Transcutaneous Auricular Vagal Nerve Stimulation in Healthy Non-Sedated Horses: A Feasibility Study.

This study aimed to evaluate the feasibility of transcutaneous auricular vagal nerve stimulation (tAVNS) in healthy horses and its effect on heart rate variability (HRV). The study comprised three phases: the selection of mares, their acclimatization to the tAVNS, and the stimulation phase. Stimulation was performed with two electrodes positioned on the right pinna. The settings were 0.5 mA, 250 µs, and 25 Hz for pulse amplitude, pulse width, and pulse frequency, respectively. HRV was analysed before (B1), during (T), and after (B2) the tAVNS. From the 44 mares initially included, only 7 completed the three phases. In these mares, the heart rate (HR) was significantly lower, and frequency domain parameters showed an increased parasympathetic tone in B2 compared with B1. However, in 3/7 mares, the HR was significantly higher during T compared with B1 and B2, compatible with a decreased parasympathetic tone, while in 4/7 mares, the HR was significantly lower and the parasympathetic nervous system index was significantly higher during T and B2 compared with B1. The tAVNS is an economical and easy procedure to perform and has the potential to stimulate vagal activity; however, it was poorly tolerated in the mares included in this study.

Use of Knotless Barbed Sutures in Laparoscopic Inguinal Hernioplasty in Horses: 40 Cases.

Inguinal hernias (IHs) and ruptures are a relatively common condition in horses, occurring in foals (congenital) and adult (acquired) animals. A retrospective observational analysis was conducted on 40 cases that underwent laparoscopic surgery to close the VRs using barbed sutures alone or combined with other techniques. Signalment, clinical presentation, surgery, and follow-up data were obtained. In total, fifty-nine VRs were closed using barbed sutures (alone or in combination with other methods), with six cases performed prophylactically and forty-four due to acquired IH. Of the forty-four cases with IH, four were non-strangulated hernias, while thirty presented with strangulated small intestines (twenty-eight acquired and two congenital). The results obtained in this study suggest that laparoscopic hernioplasty with barbed sutures is an effective and safe surgical procedure that could be recommended as a standard practice for managing inguinal hernias in horses, particularly when sparing testicles or preserving reproductive capabilities is a priority.

Long-term performance of show-jumping horses and relationship with severity of ataxia and complications associated with myeloencephalopathy caused by equine herpes virus-1.

BACKGROUND: Equine herpesvirus myeloencephalopathy (EHM) has severe impact on the sport horse population. OBJECTIVE: Study the influence of EHM on the likelihood of affected horses to return to their previous performance and investigate the association of clinical variables with prognosis. ANIMALS: Twenty-six horses positive for equine herpesvirus type 1 (EHV-1) were admitted to a veterinary teaching hospital (VTH) during a natural EHM outbreak at an international jumping event. METHODS: Data collected from the VTH, the International Equestrian Federation, and surveys completed by the riders and horse owners were retrospectively analyzed. RESULTS: Horses affected by EHM had 68% chance of returning to exercise, and 52.9% were able to achieve their preoutbreak performance level. Horses with an ataxia grade at admission ≥4/5 had an increased fatality rate (P < .05) and 10% chance of reaching their preoutbreak performance level. None of the horses with both vascular and urinary complications returned to their previous performance level. Finally, horses vaccinated against EHV-1 and those with urinary complications had a 71.4% and 43.7% fatality rate, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Horses affected by EHM were able to return to their previous performance levels, but certain clinical variables were negatively associated with postoutbreak performance. Ataxia grade upon admission and the development of systemic signs of vasculitis and urinary complications were potential poor prognostic indicators in sport horses. Variables linked to fatality included prior vaccination against EHV-1, ataxia grade upon admission, and the development of urinary complications.

Detection of equine herpesvirus-1 (EHV-1) in urine samples during outbreaks of equine herpesvirus myeloencephalopathy.

