Search

A 6‐year‐old female Friesian horse was admitted with pyrexia, dullness, weight loss, watery faeces and mild bilateral mucoid nasal discharge. Radiographic and ultrasonographic examination of the thorax indicated a large mid‐thoracic soft tissue mass, and the horse was euthanased because of a poor prognosis. At postmortem examination, it was found that the lung tissue was partly replaced by multiple to coalescing soft tissue lesions with a yellow gelatinous aspect, varying in size up to 15 × 15 × 20 cm. Histologically, the mass showed mild pyogranulomatous inflammation associated with large numbers of globular encapsulated 10–20 μm yeasts with or without narrow‐based budding, consistent with multiple coalescing cryptococcomas. Quantitative PCR testing of formalin‐fixed paraffin‐embedded tissue led to the identification of Cryptococcus gattii species complex. To the authors' knowledge, this is the first case reported in the Netherlands of pulmonary cryptococcomas due to C. gattii sensu lato in a horse that had never travelled abroad. [ABSTRACT FROM AUTHOR]

Simple Summary: Transcutaneous auricular vagal nerve stimulation is a non-invasive technique used in human medicine to prevent or treat post-operative ileus. The vagus nerve plays a crucial role in increasing intestinal motility and reducing the inflammatory response in sepsis models; thus, its stimulation constitutes an attractive strategy for modulating intestinal motility and immune response after abdominal surgery in both humans and horses. The technique has never been described in the equine species before. This study describes transcutaneous auricular vagal nerve stimulation in healthy non-sedated horses, assessing its feasibility and effect on heart rate variability (HRV). HRV was analysed as an indirect method to identify parasympathetic stimulation of the treatment. Auricular vagal nerve stimulation is an economical procedure that is easy to perform. However, it was poorly tolerated in awake horses. In the mares that tolerated the procedure, its effect on the autonomic system confirmed the potential stimulation of vagal activity, which can be of interest in preventing post-operative ileus in horses with inflammation or after exploratory laparotomy. 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. [ABSTRACT FROM AUTHOR]

Background: Hematology is a diagnostic tool used to evaluate the health status of horses. However, breed differences are often not considered. Objectives: The objective was to compare complete blood count variables among Warmbloods, Thoroughbreds, and stock horses (SH). Methods: Ninety-six healthy horses were grouped by breed (Warmbloods, Thoroughbreds, and SH). Samples were collected through venipuncture for complete blood count analysis. One-way ANOVA with Tukey's tests or Kruskal–Wallis with Dunn's post hoc tests were used to compare hematologic variables among groups. Results: Warmbloods had a significantly lower total white blood cell (WBC) count (6.08 ± 1.11 × 109/L) and lymphocyte count (1.76 ± 0.41 × 109/L) than Thoroughbreds (7.28 ± 1.45; 2.28 ± 5.16 × 109/L, respectively; P< .001) and SH (7.21 ± 1.18 × 109/L, P< .01; 2.10 ± 5.17 × 109/L; P< .05). Warmbloods had a significantly lower red blood cell count (7.7 ± 0.8 × 1012/L) and higher mean corpuscular volume (MCV, 49.4 ± 2.2 fL) than Thoroughbreds (8.42 ± 1.2 × 1012/L, P< .01; 47.3 ± 3.0 fL). Warmbloods had lower MCVs than SH (49.4 ± 2.2 vs 51.2 ± 2.6 fL). The mean cell hemoglobin concentration (MCHC) was higher in Warmbloods (35.0, 33.8–36.2 g/dL) and Thoroughbreds (34.9, 33.4–35.7 g/dL) than in SH breeds (34.0, 33.4–35.4 g/dL; P< .001, both). Total protein concentrations were significantly lower in Thoroughbreds (67, 59–80 g/L) compared with SH (71, 64–83 g/dL) (P< .05). Conclusions: Warmbloods had decreased WBC and lymphocyte counts compared with Thoroughbreds and SH, and Thoroughbreds had increased red blood cell counts. Thoroughbreds had lower total protein concentrations than SH. Clinicians should consider breed differences when interpreting hematologic values. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectivesTo investigate if hepatitis A virus cell receptor 1/kidney injury molecule 1 (HAVCR1/KIM1) in urine is detectable concurrently with increases in serum creatinine concentrations in horses receiving a recommended dose of phenylbutazone (PBZ) for 7 days.DesignPreliminary study.MethodsTen clinically healthy horses with normal physical examination and laboratory work were randomly assigned to PBZ or placebo groups (5 each). The PBZ group received PBZ at 4.4 mg/kg mixed with corn syrup orally every 12 hours. The placebo group received corn syrup orally every 12 hours. Both groups were treated for 7 days. Kidney ultrasonography was performed, and venous blood and urine samples were collected prior to commencement and at the end of treatment. Samples from 1 additional healthy horse, 3 horses with acute kidney failure, and 1 horse with chronic kidney failure were also evaluated.ResultsNone of the 10 horses had detectable HAVCR1/KIM1 in urine at baseline. Serum creatinine concentrations in placebo group did not increase, and HAVCR1/KIM1 was undetectable in urine. At the end of treatment, 3 of 5 horses receiving PBZ developed increases in serum creatinine of >26.5 μmol/L (>0.3 mg/dL), and HAVCR1/KIM1 was detectable in urine, despite normal findings on kidney ultrasonography in all horses.ConclusionsHAVCR1/KIM1 is detectable in urine and is associated with increases in serum creatinine concentrations of >26.5 μmol/L in horses following treatment with PBZ for 7 consecutive days. Thus, HAVCR1/KIM1 might aid in the early detection of acute kidney injury in horses.

Disorders of sexual development (DSD) are associated with atypical chromosomal, gonadal, or phenotypic sex. It is likely that the number of cases of DSD are underestimated in the equine population. Monorchidism in the horse is very rare. This case report describes the clinical assessment of a phenotypic mare with stallion-like behavior which led to the diagnosis of a DSD. A 4-year-old Quarter Horse mare presented in good body condition, with normal external genitalia for a mare, and normal mammary glands with two bilaterally symmetric teats. No uterus, cervix, or gonads were detected on transrectal palpation. Transrectal ultrasonography revealed a single gonad in the right dorsal abdomen with the morphologic appearance of a testicle. Presurgical hormonal evaluation revealed elevated serum testosterone and anti-Müllerian hormone (AMH) concentrations. The right gonad was successfully removed via standing exploratory laparoscopy and submitted for histopathology. No gonad was identified on the left side during laparoscopy. Histopathologic examination confirmed that the excised gonad was a testicle. Cytogenetic and molecular analysis revealed a 64,XY, SRY-positive chromosomal constitution. Hormonal evaluation 5 weeks after surgery revealed low serum testosterone and AMH levels. A diagnosis of monorchidism was based on ultrasound examination, laparoscopic exploration of the abdomen, removal of a single gonad, and a subsequent decrease in serum testosterone and AMH concentrations to basal levels. In summary, a combination of clinical signs, endocrine evaluation, chromosomal and molecular analysis, and histopathology can be used in the diagnosis of DSD conditions.

Recently, equine organizations from multiple countries around the world, including Australia, have implemented bans on the trimming of vibrissae (sensory hairs located around the muzzle and eyes) of horses competing in their events. These hairs are likely to have sensory functions that are important to horses, and the ban is based on welfare grounds. The aims of this study were to determine: the proportions of horse owners trimming equine facial hairs (ear and muzzle hair) across different types of equestrian disciplines in Australia, the types of equine facial hairs trimmed, whether horses were restrained for trimming, and attitudes related to the practice. An online survey of Australian horse owners was advertised through organizations involving equine competitive sports. A total of 422 responses were obtained, with respondents mostly female and a wide range of age groups. Respondents involved in showing competitions were more likely to trim muzzle and ear hairs than the other competition types. Respondents in showing competitions more commonly believed that trimming muzzle and ear hairs was a normal practice in their discipline, made it more likely a horse would win, and that horses did not need muzzle or ear hairs for day-to-day living. The results of this study provide valuable insight into the widespread trimming of horse muzzle and ear hairs in some horse disciplines prior to the implementation of the ban in Australia. The information gained may also be useful for the design and implementation of behaviour change interventions for other management and presentation practices used for horses and other animals. Further studies are needed to determine if and how the practice and attitudes to facial hair trimming in horses have changed with the enforcement of the ban.

