The study of blood in horses encompasses the examination of its components, functions, and its role in equine health and disease. Blood consists of various elements, including red blood cells, white blood cells, platelets, and plasma, each serving specific functions such as oxygen transport, immune response, clotting, and nutrient distribution. Analyzing blood parameters can provide insights into the physiological and pathological states of horses. Common blood tests in equine medicine assess parameters like hematocrit, hemoglobin concentration, and white cell counts to monitor health status, diagnose conditions, and guide treatment decisions. This page compiles peer-reviewed research studies and scholarly articles that explore the composition, function, and clinical applications of blood analysis in horses.
HOLTON FA.In 1941, Keilin & Mann described an optical method of studying the penetration of erythrocytes by bicarbonate ions and the intracellular activity of carbonic anhydrase. This method consists of converting the haemoglobin inside the cell to methaemoglobin and observing the transformation of the methaemoglobin from the acid to the alkaline form by the entering bicarbonate ions. During this work they noticed that this transformation did not occur if the methaemoglobin cells had been washed in acid phosphate and interpreted this as an effect on the permeability of the cells. Similar observations by...
STURGE LM, WHITTAKER VP.The research article delves into the exploration of the specificity of esterases in horse blood, particularly plasma cholinesterase and the ali-esterase, drawing a clear distinction between the two, which had […]
BAER H, KABAT EA, KNAUB V.Blood group substances have been isolated from the saliva of human beings of blood group B and from the linings of individual horse stomachs. The properties of the human B substances are similar to those of hog and human blood group substances previously isolated. The horse substances showed lower hexosamine and reducing sugar and higher total and non-hexosamine nitrogen than do the materials from the other species. Materials isolated from individual horse stomachs possess either A or B activity or both. Certain stomachs yielded products of identical analytical composition but with neither blo...
Wang J, Ren W, Li Z, Ma S, Li L, Wang R, Zeng Y, Meng J, Yao X.This study aims to analyze the whole-genome DNA methylation differences in Yili horses before and after racing, with the goal of identifying differentially methylated genes associated with racing performance and exploring the epigenetic mechanisms underlying exercise in horses. Blood samples were collected from the jugular veins of the top 3 Yili horses in a 5000 m race, which included 25 competitors, both prior to and within 5 min after the race. Genomic DNA was extracted, followed by sequencing using Whole-Genome Bisulfite Sequencing (WGBS) to assess DNA methylation levels, differentially me...
The response to exercise following a rest period may vary among horse breeds based on the importance of the hematological and hematochemical profiles of athletic horses. Ten Standardbred and ten Italian Saddlebred mares were subjected to a 4-week training program after a seasonal rest, and hematological parameters (red blood cells-RBCs; hemoglobin-Hb; hematocrit-Hct; platelets-PLTs; platelet aggregation-AG; aggregation slope-Slope; fibrinogen-Fb), as well as Albumin (Alb) and non-esterified fatty acids (NEFAs), were analyzed. Blood samples were obtained each week during the training program fo...
Petano-Duque JM, Urueña-Martinez E, Cabezas-Callejas LL, Perilla-Amaya J, Rueda-García V, Rondón-Barragán IS, Lopera-Vásquez R.EHV-1 is one of the most prevalent viral pathogens in horses; however, its prevalence is not well defined by cross-reactions of serological tests. Thus, this study aims to determine EHV-1/-4 prevalence in Colombian creole horses from Ibagué, Tolima, using molecular techniques, as well as to determine possible risk factors associated with viral infection. A cross-sectional study was carried out in 110 equines blood, serum, and semen samples from Ibagué, Tolima. Antibodies against EHV-1/-4 were determined through indirect ELISA. EHV-1 was detected by amplifying the glycoprotein H gene through ...
de Oliveira UV, Varjão JL, de Jesus Deiró AG, Maciel BM, Silva FL, Pinheiro AM, Gondim LFP, Munhoz AD.The aim of this study was to isolate from equids destined for slaughter in a Brazilian slaughterhouse. A total of 354 equids were analyzed, with blood samples collected from all the animals and samples of masseter muscle and brain tissue collected from 319 animals. A serological test was conducted to detect equids with specific antibodies for . Molecular detection of by nested PCR was performed on the tissue samples collected. Tissue samples were tested by murine bioassay in an attempt to isolate either the parasite or the parasite DNA. Real-time PCR was performed on the brain samples from 1...
