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Topic:Serum
Serum in horses refers to the component of blood that remains after the removal of cells and clotting factors. It contains a variety of proteins, electrolytes, hormones, and metabolic waste products. Serum analysis is a valuable tool in veterinary medicine for assessing the health status of horses. It provides insights into organ function, nutritional status, and the presence of disease. Common parameters measured in equine serum include enzymes, such as aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT), as well as electrolytes like sodium and potassium. This page assembles peer-reviewed research studies and scholarly articles that explore the composition, diagnostic applications, and implications of serum analysis in equine veterinary practice.
Melatonin as a daily rhythm control signal for glucose homeostasis and insulin secretion in horses. An involvement of melatonin in the regulation of glucose homeostasis and insulin secretion in pancreatic β-cells has been proposed. To evaluate the features of the daily rhythms of plasma melatonin, blood glucose, and insulin in horses, ten clinically healthy Italian Saddle geldings, 9-10 years old with a mean body weight of 490 ± 25 kg, were enrolled. The animals were housed in individual boxes under natural environmental conditions (sunrise 06:10; sunset 18:10; 12-15°C, 77% RH). All horses were cannulated the day before the start of the study for sample collection, which was perfo...
Novel serum biomarkers provide evidence for an involvement of the CCL3:CCL5 axis in fatal musculoskeletal injuries in Thoroughbred racehorses. Fatal musculoskeletal (MSK) injuries in Thoroughbred (TB) racehorses adversely affect equine welfare, negatively impact public acceptance of horse racing, and cause severe economic losses for the racing industry. Biomarker assays predicting the risk of MSK injuries are currently not available. Our hypothesis was that immune system and inflammatory markers are indicators of fatal MSK injuries in TB racehorses. Unassigned: Serum samples from TB racehorses with fatal (n = 44) and nonfatal injuries (63) were collected. Serum from 2- to 5-year-old TBs submitted for annual equine infectious anemia t...
The effect of ertugliflozin on serum insulin and glucose in healthy horses receiving dexamethasone. Sodium-glucose cotransporter 2 inhibitors (SGLT-2i) can be used to manage insulin dysregulation (ID). Their effect on corticosteroid-induced ID is unknown. Objective: Evaluate effects of ertugliflozin on serum insulin and glucose concentrations in horses receiving dexamethasone (DEX). We hypothesized that DEX would induce ID and ertugliflozin coadministration would mitigate that effect. Methods: Seven healthy horses. Methods: Randomized crossover design; horses received DEX (0.06 mg/kg IV q48h; DEX)or ertugliflozin (0.05 mg/kg PO q24h) plus DEX (SGLT-2i group) for seven days. Oral sugar (OST...
Thymidine kinase 1 activity in serum and body cavity fluids of horses with lymphoma. The accuracy of serum thymidine kinase 1 (TK1S) as a biomarker of lymphoma in horses is variable. The value of measurement in body cavity fluid (TK1F) has not been established. Objective: (1) TK1F and TK1S will be higher in horses with lymphoma compared to diseased controls (DCs); (2) TK1F will be higher than TK1S; and (3) there will be a strong correlation between both measurements. Methods: Twenty animals in the lymphoma and 31 animals with nonneoplastic, gastrointestinal/respiratory disorders in DC group. Methods: This was a cross-sectional study using prospectively collected data and sampl...
Inflammatory phenotype and response to intradermal skin testing are not predictive of equine asthma diagnosis. The role of inflammation, allergy, and air quality in the pathogenesis of equine asthma has not yet been fully elucidated. Objective: To evaluate serum inflammatory cytokines, intradermal skin testing (IDT), and air quality in asthmatic horses. It was hypothesized that there would be an association between environmental allergies and poor air quality with asthma. Methods: 52 client-owned horses with clinical signs consistent with asthma were enrolled in this cross-sectional study. Horses were diagnosed with asthma based on the results of bronchoalveolar fluid (BALF) cytology. Blood samples wer...
Biomarkers of brain injury in foals with neonatal maladjustment syndrome. Plasma concentrations of brain-derived neurotrophic factor (BDNF), glial-fibrillary-acidic protein (GFAP), and astrocytic protein S100B, might be linked to the pathophysiology of Neonatal Maladjustment Syndrome (NMS). Objective: To measure serum concentration of BDNF and S100B, plasma concentration of GFAP, and neurosteroids (progesterone and 17α-hydroxyprogesterone) in foals with NMS, foals presented for other diseases, including premature, and healthy foals, and determine their association with outcome. Methods: Fourteen healthy foals, 19 NMS foals, 39 foals hospitalized for other diseases ...