Racehorses are susceptible to underrun heel hoof conformation. Racehorses are often shod with nails placed toward the heel. It is unknown if palmar nails restrict or alter hoof deformation in a manner that could promote the development of underrun heel conformation over time with repeated loading. To determine how the addition of palmar nails affects heel deformation during limb loading, hoof expansion and hoof wall deformations were quantified using rosette strain gauges and kinematic markers during in the vitro limb loading of cadaveric limbs that simulated midstance for walk, trot, and canter loads. Nail treatments used to attach a horseshoe to the hoof included: toe nails (T), toe and quarter nails (TQ), and toe, quarter, and heel nails (TQH). The effects of nail treatment on heel expansion and hoof wall deformations were assessed using repeated measures analysis of variance (p < 0.05). Nails placed palmar to the quarters of the hoof decreased heel expansion (p < 0.001). Heel nails resulted in the largest changes in hoof wall principal strain directions distally. The application of nails palmar to the hoof quarters alters hoof wall deformation during limb loading. The continued loading of the hoof with palmer nails could alter hoof conformation over time.

IntroductionEpiglottic entrapment (EE) is a common cause of poor performance in racing standardbreds (STBs) and thoroughbreds (TBs). There is limited information published on the condition in STB racehorses and limited information on factors associated with return to racing available for either breed.MethodsThis study investigated and compared the pre surgical findings, post-surgical complications and racing performance in STBs and TBs undergoing surgery for correction of EE. Associations between signalment and pre-surgical findings, and the presence of complications and racing post-surgery were compared using logistic regression analyses. Racing performance following surgery was compared to maternal siblings using conditional logistic regression.ResultsThere were 82 cases where epiglottic entrapment surgery was performed at least once: 33 STB cases and 49 TB cases. In total, 74% of cases raced following surgery. Cases with severe inflammation post-surgery (p

Abstract Background Understanding and finding the correlation between morphometric measurements and horse blood parameters is crucial for predicting equine metabolic issues. Objective This study aims to analyse morphometric measurements and blood samples in horses with varying adiposity levels. Study design Cross‐sectional observational. Methods A total of 50 horses were included in the study and categorized into groups based on their body condition score (BCS) and cresty neck score (CNS). Results The insulin concentration was significantly higher in overweight horses (p = 0.022). Female horses exhibited higher cortisol concentrations (p = 0.025) and girth circumference at the withers (p = 0.004) compared to males. Lactating mares exhibited higher concentrations of serum total protein (p = 0.012) and globulin (p = 0.003). A positive correlation was observed between BCS and insulin concentrations (r = 0.290, p = 0.041). Negative correlations were found between neck circumference to height at withers and glucose (r = −0.309, p = 0.029), CNS and glucose (r = −0.315, p = 0.026) as well as between crest diameter and cortisol (r = −0.360, p = 0.01). Main limitations Increasing the sample size and conducting longitudinal studies would enhance the study's validity and reliability. Conclusion Although insulin, glucose and cortisol concentrations have predictive capabilities based on signs and certain morphometric measurements, their correlations are not always strong. Therefore, this study challenges the notion that all overweight horses are unhealthy, as overweight horses can still have good metabolic health. Conversely, lean horses may also experience metabolic issues. Hence, relying solely on visual cues is insufficient to diagnose the metabolic status of horses. Other factors must also be considered to assess their health status accurately.

ABSTRACT: This study explores the use of WhatsApp as a tool for identifying previously undiagnosed and underreported diseases in ruminants and horses in Mato Grosso do Sul, Brazil. The research, carried out from January 2022 to December 2023, involved a WhatsApp group of 302 public service and private sector veterinarians. The contacts were categorized as those that resulted in a necropsy by the veterinary diagnostic laboratory, the sending of a sample for histopathological analysis, or the non-sending of material. The results demonstrate the efficiency of using WhatsApp for diagnosing underreported diseases such as anaplasmosis, haemonchosis, rabies, blackleg disease, Mannheimia haemolytica pneumonia, bovine herpesvirus encephalitis, multiple mineral deficiency in cattle and copper poisoning in sheep, thus increasing diagnostic efficiency for veterinary laboratories. The tool also facilitated communication, resulting in an increase in conclusive diagnoses, the identification of previously undiagnosed diseases such as Chlamydia pecorum encephalomyelitis in buffalo, peripheral neuropathy in cattle, phosphorus deficiency in cattle, vitamin A deficiency, and perinatal pneumonia caused by Salmonella enterica subsp. arizonae in cattle. In addition, it was possible to identify underreported occurrences, such as cases of abortion and neonatal diarrhea and to implement the correction of diagnostic approaches in real-time via WhatsApp. The study concludes that WhatsApp improves communication between field veterinarians and diagnostic laboratories, providing valuable information on disease occurrence and diagnostic challenges.

ABSTRACT The objective was to verify the existence of lineages in the Mangalarga Marchador breed using microsatellites and to phenotypically characterize the lineages found using linear morphometric measurements taken at the time the animals were registered to be used as a tool for selecting individuals according to each breeder’s selection objective. The genotyping database contained 255,257 Mangalarga Marchador horses born between 2005 and 2021. In addition, a database was used with pedigree information on 622,299 animals born between 1952 and 2020 and a database of phenotypes assessed at the time of definitive registration of these animals, containing 303,248 animals born between 1950 and 2018. The databases used came from the Associação Brasileira dos Criadores do Cavalo Mangalarga Marchador. To verify the existence of genetic differences according to the lineages of the breed, a discriminant analysis of principal components (DAPC) and the Kruskall Wallis test were carried out to perform phenotypic characterization to compare the means of the morphometric measurements, both using the R software. The DAPC analysis showed the genetic differentiation of the Angaí and Herdade lineages in relation to the others. The Herdade lineage showed greater phenotypic differentiation when compared with the three separate genetic groups in this study, demonstrating that the animals of this lineage are smaller and more gathered and have higher scores for gait and morphology. When compared to the historically described Mangalarga Marchador lineages, the breed does not have so many genetic groups, separating it into just three groups (Angaí, Herdade, and General), and when compared to phenotypic characteristics, only the Herdade lineage stood out.

Abnormal blood glucose (BG) levels often seen in critically ill horses are significantly associated with adverse patient outcomes and increased mortality. Rapid and accurate BG monitoring is now considered an essential component of evidence-based equine practice and can provide critical information quickly for treatment. Although several point-of-care (POC) BG monitoring hand-held devices are commercially available for veterinary use, none contains a unique algorithm validated for use in horses. The AlphaTrak 3 (AT3) BG monitoring system is a first-of-its-kind device with an equine-specific algorithm that allows stall-side clinical decision making, and frequent monitoring at minimal cost. As such, AT3 is potentially a preferred alternative to more costly and time-consuming standard diagnostic reference laboratory methods. The objective of this study was to determine the accuracy of the AT3 device in measuring BG levels in equine whole blood samples in comparison to results obtained by the Beckman Coulter AU480 reference analyzer per ISO15197:2013 specifications. Accuracy of the AT3 equine algorithm were initially verified by testing equine blood samples with artificially adjusted blood glucose levels followed by its validation in a field study. Testing with artificially adjusted equine samples (n = 129) showed that 98.9% of glucose measurements ranging from 29 to 479 mg/dL fell within ISO accuracy threshold of ±15 mg/dL or ±15% of the average reference value. In addition, 100% of the AT3 measurements fell in consensus error grid (CEG) zone A, which indicates that test outcomes have a minimal likelihood of adverse clinical impact. In a follow-up field study involving 96 horses, 98.4% of AT3 measurements met the ISO accuracy threshold and 99.2% of AT3 measurements fell in CEG zone A. These results demonstrate that the AT3 glucometer has a high degree of accuracy in horses and is a dependable, convenient, and cost-effective device for accurately monitoring equine BG levels in farm or clinical settings.

