Horse breeds represent the diverse genetic and phenotypic variations found within the species Equus ferus caballus. These breeds are categorized based on characteristics such as size, conformation, coat color, and temperament, which have been selectively bred over centuries to fulfill specific roles and functions. Common classifications of horse breeds include light horses, draft horses, and ponies, each serving different purposes ranging from riding and racing to work and companionship. This page aggregates peer-reviewed research studies and scholarly articles that explore the genetics, history, and functional attributes of various horse breeds, as well as their impact on equine management and breeding practices.
Smith MA, Kristula MA, Aceto H, Levine DG.Fibrinogen and serum amyloid A (SAA) are commonly measured equine acute phase proteins. Limited data exist on SAA and fibrinogen responses to combination vaccination protocols in horses. A prospective cohort study evaluating SAA, fibrinogen, and rectal temperature following a standard combination vaccination. Blood for measurement of SAA and serum fibrinogen and rectal temperatures were obtained before (0 hour) and after vaccination (24, 48, 72, 96, 168 hours). After vaccination, SAA and fibrinogen increased in all horses. Imports had elevated SAA from 24-168 hours, whereas native horses retur...
van Bömmel-Wegmann S, Gehlen H, Barton AK, Büttner K, Zentek J, Paßlack N.Little is known about the animal- and diet-related factors that could interfere with the plasma zinc (Zn) concentrations of equines. Additionally, the adequacy of plasma to reflect changes in the Zn intake is unclear. In the first part of this study, the plasma Zn concentrations of hospitalized horses and ponies ( = 538) were measured and evaluated for the impact of the age, sex, horse type, and internal diseases of the animals. In the second part, the effects of increasing dietary Zn chloride hydroxide and Zn methionine supplementations were assessed on the plasma and mane hair Zn concentrati...
Grimwood K, Lancaster B, Handel I.Accurate measurement of equine body weight is important for evaluating medication dosages and feed quantities. Different methods exist for measuring body weight, including weigh tapes (WT), though accuracy varies. Measurements could be affected by external variables, such as time of day, human error, or uneven surfaces, and also horse-based variables, such as height and body condition score (BCS). The aim of this study was to investigate how different horse-based variables affect WT reading. A retrospective analysis was performed using anonymised data from feed company nutrition consultations ...
Science (New York, N.Y.)March 30, 2023
Volume 379, Issue 6639 1316-1323 doi: 10.1126/science.adc9691
Taylor WTT, Librado P, American Horse CJ, Shield Chief Gover C, Arterberry J, Afraid of Bear-Cook AL, Left Heron H, Yellow Hair RM, Gonzalez M....The horse is central to many Indigenous cultures across the American Southwest and the Great Plains. However, when and how horses were first integrated into Indigenous lifeways remain contentious, with extant models derived largely from colonial records. We conducted an interdisciplinary study of an assemblage of historic archaeological horse remains, integrating genomic, isotopic, radiocarbon, and paleopathological evidence. Archaeological and modern North American horses show strong Iberian genetic affinities, with later influx from British sources, but no Viking proximity. Horses rapidly sp...
Silva GF, Cunha R, Carvalho F, Ribeiro M, Rocha A, Amorim I, Guimarães T.A 30-year-old Lusitano stallion presented with an enlarged right epididymis. The ultrasound scan revealed a cyst-like formation and the histopathological examination was compatible with epididymal cyst located at the body/tail transition, epididymal spermatocele and sperm granuloma and epididymitis. However, these conditions did not seem to affect the animal's reproductive performance, nor did the semen parameters analyzed over the 8 years after the diagnosis show significant changes. Nevertheless, since the ejaculate contains mostly sperm cells from the tail of the epididymis, where fertile s...
Holtby AR, Hall TJ, McGivney BA, Han H, Murphy KJ, MacHugh DE, Katz LM, Hill EW.Behavioural plasticity enables horses entering an exercise training programme to adapt with reduced stress. We characterised SNPs associated with behaviour in yearling Thoroughbred horses using genomics analyses for two phenotypes: (1) handler-assessed coping with early training events [coping] (n = 96); and (2) variation in salivary cortisol concentration at the first backing event [cortisol] (n = 34). Using RNA-seq derived gene expression data for amygdala and hippocampus tissues from n = 2 Thoroughbred stallions, we refined the SNPs to those with functional relevance to behaviour by c...
