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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.
In vitro anthelmintic activity of the monoterpene linalool, alone and combined with the nematophagous fungus Duddingtonia flagrans, in the control of gastrointestinal nematodes in horses. This study evaluated, in vitro, the anthelmintic activity of the monoterpene linalool, alone and in association with the fungus Duddingtonia flagrans, against gastrointestinal nematodes of horses. Nematodes from the superfamily Strongyloidea, obtained from naturally infected horses, were used. The ovicidal activity of linalool was evaluated using the Egg Hatch Test (EHT). The larvicidal activity was evaluated using the Larval Motility Inhibition Test (LMIT), in which infective larvae (L3) were assigned to experimental groups treated with linalool alone (0.15, 0.3, 0.6, 1.25, 2.5, 5, 10, 20, 40...
New Noninvasive Long-Term Stress indicator in Horses: Analysis of Cortisol Levels in the Hoof of Foals. Noninvasive sampling methods are recommended in animals as far as possible. However, there has been no way to safely measure long-term stress in all horses including foals and stallions. Currently, nail cortisol in humans has been reported to be a promising noninvasive long-term stress indicator. This study aimed to evaluate the usefulness of a horse's hoof as a noninvasive long-term stress indicator by determining whether hoof cortisol levels varied similarly to hair cortisol levels noted in a previous study. All hooves were sampled by one farrier after a foal's birth. They were divided into ...
Multimodal characterization of equine synovitis: Correlation between arthroscopic, histopathological, and biomarker assessments in septic vs. aseptic cases. Endoscopy and synovial membrane histology are complementary modalities for evaluating synovial inflammation. Cytokine involvement in non-septic arthritis is well documented but remains poorly characterized in septic synovitis. Objective: This study aimed to characterize the inflammatory cytokine profile associated with septic and non-septic synovitis and assess correlations among endoscopic, histological, and synovial fluid biomarker findings. Methods: Three groups were defined: horses undergoing elective or therapeutic endoscopy (Group 1, n=26), horses with confirmed septic synovitis (Group 2...
Superior Post-Thaw Sperm Quality and Fertility of Epididymal Compared with Ejaculated Sperm in Subfertile Stallions. Despite the benefits of seminal plasma during breeding, its value is questionable when utilizing biotechnological approaches such as artificial insemination. In addition, deleterious effects of secretions from accessory glands on sperm viability and conception rate have been reported, especially in stallions with poor semen quality. Objective: The present study aimed to compare the kinetics, structural and functional viability, and fertility parameters of spermatozoa obtained from the ejaculate and from the cauda epididymis of subfertile stallions, as well as to evaluate the differences in the...
Effect of Different Equilibration Times in the Freezing Process on Post-Thaw Motility Parameters in Equine Spermatozoa. Cryopreservation of stallion semen remains suboptimal, with approximately one-third of stallions producing semen that is poorly tolerant to freezing. As optimization of pre-freezing procedures may improve post-thaw sperm quality, this study evaluated the effect of different equilibration times before freezing on the post-thaw quality of stallion semen. For this purpose, 21 ejaculates were initially collected from 5 stallions and 15 were included in the final analysis after predefined exclusions. These ejaculates were separated from the seminal plasma via centrifugation in INRA 96 medium. After...
Host-mediated filtering and interspecific associations structure strongyle parasite communities in Sable Island horses. Mixed-species parasite infections are common in wildlife, yet the ecological processes that structure these communities remain poorly understood. We hypothesized that host-mediated and extrinsic environmental filtering, alongside biotic interactions, act concurrently to shape parasite community composition, and that these structuring patterns would depend on parasite traits or evolutionary history. We applied nemabiome DNA metabarcoding to 3147 faecal samples from 916 feral horses with no history of anthelmintic treatment, collected over 10 years as part of a long-term individual-based study...
Validation of a point-of-care assay for simultaneous quantification of equine adrenocorticotropic hormone and corticotropin-like intermediate peptide. Plasma adrenocorticotropic hormone (ACTH) concentrations are used to diagnose equine pituitary pars intermedia dysfunction (PPID). The reference chemiluminescent immunoassay for immunoreactive ACTH (iACTH) cross-reacts with corticotropin-like intermediate peptide (CLIP), which is also abnormally high in PPID. Objective: To compare the performance of a novel point-of-care (POC) immunoassay that concurrently measures ACTH and CLIP against the reference iACTH assay. Methods: Twenty-eight university-owned horses (13 PPID, 15 non-PPID). Methods: Prospective observational study. Resting plasma hormo...
