzed using simple logistic regression, Wilcoxon matched-pairs signed-rank tests, and intraclass correlation coefficient calculations. Results: SLB desmopathy was identified in 76.5% of the population. Right forelimbs had significantly higher medial SLB grades (median:1.5, IQR:0-6.5) compared to left forelimbs (median:0, IQR:0-4), while left forelimbs had significantly higher lateral SLB grades (median:0, IQR:0-10.5) versus right forelimbs (median:0, IQR:0-1.5). Increased SLB CSA was associated with SLB desmopathy for both medial and lateral SLB when evaluated by a board-certified radiologist (medial distal odds ratio[OR]:1.62, CI:1.02-1.75, P=0.03; medial mid-length OR:1.31, CI:1.20-2.00, P=0.009; lateral distal OR:1.46, CI:1.17-1.85, P=0.0006; lateral mid-length OR:1.48, CI:1.08-2.09, P=0.01). Independent of laterality, the medial SLB (mid-length median:106.8, IQR:99.06-116.9; distal:114.6 IQR:105.4-125.9) had larger CSA than the lateral SLB (mid-length median:100.5, IQR:92.50-112.2; distal median:97.80, IQR:81.73-109). There was no difference in PSB grades between medial versus lateral or between limbs. Increasing PSB scores had increased odds of SLB desmopathy both medially (OR=1.73, CI: 1.17-2.67, P=0.04) and laterally (OR=1.24, CI: 1.03-2.37, P=0.04). Main limitations: Retrospective study only applicable to racing Thoroughbreds and limitations in imaging quality inherent to standing MRI. Conclusions: This study establishes a strong association between PSB osteopathy and SLB desmopathy on low-field MRI in Thoroughbred racehorses and documents distribution of forelimb SLB and PSB pathology.

Background: No large study has examined the treatment and response to treatment of horses with sinonasal disease confirmed by computed tomography (CT). Objectives: Report the treatment and response to treatment of referred cases of equine sinonasal disease. Study design: Retrospective case series. Methods: Data were collected from 19 equine hospitals on 1600 CT-confirmed cases of sinonasal disease. Results: Surgical sinus treatments were performed under sedation in 78.4%, under general anaesthesia in 11.0% and the remaining cases did not have surgical sinus treatments. Sinoscopic debridement with maxillary septal bulla fenestration was performed in 754 horses, under sedation in 605 horses and under general anaesthesia in 139 cases. Nasofrontal and maxillary sinusotomies were performed in 324 and 93 cases, respectively, under sedation in 302/417 cases (72.4%) and general anaesthesia in 115/417 (27.6%). Sinoscopic lavage was performed in 711 cases, usually following other procedures. Sinoscopic treatment was associated with a higher likelihood of cure, and nasofrontal sinusotomy with a lower likelihood of cure, but more difficult cases may have had more sinus osteotomies. Primary, dental and mycotic sinusitis had the highest complete cure rate (all over 79%), while sinus neoplasia (7.3%) and PEH (40.4%) had the lowest cure rates. A total of 592 cheek teeth extractions (including 323 Triadan 09s) were performed in 488 horses with dental sinusitis, including by oral extraction (n=478, 80.4%). Oral extraction was associated with the highest likelihood of complete cure (84.5%), while standard repulsion and surgical buccotomy had the lowest likelihoods of cure (78.6% and 66.7% respectively). Overall response to treatment was available for 926 cases, showing 645 horses (69.7%) cured, 156 (17.0%) partially cured, and 125 (13.5%) not cured. Main limitations: This was a retrospective study. Data on treatments and response to treatments were not available for all cases.