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Topic:Equids

Equids are members of the family Equidae, which includes modern horses, donkeys, and zebras, as well as extinct species. Equids are characterized by their long limbs, single-toed hooves, and herbivorous diet, which is primarily composed of grasses. Horses, specifically, have been domesticated for thousands of years and have played significant roles in agriculture, transportation, and sport. This page compiles peer-reviewed research studies and scholarly articles that explore various aspects of equids and horses, including their evolution, physiology, behavior, and interactions with humans. The collected works provide insights into the genetic diversity, adaptive traits, and conservation efforts related to equid species.
Favorable survival of horses with guttural pouch mycosis following hospital-based treatment.
Journal of the American Veterinary Medical Association    July 29, 2026   1-6 doi: 10.2460/javma.26.04.0248
Phillips NAI, McOnie RC, Delvescovo B, Radcliffe R, Ducharme NG, Hackett ES.To report the clinical outcomes and survival time in horses undergoing treatment of guttural pouch mycosis. Unassigned: Client-owned horses with guttural pouch mycosis admitted between 2005 and 2024 for evaluation and treatment were identified by medical record search. Signalment, disease history, and surgical and treatment details were recorded. Owners were contacted for follow-up information. Unassigned: 41 horses with guttural pouch mycosis were identified, of which 28 had epistaxis or a history of epistaxis on presentation. Thirty-five horses underwent surgical treatment, and the procedure...
Central nervous system lymphoma and neurolymphomatosis in equids.
Journal of veterinary internal medicine    July 29, 2026   Volume 40, Issue 4 aalag143 doi: 10.1093/jvimsj/aalag143
Aleman M, Calero MI, Woolard KD, O'Connell K, Berryhill E, Vernau W.Lymphoma affecting the central and peripheral nervous systems in equids is rarely reported. Objective: To describe the clinical presentation, neuroanatomical localization, laboratory and pathologic features, type of lymphoma, and outcome to further current knowledge. Methods: Fourteen equids (13 horses, 1 mule). Methods: Retrospective study. Medical records from a veterinary teaching hospital were reviewed (1993-2025). The inclusion criteria consisted of a definitive diagnosis of lymphoma of the nervous system. Data collected included signalment, neurologic findings, laboratory results, imagin...
Differences between horses (Equus caballus) displaying oral and locomotor stereotypies in their responses to a stable mirror.
Behavioural processes    July 28, 2026   105415 doi: 10.1016/j.beproc.2026.105415
Lewis K, McBride SD, Parker MO, Faithfull R, Proops L.Recent cross-species analyses suggest that the different forms of stereotypic behaviour have heterogeneous causal mechanisms. In ungulates, there are indications that some forms of locomotor stereotypy may be linked to social factors. Using the domestic horse as a model species within this clade, we investigated whether individuals displaying the locomotor stereotypy box-walking (n=6) demonstrated greater responses to a stable mirror, intended to mimic presence of a conspecific, than horses displaying the oral stereotypy crib-biting (n=5) and non-stereotypic horses (n=5). After a 24hr baseline...
Somatic cell nuclear transfer as a complementary tool for genetic conservation of the Peruvian Paso horse.
The Journal of reproduction and development    July 28, 2026   doi: 10.1262/jrd.2026-068
Cortez JV, Segura Portocarrero GT, Murga Valderrama NL, Bardales Escalante W, Encina Ruiz R, Velásquez Castillo CL, Grupen CG, Maicelo Quintana JL.The Peruvian Paso horse, a breed of national significance in Peru known for its unique gait, has been selectively bred for nearly 500 years and now faces potential risks due to reduced genetic diversity. To investigate the potential of somatic cell nuclear transfer to enhance genetic conservation strategies, a program was initiated to produce cloned Peruvian Paso foals. Skin biopsies from a highly awarded stallion with exceptional breed-defining traits were used as the source of donor somatic cells. Of the 15 cloned embryos reconstructed, seven blastocysts were produced, and five were transfer...
Ceratohyoidectomy for Management of Unilateral and Bilateral Temporohyoid Osteoarthropathy: Long-Term Outcome in 33 Equids.
