Genetics in horses encompasses the study of hereditary traits and the genetic makeup that influences various characteristics and health conditions in equine populations. This field involves the analysis of genes and their functions, inheritance patterns, and the impact of genetic variations on traits such as coat color, performance ability, and susceptibility to diseases. Research in equine genetics employs techniques such as genome mapping, sequencing, and genetic testing to identify specific genes and mutations associated with these traits. This page gathers peer-reviewed research studies and scholarly articles that explore the genetic basis of equine traits, the methodologies used in genetic research, and the implications for breeding, health management, and conservation of horse breeds.
Grilz-Seger G, Reiter S, Neuditschko M, Wallner B, Rieder S, Leeb T, Jagannathan V, Mesarič M, Cotman M, Pausch H, Lindgren G, Velie B, Horna M....The roan coat color in horses is characterized by dispersed white hair and dark points. This phenotype segregates in a broad range of horse breeds, while the underlying genetic background is still unknown. Previous studies mapped the roan locus to the KIT gene on equine chromosome 3 (ECA3). However, this association could not be validated across different horse breeds. Performing a genome-wide association analysis (GWAS) in Noriker horses, we identified a single nucleotide polymorphism (SNP) (ECA3:g.79,543.439 A > G) in the intron 17 of the KIT gene. The G -allele of the top associated SNP...
Kareskoski AM, Palviainen M, Johannisson A, Katila T.For unknown reasons, stallion fertility and sperm longevity during cooled storage of semen vary markedly between individuals. Spermatozoa from individual stallions react differently to the presence, or the removal, of seminal plasma (SP). The aim was to evaluate differences in protein content in stallion seminal plasma with either a positive or a negative effect on sperm chromatin integrity during storage. Stallion semen samples from different ejaculate fractions were stored at 5°C for 24 hr. Sperm survival was assessed after storage using a sperm chromatin structure assay. Protein expressio...
Jaworska J, Ropka-Molik K, Wocławek-Potocka I, Siemieniuch M.Polymorphism of major histocompatibility complex (MHC) genes ensures effective immune responses against a wide array of pathogens. However, artificial selection, as performed in the case of domestic animals, may influence MHC diversity. Here, we investigate and compare the MHC diversity of three populations of horses, for which different breeding policies were applied, to evaluate the impact of artificial selection and the environment on MHC polymorphism. Samples of DNA were taken from 100 Polish draft horses, 38 stabled Konik Polski horses and 32 semiferal Konik Polski horses. MHC alleles and...
LaFrentz S, Abarca E, Mohammed HH, Cuming R, Arias CR.The equine conjunctival microbiota has often been reported to be dominated by Gram-positive species such as Staphylococcus sp., Bacillus sp., and Corynebacterium sp. However, traditional culture-based methods can only recover a fraction of the bacterial species present in the sample. Objective: This pilot study aimed at exploring the diversity of the equine conjunctival microbiota using culture-independent methods. Methods: Eight horses were included in this study, and only eyes with normal ophthalmic examination (n = 15 eyes) were sampled. Methods: Conjunctival biopsies (culture-independent...
Liu S, Jiang S, Dong XG, Cui R, Ling Y, Zhao C.The Debao pony is a well-known dwarf horse breed in China. High-mobility group AT-hook 2 (HMGA2) gene is regarded as one of the important candidate genes regulating body height in horses. The aim of this study was to study the association between mutations in HMGA2 gene and withers height in Debao ponies. The polymorphisms in all exons and partial introns of the HMGA2 gene were screened with sequencing across 180 Debao ponies. And the association between the DNA variants and withers height was analyzed. Seven genetic variants were identified in HMGA2 gene, including six novel variants. Among t...