Streptococcus equi subspecies equi, commonly referred to as “strangles”, poses a significant biosecurity challenge across equine farms worldwide. The continuous prevalence and highly transmissibility of strangles necessitates a rapid and accurate diagnostic procedure. However, current “gold-standard” techniques, such as cultures and quantitative polymerase chain reaction (qPCR), are unreliable or inaccessible, and require lengthy periods between sample collection and results. Moreover, the lack of a standardized detection protocol can lead to variations in results. This study aimed to develop a reproducible and field-deployable diagnostic assay to detect strangles in real-time. Utilising the rapid technique loop-mediated isothermal amplification (LAMP), we developed an assay targeting a conserved region of the S. equi-specific M gene (SeM). Additionally, we optimised our assay with guanidine hydrochloride (GuHCl) to enhance the assay’s performance and detection capabilities. The Str-LAMP was able to detect S. equi within 13 minutes and 20 seconds for both synthetic DNA and clinical isolates, with a limit of detection (LOD) of 53 copies/µl. Our assay demonstrated high repeatability with the inter-coefficient of variation ranging from 0.17% to 3.93%. Furthermore, the clinical sensitivity and specificity was calculated at 91.3% and 93.3%, respectively, with a correct classification rate of 91.8%. The implementation of this newly developed strangles assay can be employed as an efficient aid for in-field surveillance programs. The assay’s reproducibility can allow for equine managers to undertake routine self-surveillance on their properties, without the requirement of specialised training. The Str-LAMP assay has the potential to be a valuable tool to help mitigate potential strangles outbreaks.

The lipidomic secretions of embryos provide a unique opportunity to examine the cellular processes of the early conceptus. In this study we profiled lipids released by the early equine conceptus, using high-resolution mass spectrometry to detect individual lipid species. This study examined the lipidomic profile in embryo-conditioned media from in vivo-produced, 8–9 day-old equine embryos (n = 3) cultured in vitro for 36 h, analyzed over 3 timepoints. A total of 1,077 lipid IDs were recorded across all samples, containing predominantly glycerolipids. Seventy-nine of these were significantly altered in embryo conditioned-media versus media only control (p 2 or

ABSTRACT A 7-year-old quarter horse mare showed swelling of the tongue, head and neck region, dyspnea, and red urine after eight days of administration of intravenous medications by the animal's handler. The horse was referred to the University Veterinary Hospital of the Federal University of Pará and, at the clinical examination, showed apathy, edema in the head, neck, and tongue region, which was slightly cyanotic and with loss of epithelium in the dorsal region. The maxillary, linguofacial and external jugular veins were bilaterally engorged, firm to palpation and with cord-shaped appearance, with extension of the head to the entrance to the thoracic cavity. Ultrasound examination showed a thrombi with a hyperechoic and heterogeneous appearance that completely obstructed the vessel. The horse died five days after entering the Hospital and at necropsy it was observed: maxillary, linguofacial and external jugular veins bilaterally filled with firm, dark red to blackish thrombi; ulcerated areas in the final third of the esophagus and the stomach; lighter areas on the surface of the kidneys and dark areas at the corticomedullary junction. Based on clinical, ultrasonographic and necropsy findings, iatrogenic thrombophlebitis was diagnosed, associated with repeated injections of drugs administered intravenously.

Rabies is endemic in Sudan with continuing outbreaks occurring annually, the most common animals affected are dogs, followed by goats and equids. This work focused on equid rabies, to elucidate the current situation of the disease through analysis of reports of equid rabies outbreaks in Sudan during 2010–2022 supported by laboratory confirmation of the disease. During the study period, 66 animals were affected during 35 equid rabies outbreaks. The highest incidences were found in Al Gezira (30.3%), followed by Darfur (24.2%) and Kordofan (15.2%). The highest incidence rate was observed during 2018 (33.3%), followed by 2015 (16.7%). Within seasons, the highest incidence rate was reported during October – December (33.3%), followed by July – September (30.3%). Chi-square analysis revealed a significant correlation between rabid animals and year, season, and state. Wald statistics demonstrated that year and season had a significant association with the disease. Virus antigen was identified (72.2%) in brain tissues using the fluorescent antibody test. Viral nucleic acid was amplified (n = 6) with a reverse transcriptase polymerase chain reaction assay. Contribution: As equids are kept in close contact with humans and other animals in the country, according to the present investigation, equid rabies in Sudan is a potential public health concern, emphasising the importance of implementing effective control measures.

Abstract Background Equine primary iris cysts are usually incidental findings but, if associated with clinical signs, may require intervention. The use of laser (Nd:Yag or diode) has been reported but requires specialised equipment. Transcorneal aspiration has not been previously evaluated in the standing horse. Objectives To review outcomes of standing transcorneal aspiration of primary iris cysts (STAPIC) in horses. Methods Horses were identified from electronic patient records from 2018 to 2024 across four collaborating centres. Clinical presentation and outcomes were identified and reported using descriptive statistics. Results Eighteen horses were identified. Behavioural signs reported included ‘spooking’ and changes in rideability often associated with jumping. Single large unilateral cysts were present in 11 horses, bilateral cysts in three horses and multiple unilateral cysts in four horses. Following treatment, one horse developed uveitis and fibrin in the anterior chamber associated with needle contact with the iris stroma due to movement, and a second horse developed fibrin within the anterior chamber. Both conditions resolved with anti‐inflammatory medication and administration of tissue plasminogen activator. No other adverse effects were reported. Follow‐up was available from all horses (median: 6 months, interquartile range [IQR]: 4–11 months) with no recurrence, although one horse developed an iris cyst in the contralateral eye after 3 years. All owners reported improvement in clinical signs, with 61% reporting no further signs. Conclusions STAPIC is an effective and easily accessible alternative for treating iris cysts in horses rarely associated with complications.

Abstract Background Palatal dysfunction (PD), which encompasses palatal instability (PI) and intermittent dorsal displacement of the soft palate, is the most common performance‐limiting upper respiratory tract obstruction in young Thoroughbred racehorses. Soft palate thermocautery (SPT) performed under general anaesthesia is a routinely performed procedure for PD in some countries, but the procedure for and outcome of SPT performed under standing sedation has not been published. Objectives (1) To describe a technique for SPT performed under standing sedation; and (2) to assess post‐operative performance in horses compared to controls using the Racing Post rating (RPR), British Horseracing Authority official rating (OR), Performance Index and Earnings. Study design Retrospective case series. Methods Medical records were reviewed for all horses that had SPT performed under standing sedation following topical and local infusion of lidocaine hydrochloride into the rostral soft palate, and that were identified to have PI by overground endoscopy. Two matched controls were identified for each case. The median RPR, OR, Performance Index and Earnings for the three pre‐operative and three post‐operative races were compared. Results No significant differences were identified between the SPT (n = 23) and Control groups (n = 46) for baseline characteristics or outcomes. Main limitations Retrospective study design, small sample size. Conclusions No significant differences in racing performance were identified between horses that had SPT performed under standing sedation and controls.

IntroductionIn adult horses, the development and evaluation of enteral electrolyte solutions containing sodium acetate for correcting hyperchloremic metabolic acidosis are still lacking, although these electrolyte and acid–base imbalances are commonly observed. The objective of this study was to evaluate the alkalinizing effect of two enteral electrolyte solutions containing different concentrations of acetate, administered via nasogastric tube in continuous flow, in adult horses with experimental hyperchloremic metabolic acidosis.MethodsSix mares aged between 3 and 10 years were used in a 6×2 crossover design, with each animal receiving both treatments. The horses were subjected to a protocol to induce hyperchloremic metabolic acidosis. They then received one of two treatments: HighAcetate (81.4 mmol/L) and LowAcetate (22.7 mmol/L) at an infusion rate of 15 mL/kg/h for 12 h. Plasma, serum, and urinary biochemical assessments; hematocrit; urinary volume, pH, and specific gravity; and blood gas analysis were measured at the following time points: T-12 h (beginning of the 12-h fast), T0h (end of fasting and beginning of the acidosis induction phase), every 2 h during the hyperchloremic metabolic acidosis induction phase (Ti2h and Ti4h), every 2 h during the 12-h enteral hydration phase (Tt2h, Tt4h, Tt6h, Tt8h, Tt10h, and Tt12h), with one sample taken at T24h (24 h after the start of acidosis induction) and another at T36h (36 h after the start of acidosis induction). Data were analyzed using descriptive statistics and analysis of variance based on a factorial design of repeated measures, with Tukey’s post-hoc test or the Kruskal-Wallis test with Dunn’s post-hoc test for non-parametric tests.ResultsAt the end of the induction phase, the animals developed moderate to severe hyperchloremic metabolic acidosis. The HighAcetate solution effectively corrected electrolyte and acid–base imbalances before the end of the treatment phase (Tt12h), while the LowAcetate solution was not effective in correcting those changes.ConclusionThe HighAcetate (81.4 mmol/L) solution is deemed an effective and safe alternative for the treatment of hyperchloremic metabolic acidosis in horses.