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...
Effects of two different fluid rates on tissue oxygenation and haemodynamic stability in anaesthetised horses. Perianaesthetic fluid therapy can influence oxygen delivery and tissue oxygenation, yet the optimal fluid rate in horses remains undefined. Objective: To compare two fluid strategies on peripheral tissue oxygenation (StO) and cardiorespiratory variables in isoflurane-anaesthetised horses. Methods: Randomised, controlled, experimental design with two independent groups. Methods: Sixteen euvolemic adult horses undergoing coeliotomy were anaesthetised with xylazine, ketamine, and midazolam, maintained on isoflurane with lidocaine infusion, and randomised to lactated Ringer's solution at 2.5 mL/...
Serum physiology, fecal microbiota, and metabolome signatures associated with perinatal stage transitions in Mongolian mares. Lactation is a critical reproductive trait that influences offspring survival and livestock productivity in equine production. Characterizing physiological transitions during the perinatal period can improve our understanding of how mares adapt to late gestation, parturition, and early lactation. However, in horses-a typical monogastric herbivore with unique digestive characteristics-the associations between gut microbiota and perinatal physiological adaptation, as well as related stage-associated microbial and metabolic features, remain largely uncharacterized. Unassigned: In this study, para...
Guttural pouch tympany or empyema in 38 ٍStraight Egyptian Arabian foals: clinical presentation, diagnostic features and outcome. As a breed, Straight Egyptian Arabian horses are susceptible to many disorders that mostly affect the head, such as guttural pouch (GP) tympany and empyema. This retrospective study evaluated the findings of clinical examination, ultrasonography, endoscopy, laboratory analyses and outcome of treatment of 38 Straight Egyptian Arabian foals with GP tympany and empyema. Methods: Data from medical records of foals diagnosed with GP tympany or empyema over a 2-year period (2024-2025) were reviewed. Foals with verified GP tympany or empyema who had complete medical records and had not previously rec...
Differential Serum Cytokine Profiles in Aborting and Subclinically Infected Pregnant Mares with Equine Herpesvirus Type 1. Equine herpesvirus type 1 (EHV-1) is a major cause of reproductive loss in mares. This cross-sectional field study evaluated serum concentrations of interleukin-2 (IL-2), interleukin-10 (IL-10), interferon-alpha (IFN-α), and interferon-gamma (IFN-γ), together with the IL-10/IL-2 and IFN-γ/IL-10 ratios, in 26 vaccinated pregnant Thoroughbred mares. The analytical cohort comprised healthy, EHV-1 PCR-negative mares (HM, n = 10), EHV-1 PCR-positive mares sampled within 4 h after fetal expulsion at approximately the sixth month of gestation (AM, n = 9), and EHV-1 PCR-positive pregnant mares with...
Development and validation of a liquid chromatography-tandem mass spectrometry method for the quantification of twenty-five steroids in equine serum. Steroids are potential biomarkers for monitoring equine pregnancy. However, immunoassays currently used for their quantification suffer from cross-reactivity and limited specificity, thus requiring more accurate methods. This study reports the development and validation of a robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous quantification of 25 steroids covering the main biosynthetic pathways of progestogens, corticosteroids, androgens, and estrogens. Steroids were extracted by protein precipitation followed by evaporation, derivatization, and reconstitut...
Evaluation of an Immunoturbidometric Assay for Measurement of Total Adiponectin Concentration in Equine Serum Samples. 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...
Evaluation of the Brix refractometer for diagnosing the failure of transfer of passive immunity in 12-h-old foals. Failure of transfer of passive immunity (FTPI) is the most important cause of sepsis and mortality in neonatal foals. Unassigned: This study aimed to evaluate the performance of the digital Brix refractometer for the diagnosis of FTPI in 12-h-old foals. Unassigned: Cross-sectional, diagnostic accuracy study. Unassigned: Jugular blood samples were collected from 124 foals at 12 ± 0.5 h after birth. IgG concentrations were estimated using a digital Brix refractometer and measured using the radial immunodiffusion test (RID). Correlation coefficients were calculated between serum Brix percentages...
