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The International Labor Organization estimates roughly 1.7 million children are trafficked for sex globally at any given time, yet there is a dearth of research on therapeutic interventions. In this qualitative study, we utilized psychotherapy incorporating equine to explore the experiences of commercially sexually exploited youth. We analyzed the participants’ experiences using interpretative phenomenological analysis and identified the following themes: shifting relationships with self and others, equine therapeutic factors, and learning new skills. We provide implications for future research and practice.

BACKGROUND: Anatomical location-dependent differences in transdermal opioid penetration are well described in human patients. Although this has been investigated in horses with fentanyl, there is no literature available on location-dependent plasma buprenorphine concentrations when administered as a transdermal matrix-type patch. OBJECTIVE: This study aims to compare the plasma concentrations achieved from the matrix-type transdermal buprenorphine patches placed at different anatomical sites (metacarpus, gaskin, and ventral tail base) in healthy adult horses. STUDY DESIGN: This is a randomized experimental study with a Latin square design. METHODS: Six adult horses were given each of three treatments with a minimum 10-day washout period. For each treatment, two 20 μg h-1 matrix-type buprenorphine patches were applied to the ventral aspect of the tail base (TailTDP), metacarpus region (MetacarpusTDP), or gaskin region (GaskinTDP). Whole blood samples (for determination of buprenorphine concentration) and physiological variables were collected before (0 h) and at 0.5, 2, 4, 6, 8, 10, 12, 16, 24, 32, 48, 56, 72, 96 and 120 h after patches were applied. The patches were removed 96 h following placement and were analyzed for residual buprenorphine content. Buprenorphine concentrations were measured in plasma by LC-MS/MS. A mixed-effects model was used to analyze the physiological variables. RESULTS: Between the three treatment groups, there was no change in physiological variables across timepoints as compared to baseline and when compared to each other in a single horse and between horses (p > 0.3). When comparing all three locations, the buprenorphine uptake was observed to be more consistent with respect to measurable plasma concentrations >0.1 ng ml-1 when applied to the ventral aspect of the tail base. In the TailTDP group, the mean plasma buprenorphine concentrations were >0.1 ng ml-1 from 2 to 32 h. The highest group mean was 0.25 ng ml-1 noted at 4 h. CONCLUSIONS: The metacarpal and gaskin regions presented more erratic and inconsistent buprenorphine uptake and plasma concentrations as compared to the ventral aspect of the tail base. Further research must be directed at investigating the optimal dose, achievable duration of analgesia, change in measurable plasma concentrations, and behavioral and systemic effects.

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.

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.

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.

BACKGROUND: Matrix type transdermal buprenorphine patches have not been investigated in horses and may provide an effective means of providing continuous pain control for extended period and eliminating venous catheterization. OBJECTIVE: Assessment of the physiological variables (heart rate, respiratory rate, body temperature) and thermal nociceptive threshold testing, and describing the pharmacokinetic profile of transdermal buprenorphine matrix-type patch (20 μg h-1 and 40 μg h-1 dosing) in healthy adult horses. STUDY DESIGN: Randomised experimental study with a Latin-square design. METHODS: Six adult healthy horses received each of the three treatments with a minimum 10 day washout period. BUP0 horses did not receive a patch (control). BUP20 horses received one patch (20 μg h-1) applied on the ventral aspect of the tail base resulting in a dose of 0.03-0.04 μg kg-1 h-1. BUP40 horses received two patches placed alongside each other (40 μg h-1) on the tail base resulting in a dose of 0.07-0.09 μg kg-1 h-1. Whole blood samples (for determination of buprenorphine concentration), physiological variables and thermal threshold testing were performed before (0 h) and at 2, 4, 8, 12, 16, 24, 32, 40, 48, 56, 64, 72, and 96 h after patch application. The patches were removed 72 h following placement and were analyzed for residual buprenorphine content. RESULTS: Between the three groups, there was no change in physiological variables across timepoints as compared to baseline (p > 0.1). With the higher dose, there was a significant increase in thermal thresholds from baseline values from 2 h until 48 h and these values were significantly higher than the group receiving the lower patch dose for multiple timepoints up to 40 h. 40 μg h-1 patch led to consistent measurable plasma concentrations starting at 2 h up to 96 h, with the mean plasma concentrations of > 0.1 ng/ml from 4 h to 40 h. CONCLUSIONS: 20 μg h-1 and 40 μg h-1 patch doses were well tolerated by all horses. At higher dose, plasma buprenorphine concentrations were more consistently measurable and blunted thermal thresholds for 48 h vs. 32 h with 20 μg h-1 dosing as compared to control.

BACKGROUND: Comprehensive descriptions of equids with granulocytic anaplasmosis (EGA) with neurologic or muscle disease and other atypical presentations are scarce in the literature. OBJECTIVE: Describe the clinical signs, laboratory findings, treatment, and outcome of equids with EGA with emphasis on neurologic and muscle disease. ANIMALS: Thirty-eight horses, 1 donkey. METHODS: Retrospective study. Equids with EGA were included. The electronic data base was searched from January 2000 to December 2022 using the words anaplasmosis, ehrlichiosis, granulocytic, and rickettsia. Signalment and clinical data were reviewed. Data were evaluated for normality using Shapiro-Wilk test. Parametric and nonparametric statistics were used for normally and non-normally distributed data. RESULTS: Common (41%) and other (59%) presentations were seen in horses ≥ 4 years of age (median, 14 years) with an overrepresentation of males (77%). Neurologic disease was common (41%), mainly presenting as diffuse symmetrical proprioceptive ataxia. Brain disease was less common manifesting as obtundation and cranial nerve deficits. Muscle disease was less common, with QH breeds with the variant causing myosin heavy chain myopathy (MYHM) having severe disease. Cavitary effusion, cardiomyopathy and disseminated intravascular coagulation (DIC) were uncommon. Clinical laboratory results varied depending on disease stage. Muscle enzyme activities were significantly higher in horses with muscle disease. Outcome was favorable with prompt tetracycline treatment. Death and long-term sequelae were not reported. CONCLUSIONS AND CLINICAL IMPORTANCE: Common and atypical presentations of EGA have a favorable outcome with prompt tetracycline treatment. Quarter horse breeds with muscle disease should be genotyped for MYHM.

Stress triggers a set of adaptative reactions that can compromise the homeostasis of the organism, such as transport from one environment to another. The aim of the present study was to determine whether there is a periodic variation in serotonin levels following transport stress. We used a databank to obtain data on plasma serotonin levels of healthy adult horses collected at regular eight-hour intervals for three consecutive days on two different occasions: before and after transport. The results were tabulated and submitted to Hurst statistical analysis procedures. Curves were created of the variation in serotonin levels as a function of time using the cosinor method. Plasma serotonin levels exhibited circadian variations independently of sex and age. The circadian variation pattern was significantly affected when the animals experienced transport stress (p < 0.05). Thus, plasma serotonin levels can be used as an indicator of physiological disorders and the promotion of animal wellbeing. [ABSTRACT FROM AUTHOR]

Background: Current methods for obtaining fecal egg counts in horses are often inaccurate and variable depending on the analyst's skill and experience. Automated digital scanning of fecal sample slides integrated with analysis by an artificial intelligence (AI) algorithm is a viable, emerging alternative that can mitigate operator variation compared to conventional methods in companion animal fecal parasite diagnostics. Vetscan Imagyst is a novel fecal parasite detection system that uploads the scanned image to the cloud where proprietary software analyzes captured images for diagnostic recognition by a deep learning, object detection AI algorithm. The study describes the use and validation of Vetscan Imagyst in equine parasitology. Methods: The primary objective of the study was to evaluate the performance of the Vetscan Imagyst system in terms of diagnostic sensitivity and specificity in testing equine fecal samples (n = 108) for ova from two parasites that commonly infect horses, strongyles and Parascaris spp., compared to reference assays performed by expert parasitologists using a Mini-FLOTAC technique. Two different fecal flotation solutions were used to prepare the sample slides, NaNO3 and Sheather's sugar solution. Results: Diagnostic sensitivity of the Vetscan Imagyst algorithm for strongyles versus the manual reference test was 99.2% for samples prepared with NaNO3 solution and 100.0% for samples prepared with Sheather's sugar solution. Sensitivity for Parascaris spp. was 88.9% and 99.9%, respectively, for samples prepared with NaNO3 and Sheather's sugar solutions. Diagnostic specificity for strongyles was 91.4% and 99.9%, respectively, for samples prepared with NaNO3 and Sheather's sugar solutions. Specificity for Parascaris spp. was 93.6% and 99.9%, respectively, for samples prepared with NaNO3 and Sheather's sugar solutions. Lin's concordance correlation coefficients for VETSCAN IMAGYST eggs per gram counts versus those determined by the expert parasitologist were 0.924–0.978 for strongyles and 0.944–0.955 for Parascaris spp., depending on the flotation solution. Conclusions: Sensitivity and specificity results for detecting strongyles and Parascaris spp. in equine fecal samples showed that Vetscan Imagyst can consistently provide diagnostic accuracy equivalent to manual evaluations by skilled parasitologists. As an automated method driven by a deep learning AI algorithm, VETSCAN IMAGYST has the potential to avoid variations in analyst characteristics, thus providing more consistent results in a timely manner, in either clinical or laboratory settings. [ABSTRACT FROM AUTHOR]