BACKGROUND: Real-time PCR is the diagnostic technique of choice for the diagnosis and control of equine herpesvirus-1 (EHV-1) in an outbreak setting. The presence of EHV-1 in nasal swabs (NS), whole blood, brain and spinal cord samples has been extensively described; however, there are no reports on the excretion of EHV-1 in urine, its DNA detection patterns, and the role of urine in viral spread during an outbreak. OBJECTIVES: To determine the presence of EHV-1 DNA in urine during natural infection and to compare the DNA detection patterns of EHV-1 in urine, buffy coat (BC) and NS. STUDY DESIGN: Descriptive study of natural infection. METHODS: Urine and whole blood/NS samples were collected at different time points during the hospitalisation of 21 horses involved in two EHV-1 myeloencephalopathy outbreaks in 2021 and 2023 in Spain. Quantitative real-time PCR was performed to compare the viral DNA load between BC-urine samples in 2021 and NS-urine samples in 2023. Sex, age, breed, presence of neurological signs, EHV-1 vaccination status and treatment data were recorded for all horses. RESULTS: A total of 18 hospitalised horses during the 2021 and 2023 outbreaks were positive for EHV-1, and viral DNA was detected in urine samples from a total of 11 horses in both outbreaks. Compared with BC samples, DNA presence was detected in urine samples for longer duration and with slightly higher concentration; however, compared with NS, detection of EHV-1 in urine was similar in duration with lower DNA concentrations. MAIN LIMITATIONS: Limited sample size, different sampling times and protocols (BC vs. NS) in two natural infection outbreak settings. CONCLUSIONS: EHV-1 was detected in the urine from naturally infected horses. Urine should be considered as complimentary to blood and NS in diagnosis of EHV-1 infection.

HISTORIAL: PCR en tiempo real es la técnica diagnostica de preferencia para el diagnóstico y control del herpes virus equino­1 (EHV­1) en una situación de brote. La presencia de EHV­1 en torulas nasales (TN), muestras de sangre entera, cerebro, y medula espinal ha sido descrita en forma extensa; sin embargo, no hay informes de excreción de EHV­1 en orina, la detección del patrón de ADN, y el rol de la orina en la propagación vírica durante un brote. OBJETIVOS: Determinar la presencia de ADN de EHV­1 en muestras de orina durante un brote infeccioso natural y comparar los patrones de detección de ADN de EHV­1 en orina, capa leucocitaria (CL) y TN. DISEÑO DEL ESTUDIO: Estudio prospectivo en una infección natural en caballos hospitalizados. MÉTODOS: Muestras de orina y sangre entera/TN fueron recolectadas a distintos tiempos durante la hospitalización de veintiún caballos involucrados en dos brotes de mielo encefalopatía por EHV­1 en 2021 y 2023 en España. PCR a tiempo real cuantitativo fue llevado a cabo para comparar la carga de ADN viral entre muestras de CL­orina en 2021 y muestras TN­orina en 2023. Sexo, edad, raza, presencia de síntomas neurológicos, estatus de vacunación y datos de tratamiento fueron anotados para todos los caballos. RESULTADOS: Un total de diez y ocho caballos hospitalizados durante los brotes de 2021 y 2023 resultaron positivos a EHV­1, y ADN viral fue detectado en muestras de orina en un total de 11 caballos de ambos brotes. En comparación a muestras de CL, la presencia de AND fue detectado por mas largo tiempo y con una concentración ligeramente mas alta; sin embargo, en comparación a TN, la detección de EHV­1 en orina fue similar en tiempo pero demostró menor concentración de ADN. LIMITACIONES PRINCIPALES: Tamaño de muestra limitado, tiempos de muestreo diferentes, y de protocolos (CL vs. TN) en dos situaciones de brotes naturales. CONCLUSIONES: Se detecto EHV­1 en orina de caballos infectados naturalmente. La recolección, no invasive, de orina debería considerarse como un complemento a las muestras de sangre y TN en el control de caballos infectados en situaciones de brote.

Culture Media Supplemented With 10% Equine Serum Provided Chondroprotection in an In Vitro Co-Culture of Cartilage and Synovial Membrane.