Masuda M, Nikadori A, Nikadori E, Uchida N, Takizawa Y, Ishimaru M, Yamamoto T, Yuasa R, Kugai H, Nagahama Y, Takasu M, Tozaki T.The Miyako horse is a native Japanese horse breed. As with other native Japanese horses, the number of Miyako horses decreased due to mechanization and motorization, which reduced their roles, with just 14 in 1980. Although their population had increased to 55 horses by 2021, a further increase in their numbers is required to avoid extinction. Recently, their breeding has involved natural mating during group grazing; therefore, pedigree management has been difficult, and individual identification has been inconclusive. With the aim of formulating an effective breeding plan, this study used mic...
Lauková A, Styková E, Focková V, Maďar M.Nowadays, developed more precisious identification techniques have allowed to validate newer enterococcal species. Among them, the species Enterococcus moraviensis was also validated, at first from surface waters. However, in this study, characteristics and potential to bacteriocin production by the strain E. moraviensis EMo 1-1Nik isolated from buccal mucosa of Slovak warm-blood horse breed has been studied. BLASTn analysis allotted this strain to the species E. moraviensis with percentage identity BLASTn 16S rRNA sequence in the strain up to 100% (99.93% similarity with E. moraviensis NR1139...
Sievers J, Distl O.Chronic progressive lymphedema (CPL) is a common disease in Rhenisch German draught horses. The objective of our study was to evaluate the prevalence of this disease and its progression with age in 493 Rhenish German draught horses from different regions in Germany. We employed generalized linear models with binomial, multinomial, and normal distributions to analyse the effects of breeding association, coat colour, sex and age within sex, time of examination, limb on which CPL was recorded, and farm-related factors on disease scores. The occurrence and severity of CPL were significantly influe...
Hernández-Avilés C, Ramírez-Agámez L, Pearson M, Beckham AMN, Varner DD, Love CC.Analysis of sperm morphology is an important part of the stallion breeding soundness evaluation since it provides an objective measure of a stallion's sperm quality and is one of many factors that estimate a stallion's fertility potential. To describe the effect of sperm quality level on the technique (Differential Interference Contrast - DIC; Phase-contrast - PH; Dip-Quick staining - DQ; and eosin-nigrosin staining - EN; semen samples fixed in buffered-formal saline) and evaluator (three evaluators; using only DIC), stallions were categorized based on sperm quality into three categories: High...
Walshe N, Burrell A, Kenny U, Mulcahy G, Duggan V, Regan A.In view of the rising threat of anthelmintic resistance in parasite populations and the planned change of classification of anthelmintics in Ireland for food animals to prescription-only medicines, there is a need for increased focus on parasite control strategies for horses. Effective parasite control programs (PCPs) are complex, necessitating the application of risk-assessment based on host immune status, infection pressure, type of parasite and seasonality to determine the requirement for anthelmintic administration and an understanding of parasite biology to employ effective, non- therapeu...
Tozaki T, Ohnuma A, Kikuchi M, Ishige T, Kakoi H, Hirota KI, Takahashi Y, Nagata SI.Thoroughbreds are some of the most famous racehorses worldwide and are currently animals of high economic value. To understand genomic variability in Thoroughbreds, we identified genome-wide insertions and deletions (INDELs) and obtained their allele frequencies in this study. INDELs were obtained from whole-genome sequencing data of 101 Thoroughbred racehorses by mapping sequence reads to the horse reference genome. By integrating individual data, 1,453,349 and 113,047 INDELs were identified in the autosomal (1-31) and X chromosomes, respectively, while 18 INDELs were identified on the mitoch...
Nazari-Ghadikolaei A, Fikse F, Gelinder Viklund Å, Eriksson S.Assessment protocols to describe the various aspects of conformation, gait and jumping traits on a linear scale were introduced at young horse tests for Swedish Warmblood horses in 2013. The traits scored on a linear scale are assumed to be less subjective and more easily compared across populations than the traditional evaluated traits that are scored relative to the breeding goal. However, the resulting number of traits is considerable, and several of the traits are correlated. The aim of this study was to investigate the interrelationship between the different evaluated and linearly scored ...
Hill EW, McGivney BA, MacHugh DE.The proportion of the genome containing runs of homozygosity (ROH) affects production traits in livestock populations. In European and Australasian Thoroughbreds inbreeding, quantified using ROH (F ), is associated with the probability of ever racing. Here, we measured F using 333 K SNP genotypes from 768 Thoroughbred horses born in North America to evaluate the effect of inbreeding on racing traits in that region. Among North American horses, F was not associated (p = 0.518) with the probability of ever racing but was significantly associated with the number of race starts (p = 0.002). ...