Preliminary Metabolomic Analysis: Serum Metabolomic Dynamics During Estrus Synchronization in Kazakh Mares. This study aimed to analyze the differences in serum metabolomes at different stages of estrus synchronization in Kazakh horses, to characterize dynamic changes in serum metabolites during estrus synchronization, and to screen potential metabolic markers and key regulatory pathways. Four sampling stages (M1: intravaginal device insertion; M3: device removal, labeled consistently with the pre-experiment timeline; P: 24 h post-PG injection; L: tertiary follicle emergence) were selected. The research results showed that 37 significantly different metabolites (DAMs) were identified in the M1-vs.-M...
Assessment of Thyroid Hormones Using the Immulite 2000xpi Analyzer in Healthy Donkeys. 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...
Serum Electrolyte Changes in Foals Receiving Rhodococcus equi-Specific Hyperimmune Plasma. Rhodococcus equi-specific hyperimmune plasma (Re-HIP) is routinely administered to neonatal foals to help prevent rhodococcal pneumonia. In addition to pathogen-specific immunoglobulins, frozen plasma products (FPPs) contain electrolytes that may exceed concentrations found in neonatal foal plasma. Because FPPs are also used to treat failure of passive transfer and sepsis, understanding their effects on neonate homeostasis is crucial. This study evaluated the effects of administration of Re-HIP on the serum concentrations of Na, Cl, K, albumin, and globulin of healthy neonatal foals. Results: ...
Circulating Elements in the Bloodstream of Growing Foals: Focus on Heavy Metals and Bone Remodeling Across Growth Stages. Bone tissue undergoes continuous remodelling throughout the life of the individual, and growth is the most impacting phase. In fact, tightly coordinated processes of resorption, synthesis, and mineralization of the bone matrix under systemic hormonal, biomechanical, and metabolic control occur for variable periods of time across species. The horse is a fast-growing animal and for this reason identified as precocial. It was hypothesized that blood serum levels of minerals in growing foals at different stages of accretion may vary over time. This investigation aimed to assess the dynamics of cir...
Comparative hematological and serum biochemical profiling of grassland Xichun and Xilingol horses. The Grassland Xichun horse is an emerging crossbred population developed from Xilingol mares and Thoroughbred stallions in Inner Mongolia, China, yet its blood physiological profile has not been systematically characterized. In this study, we compared 32 hematological and serum biochemical parameters between 177 Grassland Xichun horses and 35 Xilingol horses maintained under the same extensive grazing conditions. Following Benjamini-Hochberg FDR correction, 17 of 32 parameters differed significantly between breeds. Grassland Xichun horses showed markedly higher RBC count (9.145 vs 7.905 × 10...
Serum adipokines are useful for predicting hyperinsulinemia secondary to corticosteroid treatment in horses. To evaluate pretreatment biomarkers for predicting the severity of corticosteroid-induced hyperinsulinemia. Unassigned: Oral glucose tests were performed before (day 1) and after (day 8) a dexamethasone course (0.08 mg/kg, q 48 h) in 24 healthy adult Standardbreds. Associations between day 8 oral glucose test insulin parameters (baseline [T0insulin], maximal [Cmaxinsulin], and area under the curve [AUCinsulin]) and day 1 serum markers (insulin, glucose, adiponectin, leptin, and their ratios) were examined using Spearman correlation, log-linked generalized linear models. Relative risk of exceed...
Single-dose intravenous α2-agonists do not acutely alter anti-inflammatory bioactive protein profiles but reduce interleukin-8 in equine autologous protein solution and platelet-rich plasma. Determine the acute effects of xylazine and detomidine on concentrations of selected growth factors, cytokines, and α2-macroglobulin (A2M) in platelet-rich plasma (PRP) and autologous protein solution (APS) and the long-term effects of these sedatives on serum A2M. We hypothesized that sedative administration would decrease concentrations of all bioactive proteins in PRP and APS acutely and A2M in serum for 6 days following sedative administration. Unassigned: 6 horses were randomized to receive IV xylazine (200 mg) or detomidine (10 mg). Blood was collected before and 5 minutes after sedativ...
Physiological determinants of plasma biochemical parameters in horses: a structured review. The biochemical profile of horses is a cornerstone in equine clinical diagnostics, offering valuable insights into health status, disease progression, and physiological adaptation to internal and external stimuli. However, the interpretation of these biochemical parameters is far from straightforward, as they are subject to significant variation influenced by a range of physiological factors. Age, sex, breed, level of physical activity, nutritional condition, and reproductive status can all modulate baseline biochemical values, potentially leading to diagnostic inaccuracies if not properly con...