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 FROM AUTHOR]

OBJECTIVE: To determine the ability of bacteria commonly isolated from equine limb wounds to survive in saltwater obtained from an equine hydrotherapy unit at different salinity concentrations and temperatures. METHODS: Saltwater samples were obtained over a 2-week period (January 22, 2024 to February 2, 2024) from an equine hydrotherapy unit used for clinical patients, kept at either full salinity per manufacturer recommendations or diluted to half salinity to mimic the dilution that likely occurs in the clinical setting between cases when holding tanks are replenished with tap water only. Samples were then autoclaved to eliminate preexisting bacterial contamination before individual inoculation with Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus zooepidemicus. Each inoculated sample was maintained at 2, 22, or 44 °C to represent typical holding tank conditions. The bacterial concentration was determined at each condition every 24 hours up to and including 96 hours. The lower limit of detection was set at 1 CFU/mL. RESULTS: Salinity did not affect bacterial survival. Bacterial concentrations generally decreased with increasing temperature over time. Escherichia coli, S aureus, and S zooepidemicus concentrations decreased to the lower limit of detection at 44 °C by 24 to 48 hours, while P aeruginosa concentrations significantly decreased over 24 hours but remained well above the lower limit of detection. CONCLUSIONS: Common bacterial isolates of equine limb wounds can survive in typical saltwater hydrotherapy conditions. CLINICAL RELEVANCE: Further investigation is warranted to determine the CLINICAL RELEVANCE: of these findings including protocols for hydrotherapy unit disinfection, wastage of treatment water, and case inclusion/exclusion criteria. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To clarify the anti-inflammatory effect of platelet lysate (PL) on equine persistent synovitis by using a model of synovitis induced by monoiodoacetic acid (MIA). METHODS: Nonseptic synovitis was induced by administering MIA into both antebrachiocarpal joints of 6 clinically healthy horses on day 0. On days 23, 30, and 37, carpal circumference measurement and synovial fluid collection for assays (leucocytes, LDH, tumor necrosis factor-a, and TGF-ß1) were performed, after which PL was injected into 1 antebrachiocarpal joint and saline into the contralateral joint. Synovium and synovial fluid were obtained on day 44 for histological analysis and quantification of inflammation-related genes (matrix metalloproteinase-13, a disintegrin and metalloproteinase with thrombospondin motifs 4, receptor activator of nuclear factor β ligand, and collagen type I a2 chain) and the abovementioned proteins. RESULTS: The LDH level on day 44 was significantly lower in the PL-injected joint than in the saline-treated one. However, no significant differences were found in the other indices quantified, including osteoclast counts on the synovium. CONCLUSIONS: Multiple IA administration of PL does not exert anti-inflammatory effects on the equine persistent synovitis induced by MIA. CLINICAL RELEVANCE: Intra-articular PL administration did not alter many inflammatory biomarkers, suggesting that PL does not have a direct anti-inflammatory effect. However, the reduction in synovial LDH levels suggests that PL promoted joint tissue repair and may consequently alleviate inflammation at the site of administration. [ABSTRACT FROM AUTHOR]

Equine Piroplasmosis (EP) and Equine Granulocytic Anaplasmosis (EGA) are diseases that affect horses, transmitted by ixodid ticks, causing a nonspecific febrile syndrome. Equine Piroplasmosis is endemic in Brazil, and most horses are in enzootic stability. Serological and molecular studies carried out on horses in Brazil have shown the presence of Anaplasma phagocytophilum, however, the clinical relevance of this infection has not yet been established. The present study aims to evaluate the importance of Babesia caballi, Theileria equi, and A. phagocytophilum as etiological agents in horses with clinical manifestations suggestive of these diseases in the metropolitan mesoregion of Rio de Janeiro. A total of 45 animals with clinical signs were submitted to DNA extraction followed by qPCR test. Anaplasma phagocytophilum, Neorickettsia risticii and Theileria haneyi were not found in any of the horses with clinical signs, however 62.2% were infected with at least one agent of EP. Theileria equi was the most frequent etiologic agent (35.5%), followed by coinfection (15.5%) and B. caballi (11.2%). These results suggest that A. phagocytophilum has minor clinical importance in the region, while EP is frequently found in symptomatic horses, representing an important differential diagnosis in suspected cases. [ABSTRACT FROM AUTHOR]

Background: Ancillary diagnostic methods to enhance the accuracy of viability assessment have not been established for use in clinical practice. Objectives: To assess intestinal microperfusion measured by Laser Doppler Flowmetry and Spectrophotometry (LDFS) in naturally occurring small intestinal strangulations of different origins and to compare this between viable and non‐viable segments. Study design: Prospective clinical trial. Methods: Forty horses undergoing colic surgery for naturally occurring small intestinal strangulations were included. Tissue oxygen saturation (tSO2), haemoglobin (tHB) and blood flow (tBF) were determined by LDFS before and after release of the strangulation. Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia and assessed using a semi‐quantitative mucosal injury score (MIS). The LDFS measurements were compared between the different categories of strangulation causes and histopathological injury using parametric and non‐parametric tests (p < 0.05). Results: Strangulations by pedunculated lipomas had lower tBF (13.9 ± 18 arbitrary units [AU]) than epiploic foramen entrapments (65.2 ± 61 AU; CI −1.697 to −0.2498; p = 0.005). Segments with MIS > 5 showed lower tBF during strangulation than segments with MIS < 4 (mean difference 61.1 AU; CI −1.119 to −0.07361; p = 0.03). This did not differ significantly following release of strangulation. Furthermore, there was a positive correlation between the inflammatory cell count and tBF during strangulation (r 0.34; CI 0.01 to 0.60; p = 0.04). The tSO2 and tHB did not differ between the different categories of lesions or injury. Main limitations: No biopsies could be taken from the intestinal segments that did not undergo resection. The duration of strangulation could not reliably be ascertained. Conclusions: Blood flow measurements in naturally occurring strangulating lesions show a varying degree of ischaemia in different causes of strangulation. Intestinal blood flow measurements prior to release of the strangulation could potentially contribute to the identification of mucosal injury, yet a high individual variability and other contributing factors need to be considered. [ABSTRACT FROM AUTHOR]

Background Hypothesis Animals Methods Results Conclusion and Clinical Importance Gastric disease is highly prevalent in sport horses and may lead to poor performance, cause behavioral changes and impact welfare.Assess whether diet affects gastric disease and pain expression during riding, and whether it has an impact on physiological and locomotor variables during an exercise test, including jumps.Nine healthy show‐jumping Warmbloods trained at the same stable.Prospective observational cohort study. The horses receiving a pelleted diet, high in sugar and starch (>30%), were examined at T0 and after 12 weeks (T12) of changing to a cooked, muesli‐type low‐starch (11%) diet. Each time, the horses underwent a standardized exercise test (SET) and a ridden pain score (Ridden Horse Pain Ethogram [RHpE]) was calculated by 2 blinded observers. The next day, horses underwent gastroscopy and gastric lesions were scored blindly. Results were analyzed using Wilcoxon and Spearman tests.After 12 weeks of a low starch diet, the Equine Gastric Disease (EGD; 4 [3–5] at T0 vs 1 [0‐1] at T12, P < .01) and RHpE scores (6 [3–13] at T0 vs 3 [0‐6] at T12, P < .01) improved significantly. Squamous, glandular, and EGD scores were positively correlated with RHpE scores (respectively, r = .747, P < .01; r = .743, P < .01 and r = .867, P < .01).Gastric disease and pain scores correlated positively in ridden horses. A low starch diet significantly decreases the severity of gastric disease and associated pain score during riding in horses. Gastric ulcers may be mitigated and the comfort of equines athletes improved by dietary adjustments. [ABSTRACT FROM AUTHOR]