Tinel JB, Veras MM, Waked D, Alonso MA, Fernandes CB.Mules are derived from crossing horse mares with a donkey, in which the interest is due to gentleness and ability to work and equestrian sports. As the placenta is responsible for fetal development and maturation, knowing its typical microstructure allows us to understand how fetomaternal interactions occur in this interspecific pregnancy. Thus, the study performed a comparative stereological evaluation of volumetric composition and fetomaternal contact surface in the uterine body (UB), gravid uterine horn (GUH), and nongravid uterine horn (NGUH) of Mangalarga Paulista mare's term allantochori...
Pimentel F, McManus C, Soares K, Caetano AR, de Faria DA, Paiva SR, Ianella P.Optimization of DNA collection for National gene bank and conservation programs requires information on spatial and genetic distribution of animals countrywide. The relationship between genetic and geographic distances were examined in 8 Brazilian horse breeds (Baixadeiro, Crioulo, Campeiro, Lavradeiro, Marajoara, Mangalarga Marchador, Pantaneiro and Puruca) using Single Nucleotide Polymorphism markers and collection point locations. Mantel correlations, Genetic Landscape Shape Interpolation, Allelic Aggregation Index Analyses and Spatial autocorrelation tests indicated a nonrandom distributio...
Boisseau M, Mach N, Basiaga M, Kuzmina T, Laugier C, Sallé G.Equine strongyles encompass more than 64 species of nematode worms that are responsible for growth retardation and the death of animals. The factors underpinning variation in the structure of the equine strongyle community remain unknown. Methods: Using horse-based strongyle community data collected after horse deworming (48 horses in Poland, 197 horses in Ukraine), we regressed species richness and the Gini-Simpson index upon the horse's age, faecal egg count, sex and operation of origin. Using the Ukrainian observations, we applied a hierarchical diversity partitioning framework to estimate ...
Klecel W, Drobik-Czwarno W, Martyniuk E.Arabian show horses are well known for their exceptional beauty and elegance. The breed type, body conformation and movement are assessed during horse shows by licensed judges. The 5 judging categories are type, head and neck, body and topline, legs and movement, which are scored on a 20 point scale. It can be hypothesized that the scores in different categories are related to each other, and that the score for the most subjective type category depends on the scores for conformation categories. We analyzed 762 sets of average scores obtained by 583 unique horses at the World Championships. Cor...
Liu X, Seguin-Orlando A, Chauvey L, Tressières G, Schiavinato S, Tonasso-Calvière L, Aury JM, Perdereau A, Wagner S, Clavel P, Estrada O, Pan J....Age profiling of archaeological bone assemblages can inform on past animal management practices, but is limited by the fragmentary nature of the fossil record and the lack of universal skeletal markers for age. DNA methylation clocks offer new, albeit challenging, alternatives for estimating the age-at-death of ancient individuals. Here, we take advantage of the availability of a DNA methylation clock based on 31,836 CpG sites and dental age markers in horses to assess age predictions in 84 ancient remains. We evaluate our approach using whole-genome sequencing data and develop a capture assay...
Lewis N, Canesin H, Choi YH, Foss R, Felix M, Rader K, Hinrichs K.Information on factors associated with developmental competence of equine in vitro -produced (IVP) blastocysts is lacking. Objective: To determine the relationships of stage, grade, day of development, and specific morphological parameters of equine IVP blastocysts, to pregnancy and foaling rates. Methods: Photomicrographs of 316 IVP embryos with known pregnancy outcomes were scrutinised individually by four observers. Inter-observer variation was assessed, and pregnancy outcome evaluated in relation to day of blastocyst development and assigned grade and stage. Individual component analysis w...
Rajabi-Toustani R, Tsogtgerel M, Gao Y, Li C, Sakato M, Haneda S, Cheong SH, Nambo Y.Japanese native horses, which consists of 8 breeds, are threatened with extinction. Embryo transfer (ET) is used to reproduce endangered animals in various mammalian species. We aimed to perform ET using native ponies from Kiso and Hokkaido as donors and recipients, respectively. ET operation included long-distance transport of non-cryopreserved embryos from Nagano Prefecture to Hokkaido. Embryos were transported 1500 km over 9 h in a container maintained at 22°C. After transferring two embryos to two recipients, one mare delivered a healthy live foal. These results demonstrated that reciproc...