Scholtzek AD, Hanke D, Eichhorn I, Walther B, Lübke-Becker A, van Duijkeren E, Köck R, Schwarz S, Feßler AT.Based on antimicrobial susceptibility testing (AST), correct classifications as susceptible, intermediate or resistant are challenging for some antimicrobial agent-bacterial species combinations. In this study, we investigated 19 equine Staphylococcus aureus isolates for their susceptibility to the combination sulfamethoxazole/trimethoprim (SXT) by using broth microdilution (BMD), agar disk diffusion (DD) and automated test systems. To elucidate the presence of the corresponding genetic resistance properties among the isolates, whole genome sequence analysis was performed and the genomes were ...
Li F, Wang R, Guo Y, Li N, Feng Y, Xiao L.Limited data are available on infection rates and genetic identity of Enterocytozoon bieneusi and Giardia duodenalis in horses and donkeys. In this study, 865 fecal specimens were collected from donkeys (n = 540) and horses (n = 325) in three provinces and autonomous regions in northern China during 2015-2019. Enterocytozoon bieneusi was detected and genotyped by PCR and sequence analyses of the ribosomal internal transcribed spacer (ITS) and G. duodenalis was detected and genotyped by PCR and sequence analyses of the β-giardin, glutamate dehydrogenase, and triosephosphate isomerase g...
Garber A, Hastie P, Murray JA.Gastrointestinal microbiota play a crucial role in nutrient digestion, maintaining animal health and welfare. Various factors may affect microbial balance often leading to disturbances that may result in debilitating conditions such as colic and laminitis. The invention of next-generation sequencing technologies and bioinformatics has provided valuable information on the effects of factors influencing equine gut microbiota. Among those factors are nutrition and management (e.g., diet, supplements, exercise), medical substances (e.g., antimicrobials, anthelmintics, anesthetics), animal-related ...
El-Sheikh Ali H, Legacki EL, Scoggin KE, Loux SC, Dini P, Esteller-Vico A, Conley AJ, Stanley SD, Ball BA.Equine placentitis is associated with alterations in maternal peripheral steroid concentrations, which could negatively affect pregnancy outcome. This study aimed to elucidate the molecular mechanisms related to steroidogenesis and steroid-receptor signaling in the equine placenta during acute placentitis. Chorioallantois (CA) and endometrial (EN) samples were collected from mares with experimentally induced placentitis (n = 4) and un-inoculated gestationally age-matched mares (control group; n = 4). The mRNA expression of genes coding for steroidogenic enzymes (3βHSD, CYP11A1, CYP17A1, CYP19...
Walker NL, Patout AR, Cater M.Hereditary equine regional derma asthenia (HERDA), an autosomal-recessive trait, found in Quarter Horses, causes abnormal collagen structure. Owing to current breeding practices, 3.5% of registered quarter horses and 28.3% of the cow horse population are heterozygote carriers. Research demonstrated homozygote horses develop hyperextensible skin susceptible to injury and other abnormal tissues containing high fibrillar collagen content. No research exists determining the effects of the disease in heterozygote carriers. Currently, 30% of cutting sires are HERDA carriers, potentially increasing t...
Cash CM, Fitzgerald DM, Spence RJ, de Laat MA.Equine metabolic syndrome (EMS) describes a group of risk factors, including obesity and insulin dysregulation (hyperinsulinemia and/or insulin resistance), that can lead to the development of the debilitating hoof disease laminitis. Although the underlying mechanisms of EMS are not fully understood, a genetic component has been reported, and an 11 guanine polymorphism located at the FAM174A gene has been identified as a risk locus for the syndrome in Arabian horses. To examine associations between the FAM174A risk allele and the clinical signs of EMS, the allele was examined in an Australian ...
Winton CL, McMahon R, Hegarty MJ, McEwan NR, Davies-Morel MCG, Morgan C, Nash DM.The UK and Ireland have many native pony breeds with historical and cultural importance as well as being a source of uncharacterized genetic diversity. However, there is a lack of comprehensive research investigating their genetic diversity and phylogenetic interrelationships. Many studies contain a limited number of pony breeds or small sample sizes for these breeds. This may result in erroneous grouping of pony breeds that otherwise have intricate interrelationships with each other and are not evaluated correctly when placed as a token subset of a larger dataset. This is the first study that...