Background Hypothesis/Objectives Animals Methods Results Conclusions and Clinical Importance Furosemide, a commonly used diuretic, activates the renin‐angiotensin‐aldosterone system (RAAS) in other species. Little is known about RAAS peptide activation in horses.To evaluate equilibrium analysis as a practical method for RAAS quantification in horses and describe the RAAS response to a single dose of furosemide. We hypothesize that furosemide would cause transient increase in RAAS peptides in horses.14 healthy adult thoroughbreds from a university teaching herd.Horses received either furosemide (1 mg/kg IV) or saline IV in a crossover study design. Protease‐inhibited samples were compared with equilibrium analysis samples with Deming regression analysis. Renin‐angiotensin‐aldosterone system hormones were evaluated at 0, 0.25, 0.5, 4, and 24 hours postadministration, via equilibrium analysis. Values were compared with a mixed effects model.Correlation between protease inhibition and equilibrium analysis was high for angiotensin I peptide (AngI) and angiotensin II peptide (AngII) (r = .92 and .95, respectively). Baseline RAAS peptide concentrations were below the limit of detection except AngII (median, 7.5 [range, 3.5‐14.0] pmol/L). Furosemide administration resulted in an increase in AngI (8.0 [0.5‐15.5] pmol/L, P = .03), AngII (33.7 [9.6‐57.9] pmol/L, P = .0008), angiotensin III peptide (AngIII) (2.9 [0.9‐4.9] pmol/L, P = .0005), angiotensin IV peptide (AngIV) (2.0 [0.6‐3.4] pmol/L, P = .0005), and angiotensin 1‐5 peptide (Ang1‐5) (5.6 [1.2‐5.9] pmol/L, P = .003) at 4 hours. Differences are reported as difference in the mean (95% confidence interval [CI]).Furosemide produced an increase in hormones associated with both the classical and alternative RAAS pathways. Serum equilibrium analysis is practical for RAAS analysis in horses. [ABSTRACT FROM AUTHOR]

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 ±15mg/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. [ABSTRACT FROM AUTHOR]

Introduction: Protection of horse welfare during transport is crucial. The aim of this study was to determine the effect of head and neck restraint on behavior and airway bacteria. Methods: In a randomized crossover study, six healthy Thoroughbreds were transported by road for 22 h in an individual bay with tight head restraint (50 cm short-rope) or loose head restraint (95 cm long-rope). Behavioral parameters relating to head position, eating, and stress were monitored during transportation. Tracheal wash samples were obtained 6 days before and immediately after transport for bacterial culture and metagenomic analysis. Results and discussion: Compared to before transport, bacterial load (CFU/mL) after transport was significantly increased in the short-rope group (p = 0.04), whereas no changes were observed in the long-rope group. Transport significantly reduced Simpson index at phylum, class, order, and family levels in both groups (p < 0.001) of tracheal microbiota. In both groups, this reduction was associated with increases in the dominant members of relative abundance at phylum (Firmicutes: +24% in long-rope and +14% in short-rope), class (Bacilli: +20% in long-rope and +22% in short-rope) and family (Streptococcaceae: +22% in long-rope and +23% in short-rope) levels. Licking behavior during transportation with short-rope restraint was more frequent than in horses with long-rope restraint. These results suggest loose head restraint during transportation is likely to ameliorate stress and mitigate the associated increased bacterial load in the lower airways associated with transport. Further, head position during transportation is likely a more important determinant of airway hygiene and distress than duration of travel. [ABSTRACT FROM AUTHOR]

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 < 0.05, fold-change >2 or < 0.5). Fifty-five lipids were found to be released into the embryo-conditioned media, of which 54.5% were triacylglycerols and 23.6% were ceramides. The sterol lipid, cholesterol, was also identified and secreted in significant amounts as embryos developed. Further, 24 lipids were found to be depleted from the media during culture, of which 70.8% were diacylglycerols, 16.7% were triacylglycerols and 12.5% were ceramides. As lipid-free media contained consistently detectable lipid peaks, a further profile analysis of the various components of non-embryo-conditioned media consistently showed the presence of 137 lipids. Lipid peaks in non-embryo-conditioned media increased in response to incubation under mineral oil, and contained ceramides, diacylglycerols and triacylglycerols. These results emphasize the importance of a defined embryo culture medium and a need to identify the lipid requirements of the embryo precisely. This study sheds light on early embryo lipid metabolism and the transfer of lipids during in vitro culture. [ABSTRACT FROM AUTHOR]

Simple Summary: Intestinal microbiota (the gut microbiome) are important for normal gut function, especially in horses which rely on gut bacteria to break down plant material in the hindgut. Understanding normal microbiota is essential to be able to assess changes that occur during disease or in response to treatments. Post-mortem studies and biopsies have found different populations in the stomach mucosa (lining) compared to feces, but the gastric fluid has not been evaluated. The objective of this study was to describe the gastric fluid microbiome of healthy horses over time, under two housing conditions, and to compare the gastric fluid to fecal microbiome of paired samples. We found that while there were fewer bacteria (taxa) identified in the gastric juice compared to feces, there was a stable population of gastric microbiota which did not vary from week-to-week under either housing condition. There was a significant difference in compositional diversity (the relatedness of taxa present) between housing conditions, with changes in the relative proportions of a few key groups when horses moved from pasture to stable. These findings are important to inform future investigations of the gastric fluid microbiota in horses. Equine gastrointestinal microbial communities vary across the gastrointestinal tract and in response to diet or disease. Understanding the composition and stability of gastric fluid microbiota in healthy horses is a prerequisite to understanding changes associated with the development of disease. The objective of this study was to describe microbial communities in the gastric fluid and feces of healthy horses longitudinally. Horses were maintained on pasture (6 weeks), stabled (5 weeks), then returned to pasture. A consistent forage diet was provided throughout. Native gastric fluid and feces were collected weekly for full-length 16S ribosomal DNA sequencing and microbial profiling analysis. Fewer taxa were identified in the gastric fluid (770) than in the feces (5284). Species richness and diversity were significantly different between sample types (p < 0.001), but not between housing locations (p = 0.3). There was a significant effect of housing and horse on the Bray–Curtis compositional diversity of gastric (p = 0.005; p = 0.009) and fecal (p = 0.001; p = 0.001) microbiota. When horses moved from pasture to stable, the relative proportions of gastric fluid Lactobacillaceae increased and Streptococcaceae decreased, while fecal Firmicutes increased and Bacteriodota decreased. Within each housing condition, there was no significant week-to-week variation in gastric (p = 0.9) or fecal (p = 0.09) microbiota. Overall, these findings support the maintenance of stable gastric and fecal microbial populations under each management condition, providing a basis for further investigation of gastric fluid microbiota in diseases of the foregut. [ABSTRACT FROM AUTHOR]

Successful reproductive management of domestic mammals depends primarily upon timely identification of oestrous cycle stages. There is a need to develop an alternative non-invasive, welfare-friendly, accurate and reliable method to identify reproductive cycle stages. This is of particular interest for horse breeders, because horses are high-value farm animals that require careful management and individual monitoring. Saliva sampling is non-invasive, painless and welfare-friendly. Thus, we performed a metabolomic analysis of equine saliva during different reproductive stages to identify changes in the salivary metabolome during anoestrus, the oestrous cycle and early gestation. We compared the saliva and plasma metabolomes to investigate the relationship between the two fluids according to the physiological stage. We collected saliva and plasma samples from six mares during seasonal anoestrus, during the follicular phase 3 days, 2 days and 1 day before ovulation and the day when ovulation was detected, during the luteal phase 6 days after ovulation, and during early gestation 18 days after ovulation and insemination. Metabolome analysis was performed by proton-nuclear magnetic resonance spectroscopy. We identified 58 and 51 metabolites in saliva and plasma, respectively. The levels of four metabolites or groups of metabolites in saliva and five metabolites or groups of metabolites in plasma showed significant modifications during the 4 days until ovulation, ie 3 days prior to and on the day of ovulation. The levels of 11 metabolites or groups of metabolites in saliva and 17 metabolites or groups of metabolites in plasma were significantly different between the seasonal anoestrus and the ovarian cyclicity period. The physiological mechanisms involved in the onset of ovarian cyclicity and in ovulation induced modifications of the metabolome both in plasma and saliva. The metabolites whose salivary levels changed during the reproductive cycle could be potential salivary biomarkers to detect the reproductive stage in a welfare friendly production system. In particular, we propose creatine and alanine as candidate salivary biomarkers of ovulation and of the onset of ovarian cyclicity, respectively. However, extensive validation of their reliability is required. Our study contributes to extend to domestic mammals the use of saliva as a non-invasive alternative diagnostic fluid for reproduction in a welfare-friendly production system. • The metabolites level in mare saliva was analyzed according to the reproductive stage. • The saliva metabolome is modified during transition from anestrus to ovarian cyclicity. • The saliva metabolome is modified during the ovulation process. • Saliva is a non-invasive and welfare-friendly diagnostic fluid for equine reproduction. [ABSTRACT FROM AUTHOR]

