Topic:Laboratory Methods
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.
Characterization of isolated late preantral and early antral equine ovarian follicles. Understanding how to effectively isolate a large number of healthy follicles is essential for increasing success rates in ARTs, such as in vitro culture and cryopreservation. Late secondary (preantral) and early tertiary (antral) follicles isolated from the intermediary portion of equine ovarian tissue sliced at two different thicknesses (0.25 mm vs. 0.50 mm) were characterized according to regional distribution (dorsal, medial, and ventral), morphofunctional features, and epigenetic profiles. After isolation via microdissection, follicles were evaluated for membrane integrity (trypan blue), v...
Reference intervals for serum macro- and microminerals in clinically healthy horses in Northwestern Spain: Influence of age, sex, breed and diet. Serum mineral concentrations are key indicators of nutritional status, metabolic function and health in horses; however, contemporary reference intervals (RI) derived from large, well-characterised populations remain scarce. Objective: To establish serum RI for macro- and microminerals in clinically healthy horses in Northwestern Spain and to evaluate the influence of sex, age, breed and diet on mineral status. Methods: Blood samples were collected from clinically healthy horses (n = 211), and serum concentrations of essential macrominerals (calcium [Ca]; phosphorous [P]; magnesium [Mg]; sodiu...
Re-emergence of equine glanders in Mongolia based on region-wide serosurveillance. Glanders, a zoonotic disease caused by , has re-emerged in Mongolia after decades of control. We conducted nationwide serosurveillance from 2021 to 2024 to assess the prevalence and geographic distribution of glanders. Using random 3-stage cluster sampling, we collected 3,001 horse serum samples from 332 herds. Those herds were in 46 soums (administrative districts equivalent to counties) in 13 provinces and in 3 districts in Ulaanbaatar. Sera were tested using the complement fixation test, and positive results were confirmed by immunoblotting and ELISA. Overall seroprevalence was 1.03% (95% C...
Evaluation of oxidative stress and antioxidant defense biomarkers in healthy and colic horses: correlation with type of colic and outcome. Colic is a major cause of morbidity and mortality in horses, with oxidative stress implicated in its pathophysiology. Objective: Evaluate biomarkers (BIOs) of oxidative stress and antioxidant defense in healthy horses and those with non-strangulating colic (NSC) and strangulating colic (SC) and assess correlations with survival. Methods: Seventy-one adult horses: 10 healthy and 61 colic-affected (42 NSC, 19 SC) admitted to 3 veterinary teaching hospitals. Methods: Prospective, multicenter cohort study. Blood samples were collected at admission (T0) and up to 96Â h post-admission. Biomarkers me...
Isolation and characterization of seminal extracellular vesicles subsets and their impact on sperm freezability in stallions. The ability of spermatozoa to withstand cryopreservation differs between stallions. While the underlying mechanisms of these differences are not fully understood, seminal plasma (SP) may play a crucial role in modulating sperm cryotolerance. Seminal plasma contains a heterogeneous population of extracellular vesicles (sEVs), nanometer-sized membrane particles that can transfer biomolecules to sperm modulating their function. This study aimed to isolate and characterize two sized-sEV subsets-small (S-) and large (L-)-from stallion SP, and to evaluate their involvement in sperm freezability. Sem...
Serial postoperative peritoneal fluid analyses in horses with naturally-occurring strangulating and non-strangulating gastrointestinal lesions. To describe characteristics of postoperative peritoneal fluid following exploratory laparotomy for naturally-occurring gastrointestinal lesions in horses. Methods: Prospective, observational cohort study. Methods: A total of 26 client-owned horses that underwent exploratory laparotomy for naturally-occurring gastrointestinal lesions. Methods: Abdominocentesis was performed pre- or intraoperatively, and at three time points postoperatively (24, 72, and 168 h). Peritoneal lactate, total protein (TP), total nucleated cell count (TNCC), cytology, and systemic lactate were performed at each time ...
Metabolomics reveals early predictors of blastocyst formation in equine ICSI-derived embryos. Equine in vitro embryo production (IVP) via ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) has gained prominence in sport-horse breeding due to high success rates, efficient semen utilization, and year-round embryo production, including from mares with fertility challenges or postmortem. However, assessing viability of early-stage ICSI-produced equine embryos remains challenging due to subjective morphological evaluations and limited visibility of developmental features. Non-invasive metabolomic analysis of culture media offers a promising alternative to enhance embryo selectio...