Wuri L, Agca C, Agca Y.This study compared the morphometric, subcellular characteristics, in vitro fertilisation (IVF) and embryonic developmental potential of metaphase II (MII) mouse oocytes obtained from females superovulated with either anti-inhibin serum-human chorionic gonadotrophin (AIS-hCG) or pregnant mare serum gonadotrophin (PMSG)-hCG. The oocyte's quantity, quality, zona pellucida (ZP) thickness, perivitelline space (PVS), diameter, microtubules, F-actin, cortical granules (CGs) and mitochondrial distribution were determined. Superovulation using AIS-hCG resulted in a higher numbers of oocyte/donor compa...
Duquesne F, Merlin A, Pérez-Cobo I, Sedlák K, Melzer F, Overesch G, Fretin D, Iwaniak W, Breuil MF, Wernery U, Hicks J, Agüero-García M....The accurate identification of Taylorella equigenitalis strains is essential to improve worldwide prevention and control strategies for contagious equine metritis (CEM). This study compared 367 worldwide equine strains using multilocus sequence typing according to the geographical origin, isolation year and equine breed. The strains were divided into 49 sequence types (STs), including 10 described for the first time. Three major and three minor clonal complexes (CCs), and 11 singletons, were identified. The genetic heterogeneity was low (0.13 STs/strain) despite the wide diversity of geographi...
Szóstek-Mioduchowska A, Słowińska M, Pacewicz J, Skarzynski DJ, Okuda K.Equine endometrial fibrosis (endometrosis) is described as a degenerative chronic condition in the uterus. Its characteristic feature is excessive deposition of extracellular matrix (ECM) components around the endometrial glands and stroma. Although matrix metallopeptidases (MMPs) that mediate ECM turnover are important factors in the process of fibrosis, knowledge of their expression and regulation in endometrosis is limited. In other species, one of the important regulators of MMPs and tissue inhibitors of MMPs (TIMPs) is transforming growth factor (TGF)-β1. The goal of this study was to de...
Jeannerat E, Marti E, Thomas S, Herrera C, Sieme H, Wedekind C, Burger D.The major histocompatibility complex (MHC) influences sexual selection in various vertebrates. Recently, MHC-linked social signaling was also shown to influence female fertility in horses (Equus caballus) diagnosed 17 days after fertilization. However, it remained unclear at which stage the pregnancy was terminated. Here we test if MHC-linked cryptic female choice in horses happens during the first days of pregnancy, i.e., until shortly after embryonic entrance into the uterus and before fixation in the endometrium. We exposed estrous mares to one of several unrelated stallions, instrumentally...
Moreno-Irusta A, Dominguez EM, Marín-Briggiler CI, Matamoros-Volante A, Lucchesi O, Tomes CN, Treviño CL, Buffone MG, Lascano R, Losinno L....Sperm chemotaxis may facilitate the finding of the oocyte. Only capacitated spermatozoa can orient their movement by chemotaxis, which as well as capacitation, is regulated in part by the cAMP-PKA pathway. Reactive oxygen species (ROS) are produced during sperm capacitation which is closely related to chemotaxis. Then, the ROS participation in the chemotactic signaling can be expected. Here we studied the role of ROS in the chemotaxis signaling of equine spermatozoa which produce high quantities of ROS because of their energy metabolism. The level of capacitated and chemotactic spermatozoa was...
Simões J, Sales Luís JP, Tilley P.Severe equine asthma (SEA) syndrome is a chronic recurrent respiratory disease, common among adult horses. The disease occurs in genetically susceptible individuals after their exposure to organic dust. Thus, environmental management has proved essential in controlling airway challenge and disease exacerbation. This is a demanding process that can only be achieved through the horse owners' cooperation. One year after initial diagnosis of SEA in a group of 39 horses, owner compliance to an environmental management protocol was evaluated. The overall compliance to the protocol was poor and the h...