ABSTRACT: We described the first case of rhinofacial pythiosis with dissemination in an adult horse in Uruguay. The affected horse presented a partially circumscribed mass measuring 30 x 23 x 9 cm affecting the right side of the face with involvement of cutaneous, subcutaneous, and muscular tissues, the right nasal cavity, and adjacent structures. At postmortem examination, the main lesions were “kunkers” characterized by pyogranulomatous and eosinophilic dermatitis, Splendore-Hoeppli reaction and numerous intralesional hyphae immunolabeling with polyclonal anti-Pythium insidiosum antibody. Similar lesions were observed in the lung and submandibular lymph nodes. The diagnosis was made by the characteristic histological lesions and the strong immunolabelling by anti-P. insidiosum antibody.

Osteochondrosis (OC) is a developmental orthopaedic disease of significant concern in numerous sport horse breeds, with significant international relevance. Using digital radiographs, we assessed the occurrence of hock (tarsocrural joint) OC in 3 048 Pura Raza Española (PRE) horses which took part in a morpho-functional test, in three specific locations in the tarsus limbs: the Distal Intermediate Ridge of the Tibia (DIRT), the lateral trochlear ridges of the talus (LTT), and the medial trochlear ridges of the talus (MTT). An incidence rate of 13.3% was found for hock OC in the analysed sample, with the highest incidence rate observed in DIRT (10.0%) and the lowest in MTT (0.2%). Estimates of genetic predisposition to hock OC were carried out using three genetic approaches: 1a) a binomial threshold model based on the presence or absence of OC, 1b) a multinomial threshold model, on a scale from 0 (absence) to 3 (maximum), and 2) a linear model. The effects considered in the models included sex, genetic origin and stud class. All the analyses were based on the Bayesian inference methodology, using the THRGIBBS3F90 software. The binomial threshold model yielded the most suitable results, with an estimated heritability for Overall hock OC of 0.71 ± 0.055 on the underlying scale (0.53 on the observed scale), ranging in different locations from 0.48 ± 0.087 (LTT) to 0.66 ± 0.063 (DIRT) on the underlying scale (0.10 and 0.38 on the observed scale, respectively). The highest significative genetic correlation was observed between Overall and DIRT (0.97) for approach 1a, and the lowest significant genetic correlation was between Overall and LTT (0.49), for approach 2. This study contributes valuable insights into the genetic predisposition towards, as well as for the potential for selective breeding against, hock OC in PRE horses, and provides a basis for future research and breeding programmes aimed at minimising the occurrence of hock OC and promoting the overall health of this breed.

This article discusses the history, current situation, and future prospects of deworming programs for horses in the United States. In the past, the development of effective dewormers had a positive impact on equine health, but it also led to increased reports of anthelmintic resistance (AR) in internal parasites. Currently, there is a growing awareness of the problem of AR, and horse owners are seeking more advice from veterinarians on deworming protocols. The future may bring new technologies, such as genomics, gene editing, artificial intelligence, and data analytics, which could lead to the development of new anthelmintic drugs or other control practices for internal parasites. [Extracted from the article]

Methods to diagnose and monitor equine pregnancy continue to advance with improved instrumentation enabling the development of novel, non-invasive approaches to assess fetal well-being and viability using ultrasound and endocrine testing. From early embryonic loss to placentitis, that is typically encountered later in gestation, fetal viability and development as well as placental function can be evaluated using two fundamentally different, structural and functional, approaches. Ultrasound provides structural information on embryonic and fetal growth using such parameters as combined thickness of the uterus and placenta (CTUP), visual assessment of fetal fluids, activity, heart rate and multiple biometrics involving the fetal head and eyes, limbs and joints among many others, depending on the stage of gestation. Endocrine profiles that include progesterone and 5α-dihydroprogesterone, other metabolites, androgens and estrogens can be evaluated simultaneously using liquid chromatography-tandem mass spectrometry (LC-MS/MS) providing more functional information on fetal and placental competence and development. Endocrine information can be used in making clinical decisions including the need for progestin supplementation or when it can cease, and even estimating gestational stage in mares that cannot be easily palpated or scanned, as with mini-breeds or rancorous animals most notably. When used together, monitoring gestation by ultrasound and hormonal analysis provides unusual insight into feto-placental well-being and the progress of pregnancy, helping to identify problems needing therapeutic intervention.

Reproductive failure represents an important cause of economic loss for the equine industry. We reviewed the cases of equine abortion and stillbirth submitted to the California Animal Health and Food Safety Laboratory System, University of California-Davis from 1990 to 2022. A total of 1,774 cases were reviewed. A confirmed cause of abortion was determined in 29.2% of the cases. Abortion or stillbirth was attributed to infectious agents in 18.7% of the cases, with Streptococcus spp., equine herpesvirus 1, and Leptospira spp. being the most prevalent. Noninfectious causes of abortion were established in 10.5% of the cases, with umbilical cord torsion being the most common. In 70.8% of the cases, a definitive cause of abortion could not be established. Our study demonstrated the difficulties in establishing an etiologic diagnosis, even when following a standard diagnostic work-up. New diagnostic approaches are needed to improve the likelihood of reaching a final diagnosis in cases of equine abortion and stillbirth.

Background: Although relatively uncommon, lymphoma is the most prevalent haematopoietic neoplasia in horses, and multicentric lymphoma remains the most common presentation of the disease. The pathogenesis of equine lymphoma is still poorly understood and the diagnosis is usually confirmed at an advanced stage of the disease, compromising the prognosis. This study investigated the clinical, pathological and molecular features of a case of equine multicentric lymphoma. Case Description: An apparently healthy 5-year-old crossbreed mare hospitalized at Centre of Animal Reproduction of Vairao (CRAV), Portugal, suddenly presented clinical signs of supraorbital oedema and mandibular lymph node enlargement, developing fever, facial oedema and generalized lymphadenopathy. The mare ended up dying twenty-four days after the first clinical signs due to multisystem organ failure. Haematological and biochemical analyses, necropsy and microscopic and molecular evaluation of affected tissues were performed. At necropsy, the main findings were multiple multinodular lesions, distributed along the serous surface of oropharynx, trachea, pericardium, gastrointestinal tract and mesentery. Microscopically, these consisted of solid proliferations of neoplastic round cells that exhibited immunopositivity for CD3 (T cells). Based on these findings, a medium-grade multicentric T-cell lymphoma was diagnosed. Conclusion: There is still very little research regarding the molecular characterization of lymphoma in horses. As an entity itself quite heterogeneous, it is important to describe the interspecies particularities to understand its development and behaviour. [Open Vet J 2024; 14(5.000): 1294-1301]

Abstract Background Equine herpes virus type 1 (EHV‐1) infection in horses is associated with upper respiratory disease, neurological disease, abortions, and neonatal death. Review Question Does pharmacological therapy decrease either the incidence or severity of disease or infection caused by EHV‐1 in domesticated horses? Methods A systematic review was preformed searching AGRICOLA, CAB Abstracts, Cochrane, PubMed, Web of Science, and WHO Global Health Index Medicus Regional Databases to identify articles published before February 15, 2021. Selection criteria were original research reports published in peer reviewed journals, and studies investigating in vivo use of therapeutic agents for prevention or treatment of EHV‐1 in horses. Outcomes assessed included measures related to clinical outcomes that reflect symptomatic EHV‐1 infection or virus infection. We evaluated risk of bias and performed a GRADE evaluation of the quality of evidence for interventions. Results A total of 7009 unique studies were identified, of which 9 met the inclusion criteria. Two studies evaluated valacyclovir or small interfering RNAs, and single studies evaluated the use of a Parapoxvirus ovis‐based immunomodulator, human alpha interferon, an herbal supplement, a cytosine analog, and heparin. The level of evidence ranged between randomized controlled studies and observational trials. The risk of bias was moderate to high and sample sizes were small. Most studies reported either no benefit or minimal efficacy of the intervention tested. Conclusions and Clinical Importance Our review indicates minimal or limited benefit either as a prophylactic or post‐exposure treatment for any of the studied interventions in the mitigation of EHV‐1‐associated disease outcome.

