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.
Felkel S, Vogl C, Rigler D, Dobretsberger V, Chowdhary BP, Distl O, Fries R, Jagannathan V, Janečka JE, Leeb T, Lindgren G, McCue M, Metzger J....Analysis of the Y chromosome is the best-established way to reconstruct paternal family history in humans. Here, we applied fine-scaled Y-chromosomal haplotyping in horses with biallelic markers and demonstrate the potential of our approach to address the ancestry of sire lines. We de novo assembled a draft reference of the male-specific region of the Y chromosome from Illumina short reads and then screened 5.8 million basepairs for variants in 130 specimens from intensively selected and rural breeds and nine Przewalski's horses. Among domestic horses we confirmed the predominance of a young'c...
Ducheyne KD, Rizzo M, Daels PF, Stout TAE, de Ruijter-Villani M.Vitrified-warmed immature equine oocytes are able to complete the first meiotic division, but their subsequent developmental competence is compromised. Therefore, the present study investigated the effects of vitrifying immature horse oocytes on the chromosome and spindle configuration after IVM. Cumulus-oocytes complexes (COCs) were collected and divided into two groups based on mare age (young ≤14 years; old ≥16 years). COCs were then either directly matured invitro or vitrified and warmed before IVM. Spindle morphology and chromosome alignment within MII stage oocytes were assessed usin...
Sales F, Ferreira-Silva J, Vieira J, Basto S, Filho P, Rocha J, Moura MT, Oliveira M.Post-diluents could potentially increase semen cryotolerance, but remain poorly explored in horses. The aim was to evaluate the efficiency of post-diluents on frozen-thawed semen viability of two stallions (S1-S2). The cryopreserved semen was thawed at 50°C for 40 seconds. Semen motility and acrosin activity (AA) were determined during the thermo-resistance test (TRT). Progressive motility of S2 semen decreased after 60 and 90 minutes of TRT (TRT60 and TRT90) on the control compared to both post-diluents. The total motility of both S1 and S2 decreased on TRT60 and TRT90 semen control versus b...
Noll CV, Kilcoyne I, Vaughan B, Galuppo LD.To report the clinical and diagnostic findings associated with fibrotic myopathy, describe the surgical procedure for standing fibrotic myotomy and report postoperative outcomes. Methods: Retrospective study. Methods: Twenty-two horses. Methods: Records were included if a clinical diagnosis of fibrotic myopathy was based on clinical and/or ultrasonographic examination and the horse was treated with myotomy of the affected muscle. Records were reviewed for signalment, preoperative findings, perioperative complications, and outcomes. Follow-up also included a phone survey of owners. Results: Qua...
Putnová L, Štohl R.Considering the extensive data sets and statistical techniques, animal breeding embodies a branch of machine learning that has a constantly increasing impact on breeding. In our study, information regarding the potential of machine learning and data mining within a large set of horses and breeds is presented. The individual assignment methods and factors influencing the success rate of the procedure are compared at the Czech population scale. The fixation index values ranged from 0.057 (HMS1) to 0.144 (HTG6), and the overall genetic differentiation amounted to 8.9% among the breeds. The highes...
Kuhnke S, Bär K, Bosch P, Rensing M, Borstel UKV.The study compared results of the traditional horse judging system (T) using subjective grades with those of a novel system of linear scoring (LS) using an application ("Breed Show App"). The horse's quality in relation to the total breeding aim was evaluated based on weighting factors for 57 individual traits commonly regarded in T, thus allowing immediate ranking of the horses. Results were stated as total grade in percent for both systems. One thousand nine hundred nine American Quarter horses were judged at regular breed shows with either T (n = 883), LS (n = 1,026), or both systems (n ...
Seong HS, Kim NY, Kim DC, Hwang NH, Son DH, Shin JS, Lee JH, Chung WH, Choi JW.The Jeju horse is an indigenous horse breed in Korea. However, there is a severe lack of genomic studies on Korean horse breeds. The objective of this study was to report genomic characteristics of domestic horse populations that inhabit South Korea (Jeju, Jeju crossbred, and Thoroughbred) and a wild horse breed (Przewalski's horse). Using the equine reference genome assembly (EquCab 2.0), more than ~ 6.5 billion sequence reads were successfully mapped, which generated an average of 40.87-fold coverage throughout the genome. Using these data, we detected a total of 12.88 million SNPs, of w...