Gmel AI, Gmel G, von Niederhäusern R, Weishaupt MA, Neuditschko M.Gait quality, that is, the way horses move according to functional and aesthetic principles, englobes many traits that are scored by experts during breeding competitions. The experts can score a trait on a subjective valuating (SV) scale or on a linear profiling (LP) scale representing the biological extremes of the population. However, the reliability of the appraisal of gait quality traits has not been extensively evaluated. In this study, seven breed experts appraised the walk and trot quality of 24 Franches-Montagnes stallions presented in hand on a sand track. Inter-rater reliabilities of...
Hristov P, Yordanov G, Vladov V, Neov B, Palova N, Radoslavov G.It is well known that horse breeding in Bulgaria is a cultural heritage in Bulgaria, dating from prehistoric and historic times. Until now, molecular data on Bulgarian horses from the plain regions of the country were not available. Therefore, for the first time, we have collected genetic information about some modern horse breeds from the plain regions in Bulgaria. A total of 50 horses originating from different families from two different breeds were investigated: the first one was the Pleven horse (n = 11, breeding in the Danubian Plain), and the second one was the East Bulgarian horse bre...
Angel D, Canesin HS, Brom-de-Luna JG, Morado S, Dalvit G, Gomez D, Posada N, Pascottini OB, Urrego R, Hinrichs K, Velez IC.Effects of meiotic stage and cumulus status on development of equine oocytes after vitrification was evaluated. Immature oocytes with corona radiata (IMM); in vitro-matured oocytes with corona radiata (MAT CR+); and in vitro-matured oocytes denuded of cumulus (MAT CR-) were vitrified using the Cryotech® method. Warming medium was equilibrated either in 5% CO2 or Air. IMM oocytes underwent in vitro maturation after warming. Recovery, survival, and maturation rates, and cleavage and blastocyst rates after ICSI, were evaluated. Recovery was higher for oocytes warmed in CO2- than Air-equilibrated...
Hudson BJ, Chicken C, Blishen A, Todhunter KH, Begg AP, Chan L, Karagiannis T, Raymond B, Bogema D, Adkins AR, O'Sullivan CB, O'Rourke BA....We describe three cases of osteoarticular infection (OAI) in young thoroughbred horses in which the causative organism was identified by MALDI-TOF as . The pattern of OAI resembled that reported with infection in humans. Analysis by 16S rRNA PCR enabled construction of a phylogenetic tree that placed the isolates closer to and , rather than . Average nucleotide identity (ANI) comparison between the new isolate and and however revealed low probability that the new isolate belonged to either of these species. This preliminary analysis suggests the organism isolated is a previously unrecognis...
Bienzle D.This article describes the indications for sampling of bone marrow, the technical aspects of obtaining marrow core biopsies and aspirates, and the preparation of marrow smears. All aspects are illustrated with clinical cases. The information that can be expected from the pathologist's report of marrow samples is outlined, and the clinical features and prognosis of different types of leukemia are detailed.
McGivney BA, Han H, Corduff LR, Katz LM, Tozaki T, MacHugh DE, Hill EW.The Thoroughbred horse is a highly valued domestic animal population under strong selection for athletic phenotypes. Here we present a high resolution genomics-based analysis of inbreeding in the population that may form the basis for evidence-based discussion amid concerns in the breeding industry over the increasing use of small numbers of popular sire lines, which may accelerate a loss of genetic diversity. In the most comprehensive globally representative sample of Thoroughbreds to-date (n = 10,118), including prominent stallions (n = 305) from the major bloodstock regions of the w...