Animals : an open access journal from MDPI    July 28, 2026   Volume 16, Issue 15 2318 doi: 10.3390/ani16152318
McCrary HS, Stewart HL, Davis JG, Garcia-Lopez JM, Bubeck KA.Temporohyoid osteoarthropathy is a disease affecting the temporohyoid joint in equids caused by local inflammation and/or degeneration, leading to neurological deficits ranging from mild signs that affect performance to significant, acute neurological deficits such as facial nerve paralysis or vestibular signs. Multiple surgical treatment options are available, and while treatment has historically been performed unilaterally on the side of the clinical signs, advances in diagnostic imaging have highlighted the occurrence of bilateral disease of the temporohyoid joints, warranting evaluation of...
Species-Specific Mechanisms of Sperm Transport: Predominant Roles of Motility in Ewes and Uterine Contractility in Mares.
Reproduction (Cambridge, England)    July 28, 2026   xaag068 doi: 10.1093/reprod/xaag068
Barakat E, Caldas E, Reigner F, Barrière P, Blard T, Lasserre O, Cognié J, Tsikis G, de Graaf SP, Druart X.The factors controlling sperm transport within the female genital tract vary among species. The aim of this study was to quantify the respective roles of sperm motility and uterine contractions in passage of sperm within the reproductive tract of the mare and ewe. Sperm imaging was performed in vivo within the female genital tract of mares and ewes using probe-based confocal laser endomicroscopy (pCLE) after intrauterine insemination during two stages of the cycle characterized by high (oestrus) or low (luteal phase) uterine contractility. Fluorescent microbeads (2 µm in diameter) were insemi...
Combined effects of pre-freeze cholesterol-loaded cyclodextrin and post-thaw pentoxifylline on the functional longevity of cryopreserved stallion sperm.
Journal of equine veterinary science    July 28, 2026   Volume 165 106100 doi: 10.1016/j.jevs.2026.106100
Vilela VMT, Zutter BM, Miranda BN, Baldini PHO, Gomes LLO, Silva DF, Diniz JHW, Sancler-Silva YFR, Ignácio FS, Papa FO, Monteiro GA.Cryopreservation causes structural and metabolic damage to stallion spermatozoa, impairing post-thaw functional competence. Objective: This study evaluated whether cholesterol-loaded cyclodextrin (CLC) supplementation before freezing, combined with pentoxifylline (PTX) after thawing, improves the functional quality, oxidative status, mitochondrial activity, and preliminary fertility outcomes of cryopreserved stallion semen. Methods: Semen from twelve stallions was assigned to four CLC concentrations (0, 1, 1.5, and 2 mg), frozen, thawed, and divided into subgroups with or without PTX supplemen...
Perineural dexamethasone does not prolong bupivacaine sensory blockade in equine palmar digital nerve blocks: a randomized crossover trial.
American journal of veterinary research    July 27, 2026   1-6 doi: 10.2460/ajvr.26.05.0207
Larriva DS, Lopez JS, Garcia-Collao M, Farnsworth K, Villarino NF, Hall NP.To determine whether dexamethasone sodium phosphate (dexamethasone SP) prolongs the sensory blockade produced by perineural bupivacaine during medial and lateral palmar digital nerve blocks in horses. Unassigned: 8 healthy adult horses were enrolled in a blinded, randomized 4 X 4 crossover trial. Each horse received 1 of 4 perineural treatments over the palmar digital nerves of the left forelimb: bupivacaine, bupivacaine + dexamethasone SP, dexamethasone SP alone, or saline. A minimum 7-day washout was used between treatments. Mechanical nociceptive threshold (MNT) was measured at baseline and...
A Global Structural Variation Map Reveals Novel Variants for Body Conformation and Racing Ability in Horses.
Genomics, proteomics & bioinformatics    July 27, 2026   qzag071 doi: 10.1093/gpbjnl/qzag071
Gong Y, Liu X, Zheng Z, Zeng S, Zhang Y, Pu Y, Pan J, Ma Y, Jiang L.The selection of horses has been instrumental in shaping long-range mobility, advancing warfare strategies, and diversifying equine phenotypes. However, the structural variants (SVs) favored by this process remain largely unexplored. Utilizing high-fidelity Pacific Biosciences sequencing, we assembled three high-quality horse genomes, incorporating 237 Mb (9.48%) of novel sequences relative to the existing reference genome. These assemblies achieved an average Benchmarking Universal Single-Copy Orthologs completeness of 95.1%. By employing a graph-based approach, we genotyped 23,163 high-con...
SURVIVAL ON THE MARGINS: NICHE PARTITIONING AND DENSITY-DEPENDENT SPATIAL DISTRIBUTION OF EQUINE CYATHOSTOMINS.