Banfield J, Lisak R, Omar A, Domingos W, Fiaschitello A, Morales-Gomez A, Divers TJ, Mohammed HO.We carried out an investigation to identify the factors that predispose to the risk of equine motor neuron disease (EMND) and evaluated the long-term impact of an intervention. Data on several biomarkers, including antioxidants (α-tocopherols, β-carotenes, glutathione peroxidase (GSHPx)), and superoxide dismutase (SOD1), neurofilaments, and other putative risk factors hypothesized to associate with the likelihood of EMND were collected. The data were analyzed for their significance of association with the condition. The EMND outbreak started in 1991 and continued until 1998. A total of 69 EM...
Li B, He X, Zhao Y, Bai D, Bou G, Zhang X, Su S, Dao L, Liu R, Wang Y, Manglai D.P-element induced wimpy testis-interacting RNAs (piRNAs) are essential for testicular development and spermatogenesis in mammals. Comparative analyses of the molecular mechanisms of spermatogenesis among different organisms are therefore dependent on accurate characterizations of piRNAs. At present, little is known of piRNAs in non-model organisms. Here, we characterize piRNAs in the Mongolian horse, a hardy breed that reproduces under extreme circumstances. A thorough understanding of spermatogenesis and reproduction in this breed may provide insights for the improvement of fecundity and repr...
Ma H, Wang S, Zeng G, Guo J, Guo M, Dong X, Hua G, Liu Y, Wang M, Ling Y, Ding X, Zhao C, Wu C. The Jinjiang horse is a unique Chinese indigenous horse breed distributed in the southern coastal areas, but the ancestry of Jinjiang horses is not well understood. Here, we used Equine SNP70 Bead Array technology to genotype 301 horses representing 10 Chinese indigenous horse breeds, and we integrated the published genotyped data of 352 individuals from 14 foreign horse breeds to study the relationships between Jinjiang horses and horse breeds from around the world. Principal component analysis (PCA), linkage disequilibrium (LD), runs of homozygosity (ROH) analysis, and ancestry estimating m...
Zhang W, Cui S, Cheng XL, Wei F, Ma S.In this study, probe/primers of high specificity and sensitivity were selected to analyze donkey-hide gelatin for donkey DNA and to look for horse, ox, and pig DNA as possible adulterants. The mitochondrial CO I genes in donkey, horse, and ox were selected as target sequences for design and synthesis of three pairs of specific probes and primers. In addition, eight pairs of probe/primers were obtained via literature search. Out of these eleven groups of probe/primers, those with the highest specificity and sensitivity were selected, which was fulfilled by the screening firstly with animal hide...
Kobayashi I, Akita M, Takasu M, Tozaki T, Kakoi H, Nakamura K, Senju N, Matsuyama R, Horii Y.The Misaki horse is a Japanese native horse, known as the "feral horse of Cape Toi". In this study, we acquired the genetic information to establish their studbook, and analyzed their genetic characteristics for conservation. We genotyped 32 microsatellites and a mitochondrial D-loop region in 77 Misaki horses (80.2% of the population). The average number of alleles, observed heterozygosity, and expected heterozygosity were 3.4, 0.509, and 0.497, respectively. A neighbor-joining phylogenetic tree of individuals was constructed. Moreover, the results suggested that Misaki horses experienced a b...
Dutra GA, Ishak GM, Pechanova O, Pechan T, Peterson DG, Jacob JCF, Willard ST, Ryan PL, Gastal EL, Feugang JM.Proteomic studies of follicular fluid (FF) exist for several species, including the horse; however, the seasonal influence on FF proteome has not been explored in livestock. The application of high-throughput proteomics of FF in horse has the potential to identify seasonal variations of proteins involved in follicle and oocyte growth. Methods: This study (i) profiles the proteomes of equine FF collected from dominant growing follicles during the spring anovulatory season (SAN), and spring (SOV), summer (SUM), and fall (FOV) ovulatory seasons; and (ii) identifies season-dependent regulatory net...