Nishita Y, Amaike Y, Spassov N, Hristova L, Kostov D, Vladova D, Peeva S, Raichev E, Vlaeva R, Masuda R.The domestication of the horse began possibly more than 5000 years ago in the western part of the Eurasian steppe, and according to the leading hypothesis, horses first spread from the Steppe toward the region of the Thracian culture, starting in the second half of the 2nd millennium BCE and flourished from the fifth to first centuries BCE, mainly located in present-day Bulgaria. We analyzed 17 horse bone remains excavated from Thracian archaeological sites (fourth to first centuries BCE) in Bulgaria and successfully identified 17 sequences representing 14 different haplotypes of the mitocho...
Legg KA, Gee EK, Breheny M, Gibson MJ, Rogers CW.The Thoroughbred racing industry faces new and competing pressures to operate within a modern, changing society. Three major moderators drive the focus and productivity of the industry worldwide: economic sustainability, horse biology and social licence to operate. This review proposes that despite the apparent homogeneity in the structure of racing across jurisdictions due to international regulation of the sport, there are significant differences within each jurisdiction in each of the three moderators. This creates challenges for the comparison of injury risk factors for racehorses within t...
Lv S, Zhang Y, Zhang Z, Meng S, Pu Y, Liu X, Liu L, Ma Y, Liu W, Jiang L.The gut microbiomes of equine are plentiful and intricate, which plays an important part in the growth. However, there is a relative lack of information on the microbial diversity in the pony's gut. Unassigned: In this article, 118 fecal samples from DeBa pony, NiQi pony and GuZh horse were studied by 16S rRNA amplicon sequencing. Unassigned: Diversity analysis was used to determine the difference of gut microbiota composition among different breeds. Alpha diversity analysis showed that the gut microbiota of NiQi ponies were abundant and various. Beta diversity analysis showed that the microor...
Frontiers in geneticsJanuary 23, 2023
Volume 14 1099896 doi: 10.3389/fgene.2023.1099896
Capomaccio S, Ablondi M, Colombi D, Sartori C, Giontella A, Cappelli K, Mancin E, Asti V, Mantovani R, Sabbioni A, Silvestrelli M. The Italian peninsula is in the center of the Mediterranean area, and historically it has been a hub for numerous human populations, cultures, and also animal species that enriched the hosted biodiversity. Horses are no exception to this phenomenon, with the peculiarity that the gene pool has been impacted by warfare and subsequent "colonization". In this study, using a comprehensive dataset for almost the entire Italian equine population, in addition to the most influential cosmopolitan breeds, we describe the current status of the modern Italian gene pool. The Italian dataset comprised 1,3...
Gutiérrez-Cepeda L, Crespo F, Blazquez JC, Serres C.The Purebred Spanish Horse, according to our clinical experience, is characterized by having a high number of stallions that do not meet the international commercial recommendations for equine-sperm cryopreservation. This means that artificial insemination with frozen semen from these stallions is less widespread than in other breeds. In this study, we investigated if the incorporation of single-layer colloidal centrifugation prior to cryopreservation in clinical conditions could increase the number of ejaculates of Purebred Spanish stallions suitable for this processing, observing the influen...
He Z, Dai X, Lyu W, Beaumont M, Yu F.Novel technologies for recovering DNA information from archaeological and historical specimens have made available an ever-increasing amount of temporally spaced genetic samples from natural populations. These genetic time series permit the direct assessment of patterns of temporal changes in allele frequencies and hold the promise of improving power for the inference of selection. Increased time resolution can further facilitate testing hypotheses regarding the drivers of past selection events such as the incidence of plant and animal domestication. However, studying past selection processes ...
Han H, Randhawa IAS, MacHugh DE, McGivney BA, Katz LM, Dugarjaviin M, Hill EW.Thousands of years of natural and artificial selection since the domestication of the horse has shaped the distinctive genomes of Chinese Mongolian horse populations. Consequently, genomic signatures of selection can provide insights into the human-mediated selection history of specific traits and evolutionary adaptation to diverse environments. Here, we used genome-wide SNPs from five distinct Chinese Mongolian horse populations to identify genomic regions under selection for the population-specific traits, gait, black coat colour, and hoof quality. Other global breeds were used to identify r...