Husso A, Jalanka J, Alipour MJ, Huhti P, Kareskoski M, Pessa-Morikawa T, Iivanainen A, Niku M.The establishment of the intestinal microbiota is critical for the digestive and immune systems. We studied the early development of the rectal microbiota in horse, a hindgut fermenter, from birth until 7 days of age, by qPCR and 16S rRNA gene amplicon sequencing. To evaluate initial sources of the foal microbiota, we characterised dam fecal, vaginal and oral microbiotas. We utilised an amplicon sequence variant (ASV) pipeline to maximise resolution and reproducibility. Stringent ASV filtering based on prevalence and abundance in samples and controls purged contaminants while preserving intest...
equine sarcoids are the most frequent skin tumors in equidae worldwide. It is well known that delta bovine papillomaviruses are their causative agents. We have recently shown the presence in equine sarcoids of abnormal vessel structures, which could cause a hypoxic condition. The aim of this study was to analyze the expression of hypoxia-inducible factor-1 alpha (HIF-1α) in a subset of BPV positive equine sarcoids and explore the relationship with vascular endothelial growth factor (VEGF) expression. Results: 80% of equine sarcoids showed strong cytoplasmic staining in >60% of neoplastic f...
Ereqat S, Nasereddin A, Al-Jawabreh A, Al-Jawabreh H, Al-Laham N, Abdeen Z.Trypanosoma evansi is the causative agent of surra, a disease that occurs in many animal species. The disease is responsible for substantial losses in global production and can be fatal if not diagnosed early. This study aims to determine the prevalence of T. evansi in livestock, equids and dromedary camels in Palestine. Methods: Blood samples were collected during 2015-2017 from domesticated animals (n = 259 animals; 77% females and 23% males) including camels (n = 87), horses (n = 46), donkeys (n = 28), mules (n = 2), sheep (n = 49) and goats (n = 48) from eight districts: Ariha (Jericho), N...
Bergvall KE.Sarcoids are the most common skin tumors seen in horses worldwide. The pathogenesis of sarcoids is multifactorial, including an association with bovine papillomavirus types 1 and 2 and a genetic susceptibility to tumor development. Clinical manifestations vary and include occult, verrucous, nodular, fibroblastic, mixed, and malignant (malevolent) types. The tumor is nonmetastasizing but can become very aggressive locally. Multiple tumors are common. All clinical types can be present in the same horse. No treatment protocol is universally effective. The tumor has a high risk of recurrence. Recu...
Nemoto M, Oue Y, Murakami S, Kanno T, Bannai H, Tsujimura K, Yamanaka T, Kondo T.Equine coronavirus has been responsible for several outbreaks of disease in the United States and Japan. Only one complete genome sequence (NC99 isolated in the US) had been reported for this pathogenic RNA virus. Here, we report the complete genome sequences of three equine coronaviruses isolated in 2009 and 2012 in Japan. The genome sequences of Tokachi09, Obihiro12-1 and Obihiro12-2 were 30,782, 30,916 and 30,916 nucleotides in length, respectively, excluding the 3'-poly (A) tails. All three isolates were genetically similar to NC99 (98.2-98.7%), but deletions and insertions were observed i...
Druml T, Curik I, Baumung R, Aberle K, Distl O, Sölkner J.All over Europe, the number of draught horses has decreased drastically during the last 50 years. As a prerequisite for efficient management decisions, we analysed the conservation status in Austrian (Noriker Carinthia - NC, Noriker Salzburg - NS), Croatian (Croatian Coldblood - C, Posavina horse - P) and German (Altmaerkisch Coldblood - A, Black Forest horse - BF, Mecklenburg Coldblood - M, Rhenish German Draught horse - R, Saxon Thuringa Coldblood - ST, Schleswig Draught horse - Sch, South German Coldblood - SG) draught horses (434) using multilocus genotypic information from 30 (effectively...