Abstract Background The ability to perform transvenous temporary cardiac pacing (TV‐TP) is critical to stabilize horses with symptomatic bradyarrhythmias. Reports of successful TV‐TP in horses are limited, and only briefly describe short‐term pacing. Objective To describe temporary, medium‐term (24 h) transvenous right ventricular pacing in awake horses using a bipolar torque‐directed pacing catheter. Animals Six healthy adult institutional teaching horses. Methods Prospective experimental study with 2 immediately successive TV‐TP lead placements in each horse with a target location of the RV apex. One placement was performed primarily with echocardiographic guidance and 1 primarily with fluoroscopic guidance. In all placements, corresponding images were obtained with both imaging modalities. Horses were then paced for 24 h, unrestricted in a stall with continuous telemetric ECG monitoring. Echocardiographically determined lead position, episodes of pacing failure in the preceding 6 h, and pacing thresholds were recorded every 6 h. Pacing failure was defined as a period of loss of capture longer than 20 s. Results Pacing leads were placed with both guidance methods and maintained for 24 h with no complications. Two horses with leads angled caudally in the right ventricular apex had no pacing failure, the remaining 4 horses had varying degrees of loss of capture. Leads located in the right ventricular apex had longer time to pacing failure and lower capture thresholds P

Abstract Background Equine herpes virus type 1 (EHV‐1) infection in horses is associated with respiratory and neurologic disease, abortion, and neonatal death. Hypothesis Vaccines decrease the occurrence of clinical disease in EHV‐1‐infected horses. Methods A systematic review was performed searching multiple databases to identify relevant studies. Selection criteria were original peer‐reviewed research reports that investigated the in vivo use of vaccines for the prevention of disease caused by EHV‐1 in domesticated horses. Main outcomes of interest included pyrexia, abortion, neurologic disease, viremia, and nasal shedding. We evaluated risk of bias, conducted exploratory meta‐analyses of incidence data for the main outcomes, and performed a GRADE evaluation of the quality of evidence for each vaccine subtype. Results A total of 1018 unique studies were identified, of which 35 met the inclusion criteria. Experimental studies accounted for 31/35 studies, with the remainder being observational studies. Eight vaccine subclasses were identified including commercial (modified‐live, inactivated, mixed) and experimental (modified‐live, inactivated, deletion mutant, DNA, recombinant). Risk of bias was generally moderate, often because of underreporting of research methods, and sample sizes were small leading to imprecision in the estimate of the effect size. Several studies reported either no benefit or minimal vaccine efficacy for the primary outcomes of interest. Meta‐analyses revealed significant heterogeneity was present, and our confidence in the quality of evidence for most outcomes was low to moderate. Conclusions and Clinical Importance Our review indicates that commercial and experimental vaccines minimally reduce the incidence of clinical disease associated with EHV‐1 infection.

Abstract Equine herpesvirus‐1 (EHV‐1) is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). The previous consensus statement was published in 2009 and considered pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment. A recent survey of American College of Veterinary Internal Medicine large animal diplomates identified the need for a revision to this original consensus statement. This updated consensus statement is underpinned by 4 systematic reviews that addressed key questions concerning vaccination, pharmaceutical treatment, pathogenesis, and diagnostic testing. Evidence for successful vaccination against, or effective treatment of EHV‐1 infection was limited, and improvements in experimental design and reporting of results are needed in future studies of this important disease. This consensus statement also updates the topics considered previously in 2009.

Abstract Background Equine herpes virus type 1 (EHV‐1) infection in horses is associated with upper respiratory disease, neurological disease, abortions, and neonatal death. Objective To determine if there is an association between the level and duration of EHV‐1 viremia and either abortion or equine herpesvirus myeloencephalopathy (EHM) in domesticated horses? Methods A systematic review was performed searching numerous databases to identify peer reviewed reports that evaluated viremia and EHM, or viremia and abortion published before January 19, 2021. Randomized controlled trials and observational studies were assessed for risk of bias or publication quality. Results A total of 189 unique studies were identified, of which 34 met the inclusion criteria. Thirty studies evaluated viremia and neurologic outcomes including 4 observational studies. Eight experimental studies examined viremia and abortion, which used the Ab4 and OH03 virus strains or recombinant Ab4 derivatives. Incidence rates for both EHM and abortion in experimental studies varied among the studies as did the level of evidence. Viremia was generally detectable before the onset of either EHM or abortion. Risk of bias was generally low to moderate, sample sizes were small, and multiple studies reported negative outcome data. Conclusions and Clinical Importance The results of this study support that viremia is regularly present before EHM or abortion occurs. However, no inferences could be made about the relationship between the occurrence of either neurological signs or abortion and the magnitude or duration of viremia.

Abstract Background Equine herpesvirus type 1 (EHV‐1) infection is associated with upper respiratory disease, EHM, abortions, and neonatal death. Research Questions Are nasal secretions a more sensitive biological sample compared to blood for the detection of EHV‐1 infection? How long is EHV‐1 detectable after primary infection by PCR? Methods MedLine and Web of Science searches identified original peer‐reviewed reports evaluating nasal shedding and viremia using virus isolation methods or PCR published in English before October 9, 2023. Results Sixty experimental and 20 observational studies met inclusion criteria. EHV‐1 detection frequency by qPCR in nasal secretions and blood from naturally‐infected horses with fever and respiratory signs were 15% and 9%, respectively; qPCR detection rates in nasal secretions and blood from horses with suspected EHM were 94% and 70%, respectively. In experimental studies the sensitivity of qPCR matched or exceeded that seen for virus isolation from either nasal secretions or blood. Detection of nasal shedding typically occurred within 2 days after EHV‐1 inoculation with a detection period of 3 to 7 days. Viremia lasted 2 to 7 days and was usually detected ≥1 days after positive identification of EHV‐1 in nasal secretions. Nasal shedding and viremia decreased over time and remained detectable in some horses for several weeks after inoculation. Conclusions and Clinical Importance Under experimental conditions, blood and nasal secretions have similar sensitivity for the detection of EHV‐1 when horses are sampled on multiple consecutive days. In contrast, in observational studies detection of EHV‐1 in nasal secretions was consistently more successful.

Abstract Background Studies on equine air transport practices and consequences are scarce. This prospective study aimed to describe horse and air journey details and practices, document how horse behavior and health changed during the air transport phases, quantify the occurrence of welfare issues, and identify possible associations between horse and journey details, air transport practices, and welfare issues. Results Data were collected from before departure to five days after arrival on 118/597 horses traveling on 32 commercial air journeys on different routes, varying in duration and conditions. Most horses were middle-aged warmblood females, 26% of which were pregnant, and being moved by air for sales. Before flying, most were quarantined (median: 18; IQR: 9–53 days), and their fitness for travel was certified by veterinarians. At the departure airports, external temperatures varied from − 6 °C to 33 °C, and horses were loaded by experienced flight grooms (median: 35; IQR: 15–40 years) into jet stalls (three-horse: 87%, two-horse: 13%). During the flights, horses were regularly watered (water intake median: 14 L) and fed ad libitum (feed consumption median: 8 kg). At the arrival airport, horses were unloaded from the jet stalls, and external temperatures ranged from − 5 °C to 32 °C. Then, all horses were transported to arrival quarantine by road. Air transport phases affected horses’ health status and behavior; increased heart and respiratory rates and behaviors, such as pawing, head tossing, and vocalization, were mainly identified at departure and arrival. Horse interaction, nasal discharge, increased capillary refill time (CRT), and abnormal demeanor were observed more often one hour before landing while resting and normal capillary refill time were more often displayed five days after arrival (all P

Abstract To better understand molecular aspects of equine endometrial function, there is a need for advanced in vitro culture systems that more closely imitate the intricate 3-dimensional (3D) in vivo endometrial structure than current techniques. However, development of a 3D in vitro model of this complex tissue is challenging. This study aimed to develop an in vitro 3D endometrial tissue (3D-ET) with an epithelial cell phenotype optimized by treatment with a Rho-associated protein kinase (ROCK) inhibitor. Equine endometrial epithelial (eECs) and mesenchymal stromal (eMSCs) cells were isolated separately, and eECs cultured in various concentrations of Rock inhibitor (0, 5, 10 µmol) in epithelial medium (EC-medium) containing 10% knock-out serum replacement (KSR). The optimal concentration of Rock inhibitor for enhancing eEC proliferation and viability was 10 µM. However, 10 µM Rock inhibitor in the 10% KSR EC-medium was able to maintain mucin1 (Muc1) gene expression for only a short period. In contrast, fetal bovine serum (FBS) was able to maintain Muc1 gene expression for longer culture durations. An in vitro 3D-ET was successfully constructed using a collagen-based scaffold to support the eECs and eMSCs. The 3D-ET closely mimicked in vivo endometrium by displaying gland-like eEC-derived structures positive for the endometrial gland marker, Fork headbox A2 (FOXA2), and by mimicking the 3D morphology of the stromal compartment. In addition, the 3D-ET expressed the secretory protein MUC1 on its glandular epithelial surface and responded to LPS challenge by upregulating the expression of the interleukin-6 (IL6) and prostaglandin F synthase (PGFS) genes (P

The present report is about the successful surgical retrieval of eye worms in 15 horses. Most of the animals were presented with lacrimation, photophobia, and varying degrees of corneal opacity. On ophthalmic examination, worms appeared like moving white threads in the anterior chamber. Animals were restrained with xylazine-ketamine general anesthesia. Regional nerve blocks were given to minimize eyeball movements and a 2-3 mm clear corneal incision near the limbus at the 10-2 O'clock position of the eyeball was given to retrieve worms. With a single incision, worms were successfully removed in all the cases. Bolus of Ivermectin was given orally along with analgesic and antibiotics eye drops postoperatively. The vision was restored and corneal opacity subsided within 10-20 days post-surgery.