Molecular prevalence of equine parvovirus hepatitis in healthy horses from the Northern region of the state of Rio Grande do Sul, Brazil. The equine parvovirus hepatitis (EqPV-H) was initially linked to fatal cases of equine serum hepatitis but, more recently, it has also been detected in sick or asymptomatic horses around the world, including in a limited number of horses in southeastern Brazil. In this study we aimed to assess the prevalence of EqPV-H DNA in the serum of healthy horses in the northern region of Rio Grande do Sul state, Brazil. For this purpose, we used 1000 serum samples collected from horses from 40 municipalities and organized them into 200 pools of five samples each, based on origin and age. Using a nested ...
The Effects of Boron Mineral on Performance, Bone and Mineral Metabolism in Purebred Arabian Foals. Boron plays significant roles in various biological systems, including mineral, lipid, and energy metabolism, immune and endocrine systems, and brain function. It has been suggested to enhance performance and may prevent conditions such as osteoporosis, osteoarthritis, and arthritis. Despite these known benefits, its effects on growth performance and mineral metabolism in horses remain understudied, particularly in young animals like Purebred Arabian foals. The primary objective of this study was to investigate the effects of different doses of boron supplementation (0, 5, 10, and 15 mg/day ...
Comparison of in vitro degradation of immunoreactive adrenocorticotropic hormone and insulin in equine blood measured by two immunoassay methods. This study compared the in vitro stability of equine plasma adrenocorticotrophic hormone (ACTH) and serum insulin measured by chemiluminescent assay (CLA; Siemens Immulite 2000XPi) and immunofluorescent assay (IFA; Tosoh AIA-900) after storage at 4°C or room temperature (approximately 21°C) for clinically relevant periods. Fresh equine EDTA blood for ACTH and coagulated blood for insulin were aliquoted and analysed immediately (T0) and after storage. ACTH was assessed at 24, 48 and 72 hours; insulin was assessed at 24 hours, 72 hours and 7 days. Percentage recovery relative to T0 was analyse...
Clodronate disodium reduced TRAP5b independent of affecting other systemic biomarkers of bone resorption or formation in yearling, exercising Quarter Horses. Clodronate disodium (CD), a bisphosphonate, modulates bone metabolism. Though extra-label use in juvenile horses is anecdotally reported, impacts on skeletal development are unknown. The objective was to determine the effects of CD on systemic markers of bone turnover in yearling horses undergoing exercise, hypothesizing that biomarkers of bone resorption would decrease while biomarkers of bone formation would not change, and that repeat CD treatments would have greater effect. To test this, 32 yearling Quarter Horses were used in a 168-d trial. Horses were stratified by age (500 ± 13 d),...
Efficacy of an iron absorption test on assessing iron status in horses. Iron absorption tests (IATs) are used to evaluate iron absorption in humans. However, this testing has not been conducted in horses. Objective: The objective was to assess how a large dose of iron affects blood iron parameters during an IAT. Methods: Mixed-breed geldings (n=12) were offered 2% of their bodyweight (BW) in mixed-grass hay and an iron-free vitamin-mineral supplement. A baseline IAT (Baseline IAT) was performed, where horses received 25 milligrams per kilogram (mg/kg) of BW of iron (ferrous sulfate) orally. Jugular venous samples were taken before the iron dose, and 3-, 6-, 12-, a...
Competitive enzyme-linked immunosorbent assay to quantify hepcidin in horse serum. Hepcidin (Hepc) is a peptide hormone primarily produced by hepatocytes and considered the master regulator of iron homeostasis, with Hepc controlling the release of iron within the circulation. Despite the renewed interest in iron-related research due to Hepc discovery, there is limited data on serum hepcidin in horses. The objective of the study was to develop and partially validate a competitive enzyme-linked immunosorbent assay (ELISA) to quantify serum hepcidin in horses. Precision was evaluated using horse serum samples representing low, medium and high Hepc concentrations, yielding intra...
Temporal variation in incretin and insulin secretion in ponies in association with dietary macronutrients. Equine insulin dysregulation (ID) is a common condition that predisposes to hyperinsulinaemia-associated laminitis. Improved pathophysiological understanding would enable better management of ID and reduce the risk of laminitis. The incretin peptides, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), augment the insulin response to dietary glucose and GLP-1 has been implicated in the pathophysiology of ID. However, their temporal variation in response to a low-energy diet has not been reported. This study determined the variation in GLP-1, GIP and insulin ...
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...