Placental infection is an important cause of late-term pregnancy loss and neonatal diseases in horses. Detection of changes in blood parameters especially during early placentitis could improve the diagnostic accuracy, treatment decision, and potential outcomes. The objectives of this 2-part study were to identify differences in circulating immunological, inflammatory, and hormonal parameters between mares with natural ascending placentitis and control mares; evaluate each and combination of parameters as predictors of placentitis; and determine how these parameters indicate severity of placentitis. Reproductive examination and blood sampling were prospectively performed on pregnant mares in a natural setting. Study 1 enrolled mares diagnosed with early stage of ascending placentitis based on ultrasonographic findings (n = 12), and gestationally age-matched mares with healthy pregnancies as controls (n = 12). Blood samples were classified as pre-onset (before) and early onset (at the time of ultrasonographic changes) of placentitis. There were no detected statistically significant differences between groups and timepoints in immunological and inflammatory parameters, including peripheral lymphocyte subpopulations, cytokine, and serum amyloid A concentrations. The placentitis group showed a reduced (P = 0.01) DHP/20α-DHP ratio when compared to the control group at the early onset timepoint. Plasma estradiol-17β concentration <359 pg/mL predicted ascending placentitis with acceptable accuracy (area under the curve, AUC = 0.71). Combined albumin <3.7 g/dL, estradiol-17β < 499 ng/mL, and DHP <33 ng/mL predicted 100 % of cases of ascending placentitis. In study 2, samples were classified according to the presence and severity of the abnormal ultrasonographic findings as mild (n = 11) and moderate-severe (n = 23), and gestationally age-matched with samples from control mares (n = 34). Mares with moderate-severe ascending placentitis had increased (P = 0.03) plasma 20α-DHP concentration and reduced (P = 0.03) DHP/20α-DHP ratio when compared to control mares. Our results suggest that the early events of ascending placentitis detected by ultrasonographic findings include hormonal alterations of feto-placental metabolism measurable in the mare's circulation, yet without obvious systemic immunological and inflammatory changes. Additional studies are warranted to further assess how hormonal markers and cutoff values could guide decisions for timely therapeutic intervention. • Reduced DHP/20α-DHP predicted placentitis with high accuracy and sensitivity. • Estradiol-17β < 359 pg/mL also predicted placentitis with acceptable accuracy. • Combined albumin, estradiol-17β, and DHP levels increased accuracy to 100 %. • Increased 20α-DHP and reduced DHP/20α-DHP ratio were associated with severity. • Immunological and inflammatory systemic changes were not detected. [ABSTRACT FROM AUTHOR]

Purpose Case Presentation Results Conclusion To describe the first report of third eyelid cartilage eversion in an adult American Quarter Horse mare.A 22‐year‐old American Quarter Horse mare presented to the University of Missouri Veterinary Health Center Equine Hospital for a 2‐week history of a third eyelid cartilage abnormality of the left eye with no known recent trauma. Complete ophthalmic examination revealed third eyelid cartilage eversion of the left nictitans. The abnormal scrolled cartilage was surgically excised using a handheld cautery unit and submitted for histopathologic evaluation.Histopathologic findings displayed normal third eyelid cartilage, without evidence of neoplasia or inflammation. Mucosal hyperplasia and increased vascularity of the submucosa were observed. The horse healed well after electrocautery excision and normal third eyelid conformation was restored.To the authors' knowledge, this is the first report of an acquired, presumed spontaneous, third eyelid cartilage eversion in a horse. [ABSTRACT FROM AUTHOR]

Simple Summary: Assessing blood clotting in critically ill horses is important for treatment, monitoring, and prognosticating various disease states. Viscoelastic coagulation testing provides more information on an animal's blood clotting than traditional testing; however, it is prone to variability. A point-of-care viscoelastic coagulation monitoring device (VCM Vet™) has been used in the horse to assess the coagulation of fresh blood (native whole blood). The use of native whole blood requires testing within 4 min of collection, which can be limiting in many environments. This study aimed to compare the use of blood stored in an anticoagulant (citrate) for 1 and 4 h to native blood tested immediately. The results of this study show that testing of citrated blood gives different results to native blood in the horse. Viscoelastic monitoring of horse coagulation is increasing due to its advantages over traditional coagulation testing. The use of a point-of-care viscoelastic coagulation monitor (VCM Vet™) has been validated for use in horses using native whole blood (NWB) but has not been assessed using citrated whole blood (CWB), a technique that might have advantages in practicality and precision. Blood was collected from 70 horses, tested in duplicate immediately using NWB (T0), and stored at room temperature as CWB for testing in duplicate at 1 (T1) and 4 (T4) hours after venipuncture for comparison to NWB. Of these horses, 20 were classified as clinically healthy and used to determine reference intervals for CWB at 1 and 4 h post-collection. There were clinically relevant differences in all measured viscoelastic parameters of CWB compared to NWB meaning that they cannot be used interchangeably. These differences were not consistent at T1 and T4 meaning the resting time of CWB influences the results and should be kept consistent. The use of CWB in this study also resulted in more machine errors when compared to NWB resulting in measurements that might not be interpretable. [ABSTRACT FROM AUTHOR]

Simple Summary: Cortisol is a very common hormone measured when studying the stress response. While plasma cortisol is commonly utilized, concerns regarding stress caused by the sampling procedure and whether that sample represents acute vs. chronic stress have paved the way for measuring fecal cortisol metabolites (FCMs). The measurement of FCMs can be costly, and some reagents used require special permission. Commercial ELISA kits have become popular as a cost-effective method of cortisol measurement, but it is crucial to validate if these kits can detect a biologically significant change in the hormone being measured within the animal being studied. In our work, we conclude that the Arbor AssaysTM DetectX® Cortisol ELISA kit (K003-H1, Ann Arbor, MI, USA) is a reliable, economic option for the measurement of biologically relevant changes in cortisol in equine plasma and FCMs. This work helps to provide another potential tool for researchers who want to evaluate horse stress and well-being. The measurement of fecal cortisol/corticosterone metabolites (FCMs) is often used to quantify the stress response. The sampling method is relatively non-invasive, reduces concern for elevation of cortisol from the sampling method, and has been shown to measure cortisol more consistently without the daily diurnal rhythm observed in blood. Commercial ELISA (enzyme-linked immunoassay) kits offer benefits over previously validated immunoassay methods but lack validation. The objective of this study was to evaluate a commercial ELISA kit (Arbor AssaysTM DetectX® Cortisol ELISA kit, K003-H1, Ann Arbor, MI, USA) and provide analytical and biologic validation of equine fecal and plasma samples. Horses (4 male, 4 female, mean ± SD: 4 ± 5 yr) were transported for 15 min with limited physical and visual contact via a livestock trailer. Blood and fecal samples were collected pre- and post-transportation. Parallelism, accuracy, and precision tests were used to analytically validate this kit. Data were analyzed using PROC MIXED in SAS 9.4. Plasma cortisol concentrations increased in response to trailering (254.5 ± 26.4 nmol/L, 0 min post-transportation) compared to pre-transportation (142.8 ± 26.4 nmol/L). FCM concentrations increased 24 h post-trailering (10.8 ± 1.7 ng/g) when compared to pre-transportation (7.4 ± 1.7 ng/g). These data support that changes in FCMs can be observed 24 h post-stressor. In conclusion, the Arbor AssaysTM DetectX® Cortisol ELISA kit is a reliable, economic option for the measurement of biologically relevant changes in cortisol in equine plasma and FCMs. [ABSTRACT FROM AUTHOR]

Kenney–Doig scale is considered the international standard method for classifying uterine biopsies in mares; however, its objectivity has been questioned by various studies. In the present study, we analysed the degree of agreement between two pathologists when assessing the same set of 201 uterine biopsies, obtaining a slight to moderate level of agreement (κ =.34/κw =.57). Subsequently, we developed a numerical scale based on the evaluation of histological parameters, including inflammation, fibrosis, glandular density and lymphatic lacunae. Partial scores were summed to obtain a fifth parameter called Summation. The correlation between both scales was demonstrated (p <.0001), and their combined use resulted in a notable increase in the degree of agreement between the two pathologists (κ =.53/κw =.67). [ABSTRACT FROM AUTHOR]

A protocol for conventional in vitro fertilization (IVF) in horses using fresh semen has been described, using a prolonged incubation in FERT‐TALP medium (22 h) at 38.2°C in the presence of penicillamine, hypotaurine and epinephrine (PHE). Our work aimed to develop a protocol that maintains quality parameters in frozen–thawed equine spermatozoa incubated for 22 h in the presence of PHE using different media (FERT‐TALP and INRA96) and incubation temperatures (30 and 38.2°C). Twelve frozen ejaculates from four stallions were thawed and then incubated in either FERT‐TALP or INRA96 with PHE at 30 or 38.2°C for 22 h. Following incubation, total motility (TM), progressive motility (PM), viability and acrosome integrity were evaluated. The results showed that TM was significantly higher (p <.001) at 30°C in both media, while PM was higher for INRA96 at 30°C compared to 38°C (p <.05). Moreover, INRA96 at 30°C exhibited higher sperm viability and acrosome integrity (p <.001) compared to the other experimental groups. These preliminary results suggest that incubating thawed equine spermatozoa at 30°C with PHE in INRA96 successfully maintains motility, viability and acrosome integrity in equine spermatozoa, indicating its potential use for conventional equine IVF. [ABSTRACT FROM AUTHOR]