Holmes TQ, Brown AF.Equestrian sports, including racing (e.g., flat, steeple-chasing, harness or donkey derby); show-jumping; cross-country; dressage; polo; polocrosse; endurance; carriage driving; vaulting and hunting; are hugely popular in the UK, and they involve a significant number of people, both as participants and spectators, and tens of thousands of equids. In this paper, we discuss animal welfare as a complex and disputed issue, clarifying what the term means and how it can be measured. We review many aspects of welfare risk to equids used for sport, addressing issues encountered throughout their lives,...
Ishida N, Oyunsuren T, Mashima S, Mukoyama H, Saitou N.The noncoding region between tRNAPro and the large conserved sequence block is the most variable region in the mammalian mitochondrial DNA D-loop region. This variable region (ca. 270 bp) of four species of Equus, including Mongolian and Japanese native domestic horses as well as Przewalskii's (or Mongolian) wild horse, were sequenced. These data were compared with our recently published Thoroughbred horse mitochondrial DNA sequences. The evolutionary rate of this region among the four species of Equus was estimated to be 2-4 x 10(-8) per site per year. Phylogenetic trees of Equus species demo...
Marklund S, Ellegren H, Eriksson S, Sandberg K, Andersson L.Ten (TG)n positive clones, isolated from an equine genomic library and sequenced, contained 12-19 uninterrupted TG repeats. Primers for polymerase chain reaction (PCR) were synthesized and nine of these (TG)n loci (HTG7-15) were successfully amplified and utilized in this study together with five previously reported equine microsatellite loci (HTG2-6). The PCR products were analysed by polyacrylamide gel electrophoresis followed by automated laser fluorescence detection or autoradiography. All microsatellites showed polymorphism and stable Mendelian inheritance. Differences in microsatellite v...
Marín Navas C, Delgado Bermejo JV, McLean AK, León Jurado JM, Torres ARBYR, Navas González FJ.Genetic diversity and population structure were analyzed using the historical and current pedigree information of the Arabian (PRá), Spanish Purebred (PRE), and Hispano-Arabian (Há) horse breeds. Genetic diversity parameters were computed and a canonical discriminant analysis was used to determine the contributions of ancestor breeds to the genetic diversity of the Há horse. Pedigree records were available for 207,100 animals born between 1884 and 2019. Nei's distances and the equivalent subpopulations number indicated the existence of a highly structured, integrated population for the Há ...
Swinburne JE, Boursnell M, Hill G, Pettitt L, Allen T, Chowdhary B, Hasegawa T, Kurosawa M, Leeb T, Mashima S, Mickelson JR, Raudsepp T, Tozaki T....A genetic linkage map of the horse consisting of 742 markers, which comprises a single linkage group for each of the autosomes and the X chromosome, is presented. The map has been generated from two three-generation full-sibling reference families, sired by the same stallion, in which there are 61 individuals in the F2 generation. Each linkage group has been assigned to a chromosome and oriented with reference to markers mapped by fluorescence in situ hybridization. The average interval between markers is 3.7 cM and the linkage groups collectively span 2772 cM. The 742 markers comprise 734 mic...
Osterman Lind E, Höglund J, Ljungström BL, Nilsson O, Uggla A.Faecal egg counts were performed during the first quarter of 1995 on samples from 1183 horses of varying breeds, ages and gender on 110 farms in 3 regions of Sweden. The majority of the horses had been treated with ivermectin or pyrantel when stabled the previous autumn. The risk of reinfection with strongyles between treatment and sampling was therefore considered to be minimal. Consequently, the results reflect primarily the occurrence of worms originating from inhibited strongyle larvae refractory to anthelmintic treatment. A total of 922 (78%) individuals were found to shed strongyle eggs,...
Cook D, Brooks S, Bellone R, Bailey E.Champagne coat color in horses is controlled by a single, autosomal-dominant gene (CH). The phenotype produced by this gene is valued by many horse breeders, but can be difficult to distinguish from the effect produced by the Cream coat color dilution gene (CR). Three sires and their families segregating for CH were tested by genome scanning with microsatellite markers. The CH gene was mapped within a 6 cM region on horse chromosome 14 (LOD = 11.74 for theta = 0.00). Four candidate genes were identified within the region, namely SPARC [Secreted protein, acidic, cysteine-rich (osteonectin)], SL...
