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Topic:Disease Diagnosis

Disease diagnosis in horses involves the identification and characterization of illnesses through various diagnostic methods and tools. This process is essential for effective veterinary care and management of equine health. Techniques used in diagnosing diseases in horses include clinical examinations, laboratory tests, imaging modalities such as ultrasonography and radiography, and molecular diagnostics. Blood tests are frequently utilized to assess parameters such as complete blood count and biochemical profiles, which can indicate underlying health issues. Additionally, advancements in genetic testing and biomarker identification have enhanced the ability to detect specific diseases early. This page aggregates peer-reviewed research studies and scholarly articles that explore diagnostic methodologies, their applications, and their impact on equine health management.
Biomarkers of brain injury in foals with hypoxic-ischemic encephalopathy.
Journal of veterinary internal medicine    December 8, 2010   Volume 25, Issue 1 132-137 doi: 10.1111/j.1939-1676.2010.0645.x
Ringger NC, Giguère S, Morresey PR, Yang C, Shaw G.Neonatal hypoxic-ischemic encephalopathy (NHIE) is a disease affecting newborn foals for which there is no antemortem diagnostic test. Objective: Ubiquitin C-terminal hydrolase 1 (UCHL1) and the phosphorylated axonal forms of neurofilament H (pNF-H) are markers of brain injury in foals with NHIE. Methods: Thirty-three foals with a clinical diagnosis consistent with NHIE and 17 healthy foals. Methods: Retrospective study. Concentrations of UCHL1 and pNF-H in plasma were measured by ELISA. The performance of the assays for the diagnosis of NHIE was assessed by receiver operating characteristic c...
Laminar leukocyte accumulation in horses with carbohydrate overload-induced laminitis.
Journal of veterinary internal medicine    December 8, 2010   Volume 25, Issue 1 107-115 doi: 10.1111/j.1939-1676.2010.0650.x
Faleiros RR, Johnson PJ, Nuovo GJ, Messer NT, Black SJ, Belknap JK.While there is evidence of laminar leukocyte infiltration in black walnut extract (BWE)-induced laminitis, there is no such evidence for carbohydrate overload (CHO) laminitis. Objective: To assess presence of leukocytes and signs of epidermal stress/injury in the laminar tissue from horses with CHO-induced laminitis. Methods: Twenty-four adult horses. Methods: Immunohistochemistry for myeloid cell markers calprotectin (CP) and monocyte-specific marker (CD163) was performed on laminar sections obtained from 2 groups of horses in the CHO model: the developmental time point (DTP) group (n = 6) an...
Effects of clopidogrel and aspirin on platelet aggregation, thromboxane production, and serotonin secretion in horses.
Journal of veterinary internal medicine    December 8, 2010   Volume 25, Issue 1 116-122 doi: 10.1111/j.1939-1676.2010.0647.x
Brainard BM, Epstein KL, LoBato D, Kwon S, Papich MG, Moore JN.Critically ill horses are susceptible to thrombotic disease, which might be related to increased platelet reactivity and activation. Objective: To compare the effect of oral clopidogrel and aspirin (ASA) on equine platelet function. Methods: Six healthy adult horses. Methods: Horses received clopidogrel (2 mg/kg p.o. q24h) or ASA (5 mg/kg p.o. q24h) for 5 days in a prospective randomized cross-over design. Platelet aggregation responses to adenosine diphosphate (ADP) and collagen via optical aggregometry, and platelet secretion of serotonin (5HT) and production of thromboxane B(2) (TXB(2) ) by...
Characterization of equine humoral antibody response to the nonstructural proteins of equine arteritis virus.
Clinical and vaccine immunology : CVI    December 8, 2010   Volume 18, Issue 2 268-279 doi: 10.1128/CVI.00444-10
Go YY, Snijder EJ, Timoney PJ, Balasuriya UB.Equine arteritis virus (EAV) replicase consists of two polyproteins (pp1a and pp1ab) that are encoded by open reading frames (ORFs) 1a and 1b of the viral genome. These two replicase polyproteins are posttranslationally processed by three ORF 1a-encoded proteinases to yield at least 13 nonstructural proteins (nsp1 to nsp12, including nsp7α and 7β). These nsps are expressed in EAV-infected cells, but the equine immune response they induce has not been studied. Therefore, the primary purpose of this study was to evaluate the humoral immune response of horses to each of the nsps following EAV i...