No studies have evaluated the effect of culture in serum-free media (SF) vs. media supplemented with equine serum (ES) on co-culture of synovial membrane and cartilage tissue explants. The study objective was to evaluate the effects of equine serum supplementation on induced production of inflammatory and catabolic mediators from articular cartilage and synovial explants while in co-culture. Articular cartilage and synovial membrane explants were harvested from femoropatellar joints of five adult horses. Cartilage and synovial explants were harvested from the stifle of five horses, placed in co-culture, stimulated with IL-1ß (10 ng/ml) and maintained in culture for 3, 6 and 9 days in 10% ES or SF. At each time point, media was harvested for analysis of cellular viability (Lactate dehydrogenase) and elution of glycosaminoglycans (Dimethylene Blue Binding Assay). Tissue explants were harvested for histopathologic and gene expression analyses. No differences in cell viability were observed between SF and ES groups. SF culture produced an upregulation of TNF-α in synovial membrane and ADAMTS-4 and five in articular cartilage at 9 days of culture. ES produced an upregulation of aggrecan expression in cartilage at 9 days of culture. No differences in tissue viability were found between culture media, but SF media produced a higher glycosaminoglycan concentration in media at 3 days of culture. The addition of 10% ES produced a slight chondroprotective effect in an inflamed co-culture system. This effect should be considered when designing studies evaluating treatment of serum or plasma-based orthobiologic studies in vitro.

Concurrent versus delayed exposure to corticosteroids in equine articular tissues cultured with local anesthetic.

OBJECTIVE: To determine the effect of concurrent versus delayed treatment with corticosteroid on equine articular tissues also treated with local anesthetic in vitro in the presence of inflammatory mediators. STUDY DESIGN: Controlled laboratory study. ANIMALS: Five geldings, one mare (aged 3-18 years). METHODS: From each horse, 24 synovial and 12 osteochondral explants were cultured in a 12-well plate (2 wells/group, 2 synovial and 1 osteochondral explant/well, total 216 explants in the study). Explants were stimulated in culture medium with 10 µg/ml recombinant equine interleukin-1ß and 10 µg/ml tumor necrosis factor-α for 48 hours, then randomly assigned to six treatments: unstimulated control, stimulated control, triamcinolone acetonide (TA, 10-6  M), mepivacaine hydrochloride (MH, 4.4 mg/ml), MH + TA (concurrent) and MH + TA (delayed). The delayed group was treated with MH and, 6 days later, treated with TA. Every 3 days for 9 days total, medium levels of lactate dehydrogenase (LDH), prostaglandin E2 (PGE2 ), matrix metalloproteinase 13 (MMP-13) and glycosaminoglycan (GAG) were quantified via ELISA. Data were analyzed with mixed-effects models with Tukey's multiple comparisons. RESULTS: Stimulation increased medium PGE2 and MMP-13 and had no effect on LDH or GAG. Treatment with MH increased LDH and decreased PGE2 and MMP-13. Treatment with TA decreased PGE2 and MMP-13. CONCLUSION: There were no differences in cytotoxicity, inflammation or matrix degradation for delayed or concurrent MH and TA treatment groups up to 9 days in culture. CLINICAL SIGNIFICANCE: The lack of an effect of concurrent versus delayed treatment might indicate that concurrent therapy is acceptable.

Survival and racing performance after surgical treatment of rib fractures in foals.

OBJECTIVE: To evaluate the short and long-term outcomes of foals treated surgically for fractured ribs and variables that may affect outcome. STUDY DESIGN: Retrospective. ANIMALS: Seventy-three equine neonates with surgically repaired fractured ribs. METHODS: Medical records were reviewed to include sex, breed, the side of thorax affected, number of ribs fractured, co-morbidities directly associated with rib fracture, and surgical technique used. Short-term outcome was defined as survival to discharge. Long-term outcome was whether or not they started a race. Race records of maternal siblings were obtained for comparison. RESULTS: Seventy-three neonates underwent surgery for fractured ribs. Fifty-seven neonates (78%) survived to discharge from the hospital. Rib fractures were more commonly observed in colts and in the left hemithorax (61% and 57%, respectively). Sex, side affected, number of ribs fractured, co-morbidities, number of ribs repaired, and surgical technique did not affect the short- or long-term outcomes. Thirty-five of 57 (61%) foals treated surgically for rib fractures that survived to discharge started a race compared to 173 of 257 (67%) of maternal siblings that raced. CONCLUSIONS: Short- and long-term outcome were not affected by co-morbidities, surgical technique, or number of fractured ribs. CLINICAL SIGNIFICANCE: Neonates with surgically repaired fractured ribs had a good prognosis for survival and and those that survived had a similar chances of starting a race compared to maternal siblings.