Morris GJ, Faszer K, Green JE, Draper D, Grout BW, Fonseca F.The cellular damage that spermatozoa encounter at rapid rates of cooling has often been attributed to the formation of intracellular ice. However, no direct evidence of intracellular ice has been presented. An alternative mechanism has been proposed by Morris (2006) that cell damage is a result of an osmotic imbalance encountered during thawing. This paper examines whether intracellular ice forms during rapid cooling or if an alternative mechanism is present. Horse spermatozoa were cooled at a range of cooling rates from 0.3 to 3,000 degrees C/min in the presence of a cryoprotectant. The ultra...
Kakoi H, Tozaki T, Gawahara H.To assess the genetic diversity of Japanese native horse populations, we examined seven such populations using mitochondrial DNA (mtDNA) and microsatellite analyses. Four reference populations of Mongolian horses and European breeds were employed as other equids. In the mtDNA analysis, the control region (D-loop) of 411 bp was sequenced, and 12 haplotypes with 33 variable sites were identified in the Japanese native horses. The phylogenetic tree constructed by haplogrouping and using worldwide geographic references indicated that the haplotypes of the Japanese native horses were derived from s...
Klein C.Maintenance of pregnancy is dependent on the exchange of signals between the conceptus and the endometrium. The objective of this study was to use next-generation sequencing to determine transcriptome blueprints of the conceptus and endometrium 16 days after ovulation in the horse. There were 7760 and 10 182 genes expressed in the conceptus and endometrium, respectively, of which 7029 were present in both. Genes related to developmental processes were enriched among conceptus-specific transcripts, whereas many endometrium-specific genes had known roles in cell communication, cell adhesion and ...
MacLeay JM, Sorum SA, Valberg SJ, Marsh WE, Sorum MD.To determine incidence, effect on performance, and management practices associated with exertional rhabdomyolysis (ER) in Thoroughbreds. Methods: Medical records for 984 Thoroughbreds and a survey of trainers of horses with and without ER. Methods: Medical records for 984 Thoroughbreds stabled at a midwestern racetrack were examined to determine the incidence of ER during the 1995 racing season. A retrospective questionnaire was administered to trainers to determine management practices associated with ER in 59 Thoroughbreds with ER and 47 control Thoroughbreds in training. Multiple logistic r...
Sun TC, Riggs CM, Cogger N, Wright J, Al-Alawneh JI.Reports of fractures in racehorses have predominantly focused on catastrophic injuries, and there are limited data identifying the location and incidence of fractures that did not result in a fatal outcome. Objective: To describe the nature and the incidence of noncatastrophic and catastrophic fractures in Thoroughbreds racing at the Hong Kong Jockey Club (HKJC) over seven racing seasons. Methods: Retrospective cohort study. Methods: Data of fractures sustained in horses while racing and of race characteristics were extracted from the HKJC Veterinary Management Information System (VMIS) and Ra...
Szóstek-Mioduchowska AZ, Baclawska A, Okuda K, Skarzynski DJ.Equine endometrosis (endometrial fibrosis) is a degenerative chronic process that occurs in the uterus of the mare and disturbs proper endometrial function. Fibrosis is attributed to excessive deposition of extracellular matrix (ECM) components. The turnover of ECM is mediated by matrix metallopeptidases (MMP). Previously, it was shown that cytokines modulate MMP expression in other tissues and may regulate fibrosis indirectly by attracting inflammatory cells to the site of inflammation and directly on various tissues. However, the regulation of MMP expression in equine endometrosis is still r...
Boyko AR, Brooks SA, Behan-Braman A, Castelhano M, Corey E, Oliveira KC, Swinburne JE, Todhunter RJ, Zhang Z, Ainsworth DM, Robinson NE.Equine recurrent laryngeal neuropathy (RLN) is a bilateral mononeuropathy with an unknown pathogenesis that significantly affects performance in Thoroughbreds. A genetic contribution to the pathogenesis of RLN is suggested by the higher prevalence of the condition in offspring of RLN-affected than unaffected stallions. To better understand RLN pathogenesis and its genetic basis, we performed a genome-wide association (GWAS) of 282 RLN-affected and 268 control Thoroughbreds. Results: We found a significant association of RLN with the LCORL/NCAPG locus on ECA3 previously shown to affect body siz...
Gim JA, Hong CP, Kim DS, Moon JW, Choi Y, Eo J, Kwon YJ, Lee JR, Jung YD, Bae JH, Choi BH, Ko J, Song S, Ahn K, Ha HS, Yang YM, Lee HK, Park KD....Athletic performance is an important criteria used for the selection of superior horses. However, little is known about exercise-related epigenetic processes in the horse. DNA methylation is a key mechanism for regulating gene expression in response to environmental changes. We carried out comparative genomic analysis of genome-wide DNA methylation profiles in the blood samples of two different thoroughbred horses before and after exercise by methylated-DNA immunoprecipitation sequencing (MeDIP-Seq). Differentially methylated regions (DMRs) in the pre-and post-exercise blood samples of superio...