Abstract Background Salmonella enterica subspecies enterica serovar abortus equi (S. abortus equi) is one of the main pathogens that causes abortion in pregnant horses and donkeys, which was highly infectious and greatly restricts the healthy development of the horse industry. Objectives In order to investigate the prevalence and biological characteristics of S. abortus equi in different regions and breeds of horses in Xinjiang. Methods This study conducted ELISA detection of S. abortus equi antibodies on serum samples of 971 horses collected from three large-scale horse farms and five free-range horse farms in Yili Prefecture and Bayingol Mongolian Autonomous Prefecture of Xinjiang from 2020 to 2023. On this basis, bacterial isolation, culture, identification, and drug sensitivity tests were conducted on 42 samples of aborted foal tissues and 23 mare vaginal swabs. Results The results showed that the positive rate of S. abortus equi antibody was as high as 20.91% in 971 horse serum samples. Among them, the positive rate in the Ili region (29.09%) was significantly higher than that in the Bayingole region (11.24%), and the positive rate in mares (22.45%) was higher than that in stallions (14.05%). In terms of horse breeds, the positive rates of self-propagating thoroughbred horses, half-bred horses, Ili horses and Yanqi horses were 43.22%, 28.81%, 14.72% and 11.24% respectively. In addition, S. abortus equi was more susceptible to juvenile and elderly horses, with positive rates of 70.00%and 41.86%, respectively, both of which were significantly higher than young (10.97%) and adult (19.79%) horses. Further, 9 strains of S. abortus equi were obtained through bacterial isolation, culture and identification, which were resistant to five antibiotics (Clarithromycin, Clindamycin, penicillin, Sulfamethoxazole and Rifampicin), and sensitive to 13 antimicrobial agents (Amoxicillin, Ciprofloxacin and Gentamicin, et al.). Conclusion There was a high infection rate of S. abortus equi in Ili Prefecture and self-propagating thoroughbred horses, and juvenile or old mares were more susceptible, which will provide scientific basis for the prevention of S. abortus equi infection in different regions and breeds of horses in Xinjiang.

Abstract Outbreaks of West Nile virus (WNV) occur periodically, affecting both human and equine populations. There are no vaccines for humans, and those commercialised for horses do not have sufficient coverage. Specific antiviral treatments do not exist. Many drug discovery studies have been conducted, but since rodent or primate cell lines are normally used, results cannot always be transposed to horses. There is thus a need to develop relevant equine cellular models. Here, we used induced pluripotent stem cells to develop a new in vitro model of WNV-infected equine brain cells suitable for microplate assay, and assessed the cytotoxicity and antiviral activity of forty-one chemical compounds. We found that one nucleoside analog, 2′C-methylcytidine, blocked WNV infection in equine brain cells, whereas other compounds were either toxic or ineffective, despite some displaying anti-viral activity in human cell lines. We also revealed an unexpected proviral effect of statins in WNV-infected equine brain cells. Our results thus identify a potential lead for future drug development and underscore the importance of using a tissue- and species-relevant cellular model for assessing the activity of antiviral compounds.

INTRODUCTION: Equine recurrent uveitis (ERU), an immune mediated disease characterized by repeated episodes of intra-ocular inflammation, affects 25% of horses in the USA and is the most common cause of glaucoma, cataracts, and blindness. Mesenchymal stromal cells (MSCs) have immunomodulatory properties, which are upregulated by preconditioning with toll-like receptor agonists. The objective was to evaluate safety and migration of TLR-3 agonist polyinosinic, polycytidylic acid (pIC)-activated MSCs injected subconjunctivally in healthy horses prior to clinical application in horses with ERU. We hypothesized that activated allogeneic MSCs injected subconjunctivally would not induce ocular or systemic inflammation and would remain in the conjunctiva for >14 days. METHODS: Bulbar subconjunctiva of two horses was injected with 10 × 106 pIC-activated (10 μg/mL, 2 h) GFP-labeled MSCs from one donor three times at two-week intervals. Vehicle (saline) control was injected in the contralateral conjunctiva. Horses received physical and ophthalmic exams [slit lamp biomicroscopy, rebound tonometry, fundic examination, and semiquantitative preclinical ocular toxicology scoring (SPOTS)] every 1-3 days. Systemic inflammation was assessed via CBC, fibrinogen, and serum amyloid A (SAA). Horses were euthanized 14 days following final injection. Full necropsy and histopathology were performed to examine ocular tissues and 36 systemic organs for MSC presence via IVIS Spectrum. Anti-GFP immunohistochemistry was performed on ocular tissues. RESULTS: No change in physical examinations was noted. Bloodwork revealed fibrinogen 100-300 mg/dL (ref 100-400) and SAA 0-25 μg/mL (ref 0-20). Ocular effects of the subjconjucntival injection were similar between MSC and control eyes on SPOTS grading system, with conjunctival hypermia, chemosis and ocular discharge noted bilaterally, which improved without intervention within 14 days. All other ocular parameters were unaffected throughout the study. Necropsy and histopathology revealed no evidence of systemic inflammation. Ocular histopathology was similar between MSC and control eyes. Fluorescent imaging analysis did not locate MSCs. Immunohistochemistry did not identify intact MSCs in the conjunctiva, but GFP-labeled cellular components were present in conjunctival phagocytic cells. DISCUSSION: Allogeneic pIC-activated conjunctival MSC injections were well tolerated. GFP-labeled tracking identified MSC components phagocytosed by immune cells subconjunctivally. This preliminary safety and tracking information is critical towards advancing immune conditioned cellular therapies to clinical trials in horses.

Because equine tendinopathies are slow to heal and often recur, therapeutic strategies are being considered that aid tendon repair. Given the success of utilizing vitamin C to promote tenogenesis in other species, we hypothesized that vitamin C supplementation would produce dose-dependent improvements in the tenogenic properties of tendon proper (TP) and peritenon (PERI) cells of the equine superficial digital flexor tendon (SDFT). Equine TP- and PERI-progenitor-cell-seeded fibrin three-dimensional constructs were supplemented with four concentrations of vitamin C. The gene expression profiles of the constructs were assessed with 3'-Tag-Seq and real-time quantitative polymerase chain reaction (RT-qPCR); collagen content and fibril ultrastructure were also analyzed. Moreover, cells were challenged with dexamethasone to determine the levels of cytoprotection afforded by vitamin C. Expression profiling demonstrated that vitamin C had an anti-inflammatory effect on TP and PERI cell constructs. Moreover, vitamin C supplementation mitigated the degenerative pathways seen in tendinopathy and increased collagen content in tendon constructs. When challenged with dexamethasone in two-dimensional culture, vitamin C had a cytoprotective effect for TP cells but not necessarily for PERI cells. Future studies will explore the effects of vitamin C on these cells during inflammation and within the tendon niche in vivo.