Clinical assessment of blood glucose homeostasis in horses: comparison of a continuous glucose monitoring system with a combined intravenous glucose and insulin test protocol.
Journal of veterinary internal medicine    December 8, 2010   Volume 25, Issue 1 162-165 doi: 10.1111/j.1939-1676.2010.0643.x
Johnson PJ, Wiedmeyer CE, LaCarrubba A, Messer NT, Dingfelder HA, Cogswell AM, Amorim JR, Ganjam VK.The combined glucose-insulin test (CGIT) is helpful for evaluating insulin sensitivity. A continuous glucose monitoring system (CGMS) reports changes in interstitial glucose concentrations as they occur in the blood. Use of the CGMS minimizes animal contact and may be useful when performing a CGIT. Objective: Results obtained using a CGMS are useful for the evaluation of glucose responses during the evaluation of insulin sensitivity in equids. Methods: Seven mature, obese ponies. Methods: Ponies were equipped with CGMS for determination of interstitial glucose concentrations. Glucose (150 mg/k...
Evaluation of a double centrifugation technique for the detection of Anoplocephala eggs in horse faeces.
Journal of helminthology    December 8, 2010   Volume 85, Issue 4 409-414 doi: 10.1017/S0022149X10000751
Rehbein S, Lindner T, Visser M, Winter R.Faecal samples of 250 horses from farms with a known history of tapeworm infection were examined comparatively for cestode eggs using a double centrifugation/combined sedimentation-floatation technique. From each faecal sample, three 5 g and three 15 g subsamples were processed, each using either saturated NaCl solution, specific gravity (sp. g.) 1.2 [NaCl]; concentrated sugar solution, sp. g. 1.26 [sugar]; or concentrated ZnSO4 solution, sp. g. 1.3 [ZnSO4] for floatation. In total, faeces from 187 horses ( = 74.8%) tested 'positive' for Anoplocephala eggs. Percentages of samples testing '...
Induction of a Th-1-biased IgG subclass response against equine herpesvirus type 1 in horses previously infected with type 4 virus.
The Journal of veterinary medical science    December 6, 2010   Volume 73, Issue 4 535-539 doi: 10.1292/jvms.10-0456
Bannai H, Tsujimura K, Kondo T, Nemoto M, Yamanaka T, Sugiura T, Maeda K, Matsumura T.An immunoglobulin G (IgG) subclass response against equine herpesvirus type 1 (EHV-1) infection was investigated in horses that were naïve to EHV-1/4 and those that had previously been exposed to EHV-4. The IgG subclass response was determined by an ELISA using EHV-1-specific recombinant gG protein as an antigen. In most horses naïve to EHV-1/4, IgGa, IgGb, and IgG(T) were induced after experimental infection with EHV-1. In contrast, a subclass response dominated by IgGa and IgGb, with no apparent increase in IgG(T), was observed after EHV-1 infection in horses previously infected with EHV-4...
Suspected systemic calcinosis and calciphylaxis in 5 horses.
The Canadian veterinary journal = La revue veterinaire canadienne    December 2, 2010   Volume 51, Issue 9 993-999 
Tan JY, Valberg SJ, Sebastian MM, Davis GD, Kelly JR, Goehring LS, Harland MM, Kuebelbeck KL, Waldridge BM, Newton JC, Reimer JM.Five horses were presented with signs of myopathy along with systemic malaise, hyperfibrinogenemia, hyperphosphatemia, and an elevated calcium phosphorus product (Ca*P). Postmortem findings were consistent with systemic calcinosis, a syndrome of calcium deposition in the tissue of organs including lungs, kidneys, muscle, and heart that has not been previously described in horses. Cinq chevaux ont été présentés avec des signes de myopathie et un malaise systémique, d’hyperfibrinogénémie, d’hyperphosphatémie et d’un produit de phosphore de calcium élevé (Ca*P). Les constatations...
Descriptive epidemiology of equine influenza in India (2008-2009): temporal and spatial trends.