In vitro anthelmintic activity of extracts and bioactive compounds from Azadirachta indica and Cnidoscolus angustidens on strongyles L3 larvae in horses. Gastrointestinal endoparasitic diseases, particularly those caused by some strongyles, represent one of the main health challenges in equine production. The prolonged use of synthetic anthelmintics has led to the development of resistance, which has prompted the search for more sustainable therapeutic alternatives. However, plant extracts rich in secondary metabolites are emerging as a promising option. Objective: The objective of this study was to evaluate the in vitro anthelmintic activity of aqueous extracts and bioactive compounds (total phenols and saponins) from Azadirachta indica and Cn...
Nicotinic acid treatment improves the developmental potential of equine oocytes for cloned embryo production. Nicotinic acid (NA) treatment during in vitro maturation (IVM) has been shown to elevate nicotinamide adenine dinucleotide (NAD) levels and improve oocyte developmental competence. Suboptimal equine oocyte IVM systems currently limit the efficiency of viable embryo in vitro production. This study evaluated NA supplementation during IVM for cloned equine embryo production, using oocytes from abattoir-sourced ovaries and live mares via ovum pick-up (OPU). Abattoir-derived oocytes (n = 694) were treated without or with 50 or 200 μM NA during the 18 h holding period (Pre-IVM). Next, OPU-deriv...
Prognostic Significance of Erythrocyte Sedimentation Rate for Survival in Equine Colic. Accurate early prognostic assessment is a central aspect of clinical decision-making in horses presenting with colic. Despite the availability of multiple clinical and laboratory parameters, reliable biomarkers that provide useful information at the time of admission remain limited. The erythrocyte sedimentation rate is a non-specific indicator of systemic inflammation that has recently been validated for automated point-of-care use in horses. Its behaviour in equine colic has not been previously characterised. This study included 85 horses admitted for colic at two university referral hospita...
Generation and characterization of an immortalized equine osteoblast cell line. Bone is a dynamic tissue that is maintained through the co-ordination of bone resorption and bone formation. An imbalance of these processes can lead to bone disease. In vitro studies of osteoblasts can help to understand bone formation, but primary cells have a limited lifespan in culture. Herein, we report the successful generation of equine immortalized osteoblasts through the stable overexpression of human telomerase reverse transcriptase (hTERT) and Simian virus 40 (SV40) large T-antigen in osteoblasts isolated from trabecular bone taken from the third metacarpal of a two-year-old Thoroug...
A Novel Equine F[ab’]2 Veterinary Antivenom for North American Viperid Snake Envenomation Demonstrates Efficacy by Rapid Serum Venom Removal and Improvement in Snakebite Severity Score. To assess the efficacy of a new equine F[ab'] antivenom (US Department of Agriculture code 6101.05) in removing serum venom and lowering the snakebite severity score (SSS) in animals suffering from naturally occurring viperid envenomation. Methods: Retrospective study, April 2020 to October 2021. Methods: Veterinary hospitals across four North American regions. Methods: Twenty-two dogs, one cat, and one horse. Methods: All patients received the new antivenom intravenously and were assessed for clinical response. Most dogs required one vial for clinical control of signs. Results: Among the dogs...
Evaluation of oxidative stress in the newborn foal: a multibiomarker approach. During the perinatal period, neonates experience a sudden increase in oxygen exposure, predisposing them to oxidative stress. Objective: This prospective, in vivo study aimed to evaluate biomarkers of oxidative stress and antioxidant defence in healthy neonatal foals during the first 48 hours of life. Methods: Ten Standardbred foals were enrolled. Blood samples were collected at birth, 24 hours, and 48 hours after birth and analyzed for biomarkers using spectrophotometry assays. Statistical analysis was performed using non-parametric tests and linear regression. Results: The results revealed s...
Detection and Longitudinal Monitoring of Cyclosporine in Horse Plasma and Urine After Ocular Implant Administration. This paper describes the detection and longitudinal monitoring of cyclosporine in plasma and urine after subconjunctival implant administration in a horse. Sensitive liquid chromatography tandem mass spectroscopy (LC-MS/MS) methods for detecting cyclosporine in horse plasma and urine have been developed and validated, with estimated limits of detection down to 1 pg/mL in both matrices. The developed methods enabled longitudinal monitoring of cyclosporine levels in blood and urine samples collected over 6 months from a horse that had received an ocular cyclosporine implant.
Sequencing and Analysis of mtDNA Genomes from the Teeth of Early Medieval Horses in Poland. This study presents the sequencing and analysis of mitochondrial DNA (mtDNA) genomes from nine early medieval horse remains excavated across archaeological sites in Silesia region in present day Poland. Methods: Using aDNA extraction protocols optimized for short fragments, combined with target enrichment and high-throughput sequencing, we reconstructed partial mtDNA sequences for seven of the specimens. Results: The authenticity of the aDNA was confirmed through damage pattern analysis. Phylogenetic reconstruction revealed that the specimens belonged to six distinct mtDNA lineages (B, D, E, G...
