Laboratory methods in equine research encompass a variety of techniques and procedures used to analyze biological samples from horses to study health, disease, genetics, and physiology. These methods include hematological analyses, biochemical assays, molecular biology techniques, and microbiological cultures. Commonly utilized laboratory techniques involve blood tests for complete blood count (CBC) and serum chemistry, polymerase chain reaction (PCR) for genetic and infectious disease studies, and enzyme-linked immunosorbent assays (ELISA) for detecting specific proteins or antibodies. These methods provide valuable data that contribute to understanding equine health and disease mechanisms. This page compiles peer-reviewed research studies and scholarly articles that explore the application, development, and outcomes of laboratory methods in the context of equine research.
Olitsky PK, Cox HR, Syverton JT.We have studied certain properties, additional to those previously described (3), of the virus of vesicular stomatitis of horses, and of the characteristic biological reactions of the virus of equine encephalomyelitis. It has been found that the virus of stomatitis, ordinarily dermotropic, can acquire neurotropism and the neurotropic encephalomyelitis virus can, in turn, be rendered dermotropic in its action. The neurotropism in both instances is associated with definite, although not pronounced, viscerotropism. Both viruses can bring about a similar infection in the white mouse, rat, guinea p...
Parker JT, McCoy MV.1. The serum of horses immunized with increasing doses of certain anaerobically produced autolysates of pneumococci contain potent neutralizing antibodies for the pneumotoxin. 2. The method for the in vitro titration of these horse antipneumotoxic serums is given.
Abramson HA.1. The cataphoretic velocity of blood platelets (horse) in plasma has been found to be between 40 and 51 micro per sec. per volt per cm. The mean velocity obtained from five horses is . 45 micro per sec. per volt per cm. 2. The cataphoretic velocity of polymorphonuclear leucocytes in similar specimens is practically identical with that of the platelets. This is noteworthy because of the fact that lymphocytes and red cells have different speeds. 3. With spontaneous agglutination of platelets, white cells and red cells, there is no change in the cataphoretic velocity incidental to aggregation. 4...
Friedlander M, Sobotka H, Banzhaf EJ.The precipitin indices for a number of monovalent and polyvalent antipneumococcus sera were determined under known conditions, and found to vary as did the number of protective units. The ratio precipitin index/protective units in monovalent sera was found to lie between 2.8 and 4.8 for Type I and to be about ten times greater for Type III. Lower values were found in polyvalent horses and when mixing heterologous monovalent sera with each other. The influence of the duration of treatment upon the quotient was studied. Several refined and concentrated preparations showed a relative increase in ...
Reimann HA.It is conceivable that a change from the virulent, non-phagocytable S form of Pneumococcus to the avirulent phagocytable R form may take place in pneumococcus disease, but the experiments here reported do not settle the question whether or not this is an important factor in determining the outcome in natural infection. It has been shown experimentally that the degradation from the S form to the R form actually does take place in cultures of Pneumococcus growing in agar subcutaneously embedded in guinea pigs, in agar enclosed in vials subcutaneously embedded in rabbits, and spontaneously in the...
Jungeblut CW.1. A flocculation reaction has been described which occurs between alcoholic extracts of pneumococci and antipneumococcus serum. 2. The reaction appears to be species-specific. It is not strictly type-specific, as slight or moderate cross-reactions occurred between Type I serums and Type II and Type III extracts. 3. The flocculating power of the serum from five horses undergoing immunization with pneumococcus, Type I, did not develop to any extent before the end of the 4th or 5th month. 4. In the case of two of these horses in which it was possible to carry out parallel tests on a larger numbe...
Amoss HL, Marsh P.Experiments were made for the purpose of testing the reaction of protection against infection as a measure of potency of antimeningococcic serum. The results of the experiments were extremely variable and bore no relation to the quality of the sera as determined by the period of immunization of the horses from which they were obtained, or the indications of efficiency based upon their employment in human cases of epidemic meningitis. The results also failed entirely to conform to the agglutination titer of the sera tested and to be affected by the different type forms of the meningococci. We r...
Wadsworth AB, Kirkbride MB.Horses immunized to Type I pneumococci developed serum, 0.1 cc. of which protected against 0.5 cc. of a virulent culture, 0.000001 cc. of which killed mice in less than 40 hours. Protective tests of serum from horses immunized to Type II organisms varied, 0.1 cc. protecting, however, in certain instances against 0.1 and 0.01 cc. of virulent homologous culture. Types I and II sera obtained in our experiments with culture sediment and whole culture did not vary markedly for a given type and corresponded closely in their protective titer with samples of sera received from The Rockefeller Institut...