The Journal of parasitology    July 27, 2026   Volume 112, Issue 4 426-434 doi: 10.1645/26-35
Ripley NE, Gravatte HS, Reinemeyer CR, Nielsen MK.Habitat preferences of gastrointestinal nematodes are well-documented in small hosts, but equine cyathostomin diversity has largely been characterized only at farm or regional levels. While organ-level site preferences are known, within-organ spatial distributions remain unexplored. We investigated the longitudinal and radial distribution of adult cyathostomins within the large-intestinal lumen. Intact large intestines from 5 Shetland ponies were frozen post-necropsy and transected into 4-cm sections. Three micro-habitat samples (2.5 cm diameter) were collected per section. We recovered 2,444 ...
Effects of equine sperm incubation under capacitation-supporting conditions on homologous and heterologous ICSI outcomes.
Theriogenology    July 24, 2026   Volume 265 118109 doi: 10.1016/j.theriogenology.2026.118109
Arroyo-Salvo C, Cabrera P, Treulen F, Gambini A, Arias ME, Felmer R, Perez-Martinez S, Aguila L.Intracytoplasmic sperm injection (ICSI) in horses has become sufficiently efficient to be considered for clinical and commercial application; however, several factors influencing its efficiency remain poorly understood. This study evaluated whether incubating equine sperm under capacitating conditions induces capacitation-associated changes and affects embryo development following homologous equine ICSI, as well as oocyte activation, early cleavage, and 5-methylcytosine (5 mC) and 5-hydroxymethylcytosine (5hmC) levels following heterologous ICSI using bovine oocytes. Equine spermatozoa were ...
Three-year evaluation of anthelmintic treatment efficacy against equine strongyles in France using FECRT.
International journal for parasitology. Drugs and drug resistance    July 24, 2026   Volume 31 100663 doi: 10.1016/j.ijpddr.2026.100663
Reduced anthelmintic efficacy against strongyles in equids is a widespread concern, but up-to-date field data are scarce. The aim of this study was to evaluate, over a three-year period, the efficacy of the anthelmintic (AH) molecules available in France (fenbendazole, pyrantel, ivermectin and moxidectin) against strongyles in equids using faecal egg count reduction tests (FECRTs). A total of 104 complete FECRTs (i.e., required sample size reached) were conducted in 98 groups, involving 749 equids kept in 70 facilities. Fenbendazole-resistant populations were detected in 8/9 groups (89%) from ...
Molecular detection of African horse sickness virus from selected areas in Ethiopia.
Veterinary and animal science    July 24, 2026   Volume 34 100782 doi: 10.1016/j.vas.2026.100782
Esey DF, Waktole H, Gelaye E, Alene DH, Minale HA.Equines are vital to global economies and support millions of livelihoods. However, their productivity and welfare are severely hindered by infectious diseases such as African Horse Sickness, which causes major socio-economic losses in Ethiopia. A cross-sectional study was conducted from November 2022 to May 2023 to isolate and detect African horse sickness virus in equines across epidemic areas of Ethiopia. In total, 30 blood samples and 2 tissue representative specimens were aseptically collected from clinically sick and recently dead animals and transported under cold chain to the National ...
The effect of fenugreek (Trigonella foenum-graecum) on stallion spermatozoa motility and vitality in vitro.
Veterinary research communications    July 24, 2026   Volume 50, Issue 5 482 doi: 10.1007/s11259-026-11424-9
Vanivska K, Kollárová I, Mezeyová I, Galovičová L, Dianová L, Halo M, Slanina T, Lenický M, Greń A, Reisenauer R, Massányi P.This study evaluated the effects of Trigonella foenum-graecum L. (fenugreek) seed extract on stallion spermatozoa quality in vitro, focusing on motility, vitality, and functional competence. In vitro spermatozoa analyses showed that fenugreek seed extract did not demonstrate overt cytotoxicity under the tested conditions: S1 = 1562 µg/mL; S2 = 781 µg/mL; S3 = 390.5 µg/mL; S4 = 195.25 µg/mL; S5 = 97.62 µg/mL; S6 = 48.81 µg/mL; S7 = 24.40 µg/mL. Computer-assisted semen analysis (CASA) revealed a concentration- and time-dependent Treatment × Time interac...
Correction to: Seroprevalence and risk factors of African horse sickness in equines in central Gondar, Ethiopia.