Yuan X, Yao X, Zeng Y, Wang J, Ren W, Wang T, Li X, Yang L, Yang X, Meng J.Horse racing may cause stress-induced physiological changes and tissue damage in horses, but the changes in miRNA expression, protein expression, and metabolic substances in the plasma exosomes of the horse after racing are still unclear. This study detected miRNA, protein expression, and metabolic substances in the plasma exosomes of horses before and after competition, providing new insights for post-race recovery and care of horses. Methods: Eight three-year-old horses that had undergone training were selected as the research subjects, with four horses that had not competed as the contr...
Page AE, Rauber-Ramos AM, Humiston M, McPeek JL, Adam EN.Given the metabolic effects of intra-articular (IA) corticosteroids, the goal of this project was to monitor the effects of IA betamethasone in both insulin dysregulated (ID)(n = 3) and non-ID (n = 5) horses. A cross-over design was used where eight geldings were injected with either 9 mg of betamethasone or saline into both metacarpophalangeal joints, followed by regular blood collections for adrenocorticotropin releasing hormone (ACTH), cortisol, insulin, and glucose, as well as pre- and post-administration oral sugar testing. Results were analyzed via two-way repeated measures analysis of v...
Sun Y, Yu YT, Castillo XO, Anderson R, Wang M, Sun Q, Tallmadge R, Sams K, Reboul G, Zehr J, Brown J, Wang X, Marra N, Stanhope B, Grenier J....Fever of unknown origin (FUO) without a respiratory component is a frequent clinical presentation in horses. Multiple pathogens, both tick-borne and enteric, can be involved as etiologic agents. An additional potential mechanism is intestinal barrier dysfunction. This case-control study aimed to detect and associate microbial taxa in blood with disease state. Areas known for a high prevalence of tick-borne diseases in humans were chosen to survey horses with FUO, which was defined as fever of 101.5°F or higher with no signs of respiratory illness or other recognisable diseases. Blood samples ...
Tsujimura K, Bannai H, Kambayashi Y, Nemoto M, Ohta M.Equid alphaherpesvirus 1 (EqAHV1; Orthoherpesviridae, Varicellovirus equidalpha1) spreads by viremia to susceptible organs. Because EqAHV1 circulates in the bloodstream in a cell-associated manner, serum samples are not considered valuable for detecting EqAHV1 and have therefore not been tested by highly sensitive detection methods such as real-time PCR (rtPCR). We investigated whether EqAHV1 could be detected by this method in equine serum samples. We performed rtPCR on archived sera and peripheral blood mononuclear cells (PBMCs) collected from 3 horses experimentally inoculated with EqAHV1. ...
Hisaeda K, Ono T, Shimokawa-Miyama T, Hata A, Iwata E, Hiasa Y, Ohzawa E, Tozaki T, Murase H, Takasu M, Nishii N, Kitagawa H.We examined the differences in serum iron (Fe) concentrations and related variables between summer and winter in Noma horses. Blood samples were collected from 37 clinically normal horses seven consecutive times: September 2018, February 2019, October 2019, February 2020, September 2020, February 2021, and February 2022. Serum Fe concentrations ranged from 74 μg/dl to 316 μg/dl with a median of 176 μg/dl. The concentrations were lower in stallions compared with mares and geldings, tended to be low at 10-14 years of age, and then increased with age. Serum Fe concentrations were repeatedly lo...
Wilkins PA, Wong D, Slovis NM, Collins N, Barr BS, MacKenzie C, De Solis CN, Castagnetti C, Mariella J, Burns T, Perkins G, Delvescovo B, Sanchez LC....Sepsis has been defined in humans as the concurrent proven or suspected presence of microbial infection and the systemic inflammatory response syndrome (SIRS). Sepsis is the leading cause of morbidity and mortality in neonatal foals. The clinical utility of using SIRS or its individual components to predict infection and mortality in critically ill foals is currently unknown. Objective: Assess the ability of history and signalment, clinical findings, laboratory results, and SIRS-related indices to predict infection and mortality in critically ill foals. Methods: Retrospective, multi-center, cr...