Hiss PH, Atkinson JP.THE RESULTS OF THE FOREGOING EXPERIMENTS MAY BE BRIEFLY SUMMARIZED AS FOLLOWS: The amount of antitoxic substance obtained by precipitation with magnesium sulphate from the blood-serum of the horse corresponds, as nearly as can be determined by the use of test guinea-pigs, in full to the protective power of the serum from which it is obtained, i. e. the precipitate from 1 cc. of serum will protect against the same amount of toxin as 1 cc. of the serum itself. Equal amounts of the precipitates by magnesium sulphate from immunized and non-immunized horses act differently toward toxin; i. e. the p...
Atkinson JP.1. The globulins of both normal and diphtheria antitoxic serum exhibit chemically toward reagents the same reactions, being precipitated by magnesium sulphate and split up into fractions in precisely the same way. 2. All of the diphtheric antitoxic power of both normal and immunized serum is always carried by the globulin and its fractional precipitates. 3. During the fractional precipitation of the serum globulin of horses immunized from diphtheria toxin and horses not immunized from diphtheria toxin, some of the globulin is lost, likewise at the same time some of the antitoxic power of the g...
The goal of this work was the development of suitable (real-time) RT-PCR techniques for fast and sensitive diagnosis of EAV and for molecular-epidemiological characterisation of viral strains, as an alternative to virus isolation. To this purpose two conventional RT-PCR methods and one real-time RT-PCR were adapted to detect the broadest possible spectrum of viral strains. Several dilutions with Bucyrus strain showed a 100-fold higher sensitivity of real-time RT-PCR and heminested RT-PCR compared to simple RT-PCR. Making use of 11 cell culture supernatants of different EAV isolates and 7 semen...
Medica AJ, Gibb Z, Aitken RJ.In vitro semen purification techniques have been developed that seek to mimic the in vivo selection process in order to generate the highest possible chance of oocyte fertilization following artificial insemination. Numerous methods have been developed to isolate functional spermatozoa for artificial insemination, yet only one method, single-layer centrifugation using commercial preparations like EquiPure, has been widely employed. In this study, we have introduced a novel approach for isolating spermatozoa and compared their quality to those isolated using EquiPure. The AI port system (Mempha...
Hernández-Avilés C, Ramírez-Agámez L, Varner DD, Raudsepp T, Love CC.Cases of stallion subfertility due to acrosome dysfunction have been recognized since the 1990s. While some of these were observed in stallions with reduced sperm motility and morphology, a more severe form has been reported in stallions with normal-to-excellent sperm quality parameters, which is also uniquely observed in individuals of the Thoroughbred registry. These stallions carry a susceptibility genotype (A/A-A A in the gene FKBP6, exon 5) for Impaired Acrosomal Exocytosis (IAE). Current clinical observations from our group have identified a few highly subfertile stallions from other bre...
Dias Moreira AS, Weng HY, Hostnik LD, Beasley EM, Peek SF, Munsterman AS.To compare glucose measurements from capillary and venous blood samples using a point-of-care (POC) glucometer with a standard laboratory (colorimetric, glucose oxidase) assay (LABGLU) in a population of hospitalized, neonatal foals. Methods: Multicenter, prospective, experimental study, conducted between March 2019 and June 2020. Methods: Four university teaching hospitals and 1 private referral hospital. Methods: Fifty-four hospitalized neonatal (≤30 days of age) foals. Methods: Simultaneous capillary (muzzle, POCMUZ) and venous (jugular, POCJUG) blood samples were obtained to determine P...
Hoerdemann M, Sahoo DK, Allbaugh RA, Kubai MA.To assess if an affordable, commercially available 275 nm ultraviolet C (UV-C) device can inhibit fungal pathogens associated with equine keratomycosis and to establish the optimal exposure time/dose required in vitro. Methods: Fungal inhibition zone surface areas of isolates from two fungal genera (Aspergillus and Fusarium spp.) were compared in triplicates after UV-C exposure at distances of 10, 15, and 20 mm with single or repeat doses (4 h apart) of 5, 10, 15, or 30 s duration after 24, 48, and 72 h of incubation. Inhibition zones were microscopically assessed, and regrowth chec...