IntroductionLymphoma is the most common hemopoietic neoplasia in horses. Common clinicopathologic abnormalities in equine lymphoma include hyperglobulinemia, hypoalbuminemia, hyperfibrinogenemia, anemia, thrombocytopenia and lymphocytosis. Hypoglobulinemia has been reported in other species with lymphoma, however it has not been well-described in horses. The objectives of this study were to examine the prevalence of hypoglobulinemia in equine lymphoma, and to identify prognosis and clinicopathological abnormalities associated with serum globulin concentrations.MethodsNinety-six horses with lymphoma were investigated in this retrospective study. Patients were allocated into groups based on serum globulin concentration. Survival analysis was performed to determine risk factors associated with globulin concentration and outcome.ResultsNineteen horses were hypoglobulinemic (≤2.1 g/dL), 63/98 were normoglobulinemic (2.2-4.3 g/dL), and 16/98 were hyperglobulinemic (≥4.4 g/dL). Hyperglobulinemia was associated with a higher anion gap (P = 0.0005), lower bicarbonate (P = 0.006), sodium (P = 0.03) and chloride concentrations (P = 0.002), and higher total protein than hypoglobulinemic horses (P < 0.0001). For location, 37% of horses with mucocutaneous lymphoma were hypoglobulinemic, compared to none in the hyperglobulinemic group (P = 0.02). Survival times were significantly different between low, normal and high globulin groups (P = 0.0002, median [range] survival times: 333 [1-3792], 43 [1-4,001] and 4 [1-129] days, respectively). Significant risk factors for shortened time to death were hyperglobulinemia (HR 2.4, P = 0.02), T cell lymphoma (HR 3.5, P < 0.0001), and multicentric (HR 3.1, P = 0.0008) and mediastinal (HR 6.4, P = 0.006) forms of lymphoma. Lack of chemotherapy was associated with shortened survival time (HR 4.5, P < 0.0001). B cell lymphomas (P < 0.0001) and mucocutaneous lymphoma location (P < 0.0001) were associated with longer survival times.DiscussionSerum globulin concentrations are associated with location of lymphoma, clinicopathologic abnormalities, and survival times in equine lymphoma.

Background Methods Results Conclusion Factors contributing to the limited success of in vitro fertilization in horses remain to be studied. In this work, we elucidated the effect of different essential capacitation media components, bicarbonate, and bovine serum albumin or polyvinyl‐alcohol, and the incubation microenvironment on sperm parameters associated with capacitation, acrosome reaction, and their ability to activate oocytes via heterologous intracytoplasmic spermatozoa injection in equine cryopreserved spermatozoa.Frozen–thawed spermatozoa underwent incubation at different time intervals in either Tyrode's albumin lactate pyruvate medium (non‐capacitating; NC) or Tyrode's albumin lactate pyruvate supplemented with bicarbonate, bicarbonate and polyvinyl‐alcohol, bicarbonate and bovine serum albumin, polyvinyl‐alcohol and bovine serum albumin alone. Protein kinase A‐phosphorylated substrates and tyrosine phosphorylation levels, sperm motility, and acrosome reaction percentages were evaluated. After determining the best condition media (capacitating; CAP), heterologous intracytoplasmic spermatozoa injection on pig oocytes was performed and the phospholipase C zeta sperm localization pattern was evaluated.Incubation of frozen–thawed equine spermatozoa with bicarbonate and polyvinyl‐alcohol in atmospheric air for 45 min induced an increase in protein kinase A‐phosphorylated substrates and tyrosine phosphorylation levels compared to NC condition. Sperm incubation in bicarbonate and polyvinyl‐alcohol medium showed an increase in total motility and progressive motility with respect to NC (p ≤ 0.05). Interestingly, three parameters associated with sperm hyperactivation were modulated under bicarbonate and polyvinyl‐alcohol conditions. The kinematic parameters curvilinear velocity and amplitude of lateral head displacement significantly increased, while straightness significantly diminished (curvilinear velocity: bicarbonate and polyvinyl‐alcohol = 120.9 ± 2.9 vs. NC = 76.91 ± 6.9 µm/s) (amplitude of lateral head displacement: bicarbonate and polyvinyl‐alcohol = 1.15 ± 0.02 vs. NC = 0.77 ± 0.03 µm) (straightness: bicarbonate and polyvinyl‐alcohol = 0.76 ± 0.01 vs. NC = 0.87 ± 0.02) (p ≤ 0.05). Moreover, the spontaneous acrosome reaction significantly increased in spermatozoa incubated in this condition. Finally, bicarbonate and polyvinyl‐alcohol medium was established as CAP medium. Although no differences were found in phospholipase C zeta localization pattern in spermatozoa incubated under CAP, equine spermatozoa pre‐incubated in CAP condition for 45 min showed higher fertilization rates when injected into matured pig oocytes (NC: 47.6% vs. CAP 76.5%; p ≤ 0.05).These findings underscore the importance of bicarbonate and polyvinyl‐alcohol in supporting critical events associated with in vitro sperm capacitation in the horse, resulting in higher oocyte activation percentages following heterologous intracytoplasmic spermatozoa injection. This protocol could have an impact on reproductive efficiency in the equine breeding industry. [ABSTRACT FROM AUTHOR]

Objective: Develop, implement, and monitor for adverse effects of, a novel hemoperfusion therapy in adult horses. Methods: A prospective, observational feasibility study using three healthy adult horses from the North Carolina State University teaching herd. Health status was determined by physical exam, complete blood count, coagulation panel, and serum biochemistry. Each horse was instrumented with a 14 Fr × 25 cm doublelumen temporary hemodialysis catheter and underwent a 240 min polymerbased hemoperfusion session. Horses were administered unfractionated heparin to maintain anti-coagulation during the session. Given the novelty of this therapy in horses, each horse was treated as a learning opportunity that informed an iterative process of protocol development and modification. Measurements and main results: Our long-term goal is to investigate potential clinical applications of hemoperfusion in horses, including cytokine reduction in horses with severe SIRS/sepsis. Horses were monitored for changes in clinical exam, biochemistry and hematology parameters. Additionally, cytokines were quantified to determine whether extracorporeal hemadsorption therapy alone caused an inflammatory response. Our results show that hemoperfusion therapy was associated with decreased platelet counts and serum albumin concentration. There was no significant change in plasma cytokine concentrations with hemoperfusion therapy. In one horse, the cytokine concentrations decreased, as previously reported with hemoperfusion therapy in humans. Hypothesis: We hypothesized that hemoperfusion therapy could be performed in healthy adult horses without significant adverse effects. Conclusion: Polymer-based hemoperfusion is a feasible extracorporeal therapy (ECT) modality for adult horses. Additional studies are needed to further establish clinical protocols, as well as establish efficacy of polymer-based hemoperfusion for treatment of various conditions in horses, including intoxications, immunemediated conditions, and sepsis. [ABSTRACT FROM AUTHOR]

Equine leptospirosis can result in abortion, stillbirth, neonatal death, placentitis, and uveitis. Horses can also act as subclinical reservoir hosts of infection, which are characterized as asymptomatic carriers that persistently excrete leptospires and transmit disease. In this study, PCR and culture were used to assess urinary shedding of pathogenic Leptospira from 37 asymptomatic mares. Three asymptomatic mares, designated as H2, H8, and H9, were PCRpositive for lipL32, a gene specific for pathogenic species of Leptospira. One asymptomatic mare, H9, was culture-positive, and the recovered isolate was classified as L. kirschneri serogroup Australis serovar Rushan. DNA capture and enrichment of Leptospira genomic DNA from PCR-positive, culturenegative samples determined that asymptomatic mare H8 was also shedding L. kirschneri serogroup Australis, whereas asymptomatic mare H2 was shedding L. interrogans serogroup Icterohaemorrhagiae. Sera from all asymptomatic mares were tested by the microscopic agglutination test (MAT) and 35 of 37 (94.6%) were seropositive with titers ranging from 1:100 to 1:3200. In contrast to asymptomatic mares, mare H44 presented with acute spontaneous abortion and a serum MAT titer of 1:102,400 to L. interrogans serogroup Pomona serovar Pomona. Comparison of L. kirschneri serogroup Australis strain H9 with that of L. interrogans serogroup Pomona strain H44 in the hamster model of leptospirosis corroborated differences in virulence of strains. Since lipopolysaccharide (LPS) is a protective antigen in bacterin vaccines, the LPS of strain H9 (associated with subclinical carriage) was compared with strain H44 (associated with spontaneous abortion). This revealed different LPS profiles and immunoreactivity with reference antisera. It is essential to know what species and serovars of Leptospira are circulating in equine populations to design efficacious vaccines and diagnostic tests. Our results demonstrate that horses in the US can act as reservoir hosts of leptospirosis and shed diverse pathogenic Leptospira species via urine. This report also details the detection of L. kirschneri serogroup Australis serovar Rushan, a species and serotype of Leptospira, not previously reported in the US. [ABSTRACT FROM AUTHOR]