Veterinaria italiana    December 2, 2010   Volume 46, Issue 4 449-458 
Virmani N, Bera BC, Gulati BR, Karuppusamy S, Singh BK, Kumar Vaid R, Kumar S, Kumar R, Malik P, Khurana SK, Singh J, Manuja A, Dedar R, Gupta AK....Equine influenza is a contagious viral disease that affects all members of the family Equidae, i.e., horses, donkeys and mules. The authors describe the pattern of equine influenza outbreaks in a number of states of India from July 2008 to June 2009. The disease was first reported in June 2008 in Katra (Jammu and Kashmir) and spread to ten other states within a year. All outbreaks of equine influenza in the various states were confirmed by laboratory investigations (virus isolation and/or serological confirmation based on haemagglutination inhibition [HI] assays of paired samples) before decla...
An eastern equine encephalomyelitis (EEE) outbreak in Quebec in the fall of 2008.
The Canadian veterinary journal = La revue veterinaire canadienne    December 2, 2010   Volume 51, Issue 9 1011-1015 
Chénier S, Côté G, Vanderstock J, Macieira S, Laperle A, Hélie P.Eastern equine encephalomyelitis (EEE) was diagnosed in 19 horses and a flock of emus in the province of Quebec in fall 2008. The EEE virus caused unusual gross lesions in the central nervous system of one horse. This disease is not usually present in Quebec and the relation between the outbreak and favorable environmental conditions that summer are discussed. Une éclosion d’encéphalomyélite équine de l’Est (ÉÉE) s’est produite chez 19 chevaux et dans un troupeau d’émeus au Québec à l’automne de 2008. Un cheval présentait une lésion macroscopique anormale dans le système...
Effect of heparin administration on urine protein excretion during the developmental stage of experimentally induced laminitis in horses.
American journal of veterinary research    December 2, 2010   Volume 71, Issue 12 1462-1467 doi: 10.2460/ajvr.71.12.1462
Uberti B, Pressler BM, Alkabes SB, Chang CY, Moore GE, Lescun TB, Sojka JE.To investigate the effects of heparin administration on urine protein excretion during the developmental stages of experimentally induced laminitis in horses. Methods: 13 horses. Procedures-Horses received unfractionated heparin (80 U/kg, SC, q 8 h; n=7) or no treatment (control group; 6) beginning 3 days prior to induction of laminitis. All horses were given 3 oligofructose loading doses (1 g/kg each) at 24-hour intervals and a laminitis induction dose (10 g of oligofructose/kg) 24 hours following the final loading dose (designated as 0 hours) via nasogastric tube. Serum glucose and insulin c...
Skin-infiltrating T cells and cytokine expression in Icelandic horses affected with insect bite hypersensitivity: a possible role for regulatory T cells.
Veterinary immunology and immunopathology    December 1, 2010   Volume 140, Issue 1-2 63-74 doi: 10.1016/j.vetimm.2010.11.016
Heimann M, Janda J, Sigurdardottir OG, Svansson V, Klukowska J, von Tscharner C, Doherr M, Broström H, Andersson LS, Einarsson S, Marti E....Equine insect bite hypersensitivity (IBH) is a seasonally recurrent, pruritic skin disorder caused by an IgE-mediated reaction to salivary proteins of biting flies, predominantly of the genus Culicoides. The aim of this study was to define T cell subsets and cytokine profile in the skin of IBH-affected Icelandic horses with particular focus on the balance between T helper (Th) 1, Th2 and T regulatory (Treg) cells. Distribution and number of CD4+, CD8+ and Forkhead box P3 (FoxP3)+ T cells were characterized by immunohistochemical staining in lesional and non-lesional skin of moderately and seve...
Clonal complex Pseudomonas aeruginosa in horses.
Veterinary microbiology    December 1, 2010   Volume 149, Issue 3-4 508-512 doi: 10.1016/j.vetmic.2010.11.030
Kidd TJ, Gibson JS, Moss S, Greer RM, Cobbold RN, Wright JD, Ramsay KA, Grimwood K, Bell SC.Pseudomonas aeruginosa is associated with infectious endometritis in horses. Although infectious endometritis is often considered a venereal infection, there is relatively limited genotypic-based evidence to support this mode of transmission. The study sought to determine the relatedness between genital P. aeruginosa isolates collected from a limited geographical region using molecular strain typing. Enterobacterial repetitive intergenic consensus PCR typing was performed on 93 isolates collected between 2005 and 2009 from 2058 thoroughbred horses (including 18 stallions) at 66 studs. While P....