Spacek SG, Hernández-Avilés C, Ramírez-Agámez L, Pearson M, Love CC.Cryopreservation of stallion epididymal sperm has become a common clinical procedure after routine castration, euthanasia, or acute death. Unique features of epididymal sperm compared to ejaculated sperm include the requirement to remove sperm from the cauda epididymis, lack of exposure to seminal plasma, and potential recovery of large sperm numbers. In this study, the effect of the flushing technique (Extender (INRA) vs. AIR), freezing extender (LE, CMLE, MFR5, CFR5, or BOTU), and the concentration at which sperm are cryopreserved (200, 400, or 800 × 10 sperm/mL) on post-thaw epididymal s...
Vieira GS, Peneiras ABV, Soares TSC, Alonso MA, Curcio BR, Fernandes CB, Oliveira RA.Advancements in equine neonatology enable continuous monitoring of mares throughout pregnancy. However, reference values for oxygenation and biochemical parameters in newborn foals remain limited. Objective: This study aimed to assess the oxygenation status of healthy Mangalarga Marchador foals from birth to 24 h postpartum by evaluating blood gas analysis, Apgar scores, and biochemical and hematological parameters. Methods: Thirty healthy Mangalarga Marchador foals were evaluated. Blood samples were collected from the umbilical artery at birth (T0) and from the dorsal metatarsal artery at 15 ...
Alves LSS, Hasuda AL, Giordano LGP, Frederico I, Dos Santos IH, Pereira PFV, Lisbôa JAN, Flaiban KKMDC.This study investigated isolation of equine neutrophils and the assessment of their antioxidant function using the nitroblue tetrazolium (NBT) reduction test, an indicator of reactive oxygen species (ROS) activation. The objective was to test the viability of neutrophils isolated from equine whole blood and their ability to undergo respiratory burst, comparing the results with whole blood. The hypothesis tested was that isolation of equine neutrophils allows for effective functional evaluation, even after isolation process, with no significant differences between whole blood and isolated cells...
Durham AE.This study aimed to further define and quantify possible cross-reactive peptides when measuring plasma adrenocorticotropic hormone (ACTH) concentration in equids. Equine plasma samples were spiked with known concentrations of exogenous manufactured peptides comprising human ACTH, ACTH (corticotropin-like intermediate lobe peptide, CLIP) and ACTH (corticotropin inhibiting peptide, CIP). All samples were assayed in duplicate using Siemens Immulite 2000xpi chemiluminescent assay (CLA) and Tosoh AIA-900 immunoflurorescent assay (IFA). As expected, ACTH was measured by both assays although higher v...
Rey-Conejo R, Toribio RE, Möller S, Müller E, Fores-Jackson P.Insulin dysregulation is a key component of equine metabolic syndrome and is commonly assessed using basal insulin concentrations. Different analyzers may yield variable insulin results, limiting comparability. Objective: To assess the analytical performance of the ADVIA Centaur XPT chemiluminescent immunoassay (CLIA) for equine insulin measurement and to establish adapted decision thresholds based on comparison with a previously used CLIA method. Methods: Precision, linearity, and dilution recovery were assessed for the ADVIA Centaur XPT. A total of 89 equine serum samples submitted for basal...
Ramírez-Agámez L, Hernández-Avilés C, Samper JC, Love CC.Intracytoplasmic sperm injection (ICSI) using frozen/thawed (F/T) stallion sperm is a common procedure in the equine breeding industry. Historically, sex-sorted (SS) F/T stallion sperm has yielded lower cleavage (<30 %) and blastocyst rates (<5 %) after ICSI when compared to non-sorted (NS) F/T sperm. Recently, a new technology for sperm sex-sorting (Genesis III) has been validated by a commercial company. In Experiment 1, the post-thaw quality between NS-F/T and SS-F/T stallion sperm produced with this technology was compared. The post-thaw sperm motility was higher in NS-F/T (41 %) than i...
Graham AE, Colgate VA, Floyd EF.Geographical specific data is required to guide empirical antimicrobial selection in equine neonates. Objective: Evaluate antibiograms and survival in foals from a United Kingdom (UK)-based hospital to guide antimicrobial selection. Methods: Blood and synovial fluid samples from 208 foals ≤ 30 days old admitted to Rossdales Equine Hospital from 2018 to 2023. Methods: Retrospective cohort study. Antimicrobial susceptibility was assessed by disc diffusion method. Bacterial culture and susceptibility and foal survival were recorded. The effects of the presence of positive culture or multi...