Allen GP, Yeargan MR, Bryans JT.The effect of in vitro and in vivo serial virus passage on the genetic stability of equine herpesvirus 1 (EHV-1) was investigated by restriction endonuclease analysis of the viral DNA. DNAs of EHV-1 isolates at different passage levels in cultured cells or in Syrian hamsters were compared by electrophoresis of the DNA cleavage fragments produced by restriction endonuclease digestion. No changes were observed in the restriction profile of the DNAs of EHV-1 strains after 100 sequential passages in cultured equine cells. However, serial passage of the virus in hamsters or in cells of non-equine o...
Walker RL, Read DH, Hayes DC, Nordhausen RW.Direct amplification and sequencing of the 16S rRNA gene and a variable region of the flagellin gene from fetal liver-associated spirochetes belonging to the Borrelia parkeri-B. turicatae tick-borne relapsing fever spirochete group with a late-term abortion in a mare are described.
Gmel AI, Druml T, Portele K, von Niederhäusern R, Neuditschko M.Linear description (LD) of conformation traits was introduced in horse breeding to minimise subjectivity in scoring. However, recent studies have shown that LD traits show essentially the same problems as traditionally scored traits, such as data converging around the mean value with very small standard deviations. To improve the assessment of conformation traits of horses, we investigated the application of the recently described horse shape space model based upon 403 digitised photographs of 243 Franches-Montagnes (FM) stallions and extracted joint angles based on specific landmark triplets....
Castagnetti C, Mariella J, Pirrone A, Cinotti S, Mari G, Peli A.To evaluate and compare the gene expression of interleukin(IL)-1β, IL-8, and interferon-γ during the first 72 hours after birth in healthy foals and during the first 72 hours after hospitalization in sick neonatal foals and investigate correlations of clinicopathologic variables with cytokine expressions in healthy and sick neonatal foals. Methods: 33 foals < 7 days old (10 healthy foals, 7 foals with sepsis, 6 foals with peripartum asphyxia syndrome, and 12 foals with other diseases [2 with failure of passive transfer of immunity only were not further evaluated]). Methods: A blood sample...
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...
Gama A, Elias J, Ribeiro AJ, Alegria N, Schallig HD, Silva F, Santarém N, Cardoso L, Cotovio M.The first case of cutaneous leishmaniosis in a horse from the north of Portugal, with a 1.5 cm in diameter ulcerated nodular lesion on the left face, is reported. The skin nodule was surgically excised and assessed by histopathology, including an immunohistochemistry method applied for the first time to equine tissues which clearly demonstrated leishmanial amastigote forms. Two serological determinations with the direct agglutination test performed 13 months apart showed seroconversion specific for Leishmania from a <25 to a 200 antibody titre. Polymerase chain reaction followed by kinetopl...
Bao T, Han H, Li B, Zhao Y, Bou G, Zhang X, Du M, Zhao R, Mongke T, Laxima , Ding W, Jia Z, Dugarjaviin M, Bai D.Skeletal muscle is the largest organ system in the mammalian body and plays a key role in locomotion of horses. Fast and slow muscle fibers have different abilities and functions to adapt to exercises. To investigate the RNA and miRNA expression profiles in the muscles with different muscle fiber compositions on Mongolian horses. We examined the muscle fiber type population and produced deep RNA sequencing for different parts of skeletal muscles. And chose two of them with the highest difference in fast and slow muscle fiber population (splenius and gluteus medius) for comparing the gene expre...
Crowe MW, Swerczek TW.In a 13-year survey of equine congenital defects that resulted in death or required euthanasia in central Kentucky, necropsies were performed on 608 deformed fetuses or newborn foals. The following congenital anomalies were observed: contracted foal syndrome (33.2%), miscellaneous limb contraction (20%), multiple defects (5.3%), microphthalmia (4.6%), craniofacial malformations (4.3%), cleft palate (4.0%), heart defects (3.5%), umbilical defects (3.5%), and hydrocephalus (3.0%). Eleven less frequently occurring anomalies constituted the balance of the congenital defects in fetuses and newborn ...