Veterinary research communications    July 23, 2026   Volume 50, Issue 5 476 doi: 10.1007/s11259-026-11406-x
Yehulashet AA, Wondmnew F, Abat AS, Alamerew EA, Birhan M, Tafere FA, Malede BA, Sechu A, Mersha AC, Tsehay EM, Temesgen AB.No abstract available
Phenotypic Definition Influences Genetic Inference and Predictive Ability for Reining Performance in Quarter Horses Using Random Regression Models.
Animal science journal = Nihon chikusan Gakkaiho    July 23, 2026   Volume 97, Issue 1 e70223 doi: 10.1111/asj.70223
Santana ML, Bignardi AB.Reining performance is influenced by subjectivity and competition structure, challenging genetic evaluation. This study estimated genetic parameters for reining performance in Brazilian Quarter Horses using random regression models (RRM) and evaluated how alternative phenotypic definitions affect genetic inference and predictive ability. A dataset comprising 21,165 longitudinal records from 1603 horses was analyzed, comparing within-group rank (RANK) and Blom-transformed rank (BLOM). Model comparison indicated that cubic RRM provided the best fit for both phenotypes. Heritability estimates wer...
High-Throughput Equine Plasma Profiling Using Laser-Assisted Rapid Evaporative Ionisation Mass Spectrometry.
Journal of mass spectrometry : JMS    July 23, 2026   Volume 61, Issue 8 e70077 doi: 10.1002/jms.70077
Molnár A, Arko M, Troha K, Marton A, Tauber B, Iglič A, Balogh GT, Balog J, Hočevar M, Kos VK, Battelino S, Kralj-Iglič V, Schlosser G.Remnants of erythrocyte removal from blood constitute therapeutic plasma-a water-based solution containing mainly platelets, extracellular vesicles (EVs), protein and lipid complexes and ions. Plasma-based therapies, including their use to accelerate wound healing in human and animal patients, are increasingly gaining prominence in regenerative medicine; however, methods for the optimal preparation of individual plasma are still under development. Rapid and accurate analysis of plasma composition is essential for the development of therapeutic applications and for ensuring the quality of plasm...
Growth Performance, Milk Productivity, Productive Longevity, and Milk Composition of Mugalzhar Horses.
Animals : an open access journal from MDPI    July 22, 2026   Volume 16, Issue 14 2272 doi: 10.3390/ani16142272
Toishimanov M, Alikhanov O, Aubakirov K, Karibayeva D, Kargaeva M, Sapakhova Z, Begaliyeva D, Kanat R, Tugunova Y, Daurov D, Daurova A, Zhambakin K....The Mugalzhar horse is an important native breed of Kazakhstan, valued for its adaptability, milk production, and meat productivity under extensive pasture-based management. This study evaluated the relationships among first-lactation milk yield, productive longevity, lifetime milk production, growth, morphometric traits, and milk composition in the Mugalzhar horse breed using data from 100 mares with complete lifetime production records, 108 adult mares and 12 stallions for morphometric evaluation, and 68 foals (35 colts and 33 fillies) for growth analysis. The study was conducted on Mugalzha...
Penile and preputial pythiosis in Saudi Arabian horses: clinicopathological features and surgical outcomes.
Frontiers in veterinary science    July 22, 2026   Volume 13 1872270 doi: 10.3389/fvets.2026.1872270
El-Shafaey ES, Salem M, Awadin W, Mosbah E, Rizk MA, Meligy AMA, Shousha S, Aljazzar A, El Sebaei MG.Pythiosis, caused by , is a chronic granulomatous disease of horses characterized by invasive, ulcerative, and pyogranulomatous cutaneous lesions. Involvement of the external genitalia is uncommon and remains poorly characterized, particularly regarding environmental exposure and treatment outcomes. This study aimed to describe the epidemiological pattern, clinicopathological features, diagnostic findings, and surgical outcomes of penile and preputial genital pythiosis in a hospital-presented horse cohort. Unassigned: A retrospective study was conducted on 123 horses presented with cutaneous u...
Evaluation of an Immunoturbidometric Assay for Measurement of Total Adiponectin Concentration in Equine Serum Samples.