Hisaeda K, LE NAT, Kadekaru S, Ono T, Hiasa Y, Ohzawa E, Hata A, Kutara K, Sugimoto K, Une Y, Iwata E, Kunieda T, Zhang C, Kitagawa H.We evaluated metabolic abnormalities in six neonatal Noma foals (Nos. 54-57, 62, and 66) that died shortly after birth, using laboratory tests, pathological examinations, serum amino acid (AA) analyses, gas chromatography/mass spectrometry (GC/MS), and genetic analyses. Nonspecific clinical symptoms, such as poor suckling and weakness, were commonly observed at birth. Sepsis caused by various bacterial infections was detected in foal Nos. 54, 62, and 66, while a heart malformation was identified in foal No. 57. Laboratory tests showed high aspartate transaminase, lactate dehydrogenase, and cre...
Kovarikova S, Blahova J, Steffenova V, Vaskova N, Jahn P.Currently, there is relatively little published information on the urine protein-to-creatinine (UPC) ratio in horses, a parameter commonly used in dogs and cats. The aim of this study was to determine the reference range of UPC in urine samples of apparently healthy horses and to assess the influence of age and sex. Urinalysis and the determination of urinary protein and creatinine concentrations and ratios were performed. A total of 118 urine samples from apparently healthy horses were included in the study: 10 from foals younger than 6 months and 108 from horses older than 1 year. The median...
Valderrama-Martinez C, Packham A, Smith W, Mendoza-Flores JE, Zheng S, Chigerwe M, Plancarte M, Aleman M.Long-term freezing storage can alter the stability of proteins, thereby compromising accurate determination of indirect fluorescent antibody test (IFAT) titers that support the diagnosis of equine protozoal myeloencephalitis. Objective: Assess the effect of long-term storage at -80°C on IFAT against S. neurona and N. hughesi in equine serum and cerebrospinal fluid (CSF). Methods: Paired serum and CSF (n = 46), and serum only (n = 25) samples. Methods: Prospective study of samples stored 6-12, 13-18, and 19-24 months. Comparing antibody titers across time points, McNemar and Wilcoxon...
Shimizu Y, Sugai-Bannai M, Tanabe H, Saito K, Ito H, Tokushige H, Kamiya K, Hirano-Kodaira M, Yamada M, Leung GN.Somapacitan is the second generation of recombinant human growth hormone (rhGH) medication that retains the pharmacological effects of rhGH but exhibits a longer duration of action due to its reversible albumin-binding in the body. In general, the use of all recombinant growth hormone (rGH) analogues is banned by the human and animal sports regulatory authorities due to their anabolic and lipolytic effects. However, little is known about the elimination kinetics and biological effects of the newly introduced long-acting rhGH, somapacitan, in horses. This paper describes the administration stud...
Crosby CE, O'Connor A, Munsterman AS.Colic is a significant source of morbidity and mortality in horses, and no single biomarker can distinguish surgical from medical colic or predict mortality. Alactic base excess (ABE) has shown an association with mortality and renal insufficiency in humans but has not been evaluated in veterinary species. The purpose of this study was to determine the value of ABE as a diagnostic tool for horses treated for gastrointestinal disease. Unassigned: This retrospective case series evaluated horses admitted for acute gastrointestinal disease over a 5-year period (2019-2024). Signalment, physical exa...
Silva GLS, Curcio UA, Boufleur JA, Borges DGL, Nakatani MTM, Freitas MG, Borges FA, Faria FJC, Silva RHP, Franco GL.Anthelmintic resistance has led to the use of organic extracts as alternative methods of parasite control. Objective: The study aimed to assess the effects of Acacia mearnsii extract (tannin) on the control of cyathostomins in horses, both in vitro and in vivo. Methods: Thirty Pantaneiro horses naturally infected with cyathostomins were sourced from two distinct farms, designated as Farms A and B. At the start of the study, all third-stage larvae were cyathostomins, and an egg hatchability test (EHT) was performed using fecal samples from horses on both farms. Two randomized 28-day field studi...
Cullen JN, Cieslak J, Petersen JL, Bellone RR, Finno CJ, Kalbfleisch TS, Calloe K, Capomaccio S, Cappelli K, Coleman SJ, Distl O, Durward-Akhurst SA....MicroRNAs (miRNAs) are essential regulators of gene expression, yet few comprehensive databases exist for miRNA expression in non-model species, limiting our ability to characterize their roles in gene regulation, development, and disease. Similarly, isomiRs - length and sequence isoforms of canonical miRNAs with potentially altered regulatory targets and functions - have received even less attention in non-model species, including the horse, leaving a critical gap in our understanding of their biological significance. To address these challenges, we developed an open-source, containerized pip...