Renal dysplasia in horses: 25 cases (1991-2021). Renal dysplasia (RD) is a congenital malformation with variable clinical expression and limited characterization in horses. Objective: We hypothesized that RD occurs in horses across a broad age range and may be overrepresented in specific breeds. Our objective was to describe clinical, clinicopathologic, and histopathologic findings in horses with RD. Methods: Twenty-five horses with RD identified from a veterinary teaching hospital between 1991 and 2021. Horses included neonates, young horses, and adults, with ages ranging from 0 days to 24 years and representing multiple breeds and both s...
Plasma adrenocorticotropin concentrations vary with assay used in horses with and without pituitary pars intermedia dysfunction. Plasma adrenocorticotropin (ACTH) concentration is measured to support a diagnosis of pituitary pars intermedia dysfunction (PPID). However, baseline ACTH and ACTH concentrations after IV administration of thyrotropin releasing hormone (TRH) vary with season and assay used. To compare two ACTH assays (Scantibodies immunoradiometric assay [IRMA] and Immulite 2000Xpi chemiluminescent immunometric assay [CIA]) for diagnosis of PPID, ACTH was measured before and 10 minutes after administration of TRH in three groups of horses: 1) four young horses (6 ± 3 years, no hypertrichosis and a pituita...
Cumulus cell DNA fragmentation as non-invasive biomarker of equine oocyte quality in in vitro embryo production. The efficiency of in vitro embryo production in animal species is constrained by the absence of practical, non-invasive biomarkers to assess oocyte quality. Cumulus cell DNA fragmentation index (CC-DFI) has been proposed as a biomarker in humans, but data in animals remain limited. Objective: This study investigated the association of CC-DFI with in vitro maturation (IVM) and intracytoplasmic sperm injection (ICSI) outcomes in horses, and its relationship with mare-related factors, autumnal transition period, cumulus cell viability, and cumulus expansion. Methods: Cumulus-oocyte complexes (COC...
Influence of Follicle Number and Reproductive Cyclicity on Mesenchymal Stromal Cell Yield Isolated From Equine Ovarian Follicular Aspirates. Follicular aspirates have emerged as an alternative source of mesenchymal stromal cells (MSC) in mares; however, factors influencing successful MSC isolation remain unclear. This study evaluated whether reproductive cyclicity and follicle count affect MSC recovery from ovum pick-up (OPU)-derived follicular aspirates. Twenty-eight OPU procedures were performed on 13 mares, and cells were cultured until passage 3. Successful MSC cultures were obtained in 15/28 procedures (53.6%), while 13 procedures (46.4%) yielded non-MSC populations. Neither reproductive status (cycling vs. anestrous) nor foll...
Layer-Specific Quantitative Assessment of Collagen Distribution in Equine Uteri Using Masson’s Trichrome and Digital Image Analysis: A Comparative Study. Equine endometrial fibrosis is a chronic and progressive equine uterine condition characterized by fibrosis that affects mares' fertility, with a wide range of fertility outcomes being reported for these mares. Therefore, assessing layer-specific collagen (COL) distribution is essential for a comprehensive understanding of endometrial remodelling and its impact on equine reproductive potential. Full-thickness uterine samples, including stratum functionalis (SF), stratum basalis (SB) and myometrium, were collected post-mortem from healthy control mares (Category I; n = 10) and those with mo...
Effect of Uncoated Magnetic Nanoparticles on Stallion Sperm Parameters: Influence of Semen Quality. The aim of this study was to evaluate the effect of uncoated, non-functionalised magnetic nanoparticles (MNPs) on stallion sperm and to determine whether these effects depend on initial semen quality. Ten cooled ejaculates from 3 stallions were exposed to different MNP concentrations ([MNPs] = 0, 5, 25, and 50 mg/mL), agitated, and exposed to an external magnet to recover the unbound sperm fraction. Ejaculates were classified as high- or low-quality groups according to initial evaluation sperm quality index (HSQi and LSQi), and the effect of [MNPs] was evaluated within groups using GLM. ...