Navicular syndrome in equine patients anatomy, causes, and diagnosis.
Compendium (Yardley, PA)    December 1, 2010   Volume 32, Issue 12 E7 
Waguespack R, Hanson RR.Navicular syndrome is a chronic and often progressive disease affecting the navicular bone and bursa, deep digital flexor tendon (DDFT), and associated soft tissue structures composing the navicular apparatus. This syndrome has long been considered one of the most common causes of forelimb lameness in horses. Diagnosis of navicular syndrome is based on history, physical examination, lameness examination, and peripheral and/or intraarticular diagnostic anesthesia. Several imaging techniques (e.g., radiography, ultrasonography, nuclear scintigraphy, thermography, computed tomography [CT], magnet...
Subpopulations of equine blood lymphocytes expressing regulatory T cell markers.
Veterinary immunology and immunopathology    December 1, 2010   Volume 140, Issue 1-2 90-101 doi: 10.1016/j.vetimm.2010.11.020
Robbin MG, Wagner B, Noronha LE, Antczak DF, de Mestre AM.Several distinct T lymphocyte subpopulations with immunoregulatory activity have been described in a number of mammalian species. This study performed a phenotypic analysis of cells expressing regulatory T cell (Treg) markers in the peripheral blood of a cohort of 18 horses aged 6 months to 23 years, using antibodies to both intracellular and cell surface markers, including Forkhead box P3 (FOXP3), CD4, CD8, CD25, interferon gamma (IFNγ) and interleukin 10 (IL-10). In peripheral blood, a mean of 2.2 ± 0.2% CD4+ and 0.5 ± 0.1% CD8+ lymphocytes expressed FOXP3. The mean percentage of CD4+FOXP...
Equine influenza virus: a jumping virus that races with Thoroughbred horses and greyhounds.
Veterinary journal (London, England : 1997)    November 30, 2010   Volume 189, Issue 1 3-4 doi: 10.1016/j.tvjl.2010.10.023
Murcia PR, Wood JL.No abstract available
Prevalence of the mutation in cyclophilin B (PPIB), a causal candidate gene for HERDA, among Quarter Horses in France.
Veterinary dermatology    November 30, 2010   Volume 22, Issue 2 206-208 doi: 10.1111/j.1365-3164.2010.00941.x
White SD, Bourdeau P.Hereditary equine regional dermal asthenia (HERDA) in Quarter Horses is an inherited degenerative skin disease. Initially reported as hyperelastosis cutis, HERDA has a phenotype of hyperextensible, fragile skin, with secondary seromas, haematomas, ulcers and scarring. It primarily affects the dorsal aspect of the body. An autosomal recessive mode of inheritance is considered likely, with affected horses more at risk to produce affected offspring. A mutation in cyclophilin B (PPIB) as a novel, causal candidate gene for HERDA has been described, and verified as segregating with carriers and affe...
Mapping of equine cerebellar abiotrophy to ECA2 and identification of a potential causative mutation affecting expression of MUTYH.
Genomics    November 30, 2010   Volume 97, Issue 2 121-129 doi: 10.1016/j.ygeno.2010.11.006
Brault LS, Cooper CA, Famula TR, Murray JD, Penedo MC.Equine Cerebellar Abiotrophy (CA) is a neurological disease found in Arabian horses. CA is characterized by post-natal degeneration of the Purkinje cells of the cerebellum. Signs of CA include ataxia, head tremors, and a lack of balance equilibrium. We have discovered a linkage of the CA phenotype to a microsatellite marker on ECA2 and identified a region of conserved homozygosity spanning approximately 142 kb. Complete sequencing of the four genes in this region identified one SNP found only in Arabian horses, located in exon 4 of TOE1 and approximately 1200 base pairs upstream of MUTYH, adja...
Borna disease virus antibody and RNA from peripheral blood mononuclear cells of race horses and jockeys in Korea.
Psychiatry investigation    November 27, 2010   Volume 8, Issue 1 58-60 doi: 10.4306/pi.2011.8.1.58
Song JW, Na KS, Tae SH, Kim YK.During the last two decades, Borna disease virus (BDV) has received much attention as a possible zoonotic agent, particularly as a cause of psychiatric disease. Although several studies have shown that BDV is present in Asia, BDV has not been detected in Korea. This study was designed to further investigate the presence of BDV infection in Korea. Methods: Blood samples were taken from 39 race horses and 48 jockeys. Antibody to BDV was detected by indirect immunofluorescence antibody test and RNA of BDV by real time reverse transcriptase PCR (rRT-PCR). Results: No evidence of BDV was detected i...