Veterinary clinical pathology    July 22, 2026   doi: 10.1111/vcp.70118
Nolen-Walston RD, Lowndes CR, Kulp JC, Luethy D, Stefanovski D, Van Eps AW.Total adiponectin (TA) is a marker of metabolic health in equids, with values below a critical decision point of < 7.9 μg/mL conferring increased risk of laminitis. Objective: To evaluate an IT assay to measure serum [TA] in equids and to assess its correlation with [high molecular weight adiponectin] (HMWA) measured by ELISA. Methods: Total serum adiponectin concentrations from 207 adult horses were measured using both an IT assay for TA and HMWA using a previously validated ELISA assay. Data were analyzed using Spearman correlation and Passing-Bablok regression. Intra- and inter-assa...
Unveiling wolf dietary specialization on free ranging horses using forensic genetics and field monitoring.
Scientific reports    July 20, 2026   doi: 10.1038/s41598-026-59871-3
Freitas J, Godinho R, Mendonça R, Nakamura M, Rio-Maior H, Ringhofer M, Yamamoto S, Hirata S, Álvares F.Wolves occasionally specialize on free-ranging horses when they are abundant and alternative prey is scarce, potentially reducing horse productivity, triggering conflicts with owners, and hampering conservation of both species. Yet, ecological and demographic impacts of wolf predation on horses remain poorly understood. We investigated wolf-horse interactions in NW Portugal by combining wolf monitoring, diet analysis, spatial overlap between wolf and horse activity areas, and horse pedigree reconstruction from genetically identified individuals recovered from wolf scat remains, feeding sites a...
Morphological investigation of myocardial sleeves with potential relevance to atrial fibrillation in Norwegian-Swedish Coldblooded Trotters.
Veterinary journal (London, England : 1997)    July 19, 2026   Volume 318 106784 doi: 10.1016/j.tvjl.2026.106784
Kallmyr-Mack A, Hellings IR, Press CM, Ibrahim L, van Loon G, Fintl C.Myocardial sleeves (MSs) are thin layers of cardiac muscle that extend from the atria into the caval and pulmonary veins. They are recognised as important structures in both initiating and maintaining atrial tachycardia, and especially atrial fibrillation (AF), which is the most clinically important cardiac arrhythmia in horses with a reported prevalence of 1.3-2% in Standardbred racehorses. In contrast, the Norwegian-Swedish Coldblooded Trotter (NSCT) has a much lower prevalence of AF despite experiencing similar physical demands. The purpose of this study was to describe the macro-, and micr...
Prevalence of equine lungworm (Dictyocaulus arnfieldi) infection and associated risk factors in Egypt.
Frontiers in veterinary science    July 17, 2026   Volume 13 1895496 doi: 10.3389/fvets.2026.1895496
Gattan HS, Marzok M, Alruhaili MH, Ismail H, Almubarak AI, Selim A. infection is a common parasitic respiratory disease of equines that can adversely affect animal health, welfare, and productivity. However, epidemiological information on this infection remains limited in many regions of Egypt. This study aimed to determine the prevalence of and identify associated risk factors among equines in three Egyptian governorates. Unassigned: A cross-sectional study was conducted on 415 equines, including 150 donkeys, 55 mules, and 210 horses. Animals were examined for , and data on species, age, body condition, and deworming history were collected. Associations bet...
Correction to “Vaccine technology helps exported Icelandic horses”.
The Veterinary record    July 16, 2026   Volume 199, Issue 2 86 doi: 10.1002/vetr.71019
No abstract available
Mares with severe equine asthma exhibit a narrower trachea than geldings in a retrospective radiographic study of 189 horses.
American journal of veterinary research    July 16, 2026   1-10 doi: 10.2460/ajvr.26.03.0127
Arnaiz Saura P, Masseau I, Lavoie JP, Mainguy-Seers S.To evaluate potential relationships between sex, asthma severity, and tracheal diameter in adult horses through the use of thoracic radiography. Unassigned: This was a retrospective case-control study of horses that underwent thoracic radiography at the Université de Montréal from 2018 through 2024. Horses were classified as control, mild/moderate asthma, or severe asthma (SEA) according to the latest consensus statement on equine asthma. To account for radiographic magnification and body size, standardized ratios of tracheal diameter relative to the fifth thoracic vertebral body length and ...
Preliminary Assessment on Pathogenicity of an African Horse Sickness Virus Serotype 1 Strain in Guinea Pigs and Horses.