Differential Gene Expression of Mesenchymal Stromal Cell and Granulosa Cell Markers in Equine Follicular Aspirates. Equine follicular aspirates obtained during ovum pick-up contain a heterogeneous mixture of mesenchymal stromal cells (MSC) and granulosa cells (GC). This study evaluates how selective isolation and expansion of MSC decrease GC populations. Follicular aspirates-derived cells were cultured up to passage four (P4) following a previously validated protocol. While freshly isolated follicular aspirates cells (FAC) displayed heterogeneous morphologies, early passages (P3-P4) showed a uniform, spindle-shaped phenotype compatible with MSC. Gene expression analysis by RT-qPCR revealed a marked upregula...
A single-cell RNA-seq dataset characterizing cellular diversity in healthy equine skin. The skin serves as the primary barrier tissue in horses and is frequently affected by immune-mediated dermatological conditions, most notably insect bite hypersensitivity (IBH). Yet, the cellular composition and transcriptional landscape of normal equine skin have never been characterized at single-cell resolution. Here, we present a single-cell RNA sequencing dataset of healthy equine skin comprising 85,574 high-quality transcriptomes from two horses, with one skin biopsy collected from each horse, divided into two portions for independent processing via manual or automated tissue dissociatio...
Evaluation of a lateral flow immunoassay for the quantitative measurement of immunoglobulin G in foals compared with radial immunodiffusion. Reliable point-of-care diagnostic tests are essential for diagnosing failure of transfer of passive immunity (FTPI) in foals. Quantitative lateral flow immunoassays (LFIAs) could reduce subjectivity but have not been well validated in foals. Objective: To validate the performance and diagnostic accuracy of a LFIA for quantifying immunoglobulin G (IgG) concentrations in foals, using radial immunodiffusion (RID) as the reference standard. Methods: Forty-two neonatal foals were sampled within 24 h of birth. Methods: This prospective exploratory diagnostic accuracy study evaluated the diagnostic ...
Oxidative stress markers in different age ranges of healthy horses. Oxidative stress results from an imbalance between oxidants and antioxidants, impairing cellular functions and contributing to diseases and aging. Despite the growing interest in oxidative stress, studies specifically evaluating the influence of age on laboratory and oxidative stress parameters in clinically healthy horses remain limited. Thus, this study aimed to evaluate the influence of age on laboratory and oxidative stress parameters in clinically healthy horses. A total of 152 clinically healthy horses (80 females and 72 males) were selected, including young horses aged 3 to 48 months (...
Warmed intravenous fluid administration attenuated a reduction in body temperature in anaesthetised horses. Peri-anaesthetic hypothermia is a well-documented complication of general anaesthesia and is associated with prolonged recovery, impaired wound healing, and delayed coagulation. Fluid warmers can be used to mitigate heat loss, but there is little evidence supporting their effectiveness in equine anaesthesia. Objective: To determine whether administration of warmed intravenous fluids attenuates heat loss during general anaesthesia in horses. Methods: Prospective, randomised, crossover in vivo experiment. Methods: Six healthy adult horses were anaesthetised twice and administered intravenous flu...
The Influence of Season on Endocrine Testing in Equids. Endocrine function in equids is strongly influenced by season, with photoperiod as the primary driver and additional modulation by factors such as breed, geography, age, and nutrition. These seasonal effects have important implications for the interpretation of endocrine diagnostic tests. Circannual rhythms influence pituitary activity, resulting in predictable seasonal variation in adrenocorticotropic hormone concentrations and forming the basis for seasonally adjusted diagnostic thresholds for pituitary pars intermedia dysfunction. Seasonal effects on insulin dynamics are less understood but...
Genome-wide exploration of coat color-associated loci in Hokkaido Native Horses, with a novel locus implicated in the roan phenotype. Genes and loci regulating horse coat color have been investigated in many breeds, but their associations with the 16 coat colors of the Hokkaido Native Horse (HKD) remain unknown. HKDs were classified according to coat-color groups based on pedigree-recorded coat color, and genome-wide association (GWA) analyses were performed. Except for gray and roan, a clear single signal corresponding to the known locus was obtained for each coat color, suggesting that the reported loci are the primary causes of these coat colors. Because gray and roan are difficult to distinguish visually and may therefor...