Grilz-Seger G, Druml T, Neuditschko M, Dobretsberger M, Horna M, Brem G.The sample ascertainment bias due to complex population structures remains a major challenge in genome-wide investigations of complex traits. In this study we derived the high-resolution population structure and levels of autozygosity of 377 Lipizzan horses originating from five different European stud farms utilizing the SNP genotype information of the high density 700 k Affymetrix Axiom™ Equine genotyping array. Scanning the genome for overlapping runs of homozygosity (ROH) shared by more than 50% of horses, we identified homozygous regions (ROH islands) in order to investigate the gene ...
Victor S, Binnmyr J, Lampa E, Rask-Andersen A, Elfman L.Horses are an important source of allergens, but the distribution of horse allergens is poorly understood. Five horse allergens have been identified, Equ c 1-4 and 6. Equ c 4 seems to be an important allergen, with an IgE-binding frequency of 77% in horse-sensitized individuals. The aim of this study was to investigate levels of horse allergen Equ c 4 in dander, saliva and urine from ten horse breeds. The study population included 170 horses (87 mares, 27 stallions, 56 geldings) from ten breeds. Horse dander, saliva and urine samples were collected. Levels of horse allergen Equ c 4 were quanti...
Tozaki T, Miyake T, Kikuchi M, Kakoi H, Hirota KI, Kusano K, Ishikawa Y, Nomura M, Kushiro A, Nagata SI.Thoroughbred racehorses are produced by mating small numbers of Arabian stallions and native British mares, and have been improved by selection of horseracing performance for about 300 years. While these improvements led to good performance as racehorses, they exposed horses to numerous medical disorders, aggravated by extensive exercise. Fractures are frequent medical disorders in Thoroughbred racehorses. In this study, fracture heritability was estimated using 3,927 Japanese Thoroughbred racehorses to elucidate the risk of racehorse fractures. The heritability estimates of all examined frac...
Shang S, Yu Y, Zhao Y, Dang W, Zhang J, Qin X, Irwin DM, Wang Q, Liu F, Wang Z, Zhang S, Wang Z.Through domestication and human selection, horses have acquired various coat colors, including seven phenotypes: black, brown, dark bay, bay, chestnut, white, and gray. Here we determined the genotypes for melanocortin-1 receptor (MC1R) and agouti signaling protein (ASIP) in 709 horses from 15 breeds. We found that the EEEE genotype frequency at MC1R decreased from dark to light colors (black = 64.5%, brown = 67.5%, dark bay = 47.0%, bay = 16.5%, and chestnut = 0.0%), whereas the AAAA genotype frequency at ASIP increased as coat color lightened (black = 0.0%, brown = 22.9%, dark bay = 69.2%, a...
Asadollahpour Nanaei H, Ayatollahi Mehrgardi A, Esmailizadeh A.Equine athletes have a genetic heritage that has been evolved for millions of years, which provides an opportunity to study the genetics of locomotion pattern and performance in mammals. The Hanoverian, a breed originating in Germany, is arguably among the most athletic of horse breeds, as well as possessing a balanced character and beautiful appearance. Here, we compared the whole genomes of Hanoverian with three other horse breeds (Akhal-Teke, Franches-Montagnes, and Standardbred), using the fixation index (Fst) and cross-population composite likelihood ratio (XP-CLR) methods for testing the...
Copy number variation (CNV) has been proved to be widespread in human, animal and plant genomes. Together with single nucleotide polymorphisms (SNPs), CVNs play a key role in genetic diversity. In this study, genome-wide detection of CNVs was performed based on SNP data from 24 Criollo Argentino horses genotyped with the GGP Equine70k array. Overall, 165 CNVs meeting stringent quality control criteria were identified and then aggregated into 87 CNV regions (CNVRs), representing a horse genome coverage of 13.69 Mb. Functional analysis of CNVRs allowed the identification of 337 genes implicate...
Neis A, Kremer FS, Pinto LS, Leon PMM.The prolactin hormone is involved in several biological functions, although its main role resides on reproduction. As it interferes on fertility changes, studies focused on human health have established a linkage of this hormone to fertility losses. Regarding animal research, there is still a lack of information about the structure of prolactin. In case of horse breeding, prolactin has a particular influence; once there is an individualization of these animals and equines are known for presenting several reproductive disorders. As there is no molecular structure available for the prolactin hor...