RT-qPCR comparison of mast cell populations in whole blood from healthy horses and those with laminitis.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 16-22 doi: 10.1111/j.1365-2052.2010.02093.x
Brooks SA, Bailey E.Inflammatory damage to the digital laminae, a structure responsible for suspension of the distal skeleton within the hoof capsule, results in a painful and often life-threatening disease in horses called laminitis. There can be many diverse causes of laminitis; however, previous work in the horse has suggested that in each case, the inflammation and resulting tissue damage is consistent with the action of mediators released from mast cells (MC), as well as the downstream consequences of their activation. The recent development of molecular genetics tools to characterize cells based on their tr...
Genome-wide SNP association-based localization of a dwarfism gene in Friesian dwarf horses.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 2-7 doi: 10.1111/j.1365-2052.2010.02091.x
Orr N, Back W, Gu J, Leegwater P, Govindarajan P, Conroy J, Ducro B, Van Arendonk JA, MacHugh DE, Ennis S, Hill EW, Brama PA.The recent completion of the horse genome and commercial availability of an equine SNP genotyping array has facilitated the mapping of disease genes. We report putative localization of the gene responsible for dwarfism, a trait in Friesian horses that is thought to have a recessive mode of inheritance, to a 2-MB region of chromosome 14 using just 10 affected animals and 10 controls. We successfully genotyped 34,429 SNPs that were tested for association with dwarfism using chi-square tests. The most significant SNP in our study, BIEC2-239376 (P(2df)=4.54 × 10(-5), P(rec)=7.74 × 10(-6)), is lo...
Genetics of swayback in American Saddlebred horses.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 64-71 doi: 10.1111/j.1365-2052.2010.02108.x
Cook D, Gallagher PC, Bailey E.Extreme lordosis, also called swayback, lowback or softback, can occur as a congenital trait or as a degenerative trait associated with ageing. In this study, the hereditary aspect of congenital swayback was investigated using whole genome association studies of 20 affected and 20 unaffected American Saddlebred (ASB) Horses for 48,165 single-nucleotide polymorphisms (SNPs). A statistically significant association was identified on ECA20 (corrected P=0.017) for SNP BIEC2-532523. Of the 20 affected horses, 17 were homozygous for this SNP when compared to seven homozygotes among the unaffected ho...
IgE, IgGa, IgGb and IgG(T) serum antibody levels in offspring of two sires affected with equine recurrent airway obstruction.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 131-137 doi: 10.1111/j.1365-2052.2010.02122.x
Scharrenberg A, Gerber V, Swinburne JE, Wilson AD, Klukowska-Rötzler J, Laumen E, Marti E.Equine recurrent airway obstruction (RAO) is a chronic lower airway disease of the horse caused by hypersensitivity reactions to inhaled stable dust, including mould spores such as Aspergillus fumigatus. The goals of this study were to investigate whether total serum IgE levels and allergen-specific IgE and IgG subclasses are influenced by genetic factors and/or RAO and whether quantitative trait loci (QTL) could be identified for these parameters. The offspring of two RAO-affected sires (S1: n=56 and S2: n=65) were grouped by stallion and disease status, and total serum IgE levels and specifi...
Fine mapping of a quantitative trait locus for osteochondrosis on horse chromosome 2.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 87-90 doi: 10.1111/j.1365-2052.2010.02113.x
Dierks C, Komm K, Lampe V, Distl O.In this study, we refine a quantitative trait locus for equine osteochondrosis (OC) on horse chromosome (ECA) 2 to a genome-wide significant interval at 20.08-30.94 Mb. The marker set contained 27 newly developed microsatellites equidistantly distributed over ECA2 and 44 nucleotide polymorphisms, located in 16 positional candidate genes for OC. Genotyping was performed in 211 Hanoverian horses from 14 paternal half-sib groups. A NCDN-associated SNP and haplotype were significantly associated with OC in fetlock and/or hock joints. This study is a further step towards the identification of genes...
High prevalence of EEE in Michigan.