Holmes CM, Violette N, Miller D, Wagner B, Svansson V, Antczak DF.The Icelandic horse has been maintained as a closed population in its eponymous homeland for many generations, with no recorded introductions of new horses of any breed since the year 1000 CE. Here we determined the diversity of major histocompatibility complex (MHC) haplotypes in 156 Icelandic horses from two groups, based on a panel of 12 polymorphic intra-MHC microsatellites tested in families of various composition. We identified a total of 79 MHC haplotypes in these two groups, including one documented intra-MHC recombination event from a total of 147 observed meioses. None of these MHC h...
ROCKEY JH, KLINMAN NR, KARUSH F.Anti-p-azophenyl-beta-lactoside (Lac) antibody has been isolated from equine antiserum by specific precipitation with Lac-HSA (human serum albumin) and Lac-Hy (hemocyanin). Antibody was separated from antigen by chromatography on DEAE cellulose and zone electrophoresis in solvents containing lactose. Six antigenically distinct immunoglobulins have been identified in purified equine anti-Lac antibody: 7S beta(2A)-globulin, 19S gamma-globulin, a 10S gamma(1) globulin, and three antigenically distinct 7S gamma-globulins. The specific hapten-binding activity of the 7S beta(2A)-antibody and of the ...
Waller AS, Paillot R, Timoney JF.Strangles caused by the host adapted Lancefield group C Streptococcus equi subspecies equi (S. equi) is a frequently diagnosed infectious disease of horses worldwide. Critical to the global success of S. equi is its ability to establish persistent infections within the guttural pouches of recovered apparently healthy horses that can result in transmission to in-contact animals. Recent research has identified key events in the S. equi genome, which occurred during its evolution from an ancestral strain of S. equi subspecies zooepidemicus, that may enhance its ability to evade host innate immune...
Harty RN, Caughman GB, Holden VR, O'Callaghan DJ.Equine herpesvirus 1 (EHV-1, Kentucky A strain) preparations enriched for defective interfering particles (DIPs) can readily establish persistent infection. The UL1 gene, which is conserved in the genome of DIPs that mediate persistent infection, maps between nucleotides 1418 and 2192 (258 amino acids) from the L (long) terminus. UL1 has no homology with any known gene encoded by herpes simplex virus type 1 but has limited homology to open reading frame 2 of varicella-zoster virus and the "circ" gene of bovine herpesvirus type 1. Previous work showed that the EHV-1 UL1 gene belongs to the earl...
Achmann R, Curik I, Dovc P, Kavar T, Bodo I, Habe F, Marti E, Sölkner J, Brem G.Blood samples of 561 Lipizzan horses from subpopulations (studs) of seven European countries representing a large fraction of the breed's population were used to examine the genetic diversity, population subdivision and gene flow in the breed. DNA analysis based on 18 microsatellite loci revealed that genetic diversity (observed heterozygosity = 0.663, gene diversity = 0.675 and the mean number of alleles = 7.056) in the Lipizzan horse is similar to other horse breeds as well as to other domestic animal species. The genetic differentiation between Lipizzan horses from different studs, although...
Livolant F.The fine structure of chromatin in sperm heads was investigated by different microscopic techniques: in vivo examinations in the polarizing microscope, thin sections and freeze-fracture replicas observed by transmission electron microscopy. The freeze-fractured chromatin appears to be formed of superimposed lamellae, each one 330 A thick. These lamellae are parallel to the flattening plane of the sperm head. This situation was already described in other mammal spermatozoa and in particular in the bull and the rabbit. This work presents a new interpretation of this lamellated aspect. The chroma...
Takai S, Takeda K, Nakano Y, Karasawa T, Furugoori J, Sasaki Y, Tsubaki S, Higuchi T, Anzai T, Wada R, Kamada M.To investigate the emergence of rifampin resistance in Rhodococcus equi strains isolated from foals and their environment in Japan, we compared the in vitro antimicrobial susceptibilities to rifampin of 640 isolates from 64 infected foals and 98 soil isolates from their horse-breeding farms. As a control, 39 human isolates from patients with and without AIDS were also tested for susceptibility to rifampin. All of the isolates showed rifampin sensitivity, except isolates from one infected foal and two patients with AIDS that showed rifampin resistance. To investigate the emergence of rifampin-r...