Kolb DS, Klein C.Congenital hydrocephalus has been reported for a number of horse breeds, and for Friesian horses this condition has been associated with a nonsense mutation of B3GALNT2. We report the first case of congenital hydrocephalus associated with the said mutation in a Belgian draft horse. Genetic testing and consideration of the testing results in breeding programs are warranted. Hydrocéphalie congénitale chez un cheval de trait Belge associée à une mutation non-sens de B3GALNT2. L’hydrocéphalie congénitale a été signalée pour plusieurs races de chevaux et, pour les chevaux Frisons, cette ...
Sánchez-Guerrero MJ, Solé M, Azor PJ, Sölkner J, Valera M.Vitiligo and melanoma are relatively common disorders in grey Pura Raza Español horses and other horse breeds with grey-coloured coats. Objective: To determine the breed prevalence, environmental risks factors and estimate the genetic parameters for vitiligo and melanoma in Pura Raza Español horses. Methods: Retrospective cohort study. Methods: We analysed data from a large worldwide population of Pura Raza Español horses. The database included the vitiligo and melanoma scores, on either a four- or six-point linear scale, of 11,436 horses. Genetic parameters were estimated using a Bayesian ...
Gurgul A, Jasielczuk I, Semik-Gurgul E, Pawlina-Tyszko K, Stefaniuk-Szmukier M, Szmatoła T, Polak G, Tomczyk-Wrona I, Bugno-Poniewierska M.The genetic differentiation of the current horse population was evolutionarily created by natural or artificial selection which shaped the genomes of individual breeds in several unique ways. The availability of high throughput genotyping methods created the opportunity to study this genetic variation on a genome-wide level allowing detection of genome regions divergently selected between separate breeds as well as among different horse types sharing similar phenotypic features. In this study, we used the population differentiation index (FST) that is generally used for measuring locus-specifi...
Slivinska K, Karbowiak G, Gawor J, Wróblewski Z, Jaworski Z, Jastrzębska E, Demeshkant V.The influence of internal and external parasites on the health of Polish konik horses housed in different types of management strategies in Poland is discussed. This study includes consolidated data of different authors from the past 50 years, supplemented by results of more recent research. A total of 38 species of helminths (i.e., 37 Nematoda and one Cestoda) and five Diptera species were recorded from the horses. Protozoan parasites, Cryptosporidium spp. and Theileria equi, and the Rickettsiales, Anaplasma phagocytophilum, were observed for the first time in Poland.
Norton EM, Avila F, Schultz NE, Mickelson JR, Geor RJ, McCue ME.Ponies are highly susceptible to metabolic derangements including hyperinsulinemia, insulin resistance, and adiposity. Objective: Genetic loci affecting height in ponies have pleiotropic effects on metabolic pathways and increase the susceptibility to equine metabolic syndrome (EMS). Methods: Two hundred ninety-four Welsh ponies and 529 horses. Methods: Retrospective study of horses phenotyped for metabolic traits. Correlations between height and metabolic traits were assessed by Pearson's correlation coefficients. Complementary genome-wide analysis methods were used to identify a region of in...
Pereira GL, Malheiros JM, Ospina AMT, Chardulo LAL, Curi RA.Among horses selected for speed, the racing line of Quarter Horses is characterized by high performance in sprint races, with these animals being considered the fastest horses in the world. However, few studies have investigated in more detail the polymorphisms and genes that act on this trait. The objective of this study was to analyze exomes and UTRs in regions previously associated with this trait by GWAS in Quarter Horse racehorses with contrasting maximum speed index (SImax), prospecting causal gene polymorphisms that are related to or are in strong linkage disequilibrium with racing perf...
Duguma A, Lemma A, Hibste A.Equine reproduction is unique by having long behavioral estrus and differences in time of breeding between breeds and individuals of mares. An experimental study was conducted at the Balderas Sport Horses and Recreational Center, Addis Ababa, Ethiopia, from January to June, 2018, to evaluate conception rate to frozen semen in local and exotic crossbreed mares. Mares were teased to characterize estrus behavior and examined by ultrasound in determining imminent ovulation. Inseminations were done post ovulation within an average of 6-9 h using frozen-thawed semen. The overall conception rate to ...