Heitor F, do Mar Oom M, Vicente L.The influence of age, dominance rank, kinship and aggressiveness over affiliative relationships and sexual behaviours were analysed in a herd of Sorraia horses, Equus caballus, kept under extensive management. Subjects were 10 adult mares 5-18 years old that had known each other since birth, and a stallion introduced into the group for breeding for the first time. Kinship coefficient and dominance rank were the most important factors affecting affiliative relationships. Bonds were reciprocal and stronger among mares with higher kinship. Mares spent more time in proximity to close-ranking and l...
Felkel S, Vogl C, Rigler D, Jagannathan V, Leeb T, Fries R, Neuditschko M, Rieder S, Velie B, Lindgren G, Rubin CJ, Schlötterer C, Rattei T, Brem G....Humans have shaped the population history of the horse ever since domestication about 5500 years ago. Comparative analyses of the Y chromosome can illuminate the paternal origin of modern horse breeds. This may also reveal different breeding strategies that led to the formation of extant breeds. Recently, a horse Y-chromosomal phylogeny of modern horses based on 1.46 Mb of the male-specific Y (MSY) was generated. We extended this dataset with 52 samples from five European, two American and seven Asian breeds. As in the previous study, almost all modern European horses fall into a crown group...
Dobrinski I, Smith TT, Suarez SS, Ball BA.Interaction of equine spermatozoa with oviductal epithelial cells (OEC) prolongs sperm viability and maintains low intracellular calcium concentration ([Ca2+]i) in spermatozoa. Experiments were designed to investigate 1) whether release of spermatozoa from OEC in vitro is associated with elevated [Ca2+]i and 2) whether soluble products from OEC or direct membrane contact between spermatozoa and OEC mediates the effects of OEC on sperm [Ca2+]i. In the first experiment, changes in [Ca2+]i in spermatozoa loaded with indo-1 acetoxymethylester were determined in motile spermatozoa released from OEC...
The Journal of heredityNovember 2, 2005
Volume 96, Issue 6 670-678 doi: 10.1093/jhered/esi123
Solis A, Jugo BM, Mériaux JC, Iriondo M, Mazón LI, Aguirre AI, Vicario A, Estomba A.In the present study, genetic analyses of diversity and differentiation were performed on four Basque-Navarrese semiferal native horse breeds. In total, 417 animals were genotyped for 12 microsatellite markers. Mean heterozygosity was higher than in other horse breeds, surely as a consequence of management. Although the population size of some of these breeds has declined appreciably in the past century, no genetic bottleneck was detected in any of the breeds, possibly because it was not narrow enough to be detectable. In the phylogenetic tree, the Jaca Navarra breed was very similar to the Po...
Kader A, Li Y, Dong K, Irwin DM, Zhao Q, He X, Liu J, Pu Y, Gorkhali NA, Liu X, Jiang L, Li X, Guan W, Zhang Y, Wu DD, Ma Y.Body size, one of the most important quantitative traits under evolutionary scrutiny, varies considerably among species and among populations within species. Revealing the genetic basis underlying this variation is very important, particularly in humans where there is a close relationship with diseases and in domestic animals as the selective patterns are associated with improvements in production traits. The Debao pony is a horse breed with small body size that is unique to China; however, it is unknown whether the size-related candidate genes identified in Western breeds also account for the...
Li B, He X, Zhao Y, Bai D, Du M, Song L, Liu Z, Yin Z, Manglai D.Horse testis development and spermatogenesis are complex physiological processes. To study these processes, three immature and three mature testes were collected from the Mongolian horse, and six libraries were established using high-throughput RNA sequencing technology (RNA-Seq) to screen for genes related to testis development and spermatogenesis. A total of 16,237 upregulated genes and 8,641 downregulated genes were detected in the testis of the Mongolian horse. These genes play important roles in different developmental stages of spermatogenesis and testicular development. Five genes with ...