Şahinkesen İ, Bilge-Dağalp S.Equine herpesvirus 1 (EHV-1) and Equine herpesvirus 4 (EHV-4) are major viral pathogens of horses that contribute to respiratory disease, abortion, and neurological disorders, leading to economic losses in the equine industry. Accurate serological diagnosis is critical for disease surveillance and control. This study aimed to develop and validate an in-house enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against EHV-1 and EHV-4 in horse sera. Serum samples previously confirmed by virus neutralization test (VNT) and a commercial ELISA were used to optimize the assay. Cut-off...
Robel M, Grest P, Riond B, Zablotski Y, Schoster A.Limited data are available on immune cells in the intestinal wall of healthy horses, hampering interpretation of results in case of disease. Objective: Characterize and quantify the immune cell populations and their distribution in duodenal and rectal biopsies of horses without gastrointestinal disease; compare immune cell counts (ICCTs) between full thickness- and mucosal biopsies. Methods: Twenty horses fit for slaughter, slaughtered for meat production. Methods: Full-thickness and endoscopic forceps obtained mucosal biopsies were taken within 30 min after slaughter from the duodenum and rec...
Dubey S, Lomnicka I, Waller P, Vora D, Dirikolu L.The complexity of the drug market and the constant updating of drugs have been challenging issues for drug regulatory authorities. In this manuscript, a high-throughput automated assay based on Liquid Chromatography High Resolution Mass Spectrometry (LC-HRMS) suitable for use as an initial testing procedure covering multiple classes of compounds prohibited in horse racing is described. The assay requires a 250-μL urine aliquot, which is subjected to enzymatic hydrolysis followed by Biotage Isolute supported liquid extraction plates using Biotage Extrahera system, evaporation, and reconstituti...
Studzińska M, Klockiewicz M, Szczepaniak K, Demkowska-Kutrzepa M, Roczeń-Karczmarz M, Tomczuk K.The resistance of strongyles to pyrantel pamoate has been reported in publications worldwide. There is no data on its efficacy in horses in Poland. Therefore, the aim of this study was to evaluate the effectiveness of pyrantel pamoate to control strongyle invasions in young horses. The study involved horses of both sexes, aged 1 to 2 years, and was conducted in two seasons (spring and the end of summer). Feces were collected 24 hours before and 14 days after deworming, and they were then examined using McMaster's and combined sedimentation-flotation methods. Results revealed that in spring, th...
Brito LFC, Linardi RL, Rosales LAS, Balamurugan NS, Hernández-Avilés C, Ramírez-Agámez L.Efficient use of stallion semen in liquid state is limited by its relatively short shelf-life. A chemically defined extender (Beyond) is now available for long-term liquid semen preservation. The objectives of the present study were to compare Beyond with milk extenders for the preservation of semen at two temperatures, and to evaluate fertility of semen cooled for 4-8 days before artificial insemination. Semen was processed using different extenders: milk, cholesterol (BotuSemen Special); milk-based (INRA 96); and Beyond. Sperm motility, membrane and acrosome integrity, and chromatin struct...
Kim D, Lee S, Oyungerel B, Cho G.This study aimed to generate information for parentage testing in horse breeds using microsatellites (STRs) and single-nucleotide polymorphisms (SNPs). Genotype data were obtained from 189 horse hair root samples, including 38 Thoroughbreds (TBs), 17 Jeju horses (JHs), 20 Quarter horses (QHs), 21 American Miniatures (AMs), and 93 Mongolian horses (MHs), using 15 STR markers and 71 SNP markers. Comparative analysis revealed that the mean expected heterozygosity ranged from 0.468 (AM) to 0.491 (JH) for SNPs and from 0.695 (TB) to 0.791 (MH) for STRs. The mean observed heterozygosity ranged from ...
Lugo T, Myers S, Nguyen TA.In vitro models have revolutionized our understanding of biological pathways and mechanisms, offering a viable alternative to direct patient testing. However, there is a significant lack of models for different animals, particularly equine models. This study presents a novel primary cell culture extracted from a 3-year-old horse diagnosed with multisystemic eosinophilic epitheliotropic disease. Tissue samples were collected from lymph nodes at various locations. Growth curves of extracted primary cells were analyzed and the optimal conditions were assessed. Biomarkers, such as CD31, ZO-1, CD79...