Henkel J, Lafayette C, Brooks SA, Martin K, Patterson-Rosa L, Cook D, Jagannathan V, Leeb T.White spotting phenotypes in horses are highly valued in some breeds. They are quite variable and may range from the common white markings up to completely white horses. EDNRB, KIT, MITF, PAX3 and TRPM1 represent known candidate genes for white spotting phenotypes in horses. For the present study, we investigated an American Paint Horse family segregating a phenotype involving white spotting and blue eyes. Six of eight horses with the white-spotting phenotype were deaf. We obtained whole-genome sequence data from an affected horse and specifically searched for structural variants in the known ...
Gianino GM, Valberg SJ, Perumbakkam S, Henry ML, Gardner K, Penedo C, Finno CJ.Immune-mediated myositis (IMM) in American Quarter Horses (QHs) causes acute muscle atrophy and lymphocytic infiltration of myofibers. Recently, an E321G mutation in a highly conserved region of the myosin heavy chain 1 (MYH1) gene was associated with susceptibility to IMM and nonexertional rhabdomyolysis. Objective: To estimate prevalence of the E321G MYH1 variant in the QH breed and performance subgroups. Methods: Three-hundred seven elite performance QHs and 146 random registered QH controls. Methods: Prospective genetic survey. Elite QHs from barrel racing, cutting, halter, racing, reining...
Mackowski M, Wodas L, Brooks SA, Cieslak J.Although only a few specific pigmentation types are allowed within the Hucul horse registry, accurate determination of particular coat colors can be uncertain due to the presence of variation in color shades and segregation of multiple dun dilution variants. Herein, we genotyped the previously identified polymorphisms within two coat color loci TBX3 (T-box 3) and ASIP (Agouti Signaling Protein) in 462 Hucul individuals and compared the genotype predicted phenotypes with observed pigmentation types provided in the Polish Horse Breeders Association database. We identified disagreement between th...
Salek Ardestani S, Aminafshar M, Zandi Baghche Maryam MB, Banabazi MH, Sargolzaei M, Miar Y.Selective breeding has led to gradual changes at the genome level of horses. Deciphering selective pressure patterns is progressive to understand how breeding strategies have shaped the sport horse genome; although, little is known about the genomic regions under selective pressures in sport horse breeds. The major goal of this study was to shed light on genomic regions and biological pathways under selective pressures in sport horses. In this study, whole-genome sequences of 16 modern sport and 35 non-sport horses were used to investigate the genomic selective signals of sport performance, by...
Kornaś S, Sallé G, Skalska M, David I, Ricard A, Cabaret J.Equine internal parasites, mostly cyathostomins, affect both horse welfare and performance. The appearance of anthelmintic-resistant parasites creates a pressing need for optimising drenching schemes. This optimization may be achieved by identifying genetic markers associated with host susceptibility to infection and then to drench carriers of these markers. The aim of our study was to characterise the genetics of horse resistance to strongyle infection by estimating heritability of this trait in an Arabian pure blood population. A population of 789 Arabian pure blood horses from the Michałó...
Klouth E, Zablotski Y, Goehring LS.Equid herpesvirus type 1 (EHV-1) causes several outbreaks of abortion and/or equid herpesvirus-associated myeloencephalopathy (EHM) worldwide each year. EHM is of great concern, as permanent neurological gait anomalies can leave a horse unfit for future use. The study assesses the risk factors associated with the occurrence of EHM. During an unmitigated outbreak, 141 adult horses/ponies of several distinct breeds were evaluated-using multiple Bayesian logistic regression calculating the odds ratios for breed, age, and sex. In total, 33 of the 141 horses showed signs of EHM. Fjord horses and wa...
Foote AK, Ricketts SW, Whitwell KE.Significant progress has been made in understanding and monitoring the causes of equine abortion over past decades. However, not all in utero pathology results in abortion. It has long been recognised that some in utero pathology, such as twinning or chronic placentitis, can result in the birth of live but growth-retarded foals and there is historical evidence that birth weight may influence future athletic performance. Clinical experience (e.g. from twins) and experimental studies (pony-Thoroughbred embryo transfer) have highlighted the importance of reduced functional placental area in limit...