Journal of the American Veterinary Medical Association    November 26, 2010   Volume 237, Issue 9 1001 
Larkin M.No abstract available
Genome-wide association analysis of osteochondrosis of the tibiotarsal joint in Norwegian Standardbred trotters.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 111-120 doi: 10.1111/j.1365-2052.2010.02117.x
Lykkjen S, Dolvik NI, McCue ME, Rendahl AK, Mickelson JR, Roed KH.Osteochondrosis (OC), a disturbance in the process of endochondral ossification, is by far the most important equine developmental orthopaedic disease and is also common in other domestic animals and humans. The purpose of this study was to identify quantitative trait loci (QTL) associated with osteochondrosis dissecans (OCD) at the intermediate ridge of the distal tibia in Norwegian Standardbred (SB) using the Illumina Equine SNP50 BeadChip whole-genome single-nucleotide polymorphism (SNP) assay. Radiographic data and blood samples were obtained from 464 SB yearlings. Based on the radiographi...
Refinement of quantitative trait loci on equine chromosome 10 for radiological signs of navicular disease in Hanoverian warmblood horses.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 36-40 doi: 10.1111/j.1365-2052.2010.02096.x
Lopes MS, Diesterbeck U, Machado Ada C, Distl O.Navicular disease is characterized by a progressive degenerative alteration of the equine podotrochlea. In this study, we refined a previously identified quantitative trait locus (QTL) on horse chromosome 10 for the abnormal development of canales sesamoidales (DCS) of the navicular bone in Hanoverian warmblood horses. Genotyping was done in 192 Hanoverian warmblood horses from 17 paternal half-sib groups. The whole marker set comprised 45 markers including seven newly developed microsatellites and 13 single nucleotide polymorphisms (SNPs) within positional candidate genes. Chromosome-wide sig...
A survey of aged horses in Queensland, Australia. Part 2: Clinical signs and owners’ perceptions of health and welfare.
Australian veterinary journal    November 26, 2010   Volume 88, Issue 12 465-471 doi: 10.1111/j.1751-0813.2010.00638.x
McGowan TW, Pinchbeck G, Phillips CJ, Perkins N, Hodgson DR, McGowan CM.To describe the prevalence and risk factors for clinical signs of disease and owner-reported health or welfare issues of aged horses in Queensland, Australia. Methods: Owners of horses were contacted via an equestrian organisation in Queensland and asked to complete a questionnaire about their horses aged 15 years and older, to gain information about clinical signs observed in the horse and disease history. Owners were asked to identify health or welfare issues they felt were important in aged horses. Results: Owners were able to identify many clinical signs of disease, with 83% of horses havi...
Identification of equine major histocompatibility complex haplotypes using polymorphic microsatellites.
Animal genetics    November 26, 2010   Volume 41 Suppl 2, Issue Suppl 2 150-153 doi: 10.1111/j.1365-2052.2010.02125.x
Tseng CT, Miller D, Cassano J, Bailey E, Antczak DF.A system for identifying equine major histocompatibility complex (MHC) haplotypes was developed based on five polymorphic microsatellites located within the MHC region on ECA 20. Molecular signatures for 50 microsatellite haplotypes were recognized from typing 353 horses. Of these, 23 microsatellite haplotypes were associated with 12 established equine leucocyte antigen (ELA) haplotypes in Thoroughbreds and Standardbreds. Five ELA serotypes were associated with multiple microsatellite subhaplotypes, expanding the estimates of diversity in the equine MHC. The strong correlations between serolog...
Molecular heterogeneity of XY sex reversal in horses.
Animal genetics    November 26, 2010   Volume 41 Suppl 2 41-52 doi: 10.1111/j.1365-2052.2010.02101.x
Raudsepp T, Durkin K, Lear TL, Das PJ, Avila F, Kachroo P, Chowdhary BP.Male-to-female 64,XY sex reversal is a frequently reported chromosome abnormality in horses. Despite this, the molecular causes of the condition are as yet poorly understood. This is partially because only limited molecular information is available for the horse Y chromosome (ECAY). Here, we used the recently developed ECAY map and carried out the first comprehensive study of the Y chromosome in XY mares (n=18). The integrity of the ECAY in XY females was studied by FISH and PCR using markers evenly distributed along the euchromatic region. The results showed that the XY sex reversal condition...