Loos CMM, Urschel KL.Insulin dysregulation (ID) is a common metabolic disorder in horses, characterized by hyperinsulinemia and/or peripheral insulin resistance. The critical role of hyperinsulinemia in endocrinopathic laminitis has driven research into the insulinotropic effects of dietary nutrients and the reciprocal impact of ID on nutrient metabolism. The relationship between ID and carbohydrate metabolism has been extensively studied; however, the effects of ID on protein metabolism in horses remain largely unexplored. This review begins with an overview of the importance of insulin in the regulation of muscl...
Holbrook T, Hernandez J, McCarrel T, Lester G, Sleeper M, Domenig O, Adin D.The impact of exercise on the classical and alternative renin-angiotensin-aldosterone system (RAAS) pathways has not been studied in horses. Objective: We hypothesized that exercise would activate both RAAS pathways and that endurance exercise would cause more activation of the classical pathway compared to short-duration, high-intensity exercise in horses. Methods: Twenty-five horses (21 client-owned and 4 research) were included in 4 exercise groups (10 Arabians, 50-mile ride [A-E]; 4 thoroughbreds, 1-mile treadmill exercise [TB-TM]; 5 thoroughbreds, 1-1/16th-mile race [TB-R]; and 6 quarter ...
Bindi F, Nocera I, Meucci V, Vallesi G, Sala G, Spadari A, Rinnovati R, Bonelli F, Sgorbini M.This study investigated the plasma concentrations of symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA) in healthy horses and in horses affected by colic in relation to the type of colic and systemic inflammation response syndrome (SIRS) status. Upon admission (T0), horses underwent a physical examination, and the SIRS status was assessed. The horses with colic were divided retrospectively based on the type of colic, SIRS status, treatment, and outcome. SDMA and ADMA levels were measured at T0 and then every 24 h at four time points (T1, T2, T3, T4). Differences between ...
Wang J, Ren W, Li Z, Li L, Wang R, Ma S, Zeng Y, Meng J, Yao X.Equine endurance exercise induces physiological changes that alter metabolism and molecular pathways to maintain balance after intense physical activity. However, the specific regulatory mechanisms remain under debate. Identifying differentially expressed genes (DEGs) and differential metabolites (DMs) associated with equine endurance is essential for elucidating these regulatory mechanisms. This study collected blood samples from six Yili horses before and after an 80 km race and conducted transcriptomics and metabolomics analyses, yielding 722 DEGs and 256 DMs. These DEGs were primarily enri...
Stapley ED, Bertin FR.Pituitary pars intermedia dysfunction is diagnosed using immunoreactive ACTH concentrations. Glass reportedly binds ACTH, but the clinical relevance of using glass blood tubes for measuring equine ACTH concentrations is controversial. This study investigates whether the collection of whole blood into glass EDTA tubes and storage for up to 6 hours changes ACTH concentrations compared to plastic EDTA tubes. Unassigned: This was a cohort study. Whole blood was collected into both glass and plastic EDTA tubes from 9 horses > 12 years of age, including 4 with pituitary pars intermedia dysfunction a...
Simms N, Bertone JJ, Melgarejo T, O'Shea C, Linde A.Emerging research suggests the presence of a blood microbiome in clinically healthy individuals. Characterizing bacterial composition and abundance in blood from a group of healthy horses is of clinical interest. Objective: Horses in a closed herd environment will have blood microbiomes with similarities among individuals. Methods: Twenty trail-riding horses of different breeds and ages living in relative isolation on a dry lot pasture in Colorado at 7680 ft elevation. Methods: Cross-sectional study. Blood was collected from the jugular vein into serum, blood collection, and EDTA tubes. Samp...