McCoy AM, Beeson SK, Rubin CJ, Andersson L, Caputo P, Lykkjen S, Moore A, Piercy RJ, Mickelson JR, McCue ME.Several horse breeds have been specifically selected for the ability to exhibit alternative patterns of locomotion, or gaits. A premature stop codon in the gene DMRT3 is permissive for "gaitedness" across breeds. However, this mutation is nearly fixed in both American Standardbred trotters and pacers, which perform a diagonal and lateral gait, respectively, during harness racing. This suggests that modifying alleles must influence the preferred gait at racing speeds in these populations. A genome-wide association analysis for the ability to pace was performed in 542 Standardbred horses (n = 17...
Chowdhary BP, Raudsepp T.Despite a late start, analysis of the horse genome has progressed rapidly during the past ten years. With synteny, genetic linkage, radiation hybrid, cytogenetic and comparative maps presently generated for all equine chromosomes including the Y chromosome, the map of the equine genome contains approximately 4,000 markers. The average resolution of the mapped markers is approximately 700 kb, which makes the horse gene map the densest among the domestic animal species hitherto not sequenced. This map is currently used by researchers worldwide to discover genes associated with various traits of ...
Arai T, Inoue A, Uematsu Y, Sako T, Kimura N.The activities of the enzymes involved in the malate-aspartate shuttle and lactate dehydrogenase (LDH) and the pattern of the isoenzymes of LDH were determined in plasma and peripheral leukocytes of lactating Holstein cows and thoroughbred riding horses as representative herbivorous animals. In the horse plasma, LDH activities were significantly lower and AST activities were significantly higher than those in the cow plasma. The specific activities of cytosolic malate dehydrogenase (MDH), LDH and AST in the horse leukocytes were higher than those in the cows. The cytosolic ratio of MDH/LDH act...
Velie BD, Solé M, Fegraeus KJ, Rosengren MK, Røed KH, Ihler CF, Strand E, Lindgren G.Since the 1950s, the Norwegian-Swedish Coldblooded trotter (NSCT) has been intensively selected for harness racing performance. As a result, the racing performance of the NSCT has improved remarkably; however, this improved racing performance has also been accompanied by a gradual increase in inbreeding level. Inbreeding in NSCT has historically been monitored by using traditional methods that are based on pedigree analysis, but with recent advancements in genomics, the NSCT industry has shown interest in adopting molecular approaches for the selection and maintenance of this breed. Consequent...
Walter J, Balzer HJ, Seeh C, Fey K, Bleul U, Osterrieder N.Equid herpesvirus 1 (EHV-1) is a highly prevalent pathogen in horse populations worldwide. Oronasal infection represents the classic route of disease transmission. Venereal shedding of EHV-1 is not regarded relevant in terms of virus spreading, which is in contrast to the close relatives of EHV-1, bovine and suid alphaherpesvirus, for which artificial insemination is a well-documented and accepted means of virus spread. Objective: Documentation of venereal EHV-1 shedding in 3 naturally infected stallions. Methods: Three stallions were infected during an acute outbreak by an EHV-1 strain with t...
Kim SM, Yun SW, Cho GJ.The study aimed to evaluate the diversity of donkey populations by comparing with the diversity of Thoroughbred and Jeju Halla horses; identified breeding backgrounds can contribute to management and conservation of donkeys in South Korea. Methods: A total of 100 horse (50 Thoroughbreds and 50 Jeju Halla horses) and 79 donkeys samples were genotyped with 15 microsatellite markers (AHT4, AHT5, ASB2, ASB17, ASB23, CA425, HMS1, HMS2, HMS3, HMS6, HMS7, HTG4, HTG10, LEX3, and VHL20), to identify genetic diversity and relationships among horses and donkeys. Results: The observed number of alleles pe...
Cothran EG, MacCluer JW, Weitkamp LR, Bailey E.American Standardbred horses are divided into two groups based upon gait: the trot and the pace. The tendency to trot (diagonally opposite legs moving forward together) or pace (the two legs on the same side of the body moving forward together) appears to be genetically determined, although no formal genetic analysis has been undertaken. There is nearly complete assortative mating for gait; however, about 20% of the offspring sired by trotters are registered as pacers, while fewer than 1% of those sired by pacers are registered as trotters. Electrophoretically detectable genic variation at 13 ...