Oocyte and Embryo Vitrification in Horses. Vitrification has emerged as a decisive technique in assisted reproductive technology, offering superior cryopreservation outcomes for both oocytes and embryos compared with traditional slow freezing. This chapter provides a comprehensive overview of the vitrification of equine oocytes and embryos, emphasizing the influence of technical factors, including cryoprotectant selection, exposure time, temperature control, and device volume, on vitrification outcomes. Biological factors such as the oocyte maturation stage, the presence of cumulus cells, and embryo size are also explored, highlighting...
Coprological assessment of gastrointestinal helminths in Arabian Thoroughbred horses housed in a stable in the Constantine region, Algeria. This study assesses the gastrointestinal parasitological status of Arabian Thoroughbred horses at the Eastern Equestrian Club in Constantine (Algeria). In this semi-arid region, epidemiological data on equine parasitoses are lacking. Twenty fecal samples were analyzed using qualitative (flotation) and quantitative (McMaster) methods, complemented by morphological identification of parasitic eggs. The results reveal an overall prevalence of 50 %, with species diversity dominated by strongyles (60 % of positive cases), followed by (40 %), spp. (30 %), (20 %), and spp. (10 %). The excretion i...
Cyathostomin species richness and alpha diversity at egg reappearance following fecal egg count-based selective ivermectin treatment. Cyathostomin nematodes are ubiquitous in grazing horses. The overuse of anthelmintics has led to increasing problems with drug resistance to benzimidazoles and pyrantel. Although macrocyclic lactones (ML), such as ivermectin, generally retain the highest efficacy, reduced ML efficacy has increasingly been reported. A shortened egg reappearance period (ERP) is frequently used as an indicator of reduced susceptibility. However, the species-specific response dynamics after ivermectin treatment are inadequately characterized in cyathostomins. The objective of this study was to compare the cyathost...
Effects of steaming and storage on microbial quality and nutrient losses of hay. Steaming reduces microbial content of hay but the effect of steaming on nutrient quality and the effects of storage after steaming on microbial content are incompletely known. Objective: It was hypothesized that steamed hay can be stored for up to 24 h without an increase in microbial content and that steaming of hay favors the increase in measurable Maillard reaction products. Methods: Spoiled hay was steamed and then stored in hay nets, buckets or the hay steamer itself under summer and winter climate conditions. Microbial content was assessed by bacterial and fungal culture before and after...
Evaluation of a new immunoassay for measuring equine serum insulin and plasma adrenocorticotrophic hormone: A method comparison study. Insulin dysregulation (ID) and pituitary pars intermedia dysfunction (PPID) are common equine endocrinopathies detected by measurement of circulating insulin and adrenocorticotrophic hormone (ACTH) concentrations. Different assays may yield variable results, limiting comparability. Objective: To compare immunoassays developed specifically to measure equine insulin (VIDAS® Equine Insulin; enzyme-linked fluorescent assay [ELFA]) and equine ACTH (VIDAS® Equine ACTH; ELFA) with results obtained from a chemiluminescence immunoassay (CLIA) measured using IMMULITE 2000XPi, a chemiluminescence enzym...
Evaluation of mosquito transmission of equine hepacivirus in laboratory and field studies. Equine hepacivirus (EqHV) is a hepatotropic virus, closely related to human hepatitis C virus (HCV), that can cause acute or chronic infection in horses. As with HCV, transmission is thought to occur primarily through parenteral, particularly blood-borne, routes. Vertical transmission from mare to foal has been reported but appears to be uncommon. The high seroprevalence in horse populations and the occurrence of infection in isolated horses indicate efficient horizontal transmission routes exist. One such possibility is biological or mechanical transmission by arthropods, such as mosquitoes, ...
Blood pressure, electrolyte and fluid balance in horses with insulin dysregulation after short-term treatment with canagliflozin. Short-term treatment with SGLT-2 inhibitors decreases blood pressure in people with type 2 diabetes. The aim was to investigate the impact of a 3-week treatment with canagliflozin on blood pressure in insulin dysregulated (ID) horses and to study effects on fluid balance. This was a single-centre, randomised, double-blind, placebo-controlled, parallel design study. The primary study evaluated glucose and insulin responses during an oral sugar test, and these results have been published previously. Here we report the effect of canagliflozin treatment on blood pressure, PCV, serum proteins and e...