Hestand MS, Kalbfleisch TS, Coleman SJ, Zeng Z, Liu J, Orlando L, MacLeod JN.Current gene annotation of the horse genome is largely derived from in silico predictions and cross-species alignments. Only a small number of genes are annotated based on equine EST and mRNA sequences. To expand the number of equine genes annotated from equine experimental evidence, we sequenced mRNA from a pool of forty-three different tissues. From these, we derived the structures of 68,594 transcripts. In addition, we identified 301,829 positions with SNPs or small indels within these transcripts relative to EquCab2. Interestingly, 780 variants extend the open reading frame of the transcri...
Ho JX, Holowachuk EW, Norton EJ, Twigg PD, Carter DC.The amino-acid sequence and three-dimensional structure of equine serum albumin have been determined. The amino-acid sequence was deduced from cDNA isolated from equine liver. Comparisons of the primary structure of equine serum albumin with human serum albumin and bovine serum albumin reveal 76.1% and 73.9% sequence identity, respectively. The three-dimensional structure was determined crystallographically by the molecular-replacement method using molecular coordinates from the previously determined structure of human serum albumin, to a resolution of 0.27 nm. In accordance with the primary s...
Egenvall A, Penell JC, Bonnett BN, Olson P, Pringle J.The aim of this study was to evaluate the potential usefulness of the database maintained by the Swedish insurance company Agria for providing mortality statistics on Swedish horses. Mortality statistics (incidence rates and survival) were calculated, both crudely and stratified by sex, age, breed, breed group and diagnosis, for the horses with complete life insurance, which covers most health problems. The total mortality was 415 (95 per cent confidence interval [CI] 399 to 432) deaths per 10,000 horse-years at risk, and the diagnostic mortality, including only deaths with an assigned diagnos...
Morrell JM, Johannisson A, Dalin AM, Rodriguez-Martinez H.The objective was to investigate whether it is possible to improve the quality of stallion semen, with respect to sperm morphology and chromatin integrity, both of which have been linked to fertility, using either density gradient centrifugation (DGC) or a new method, hereby named single layer centrifugation (SLC). The two methods of colloidal centrifugation were evaluated using 38 ejaculates from 10 stallions. Sperm morphology, subjective motility and sperm chromatin integrity were compared in uncentrifuged samples and in centrifuged sperm preparations. The proportion of morphologically norma...
Palmer E, Bézard J, Magistrini M, Duchamp G.Since the first successful collection of oocytes by non-surgical puncture, there have been numerous attempts to fertilize them but few segmented embryos have resulted. The latest attempts at follicular puncture (Palmer et al., 1987) provided 159 oocytes. Oocytes found broken (18%) were probably already broken, or at least fragile, before puncture. The 41 oocytes were fertilized only with semen treated with Ionophore A23187. Following ionophore treatment of semen, 16 ova segmented (of 113 inseminated oocytes) indicating fertilization, and another 7 showed signs of fertilization but not segmenta...
Avila F, Mickelson JR, Schaefer RJ, McCue ME.Selective breeding for athletic performance in various disciplines has resulted in population stratification within the American Quarter Horse (QH) breed. The goals of this study were to utilize high density genotype data to: (1) identify genomic regions undergoing positive selection within and among QH subpopulations; (2) investigate haplotype structure within each QH subpopulation; and (3) identify candidate genes within genomic regions of interest (ROI), as well as biological pathways, predicted to play a role in elite performance in each group. For that, 65K SNP genotyping data on 143 elit...
Ling Y, Ma Y, Guan W, Cheng Y, Wang Y, Han J, Jin D, Mang L, Mahmut H.Y chromosome acts as a single nonrecombining unit that is male specific and in effect haploid, thus ensuring the preservation of mutational events as a single haplotype via male lines. In this study, 6 Y chromosome-specific microsatellites (SSR) were tested for the patrilineal genetic variations of 573 male samples from Chinese domestic horse (30 breeds), Przewalski's horse, and donkey. All the 6 loci appeared as a haplotype block in Przewalski's horse and the domestic donkey. There were notable differences, however, at Y chromosome markers between horse and donkey. There were 2 haplotypes of ...
Barrey E, Desliens F, Poirel D, Biau S, Lemaire S, Rivero JL, Langlois B.Dressage is one of the Olympic equestrian sports practiced in several countries using different horse breeds. Specific characteristics of the walk, trot and canter are required for dressage. It has been assumed that some of these traits could be selected for genetically and contribute to dressage performance. The purpose of this study was to compare the walk, trot and conformation characteristics in young horses of different breeds used for dressage. A total of 142 horses age 3 years were classified into 3 groups of breeds (German, French and Spanish saddle horses) and tested using the same pr...