Multipotent mesenchymal stromal cells (MSC) play an increasing role in the treatment of immune-mediated diseases and inflammatory processes. They regulate immune cells via cell-cell contacts and by secreting various anti-inflammatory molecules but are in turn influenced by many factors such as cytokines. For MSC culture, platelet lysate (PL), which contains a variety of cytokines, is a promising alternative to fetal bovine serum (FBS). We aimed to analyze if PL with its cytokines improves MSC immunoregulatory characteristics, with the perspective that PL could be useful for priming the MSC prior to therapeutic application. MSC, activated peripheral blood mononuclear cells (PBMC) and indirect co-cultures of both were cultivated in media supplemented with either PL, FBS, FBS+INF-g or FBS+IL-10. After incubation, cytokine concentrations were measured in supernatants and control media. MSC were analyzed regarding their expression of immunoregulatory genes and PBMC regarding their proliferation and percentage of FoxP3+ cells. Cytokines, particularly IFN-g and IL-10, remained at high levels in PL control medium without cells but decreased in cytokine-supplemented control FBS media without cells during incubation. PBMC released IFN-g and IL-10 in various culture conditions. MSC alone only released IFN-g and overall, cytokine levels in media were lowest when MSC were cultured alone. Stimulation of MSC either by PBMC or by PL resulted in an altered expression of immunoregulatory genes. In co-culture with PBMC, the MSC gene expression of COX2, TNFAIP6, IDO1, CXCR4 and MHC2 was upregulated and VCAM1 was downregulated. In the presence of PL, COX2, TNFAIP6, VCAM1, CXCR4 and HIF1A were upregulated. Functionally, while no consistent changes were found regarding the percentage of FoxP3+ cells, MSC decreased PBMC proliferation in all media, with the strongest effect in FBS media supplemented with IL-10 or IFN-g. This study provides further evidence that PL supports MSC functionality, including their immunoregulatory mechanisms. The results justify to investigate functional effects of MSC cultured in PL-supplemented medium on different types of immune cells in more detail. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis is a prevalent degenerative joint disease initiating chronic pain and lameness in horses. While several objective gait analysis systems have been developed and validated to quantify lameness severity in horses, methods to evaluate whether peripheral sensitization contributes to the pain experienced are missing. Objectives: To evaluate whether periarticular pressure pain mapping could be proposed as an auxiliary assessment tool in horses. Specific aims were to evaluate the feasibility and intra- and inter-rater reliability of pressure pain thresholds (PPT) determination at sites overlying the distal thoracic limb joints of clinically healthy horses. Study design: Prospective, randomized validation study. Methods: For feasibility assessment, PPT were measured with a hand-held digital algometer at six periarticular landmarks (2 sites per joint, 3 joints) bilaterally on the distal thoracic limb of 40 healthy horses (20 warmblood and 20 Freiberger). The joints tested were the metacarpophalangeal, on the lateropalmar and dorsal aspects (L-MCP and D-MCP), the proximal interphalangeal, on the dorsal and palmar aspect (D-PIP and P-PIP) and the distal interphalangeal, on the dorsal and lateral aspect (D-DIP and L-DIP). A feasibility score, ranging from 0 to 5, was attributed to each testing session. For intra- and inter-rater reliability assessment, L-MCP and D-MCP were selected to be tested again at 2 weeks intervals in 20 out of the 40 horses. Data were analyzed using a mixed-effect linear model to test differences in threshold per site and limb. Intra- and inter-rater correlation was calculated. Bland-Altman plots were performed to evaluate the variability of the measures. Results: The procedure was considered feasible (score <2) in 95% of horses (95% CI 88%--100%). Overall, median [interquartile range (IQR)] PPT was 9.4 (7.5--11.3) N. No significant side differences were found. P-PIP and D-DIP recorded significantly lower PPT (p < 0.001 and p = 0.002, respectively) than L-MCP. Median (IQR) were 9.9 (7.3--12.4) N, 8.4 (6.1--10.5) N and 9.0 (7.4--10.6) N for L-MCP, P-PIP and D-DIP, respectively. The intra-rater agreement was 0.68 (95% CI 0.35--0.86) for L-MCP, and 0.50 (95% CI 0.08--0.76) for D-MCP. Inter-rater agreement was 0.85 (95% CI 0.66--0.94) for L-MCP and 0.81 (0.57, 0.92) for D-MCP. Main limitations: Evaluation of feasibility was performed only for distal thoracic limbs joints; no data are provided for hind limbs or proximal joints. Only warmblood and Freiberger horses were included. Intra- and inter-rater reliability assessments were performed exclusively on data collected at the MCP joint. Conclusion: Pressure pain mapping of distal thoracic limb joints was feasible in horses. Local sensitivity differed among sites and no side differences were noticed. Data collected from the MCP joint suggest highly variable, subject dependent intra-rater reliability, ranging from poor to good, and good to excellent inter-rater reliability. Further studies evaluating pathologic vs. healthy joints are needed before recommendations can be made about clinical usability and diagnostic validity. [ABSTRACT FROM AUTHOR]

Introduction: The end of gestation, ensuing parturition, and the neonatal period represent highly dynamic phases for immunological changes in both mother and offspring. The regulation of innate immune cells at the maternal-fetal interface during late term pregnancy, after birth, and during microbial colonization of the neonatal gut and other mucosal surfaces, is crucial for controlling inflammation and maintaining homeostasis. Innate immune cells and mucosal epithelial cells express antileukoproteinase (SLPI), which has anti-inflammatory and antiprotease activity that can regulate cellular activation. Methods: Here, we developed and validated new monoclonal antibodies (mAbs) to characterize SLPI for the first time in horses. Peripheral blood and mucosal samples were collected from healthy adults horses and a cohort of mares and their foals directly following parturition to assess this crucial stage. Results: First, we defined the cell types producing SLPI in peripheral blood by flow cytometry, highlighting the neutrophils and a subset of the CD14+ monocytes as SLPI secreting immune cells. A fluorescent bead-based assay was developed with the new SLPI mAbs and used to establish baseline concentrations for secreted SLPI in serum and secretion samples from mucosal surfaces, including saliva, nasal secretion, colostrum, and milk. This demonstrated constitutive secretion of SLPI in a variety of equine tissues, including high colostrum concentrations. Using immunofluorescence, we identified production of SLPI in mucosal tissue. Finally, longitudinal sampling of clinically healthy mares and foals allowed monitoring of serum SLPI concentrations. In neonates and postpartum mares, SLPI peaked on the day of parturition, with mares returning to the adult normal within a week and foals maintaining significantly higher SLPI secretion until three months of age. Conclusion: This demonstrated a physiological systemic change in SLPI in both mares and their foals, particularly at the time around birth, likely contributing to the regulation of innate immune responses during this critical period. [ABSTRACT FROM AUTHOR]

Background: Although relatively uncommon, lymphoma is the most prevalent haematopoietic neoplasia in horses, and multicentric lymphoma remains the most common presentation of the disease. The pathogenesis of equine lymphoma is still poorly understood and the diagnosis is usually confirmed at an advanced stage of the disease, compromising the prognosis. This study investigated the clinical, pathological, and molecular features of a case of equine multicentric lymphoma. Case Description: An apparently healthy 5-year-old crossbreed mare hospitalized at the Centre of Animal Reproduction of Vairão, Portugal, suddenly presented clinical signs of supraorbital oedema and mandibular lymph node enlargement, developing fever, facial oedema, and generalized lymphadenopathy. The mare ended up dying twenty-four days after the first clinical signs due to multisystem organ failure. Haematological and biochemical analyses, necropsy, and microscopic and molecular evaluation of affected tissues were performed. At necropsy, the main findings were multiple multinodular lesions, distributed along the serous surface of oropharynx, trachea, pericardium, gastrointestinal tract, and mesentery. Microscopically, these consisted of solid proliferations of neoplastic round cells that exhibited immunopositivity for CD3 (T cells). Based on these findings, a medium-grade multicentric T-cell lymphoma was diagnosed. Conclusion: There is still very little research regarding the molecular characterization of lymphoma in horses. As an entity itself is quite heterogeneous, it is important to describe the interspecies particularities to understand its development and behaviour. [ABSTRACT FROM AUTHOR]