Han H, Wallner B, Rigler D, MacHugh DE, Manglai D, Hill EW.The Mongolian horse represents one of the most ancient extant horse populations. In this study we determined the male-specific region of the Y chromosome (MSY) haplotype distribution in 60 Chinese Mongolian horses representing five distinct populations. Cosmopolitan male lineages were predominant in horses from one improved (Sanhe), one Chinese Mongolian subtype (Baicha Iron Hoof) and one indigenous (Abaga Black) population. In contrast, autochthonous Y chromosome diversity was evident among the two landrace populations (Wushen and Wuzhumuqin), as the majority of their MSY haplotypes were situ...
Barlough JE, Reubel GH, Madigan JE, Vredevoe LK, Miller PE, Rikihisa Y.Ehrlichia DNA was identified by nested PCR in operculate snails (Pleuroceridae: Juga spp.) collected from stream water in a northern California pasture in which Potomac horse fever (PHF) is enzootic. Sequencing of PCR-amplified DNA from a suite of genes (the 16S rRNA, groESL heat shock operon, 51-kDa major antigen genes) indicated that the source organism closely resembled Ehrlichia risticii, the causative agent of PHF. The minimum percentage of Juga spp. harboring the organism in the population studied was 3.5% (2 of 57 snails). No ehrlichia DNA was found in tissues of 123 lymnaeid, physid, a...
Jorm LR, Love DN, Bailey GD, McKay GM, Briscoe DA.The genetic structure of beta-haemolytic Lancefield group C streptococci isolated from horses in Australia was examined by multilocus enzyme electrophoresis. The 249 isolates comprised 70 classified phenotypically as Streptococcus equi subspecies equi, 177 classified as S equi subspecies zooepidemicus and two which were unclassifiable. Forty-one electrophoretic types were identified which could be classified into three major clusters, A, B and C. Of the isolates, 178 fell into cluster B (types 4 to 22) and lay within a genetic distance of 0.36. Sixty-nine of the 70 S equi subspecies equi isola...
Hébert L, Moumen B, Duquesne F, Breuil MF, Laugier C, Batto JM, Renault P, Petry S.Taylorella equigenitalis is the causative agent of contagious equine metritis (CEM), a sexually transmitted infection of horses. We herein report the genome sequence of T. equigenitalis strain MCE9, isolated in 2005 from the urethral fossa of a 4-year-old stallion in France.
Andersson LS, Juras R, Ramsey DT, Eason-Butler J, Ewart S, Cothran G, Lindgren G.Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome consists of a diverse set of abnormalities predominantly localized to the frontal part of the eye. The disease is in agreement with a codominant mode of inheritance in our horse material. Animals presumed to be heterozygous for the mutant allele have cysts originating from the temporal ciliary body, peripheral retina and/or iris. In contrast, animals predicted to be homozygous for the disease-causing allele possess a wide range of multiple abnormalities, including iridociliary and/or peripheral retinal cysts, iridocorneal angle abnorm...
Pape M, Posedi J, Failing K, Schnieder T, von Samson-Himmelstjerna G.To study the prevalence of the polymorphism in position 200 of the beta-tubulin gene in the mechanism of benzimidazole (BZ) resistance in cyathostomes of horses, an allele-specific PCR was used to detect the genotype of individuals of BZ-susceptible and BZ-resistant populations. The molecular analysis of 100 adults recovered from an anthelmintic-naïve horse revealed 80% homozygous TTC/TTC individuals, 17% heterozygous TTC/TAC and 3% homozygous TAC/TAC. A naturally infected horse was treated with increasing fenbendazole (FBZ) dosages to select a BZ-resistant population of cyathostomes. The PCR...