Changes in the global climate pose a severe threat to human and animal welfare and productivity. Total proteins (TP), globulins (GLOB), albumins (ALB), alkaline phosphatase (ALP), creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), blood urea nitrogen (BUN), γ-glutamyl transferase (GGT), and creatinine (CREA) were evaluated during a three-year monitoring period (2021-23) on 16 Thoroughbred retired mares from the regional Golkoy Breeding Farm in Kastamonu- Turkey. The following thermal and hygrometric parameters were gathered: ambient temperature (AT), relative...
Hardy L, Martin M, Barré C, Tanquerel L.Equine gastric ulceration syndrome (EGUS) is a common condition, affecting both glandular (EGGD) and squamous (ESGD) mucosa of the stomach. It has a high prevalence, particularly in racehorses and sport horses, causing clinical signs from poor performance to colic. Gastroscopy, the reference standard diagnostic method, is expensive, prompting the search for alternative tests. Previous studies noted changes in blood markers, including elevated gamma-glutamyl transpeptidase (GGT) activity in ulcerated horses. This study aimed to report the prevalence of EGUS in sport horses and evaluate the asso...
Muir WW, Yiew XT, Bateman SW, Hahn RG.Fluid therapy in horses is primarily empirical. Evidence-based quantification of the disposition of intravenous (IV) crystalloids used in clinical practice could enhance the effectiveness of fluid therapy. Objective: To determine the pharmacokinetics (i.e., volume kinetics: VK) and associated haemodynamic effects of IV lactated Ringer's solution (LRS) in adult euvolemic horses. Methods: Unmasked multiple subjects, single baseline design. Methods: Thirteen healthy, euvolemic adult female horses were administered an IV bolus of LRS and monitored over 4 h. Haemoglobin, albumin and haematocrit c...
Davis EL, Wood AD, Potier JFN.Prevalence of endocrine disease in sport horses has been sparsely reported. They often compete well into their teenage years; thus, diagnosis and control of endocrine disease could be important to maintain performance and optimise health and welfare. The aim was to compare the prevalence of pituitary pars intermedia dysfunction (PPID), insulin dysregulation (ID) and metabolic obesity between sport and non-sport type breeds and assess disease progression. Blood samples submitted for plasma adrenocorticotropic hormone (ACTH), serum insulin or adiponectin were included in this study. Horses were ...
Zhang X, Liu Y, Li L, Ma W, Bai D, Dugarjaviin M.The traditional horse industry has undergone a remarkable evolution, with horse racing emerging as a prominent and pivotal economic driver within the sector. Among the various breeds, Mongolian horses, renowned for their exceptional endurance and speed, occupy a significant position in the horse industry. To investigate their homeostasis mechanisms during and after a 20 km endurance exercise and identify novel oxidative-imbalance markers, we selected 12 two-year-old horses and collected blood samples at various time points before, during (at 5, 10, 15, and 20 km), and after the exercise (at 1,...
Davie A, Beavers R, Denham J.The purpose of this review was to analyze the scientific background and practical application of a very successful human training methodology, the pyramidal training model, to the Thoroughbred racehorse. Despite years of research and accumulated knowledge on human training methods to enhance endurance performance, Thoroughbred training programs have lacked significant change. This review introduces the pyramidal training model, explains the science that underpins this training concept and outlines one approach to translate this science into the equine field. It also discusses the importance of...
Wang J, Ren W, Li Z, Li L, Wang R, Ma S, Zeng Y, Meng J, Yao X.The impact of exercise on human metabolism has been extensively studied, yet limited research exists on the effects of high-intensity racing on equine metabolism. The aim of this study was to screen the effect of a 5000 m race on lipids and proteins in the plasma of Yili horses for the breeding of racehorses. Blood samples were collected from the top three finishers, and lipidomics and proteomics analyses were performed. Lipidomic analysis identified 10 differential lipids. Compared to pre-race levels, phosphatidylethanolamine (18:0/16:0) (PE (18:0/16:0)) and phosphatidylcholine (18:0/18:2) (P...