Effects of sample storage time and temperature on equine complete blood counts. Equine blood samples are often collected in uncontrolled, distant environments and stored for later analysis. Objective: This study aimed to determine how sample storage methods influence complete blood count (CBC) parameters, hypothesizing that temperature and time elapsed from collection to analysis would affect CBC parameters. Methods: Blood samples were collected from 10 healthy Quarter Horse mares (age: 13 ± 4.5 years old) and stored in EDTA tubes at room temperature (22°C), above ice (8°C), refrigerated (4°C), or in contact with ice (2°C). The IDEXX ProcyteDx was used to obtain CBCs...
Functional and molecular characterization of equine intestinal organoids across media conditions and intestinal segments. Gastrointestinal (GI) disease is a major cause of morbidity and mortality in horses, with disruption of the intestinal epithelial barrier playing a central role in disease pathogenesis. A deeper understanding of the molecular and functional properties of the equine intestinal barrier is essential to improve diagnostics and therapeutics. While intestinal organoids have emerged as a promising tool for modeling GI physiology and disease, equine-specific data remain limited. Existing studies vary in methodology and often lack functional characterization, particularly across different intestinal re...
Clinical and laboratory evaluation in horses submitted to intracecal fluid therapy administered in two different rates. Two routes of administration for electrolyte solutions are commonly used in horses with fluid, electrolyte, and acid-base imbalances: intravenous and nasogastric. Despite the frequent use of these routes, there are situations in which they cannot be applied. In such cases, intracecal fluid therapy represents a viable alternative, as this route enables the administration of enteral electrolyte solutions even in animals lacking normal anterior gastrointestinal function. This study aimed to evaluate the effects of a neutral hypotonic enteral electrolyte solution administered intracecally at two d...
Evaluation of Laboratory Techniques for the Diagnosis of Leptospira-Associated Equine Recurrent Uveitis (ERU) With Focus on the Goldmann-Witmer Coefficient. To evaluate different laboratory procedures for determining the etiologic diagnosis of equine recurrent uveitis regarding intraocular infection with Leptospira spp. and to establish a diagnostic guideline. Methods: Eighty horses with a history of ERU were ophthalmologically examined. Serum and aqueous humor were collected. Total protein, albumin level, and MAT against Leptospira spp. were evaluated on serum and aqueous humor. PCR for Leptospira spp., EHV-1 and -4 was performed on aqueous humor. Goldmann-Witmer coefficient (GWC) and C-value (CC) were calculated based on MAT. In 42 cases, an add...
Bacterial contamination of covered versus non-covered plates in a sterile operating room in an equine referral center. Surgical site infections (SSI) are a common postoperative complication of equine orthopedic surgery and often increase morbidity and mortality. Objective: This study aimed to determine if covering surgical instruments during surgery decreased bacterial environmental air contamination during early opening of surgical packs (EOSP). The authors hypothesized that covering instruments with sterile surgical towels would reduce the total number of bacterial colonies to which the instruments were exposed. Methods: Blood agar plates (BAP) were allocated into two groups (non-covered vs. covered with a s...
Retrospective Evaluation of Synchronous Diaphragmatic Flutter in Horses: 37 Cases (2004-2022). To describe the clinical presentation of horses with synchronous diaphragmatic flutter (SDF) and identify clinical and laboratory variables associated with survival. Methods: Retrospective study from January 2004 to September 2022. Methods: Five large animal referral hospitals in the United States. Methods: Thirty-seven horses of various breeds and ages presenting with clinical signs of SDF, excluding animals participating in an endurance competition. All horses were >1Â year of age. Methods: None. Results: Variables recorded and analyzed included signalment, clinical and laboratory data, trea...
Quantitative modeling reveals prolonged lactate clearance in young and unraced Jeju horses following high-intensity exercise under passive recovery conditions. To model lactate recovery kinetics in relation to sex, age, running speed, and racing experience, and to estimate blood lactate clearance time under passive recovery conditions that reflect current management practices in Jeju horses, a less well-characterized pony-sized indigenous breed. Unassigned: From October through December 2022, BLC was measured at baseline, 10 minutes after 800-m barrier trials (time [T]-1), and 50 minutes (T2) after 800-m barrier trials in 40 race-trained Jeju horses (2 to 4 years old). Lactate clearance was modeled using nonlinear regression with an exponential decay...
A Markerless Approach for Full-Body Biomechanics of Horses. The ability to quantify equine kinematics is essential for clinical evaluation, research, and performance feedback. However, current methods are challenging to implement. This study presents a motion capture methodology for horses, where three-dimensional, full-body kinematics are calculated without instrumentation on the animal, offering a more scalable and labor-efficient approach when compared with traditional techniques. Kinematic trajectories are calculated from multi-camera video data. First, a neural network identifies skeletal landmarks (markers) in each camera view and the 3D location...