OBJECTIVE To describe the development and maturation of equine proximal sesamoid bones (PSBs) in fetuses and young horses using radiography, microcomputed (micro)-CT, and histology. METHODS A descriptive study. Forelimb PSBs from 12 equids ranging in age from 105 days of gestation to 540 days postgestation were evaluated. Radiography was used for preliminary assessment of metacarpophalangeal joint and PSB mineralization, and micro-CT imaging was performed to assess mineralized PSBs. Tissue volume, bone volume fraction, height, width, depth, trabecular thickness, and anisotropy were quantified from midplanar micro-CT sections in 3 dimensions. Midsagittal PSB histologic sections stained with H&E and Safranin O/Fast Green were used to determine the ratio of ossification center to cartilage template size and to describe the formation and development of the cartilage template, ossification center, spherical growth plate, articular cartilage, and entheses. RESULTS Mineralization of equine PSBs is associated with cartilage canals and a spherical growth plate that undergoes endochondral ossification during the late gestation to early postgestational period. The apical, flexor, basilar, and articular ossification fronts demonstrate morphologic variability. Structural organization of the articular cartilage and entheses occurs concurrently with the development of an underlying plate of compact bone. At 540 days postgestation, the fibrocartilaginous entheses of the flexor cortex of the PSB had yet to mature. CONCLUSIONS Equine PSBs mineralize predominantly by endochondral ossification during the late gestation to early postgestational period. Mineralization precedes maturation of the articular cartilage and fibrocartilaginous entheses. CLINICAL RELEVANCE The postgestational maturation of the PSB and its surrounding tissues may predispose young horses to developing lesions at these sites, such as apical avulsion fractures, warranting further investigation. [ABSTRACT FROM AUTHOR]

Poor sperm quality in cooled-shipped semen has been related to subpar fertility in horses. Therefore, this study aimed to evaluate the ability of post-cooling sperm processing to improve sperm parameters of cooled-stored stallion semen for artificial insemination. For all experiments, ejaculates were collected, processed, and diluted in skimmed milk-based (SM) medium and stored at 5 °C/24h. In all experiments an aliquot of unprocessed cooled semen was used as a control. In the first experiment (Exp 1.), cooled-stored semen from 16 stallions (n = 32) was processed by SpermFilter or centrifugation (600× g /10min) and resuspended in an egg yolk-based freezing medium containing permeating cryoprotectants (EY-C) for cryopreservation. Sperm recovery and motility parameters were immediately assessed after sperm resuspension in both groups and compared with unprocessed (Unp) samples. In Exp 2., cooled semen samples from six stallions (n = 18) were processed using SpermFilter and resuspended in SM or EY-C. Motility parameters and plasma membrane integrity were assessed in all groups (Unp, SM, and EY-C). In Exp 3, cooled semen from four stallions (n = 20) was processed by SpermFilter, resuspended in SM, EY-C, or egg yolk-based medium without cryoprotectants (EY-nC); and submitted to a thermoresistance test (37 °C/3h). Motility parameters, plasma membrane integrity and stability, mitochondrial membrane potential, mitochondrial superoxide generation, and DNA fragmentation index were evaluated in all groups. Finally, in Exp 4, 39 estrous cycles of 11 mares were inseminated with unprocessed (n = 6) cooled-stored semen or semen cooled at 5 °C/24h and then processed by SpermFilter and resuspended in SM (n = 5), EY-C (n = 11), EY-nC (n = 11), or centrifuged and resuspended in EY-C (n = 6). Overall, semen processing and resuspension in EY mediums (EY-C and EY-nC) improved sperm parameters compared with those of unprocessed semen (P < 0.05). Centrifugation (91 ± 5 %) recovered more sperm than SpermFilter (84 ± 9 %; P < 0.05). Sperm resuspended in EY-nC maintained better sperm parameters throughout the thermoresistance test than those in the other groups (P < 0.05). The fertility rates were similar between all groups (P > 0.05). In conclusion, processing and resuspension in EY medium can improve sperm parameters in post-cooled-stored stallion semen. • Extender exchange may enhance sperm quality of cooled-transported stallion semen. • SpermFilter and centrifugation yield similar sperm parameters of cooled-shipped processed semen. • Cryoprotectants are detrimental for long-term sperm parameters of cooled-shipped stallion semen. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The parotid duct has been reported to be the most common site of sialoliths in horses. In this case report, we described the first confirmed case of the equine sialolithiasis in Slovakia. The work was aimed to describe the transcutaneous approach to removing the sialolith, which manifested as a hard painless mass in the area of the maxillary cheek teeth, in a 14-year-old Slovakian warmblood mare. Pathological-anatomical and histological examination after extirpation confirmed the presence of parotid duct ectasia resulting from calculus. The mineral composition of the sialolith was determined with atomic absorption spectroscopy using X-ray powder diffraction. The sialolith was successfully extirpated transcutaneously, without complications or recurrence. [ABSTRACT FROM AUTHOR]

Methandienone is an anabolic‐androgenic steroid that is prohibited in equine sports due to its potential performance enhancing properties. Metabolism and detection of methandienone in equine urine have been investigated comprehensively in literature; however, there is a limited knowledge about its metabolites in equine plasma and no information about its detection in equine hair. Following a multi‐dose oral administration of methandienone to two Thoroughbred horses, 17‐epimethandienone, methyltestosterone, two mono‐hydroxylated, two di‐hydroxylated and three 17α‐methylandrostanetriol metabolites were detected in plasma. The majority of these were present as free analytes, whilst the mono‐hydroxylated metabolites and one isomer of 17α‐methylandrostanetriol were partially conjugated. Estimated peak concentrations of methandienone were 6,000 and 11,100 pg/ml; meanwhile, they were 25.4 and 40.5 pg/ml for methyltestosterone. The most abundant analyte in the post‐administration plasma samples of both horses was the mono‐hydroxylated metabolite; however, the parent compound provided the longest detection (up to 96 h). Screening analysis of hair enabled the detection of methandienone in mane hair samples only, for up to 3 months. Its mono‐ and di‐hydroxylated metabolites were detected with greater peak responses for up to 6 months post‐administration in both mane and tail samples, showing that these metabolites could be better analytical targets for hair analysis when administered orally. A follow‐up methodology with an extensive wash procedure confirmed the presence of methandienone and its metabolites in a number of post‐administration hair samples. Final wash samples were also analysed to assess the degree of internal incorporation (via bloodstream) against possible external deposition (via sweat/sebum). [ABSTRACT FROM AUTHOR]

Simple Summary: Equine colitis, or inflammation of the colon of the domestic horse, can occur rapidly and lead to death within hours to days. It is often associated with severe diarrhea leading to dehydration. There are many different causes of colitis, including infections with bacteria, viruses, and parasites, as well as non-infectious causes. Antimicrobial administration can be associated with the development of infectious colitis, likely because of disrupted intestinal microbiota allowing for the expansion of pathogenic bacteria. Ion channels regulate electrolyte and fluid movement into and out of the colon lumen. These channels can be manipulated by different infectious organisms to drive increased fluid movement into the intestinal lumen. Current treatments for equine colitis are untargeted and largely supportive in nature. In other species, targeting ion channels has emerged as a potential treatment for diarrhea. This may represent a novel avenue for anti-diarrheal therapies in the horse. However, ion channels have not been well studied in the colon of the horse. This review provides an overview of what is known about colonic ion channels and their known or putative role in specific types of equine colitis due to various pathogens. Equine colitis is a devastating disease with a high mortality rate. Infectious pathogens associated with colitis in the adult horse include Clostridioides difficile, Clostridium perfringens, Salmonella spp., Neorickettsia risticii/findlaynesis, and equine coronavirus. Antimicrobial-associated colitis can be associated with the presence of infectious pathogens. Colitis can also be due to non-infectious causes, including non-steroidal anti-inflammatory drug administration, sand ingestion, and infiltrative bowel disease. Current treatments focus on symptomatic treatment (restoring fluid and electrolyte balance, preventing laminitis and sepsis). Intestinal epithelial ion channels are key regulators of electrolyte (especially sodium and chloride) and water movement into the lumen. Dysfunctional ion channels play a key role in the development of diarrhea. Infectious pathogens, including Salmonella spp. and C. difficile, have been shown to regulate ion channels in a variety of ways. In other species, there has been an increased interest in ion channel manipulation as an anti-diarrheal treatment. While targeting ion channels also represents a promising way to manage diarrhea associated with equine colitis, ion channels have not been well studied in the equine colon. This review provides an overview of what is known about colonic ion channels and their known or putative role in specific types of equine colitis due to various pathogens. [ABSTRACT FROM AUTHOR]