A Survey of Clinical Usage of Non-steroidal Intra-Articular Therapeutics by Equine Practitioners.

There are several non-steroidal intra-articular therapeutics (NSIATs) available for use by equine practitioners for the treatment of performance-limiting joint-related pathology. Information is limited on perceived clinical efficacy, recommended treatment protocols, and associated complications. Our objective with this cross-sectional survey was to investigate the current clinical usage of NSIATs by equine practitioners. An electronic cross-sectional convenience survey inquiring about the use of steroidal and NSIATS (platelet-rich plasma, autologous conditioned serum, autologous protein solution, cellular therapies, and polyacrylamide hydrogel) was distributed internationally to equine practitioners. A total of 353 surveys were completed. NSIATs were used by 87.5% of the participants. Corticosteroids and hyaluronic acid remain the intra-articular therapeutic of choice among practitioners, followed by autologous conditioned serum, platelet-rich plasma and autologous conditioned protein. Polyacrylamide hydrogel was the least used. Practitioners were more likely to use NSIATs if their caseload was > 50% equine (P < 0.001), they treated more than 10 horses intra-articularly per month (P < 0.001), and horses treated were considered English sport horses (P = 0.02). Years in practice and practice location did not influence the use of NSIATs. One of the most common reasons why NSIATs were chosen was to treat acute articular pathologies. As survey limitations, answers to questions regarding clinical response and complication rates were based on subjective estimation and practitioners recall, not clinical records. In conclusion, corticosteroids remain the most widely used intra-articular therapeutic. Among the NSIATs, blood-based products are more commonly used by practitioners, followed by cellular and synthetic products. Equine practitioners frequently use NSIATs, choosing to treat acute joint pathology more than previously reported.

Effects of Autologous Conditioned Serum, Autologous Protein Solution, and Triamcinolone on Inflammatory and Catabolic Gene Expression in Equine Cartilage and Synovial Explants Treated With IL-1ß in Co-culture.

Autologous conditioned serum (ACS) and autologous protein solution (APS) are newer therapeutic options for osteoarthritis (OA). Co-culture of cartilage and synovium stimulated with IL-1ß produces a similar physiologic response to tissues from naturally-ocurring OA. The study objective was to investigate the effects of ACS, APS, and triamcinolone (TA) on inflammatory and catabolic gene expression of inflamed joint tissues in co-culture. Blood was collected and processed for ACS and APS from six horses. Cartilage and synovial explants were harvested from the stifle, placed in co-culture, and treated as: (1) unstimulated control (2) stimulated control (3) ACS at 25% v/v (4) ACS at 50% v/v (5) APS at 25% v/v (6) APS at 50% v/v, (7) TA (10-6 M). Treatment groups 2-7 were stimulated with IL-1ß (10 ng/ml). Cultures were maintained for 96 hours, and then both media and explants were harvested for measurement of gene expression and protein. IL-1ß stimulation significantly increased IL-1ß (p = 0.029), IL-8 (p = 0.011) and MMP-3 (p = 0.043) expression in synovium and IL-1ß (p = 0.003) and TNF-α (p = 0.001) expression in cartilage. Treatment with 50% ACS and APS v/v downregulated IL-1ß expression in cartilage more than TA treatment (p = 0.001 and p = 0.0004) and APS downregulated MMP-1 expression in synovial membrane (p = 0.025). Treatment with ACS and APS caused a trend in upregulation of IL-10 expression in synovium and type II collagen and aggrecan expression in cartilage. PGE2 media concentrations were significantly reduced following treatment with APS (13.7-fold decrease, p = 0.0001) and ACS (4.13-fold decrease, p = 0.024); while TA did not reduce PGE2 significantly (2.3-fold decreased p = 0.406). As disease-modifying therapies, ACS and APS modified the cellular response from synovial membrane and articular cartilage. ACS and APS may offer an improved strategy to improve clinical signs of horses with naturally occurring OA, compared to TA treatment.