Poh KC, Oyen K, Onzere CK, Kappmeyer LS, Bastos RG.The recent discovery of , a tick-borne hemoparasite that causes mild clinical signs of equine piroplasmosis, has added complexity to the diagnosis of this reportable disease, which is prevalent among equids globally. Knowledge gaps regarding competent tick vectors that can transmit and the recent outbreak of in the US has prompted us to conduct this study. Our objective was to investigate whether can transstadially transmit to horses. Unassigned: larvae (0.5 g) and nymphs ( = 500) were fed on a splenectomized -infected horse for parasite acquisition. During the tick feeding period, ...
Cheung HW, Wong KS, Cheng PCF, Tsang CYN, Farrington AF, Wan TSM, Ho ENM.Erythropoiesis-stimulating agents (ESAs) continue to be a significant threat to the integrity of human and equine sports. Besides conventional direct testing, monitoring the biomarkers associated with the effects of ESAs may provide a complementary approach via indirect detection to enhance doping control. In this study, we applied RNA-sequencing (RNA-seq) to discover blood RNA biomarkers in Thoroughbred horses after administration with a long-acting form of recombinant human erythropoietin (rhEPO), methoxy polyethylene glycol epoetin beta, Mircera®. A single subcutaneous administration of Mi...
Wang T, Meng J, Wang J, Ren W, Yang X, Adina W, Bao Y, Zeng Y, Yao X.The purpose of this study was to explore the relationship between blood lipid levels and the differences in cardiac structure and function of trained and untrained Yili horses as related to exercise performance. We utilized quantitative lipidomics technology to elucidate how the differences in lipid compounds in the blood influenced performance outcomes. Sixteen 18-month-old Yili horses were selected, ten of which received a 15-week training regimen, and six were kept as untrained controls. Cardiac structure and function were assessed by echocardiography, while plasma lipid metabolites were de...
Van den Branden E, Salamone M, Broothaers K, Peere S, Polfliet E, Dewulf M, Van Steenkiste G, van Loon G, Smits K, Govaere J.The use of transvaginal ultrasound-guided follicle aspiration (TVA) for oocyte collection has become a widely used procedure in horses for embryo production (IVEP). The TVA procedure is characterized by various manipulations, which are physical restraint, perineal preparation, transrectal palpation, insertion of an intravaginal device, and needle punctures. These repeated transvaginal and transovarian punctures have raised concerns about their potential effects on mare welfare. Our study aimed to investigate the effects of TVA manipulations, and especially puncturing, on pain and stress in ma...
Macleod BM, Wilkins PA, McCoy AM, Bishop RC.Viscoelastic coagulation testing (VCT) identifies subclinical disruption of coagulation homeostasis and may improve prognostication, particularly for patients with severe systemic inflammation or shock. Machine learning (ML) algorithms may capture complex relationships between clinical variables better than linear regression (GLM). Objective: To evaluate the utility of ML models incorporating VCT and clinical data to predict survival outcomes in horses with acute abdominal pain. Methods: Retrospective observational cohort study. Methods: VCT (VCM Vet™) was performed on 57 horses with acute a...
The objective of the present study was to investigate the influence of daily rhythms on the immune and inflammatory systems in horses, considering white blood cell count (WBCs), leukocyte subpopulations (neutrophils, basophils, eosinophils, lymphocytes, and monocytes), CD4+, and CD8+ lymphocyte populations, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Ten Italian Saddle horses (7-12 years old, body weight 480 ± 30 kg) underwent blood sampling every 4 h over a 24-h period. The COSINOR method was used to identify rhythms and their parameters. A one-way ...
Kawaida MY, Kwon OS, Ahn A, Reiter AS, Tillquist NM, Noh SG, Lee JW, Moore TE, Reed SA.This study investigated the effects of astaxanthin (ASTX) supplementation on oxidative status during a deconditioning-reconditioning cycle. Twelve polo ponies were assigned to no supplementation (CON) or an ASTX supplemented group, which received oral administration of a supplement containing 75 mg ASTX daily for 32 weeks. Polo ponies underwent a 16-week deconditioning period (DECON) followed by a 16-week reconditioning program (RECON). Submaximal exercise tests (SETs) were performed at the beginning of the study (Baseline), after DECON, and after RECON. Blood samples were collected at -30...