Simple Summary: Insect bite hypersensitivity (IBH) is a common skin allergic condition in horses caused by insect bites, mainly of Culiocides species. Affected horses develop severe itchy lesions, up to traumatic skin injuries. Eosinophils are known to play a crucial role in the pathogenesis of IBH. Recently, we described two subsets of eosinophils: inflammatory eosinophils (iEos) dominant in blood of IBH-affected horses, and resident eosinophils (rEos) present in blood of healthy horses. iEos and rEos were distinguishable by size, granularity, and proteins present on their cell surface. Interleukin (IL)-5, the main activator and regulator of eosinophils, is our vaccine target. Vaccinated horses showed a significant reduction of total eosinophils, in particular iEos, where the very few remaining eosinophils still showed iEos phenotype. In the present study, we followed the phenotype of eosinophil subsets in the 2nd year of vaccination in IBH-affected horses. Our results showed comparably lower levels of iEos and a significant increase of rEos in 2nd compared to 1st year vaccinated and unvaccinated horses. This suggests a shift from iEos to the rEos phenotype, the dominant eosinophil type of healthy horses. The change in size, granularity and migration properties suggests a benefit of long term vaccination of IBH-affected horses. Eosinophils play a key role in allergic diseases such as insect bite hypersensitivity (IBH). Together with Th2 cells, they shape the course of inflammation in associated type I/IVb allergies. Therefore, a virus-like particle (VLP)-based vaccine targeting equine interleukin-5 (eIL-5), eIL-5-CuMV-TT, was developed to interfere with the IL-5 dependency of eosinophils by inducing the production of anti-self-IL-5 antibodies and alleviating clinical signs in IBH-affected horses. A previous study highlighted the presence of two eosinophil subsets, steady-state resident eosinophils (rEos) and inflammatory eosinophils (iEos), circulating in the blood of healthy and IBH-affected horses, distinguishable by the expression of integrin CD49f. Furthermore, eIL-5-CuMV-TT 1st year vaccination showed a significant decrease of total eosinophils and, in particular, iEos. Nevertheless, the very few remaining eosinophils still shared an iEos phenotype, reflected by bigger size and higher granularity. The aim of this study was to follow up on the phenotype of eosinophils in the 2nd year of vaccination of IBH-affected horses with eIL-5-CuMV-TT. Using flow cytometry analysis of the blood of healthy, IBH, IBH-placebo, and IBH-vaccinated horses, the percentage and count of cells were compared between groups with a focus on pair analysis of eosinophils in 1st and 2nd year vaccinated horses. Our data showed comparably low levels of iEos and a significant increase of rEos in 2nd year compared to 1st year vaccinated horses, suggesting a phenotypic shift toward a resident-like eosinophil population, primarily associated with the phenotype of healthy horses. The reduction of size, granularity, and expression of integrin CD49f in the 2nd year suggests a benefit of long-term treatment with the eIL-5-CuMV-TT vaccine. [ABSTRACT FROM AUTHOR]

The aim of the present study was to conduct molecular investigation and potential risks associated with Streptococcus equi infection in horses with upper respiratory tract infection. For this aim, sixty-nine horses were used (50 diseased and 19 apparently healthy). Horses under investigation were subjected to clinical examination and bacteriological investigation of nasal swabs. Polymerase chain reaction (PCR) for confirmatory identification of Streptococcus equi subspecies equi came to match the isolation percentage on its selective medium. For Streptococcus equi subspecies equi, sodA and seeI genes were detected at molecular weights of 235 bp and 520 bp, respectively. There was a significant (P value <0.05) association between breed, use, vaccination, number of affected animals in the premises, over-crowding and climatic conditions and the isolation frequency of Streptococcus equi subspecies Equi infection. The highest percentage of isolation was recorded in Arabian horses (32/53; 60.4%) compared with other breeds (21/53; 39.6%). Horses kept for racing or showing revealed higher isolation percentage (32/53; 60.4%) compared with draft horses that showed isolation percentage of (21/53; 39.6%). Vaccinated horses also showed a higher rate of isolation (29/53; 54.7%), compared with non-vaccinated ones (24/53;45.3%). The results of the present study highlighted the potential risk factors associated with S. equi subspecies equi in horses with upper respiratory tract infection. The present finding may support the authorities to construct strict preventive measures for this infection. [ABSTRACT FROM AUTHOR]

Introduction: In 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. Methods: Six 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. Results: At 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. Conclusion: The HighAcetate (81.4 mmol/L) solution is deemed an effective and safe alternative for the treatment of hyperchloremic metabolic acidosis in horses. [ABSTRACT FROM AUTHOR]

Simple Summary: The description of health patterns of eventing horses outside of veterinary clinics is limited. It is important to determine the relative impact of different health problems in this group of horses. The study aimed to describe the prevalence and patterns of lameness/illness in registered British eventing horses in 2018 by use of an online survey. Data were collated and descriptive analyses undertaken. In total, 1677 surveys were completed, and 49.4% reported a previous lameness/musculoskeletal problem, with 26% in the previous six months. The most frequently reported musculoskeletal problems were to the foot (421), joints (382), wounds (340), back (333), ligament (205), tendon (213), bones (140) and muscles (135). The most frequent non-musculoskeletal problems were to the skin (183), gastric ulceration (173), colic (145) and infection (88). Injuries to the sole of the foot/muscles/tendons were most frequently sustained in competition, suspensory ligament/splint bone/stifle/hock injuries were more frequently sustained in training and foot abscesses/penetration injuries at rest. Horses with deep digital flexor tendon injuries were out of training for the most amount of time (>12 months) and horses with hock/sole bruising/foot abscesses for the least amount of time (<2 weeks). A greater understanding of health problems in eventing horses could be useful for veterinarians working with them. There has been little investigation into the health patterns of the eventing horse population outside veterinary clinics. To target health problems in the eventing horse population, it is important to determine the relative impact of different health problems. The objectives were to describe the prevalence and patterns of lameness/illness in registered British eventing horses. An online survey was released for all horses registered with British eventing in 2018. Data were collated and descriptive analyses undertaken. A total of 1677 surveys were completed, among which 49.4% reported a previous lameness/musculoskeletal problem, 26% being in the previous six months. The most frequently reported musculoskeletal problems were in the foot (421), joints (382), wounds (340), back (333), ligament (205), tendon (213), bones (140) and muscles (135). The most frequent non-musculoskeletal problems related to the skin (183), gastric ulceration (173), colic (145) and infection (88). Injuries to the hoof sole/muscles/tendons were most frequently sustained in competition, suspensory ligament/splint bone/stifle/tarsal injuries were more frequently sustained in training and abscess/foot penetration at rest. DDFT injuries were most frequently out of training for >12 months, SDFT/stifle/suspensory ligament for <12 months, tendon sheath/splint bone for <3 months and tarsal/sole bruising/abscess for <2 weeks. A greater understanding of injuries/illnesses frequently sustained could be useful for veterinarians working with event horses. [ABSTRACT FROM AUTHOR]

Simple Summary: Asinara donkeys are unique worldwide for expressing a particular form of albinism spread to all individuals of the breed. This peculiar condition of oculo-cutaneous albinism of type 1 (OCA1) is a rare condition from a recessive autosomic mutation, fixed through generations, thanks to the isolation of donkeys on Asinara Island (from which the breed name originates) favoring inbreeding. Asinara island is a small island of Sardinia, one of the biggest islands in the Mediterranean sea. Asinara donkeys have shown good adaptation to the Mediterranean climate through various metabolic strategies, one of which relies on endogenous retinol mobilization during the positive photoperiod for protective effect and adequate circulating vitamin E. Indeed, their exposure to sun radiation and high temperature on one hand, and the lack of melanin in the coat, skin, iris and mucocutaneous junctions on the other, require them to overcome such an extended lack of photoprotective pigment (melanin) in alternative ways to prevent UV radiation damage. In this investigation, our interest was oriented toward screening the complete blood cell count to understand whether metabolic adaptation to the environment involved blood cell lines. Such an idea comes from the fact that in humans, a particular condition of albinism is reported to share the same gene with other mutations involving hemoglobin synthesis. In our case, significant differences were observed in relation to red blood cells (RBCs), in terms of their average volume (MCV), width distribution (RDW-CV), and width deviation (RDW-SD), in comparison to pigmented (gray) Sardo donkeys. The complete blood cell count (CBC) was screened in a group of 15 donkeys, of which 8 were of Asinara breed (oculocutaneous albinism type 1, OCA1) and 7 of Sardo breed (gray coat). All donkeys were kept under same management and dietary conditions and underwent periodic health monitoring in the month of June 2024, at the peak of the positive photoperiod, at Mediterranean latitudes. One aliquot of whole blood, drawn from each individual into K2-EDTA containing tubes, was analyzed for the complete blood cell count through an automatic analyzer, within two hours of sampling. Data were analyzed and compared by one-way ANOVA, where the breed was an independent variable. All animals appeared clinically healthy, though mild eosinophilia was observed in Sardo donkeys. The red blood cell line showed peculiar traits for Asinara donkeys, which displayed significantly higher circulating red blood cell numbers than gray coat Sardo donkeys (RBC, 5.19 vs. 3.80 1012/mL ± 0.98 pooled-St. Dev, respectively; p = 0.017). RBCs also exhibited a smaller diameter and higher degree of anisocytosis in Asinara donkeys, along with lower hematocrit value, albeit within physiological ranges. Taken all together, such hematological profile depicts a peculiar trait of the red blood cell line in albino donkeys during the positive photoperiod. [ABSTRACT FROM AUTHOR]