Microorganisms    July 16, 2026   Volume 14, Issue 7 1557 doi: 10.3390/microorganisms14071557
Zhang M, Wang XF, Fu BF, Guo SF, Wang L, Zhang B, Guan FH, Song YF, Yang XY, Wang LL, Zhang QY, Yang CH.African horse sickness (AHS), a noncontagious insect-borne disease affecting equids, is caused by the African horse sickness virus (AHSV) and is associated with extremely high morbidity and mortality. AHSV has nine distinct serotypes (AHSV-1 to AHSV-9). In a previous study, we characterized the genome and in vitro growth properties of AHSV/C, a cell-adapted derivative of an AHSV-1 strain imported into China 60 years ago, and verified its safety in mice. This study preliminarily explored the pathogenicity of AHSV/C in guinea pigs and horses (its natural host). Six groups of guinea pigs were ino...
Sequencing and Differential Analysis of miRNA in the Ovaries of Kazakh Horses During Estrus and Anestrus States.
Animals : an open access journal from MDPI    July 15, 2026   Volume 16, Issue 14 2197 doi: 10.3390/ani16142197
Liu J, Yao X, Meng J, Wang J, Zeng Y, Ren W.To reveal the regulatory role of miRNA in the estrous cycle transition of Kazakh horse ovaries and improve their reproductive efficiency, this study took the ovaries of Kazakh horses in the estrus period (DY group) and the quiescent period (DB group) as research objects. Small RNA sequencing and bioinformatics analysis were used to systematically analyze the expression characteristics and functional pathways of miRNA under the two physiological states. A total of 161 million high-quality miRNA tags were obtained through sequencing. Principal component analysis showed that the intra-group repea...
Prevalence and Molecular Characterisation of Cryptosporidium spp. and Giardia duodenalis in Equines in Algeria.
Veterinary medicine and science    July 15, 2026   Volume 12, Issue 4 e71083 doi: 10.1002/vms3.71083
Reghaissia N, Al-Adilee YMS, Laatamna A, Dahmane A, Berghiche A, Samari H, Ansel S, Laadjailia Y, Gentekaki E, Kváč M, Holubová N, Tsaousis AD.Limited data are available on the epidemiology of Cryptosporidium spp. and Giardia duodenalis in equines in Algeria. No prior molecular data existed on giardiasis in this host population. Objective: This cross-sectional study aimed to determine the prevalence and molecular diversity of Cryptosporidium spp. and G. duodenalis in equines across multiple regions of Algeria, and to characterise species, subtypes and assemblages present. Methods: Between December 2021 and December 2022, 197 faecal samples were collected from 104 horses, 89 donkeys, 2 ponies, 1 zebra and 1 mule from 46 private farms,...
Assessment of Thyroid Hormones Using the Immulite 2000xpi Analyzer in Healthy Donkeys.
Veterinary sciences    July 15, 2026   Volume 13, Issue 7 690 doi: 10.3390/vetsci13070690
Davias C, Perez-Ecija A, Ruiz-Lastra D, Heras AL, Toribio R, Mendoza FJ.The Immulite 2000xpi, a chemiluminescent immunoassay (CLIA)-based analyzer, is currently recommended for measuring thyroid hormones (TH) concentrations in equids. However, scarce data are available on TH measurements in donkeys using this technique. Similarly, the effects of factors such as age and gender on TH concentrations have not been assessed with this analyzer. Serum free and total T4 and T3 concentrations were measured in 40 healthy donkeys (6.1 ± 0.8 years old; 8 intact jacks and 32 jennies) and 41 horses (10.7 ± 0.5 years old; 15 stallions and 26 geldings) using the Immulite 2000xp...
Plasma and Urinary Concentrations of Synephrine in Horses Following Controlled Oral Administration.
Journal of equine veterinary science    July 14, 2026   106096 doi: 10.1016/j.jevs.2026.106096
Minamijima Y, Miida T, Mori M, Arima D, Ito H, Araki M, Ishikawa Y, Kuroda T, Leung GN, Kinoshita K, Yamada M.Synephrine is a sympathomimetic alkaloid of regulatory interest in both horse racing and equestrian sports, where feed‑related exposure may lead to its detection in equine blood and urine. This study characterized plasma and urinary concentrations of synephrine in horses following controlled oral administration. Six Thoroughbred horses received single oral doses of 100 mg or 800 mg synephrine, and blood and urine samples were collected sequentially. Each sample was analyzed both before and after β‑glucuronidase hydrolysis, demonstrating that synephrine was present predominantly as conjuga...