α2-Macroglobulin Concentrations in Canine and Equine Serum Donors. To determine if serum α2-macroglobulin (A2M) concentration varies based on donor species-canine or equine-and signalment. Methods: Serum A2M concentration ([A2M]) was measured in healthy dogs (n = 30) and horses (n = 31) using species-specific ELISAs. Results: Canine and equine [A2M] median (IQR; range) were 98.70 ng/mL (92.79 ng/mL; 34.33-696.18 ng/mL) and 557 000 ng/mL (437 900 ng/mL; 62 600-3 042 900 ng/mL), respectively. Equine [A2M] was significantly higher than canine [A2M]. Depending on the statistical analysis performed, sex had either no statistical (pâ€...
Seasonal elevation in equine adrenocorticotropic hormone occurs throughout the contiguous United States and is influenced by latitude and age. To determine whether seasonal variation in equine plasma ACTH concentrations is affected by latitude between 29.7°N and 45.0°N in the US. Unassigned: A cohort study was performed between June 2019 and May 2020 in which plasma ACTH was measured monthly by chemiluminescence immunoassay. The study involved 201 apparently healthy horses from 9 locations within the US classified into northern, central, and southern latitude cohorts. Data analysis was performed with 3 major objectives: (1) identify outlier ACTH concentrations and horses; (2) estimate ACTH upper reference limits to define expected ...
Blastocyst production by conventional in vitro fertilization (cIVF) in horses: Effects of sperm storage method, incubation timing of cool-stored semen before gamete co-incubation, and comparisons between cIVF and intracytoplasmic sperm injection (ICSI). Currently, Intracytoplasmic Sperm Injection (ICSI) on in vitro-matured equine oocytes obtained by transvaginal oocyte aspiration (TVA) is the method of choice for in vitro production of equine blastocysts in a clinical setting. A protocol for conventional in vitro fertilization (cIVF) using either fresh or frozen/thawed stallion sperm incubated under capacitating conditions (Tyrode's Albumin Lactate Pyruvate medium + penicillamine, hypotaurine, epinephrine; FERT-PHE) has been recently reported. Several factors that may impact the clinical applicability of this cIVF protocol have yet to be st...
Histopathological and molecular evaluation of hydatid cysts according to necropsy findings of 52 equids in Türkiye. is a parasitic cestode primarily maintained within an equine-canine life cycle, with horses, donkeys, mules, and other ungulates serving as intermediate hosts. Although has historically been considered non-zoonotic, recent molecular studies suggest that this assumption may need to be reevaluated. This study aimed to investigate the presence and molecular characterization of in equids from Türkiye. A retrospective analysis of 52 equine necropsies performed between 2020 and 2025 identified hydatid cysts in one Arabian horse and two donkeys. Gross and histopathological examination confirmed t...
Using an Equine Cadaver Head to Investigate Associations Between Sub-Noseband Space, Noseband Tension, and Sub-Noseband Pressure at Three Locations. Pressures applied to horses via nosebands are of growing concern. The current study applied noseband pressure to the head of a dead horse. Pressure sensors were placed on the left nasal bone to record pressures as the noseband was progressively tightened. Tightness increased as predicated by holes in the strap of the noseband (as supplied) through eight steps from two fingers' space, assessed using the standard International Society for Equitation Science Taper Gauge through to zero space. Sensors were also placed at the midline frontal plane and intra-orally at the level of the second premola...
The magnitude of hyperchloremia in horses is associated with diarrhea and renal function. To describe the signalment, diagnosis, treatment, and laboratory characteristics of horses with hyperchloremia and identify factors associated with the magnitude of the increased chloride concentration. Unassigned: Horses with a chloride concentration greater than 108 mEq/L were included in this retrospective study. Descriptive statistics and multiple linear regression analysis were used to identify associations between diagnosis, treatment, and laboratory variables and the magnitude of hyperchloremia. Unassigned: 134 horses met the inclusion criteria for this study. Creatinine was a significa...
Reference Intervals for Biochemical Analytes in Clinically Healthy Adult Lusitano Horses. To date, serum biochemical analytes reference intervals (RIs) in Lusitano horses have not been studied. This study aimed to establish the RIs for biochemical analytes following the American Society of Veterinary Clinical Pathology guidelines and to compare them with the general equine population's RIs. Blood samples were collected from 76 clinically healthy adult Lusitano horses, and RIs of 22 biochemical variables were determined using Reference Value Advisor software. Lusitano horse-specific RIs are proposed for the following variables: total protein (3.9-7.0 g/dL), albumin (2.5-3.8 g/dL), g...