Equine endometritis is one of the main causes of subfertility in the mare. Unraveling the molecular mechanisms involved in this condition and pinpointing proteins with biomarker potential could be crucial in both diagnosing and treating this condition. This study aimed to identify the endometritis-induced changes in the endometrial proteome in mares and to elucidate potential biological processes in which these proteins may be involved. Secondly, biomarkers related to bacterial endometritis (BE) in mares were identified. Uterine lavage fluid samples were collected from 28 mares (14 healthy: negative cytology and culture, and no clinical signs and 14 mares with endometritis: positive cytology and culture, in addition to clinical signs). Proteomic analysis was performed with a UHPLC-MS/MS system and bioinformatic analysis was carried out using Qlucore Omics Explorer. Gene Ontology enrichment and pathway analysis (PANTHER and KEGG) of the uterine proteome were performed to identify active biological pathways in enriched proteins from each group. Quantitative analysis revealed 38 proteins differentially abundant in endometritis mares when compared to healthy mares (fold changes >4.25, and q-value = 0.002). The proteins upregulated in the secretome of mares with BE were involved in biological processes related to the generation of energy and REDOX regulation and to the defense response to bacterium. A total of 24 biomarkers for BE were identified using the biomarker workbench algorithm. Some of the proteins identified were related to the innate immune system such as isoforms of histones H2A and H2B involvement in neutrophil extracellular trap (NET) formation, complement C3a, or gelsolin and profilin, two actin-binding proteins which are essential for dynamic remodeling of the actin cytoskeleton during cell migration. The other group of biomarkers were three known antimicrobial peptides (lysosome, equine cathelicidin 2 and myeloperoxidase (MPO)) and two uncharacterized proteins with a high homology with cathelicidin families. Findings in this study provide the first evidence that innate immune cells in the equine endometrium undergo reprogramming of metabolic pathways similar to the Warburg effect during activation. In addition, biomarkers of BE in uterine fluid of mares including the new proteins identified, as well as other antimicrobial peptides already known, offer future lines of research for alternative treatments to antibiotics. • Mares with bacterial endometritis exhibited a significantly higher relative abundance of endometrial proteins compared to clinically healthy mares. • The proteins upregulated in the secretome of mares with bacterial endometritis were involved in biological processes related to the generation of energy and REDOX regulation and to the defense response to bacterium (neutrophil extracellular trap (NET) formation pathway). • A total of 24 biomarkers for bacterial endometritis were identified. Some of the proteins identified were related to the innate immune system such as isoforms of histones H2A and H2B, complement C3a, or gelsolin and profilin. The other group of biomarkers were three known antimicrobial peptides (lysosome, equine cathelicidin 2 and MPO) and two uncharacterized proteins with a high homology with cathelicidin families. [ABSTRACT FROM AUTHOR]

Previous studies indicate a positive correlation between the duration of estrus prior to ovulation and likelihood of pregnancy in embryo recipient mares. However, the mechanisms by which the duration of estrus before may affect fertility remains unclear. This study aimed to determine the effect of different durations of estradiol exposure, prior to progesterone administration, on embryo viability in anestrous recipient mares, and endometrial expression of genes thought to influence embryo survival. Three groups of anestrous recipient mares treated with different duration of estradiol were used: long (LE), short (SE) and no treatment (NE). Day 8 embryos were transferred into recipient mares four days after long-acting progesterone administration and recovered 48h later to examine embryo growth and viability. The endometrial gene expression profile of selected genes was also investigated. The likelihood of recovering an embryo 48h after transfer was 46.1% (6/13), 62.5% (5/8) and 85.7% (6/7) for recipient mares from the NE, SE and LE groups, respectively (P =.09). Embryos recovered from the different groups of recipients did not, however, differ in size, morphology or the proportion of nuclei undergoing mitosis (P >.05). Abundance of mRNA for uterocalin (P19) and insulin-like growth factor 1 (IGF1) were increased in the LE compared to the NE group, while fibroblast growth factor 2 (FGF2), progesterone receptor (PGR) and insulin-like growth factor 1 receptor (IGF1R) transcript abundances were increased (P < 0.05) in the NE group compared to both SE and LE groups. In conclusion, a longer exposure of the endometrium to estradiol before progesterone tended to improve embryo survival within 48h of transfer. However, the grade, growth rate, and proportion of mitotic cells in surviving embryos did not differ among groups. If embryos are destined to fail in a suboptimal endometrial environment, they die and disappear quickly. Moreover, a more adequately estradiol-primed uterus, before the progesterone rise, seems to create a uterine environment, in terms of P19 , IGF1 , FGF2 and PGR gene expression, more conducive to embryo survival and further development. • Embryo survival after transfer tended to be influenced by the duration of estradiol treatment. • Viability of surviving embryos within 48h of transfer was not affected by estradiol-primed uterus. • Endometrial expression of selected genes was influenced by estradiol-primed uterus. [ABSTRACT FROM AUTHOR]

Although under appropriate laboratory conditions, sperm from different mammalian species can be capacitated in vitro , the optimal conditions for sperm capacitation in the stallion have been elusive. This study evaluated the effect of different capacitating inducers in Whitten and Tyrode media and assessed their impact on capacitation-related factors. Stallion sperm were incubated with different combinations of capacitating inducers at 38.5 °C in an air atmosphere. Sperm quality variables such as motility, mitochondrial membrane potential, and lipid peroxidation were assessed. Membrane fluidity and intracellular calcium levels were evaluated as early markers of capacitation, while tyrosine phosphorylation events and the sperm's ability to perform acrosomal exocytosis were used as late capacitation markers. Finally, these sperm were evaluated using a heterologous zona pellucida binding assay. The findings confirm that capacitating conditions evaluated increase intracellular calcium levels and membrane fluidity in both media. Similarly, including 2 or 3 inducers in both media increased tyrosine phosphorylation levels and acrosomal exocytosis after exposure to progesterone, confirming that stallion sperm incubated in these conditions shows cellular and molecular changes consistent with sperm capacitation. Furthermore, the zona pellucida binding assay confirmed the binding capacity of sperm incubated in capacitation conditions, a key step for stallion in vitro fertilization success. Further studies are needed to evaluate the effect of these conditions on in vitro fertilization in the horse. • Different treatments for equine sperm capacitation were evaluated in two media. • Combination of capacitating inducers boosts phosphorylation and acrosomal exocytosis. • Capacitating conditions improve sperm's zona pellucida binding capacity. [ABSTRACT FROM AUTHOR]

Background: Extended-spectrum β-lactamase -producing Enterobacterales (ESBL-E) are important zoonotic pathogens that can cause serious clinical infections, also in horses. Preventing the spread of ESBL-E, especially in the equine hospital environment, is key to reducing the number of difficult-to-treat infections. Estimating the local prevalence of ESBL-E in horses is crucial to establish targeted infection control programs at equine hospitals. We conducted a prevalence and risk factor study in equine patients on admission to an equine teaching hospital in Finland through a rectal ESBL-E screening specimen of the horse and a questionnaire. Results: The prevalence of ESBL-E in admitted horses was 3% (5/161, 95% CI 1–7%); none of the tested factors remained statistically significant in multivariate analysis, although antimicrobial treatment within three months was borderline significant (p = 0.052). Extended-spectrum β-lactamase -producing Klebsiella pneumoniae ST6179:CTX-M-15 was detected in three horses using whole-genome sequencing, which in combination with patient records suggested nosocomial transmission. Escherichia coli isolates were ST1250:CTX-M-1 (n = 1), ST1079:CTX-M-1 (n = 1), and ST1245:CTX-M-14 (n = 1). Multiple virulence genes were detected in the ESBL-E isolates. In the ESBL-E positive horses enrolled in a one-year follow-up study, ESBL-E were unlikely to be isolated in rectal screening specimens after the initial positive specimen. Conclusions: The prevalence of ESBL-E in horses visiting a veterinary teaching hospital in Finland is low, indicating an overall low prevalence estimate in the country's equine population. No statistically significant risk factors were identified, likely due to the low number of cases. The duration of ESBL-E carriage is likely to be very short in horses. [ABSTRACT FROM AUTHOR]

Placental structure is linked to function across morphological scales. In the placenta, changes to gross anatomy, such as surface area, volume, or blood vessel arrangement, are associated with suboptimal physiological outcomes. However, quantifying each of these metrics requires different laborious semi-quantitative methods. Here, we demonstrate how, with minimal sample preparation, whole-organ computed microtomography (microCT) can be used to calculate gross morphometry of the equine placenta and a range of additional metrics, including branching morphometry of placental vasculature, non-destructively from a single dataset. Our approach can be applied to quantify the gross structure of any large mammalian placenta. • Using a walk-in microCT system, we quantitatively imaged a whole equine placenta. • From our microCT dataset, we could quantify key anatomical metrics. • Our approach is transferrable to quantifying any large mammalian placenta. [ABSTRACT FROM AUTHOR]

This study describes a case of poisoning by pyrrolizidine alkaloids in a horse. To the best of the author's knowledge, this is the first confirmed case of Senecio ovatus poisoning. A six-year-old 450-kg Irish cob mare was presented to the Equine Clinic of the University of Veterinary Sciences Brno (Czechia) with symptoms of hepatic encephalopathy, which progressively worsened with time despite intensive therapy and led to euthanasia. A complex diagnostic and therapeutic approach including the post-mortem patoanatomical and histopathological examination is described here. Regarding the histopathology of the liver, there was necrosis with haemorrhage, fatty changes and inflammation. A later inspection of the grazing area revealed the presence of Senecio ovatus (wood ragwort). A sensitive chromatographic method was used to determine the pyrrolizidine alkaloids and their metabolites in the plasma and the liver. In both of the samples, metabolites of pyrrolizidine alkaloids were detected. Although pyrrolizidine alkaloid poisoning was proven, the histopathological findings typical for this disease were absent. It is clear from our case that the histopathology in cases of poisoning by pyrrolizidine alkaloids may not always be conclusive. [ABSTRACT FROM AUTHOR]

Respiratory issues significantly impact horses, affecting performance and their overall health. Factors like weather, stress from racing, and exposure to irritants contribute to upper and lower respiratory tract problems. Nasal breathing and the lengthy nasopharynx of horses predispose them to airborne irritants. Diseases like nasal polyps, ethmoid hematomas, sinusitis, guttural pouch diseases, laryngeal issues, and pneumonia affect horses across ages and breeds, leading to symptoms such as nasal discharge, breathing difficulties, and exercise intolerance. Diagnosis often involves endoscopy, radiography, and cytology. Treatment varies from surgical interventions to environmental modifications, emphasizing early detection for effective management. This review focuses on understanding how the complexity of these respiratory disorders can enable targeted strategies to safeguard the health and performance of horses. [ABSTRACT FROM AUTHOR]

The addition of antioxidants to cryopreservation media reportedly improves sperm post‐thaw quality and reproductive performance after artificial insemination. Therefore, the objectives of this study were to evaluate if the addition of L‐carnitine and pyruvate to freezing media, or their addition to samples after thawing, improves the post‐thaw quality of equine spermatozoa. Thus, in Experiment 1, stallion semen samples were cryopreserved in: (1) EDTA–glucose–based extender with 20% egg yolk and 5% dimethylformamide (EDTA control); (2) skim milk–based extender with 20% egg yolk and 5% dimethylformamide (milk control); (3) Extender 1 supplemented with 50 mM L‐carnitine and 10 mM pyruvate (EDTA‐carnitine‐pyruvate); and (4) Extender 2 supplemented with 50 mM L‐carnitine and 10 mM pyruvate (milk‐carnitine‐pyruvate). In Experiment 2, 50 mM L‐carnitine and 10 mM pyruvate were added post‐thaw to samples cryopreserved with extenders 1 and 2 (EDTA control and milk control). Sperm kinematic parameters, DNA fragmentation, membrane lipid peroxidation, acrosome status and viability were evaluated after thawing. No significant differences (p > 0.05) were observed for most of the kinematic parameters, DNA fragmentation, membrane lipid peroxidation, acrosome status and viability of spermatozoa, between the samples frozen in the presence or absence of L‐carnitine and pyruvate, nor between the samples after the post‐thaw addition of these components. A higher (p < 0.05) mean velocity and higher (p < 0.05) amplitude of lateral head displacement were observed in the samples frozen in the milk‐based extender with the addition of L‐carnitine and pyruvate after thawing. The addition of 50 mM L‐carnitine and 10 mM pyruvate, either to the freezing extenders or after thawing, was not deleterious for sperm; however, it did not improve equine sperm motility, viability, acrosome and DNA integrity, nor decrease membrane lipid peroxidation after thawing. [ABSTRACT FROM AUTHOR]

Background: Trigeminal‐mediated headshaking is a neuropathic facial pain condition in horses. No treatment has been entirely successful. Repetitive transcranial magnetic stimulation (rTMS) is used in human medicine as a treatment for various neuropathic pain conditions, and good results have been achieved in cases of trigeminal neuralgia. Objectives: Apply rTMS to horses with trigeminal‐mediated headshaking (TMHS) and to evaluate tolerability, application of the setting, and success rate. Animals: Seventeen horses with nonseasonal signs of TMHS. Methods: Other underlying causes of headshaking were ruled out. The rTMS was performed under standing sedation on 5 consecutive days applying 3 sets of 500 stimulations each, with a stimulation strength of 5 Hz. Horses were evaluated on Day 1 (t0) and Day 5 (t1) of the treatment and 2 (t2) and 4 weeks (t3) afterwards using a special scoring system. Results: The rTMS was well tolerated. Headshaking signs during exercise were decreased by 70% (Day 5; t1). Four weeks after rTMS, signs were still decreased (mean reduction of 50%) during exercise. Improvement of mean resting and exercise scores was significant (P <.05) and effect sizes between pretreatment and all time points after treatment (t1, t2, t3) were large (>±0.8). Conclusions and Clinical Importance: Repetitive transcranial magnetic stimulation may be a promising treatment for neuropathic pain and headshaking in affected horses. Pain‐free periods after treatment differ individually, and repeated treatment may be necessary. More studies should be performed to determine ideal settings for horses. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is a rarely reported arrhythmia in otherwise healthy newborn foals, with a single case of cardioversion using procainamide administration described in the literature. Two neonatal Thoroughbred colts were presented to an equine hospital because of an irregularly irregular tachyarrhythmia and poor latching when trying to nurse. History, physical examination, and initial diagnostic testing including ECG and echocardiography confirmed AF without structural heart disease. The 1st foal converted into normal sinus rhythm after treatment with IV metoprolol and quinidine. The 2nd foal converted to normal sinus rhythm after a single IV dose of metoprolol, intended for rate control. Demeanor and nursing behavior improved markedly after conversion. The 2 foals had normal heart rates and sinus rhythm that persisted for 6 weeks until euthanasia in the 1st foal and for 2 years in the 2nd foal. Rate control and cardioversion should be considered as a treatment for persistent lone AF in neonatal foals. [ABSTRACT FROM AUTHOR]

Background: Bronchoalveolar lavage (BAL) is a common procedure for evaluation of the equine lower airways. Time to resolution of post‐BAL inflammation has not been clearly defined. Hypothesis: Residual inflammation, evident by changes in immune cell populations and inflammatory cytokines, will resolve by 72 hours after BAL. Animals: Six adult, healthy, institution‐owned horses. Methods: Randomized, complete cross‐over design. Each horse underwent 3 paired BALs, including a baseline and then 48, 72, and 96 hours later, with a 7‐day washout between paired BALs. Each sample underwent cytological evaluation and cytokine concentrations were determined by a commercially available multiplex bead immunoassay. Statistical analysis was performed by multilevel mixed‐effects Poisson regression analysis. Data are reported as marginal means and 95% confidence interval (CI). Results: Neutrophil, eosinophil and mast cell percentages were not significantly different at any time points. Macrophage percentages were higher at 72 hours (45.0 [95% CI, 41.6‐48.4]%) and 96 hours (45.3 [95% CI, 42.9‐47.7]%) vs baseline (37.4 [95% CI, 33.5‐41.4]%; P <.001 and P =.01, respectively), and at 72 hours and 96 hours vs 48 hours (31.9 [95% CI, 28.1‐35.6]%; P <.001). Neutrophil percentage was not significantly increased at 48 hours (P =.11). Interleukin (IL)‐6 concentration was increased at 72 hours (5.22 [95% CI, 3.44‐6.99] pg/mL) vs 48 hours (4.38 [95% CI, 2.99‐5.78] pg/mL; P <.001). Conclusions and Clinical Importance: Significant lung inflammation was not detected at 72 and 96 hours, suggesting that repeating BAL at 72 hours or more can be done without concern of residual inflammation. [ABSTRACT FROM AUTHOR]

An 8‐year‐old American Quarter Horse gelding was treated with extracorporeal hemoperfusion (HP) therapy for treatment of Clostridioides difficile (C. difficile) colitis‐induced systemic inflammatory response syndrome (SIRS). The gelding developed C. difficile associated peracute colitis and severe SIRS as evidenced by a positive fecal C. difficile PCR and tachypnea, tachycardia, fever, neutropenia, altered mucous membrane color, and hyperlactatemia. Concurrent acute kidney injury in the horse limited the use of routine anti‐inflammatory and anti‐lipopolysaccharide treatments, including flunixin meglumine and polymyxin B, because of potential for nephrosis. Extracorporeal HP therapy was performed twice within 48 hours of the onset of severe SIRS during which the horse's physical examination variables stabilized. The horse was euthanized after 4 days because of laminitis. These findings support further investigation of extracorporeal HP therapy as an adjunctive treatment for severe SIRS/sepsis in horses. [ABSTRACT FROM AUTHOR]