Durward-Akhurst SA, Marlowe JL, Schaefer RJ, Springer K, Grantham B, Carey WK, Bellone RR, Mickelson JR, McCue ME.Disease-causing variants have been identified for less than 20% of suspected equine genetic diseases. Whole genome sequencing (WGS) allows rapid identification of rare disease causal variants. However, interpreting the clinical variant consequence is confounded by the number of predicted deleterious variants that healthy individuals carry (predicted genetic burden). Estimation of the predicted genetic burden and baseline frequencies of known deleterious or phenotype associated variants within and across the major horse breeds have not been performed. We used WGS of 605 horses across 48 breeds ...
Frischknecht M, Signer-Hasler H, Leeb T, Rieder S, Neuditschko M.To identify novel quantitative trait loci (QTL) within horses, we performed genome-wide association studies (GWAS) based on sequence-level genotypes for conformation and performance traits in the Franches-Montagnes (FM) horse breed. Sequence-level genotypes of FM horses were derived by re-sequencing 30 key founders and imputing 50K data of genotyped horses. In total, we included 1077 FM horses genotyped for ~4 million SNPs and their respective de-regressed breeding values of the traits in the analysis. Based on this dataset, we identified a total of 14 QTL associated with 18 conformation trai...
Felicetti M, Lopes MS, Verini-Supplizi A, Machado Ada C, Silvestrelli M, Mendonça D, Distl O.The Maremmano is an Italian warmblood horse breed from central Italy. We characterized the genetic diversity and the degree of admixture in Maremmano in comparison to 14 other European horse breeds using 30 microsatellites. Between-breed diversity explained about 9 per cent of the total genetic diversity. Cluster analysis, genetic distances and genetic differentiation coefficients showed a close relationship of Maremmano with Hanoverian and Lusitano in accordance with breed history.
Denoix JM, Jacquet S, Lepeule J, Crevier-Denoix N, Valette JP, Robert C.Radiographic examination in young horses is commonly used to detect juvenile osteochondral conditions (JOCC). The aim of this study is to present the radiographic findings (RF) detected at the age of 6months in the joints of 392 foals from three breeds: French Trotter Standardbreds (FT), Selle-Français Warmbloods (SF) and Thoroughbreds (TB). Radiographic examination included lateromedial views of the fore and hind digits, tarsi and stifles, and dorsopalmar projections of both carpi. In all areas RF indicative of JOCC were classified according to a four-grade severity scoring system. Distribut...
van Hoogmoed LM, Snyder JR, Thomas HL, Harmon FA.Prepurchase examinations of horses are used increasingly as a means of evaluating future soundness. Data is lacking in the literature of the radiographic findings and results of the lameness examination of comprehensive prepurchase examinations. Objective: To summarise the clinical and radiographic findings of prepurchase examinations and determine if radiographic findings correlated with the lameness examination and sale outcome. Methods: Records of 510 cases were reviewed, radiographs evaluated and grades assigned the navicular bone, distal phalanx, and tarsus. Follow-up information on the h...
Colton SW, Downing DT.Skin surface lipids from Equus caballus, E. przewalskii, E. asinus, E. grevyi, E. hemionus onager and a mule (E. asinus/E. caballus) were analyzed in detail. In all species the surface lipid mixtures consisted of giant-ring lactones, cholesterol, cholesteryl esters and minor amounts of wax diesters. In E. caballus, the lactone hydroxyacids were entirely branched chained, while in E. asinus and E. grevyi they were almost exclusively straight chained. In E. przewalskii, the onager and the mule there were both straight and branched chain hydroxyacid lactones. These results are in harmony with pub...
Mason TA, Bourke JM.The careers of many Thoroughbred racehorses
are marred or terminated prematurely by unsoundness which develop when racing as two year
olds. Common problems are sore-shins, carpitis,
splints, sesamoiditis, sesamoid fractures and
sprained joints and tendons. There appears to
be no recorded information on the incidence of
these conditions or of overall wastage in two year old Thoroughbreds but the results of personal
observations and communications with practising
veterinarians suggest that the incidence of unsoundnesses and relate these to skeletal maturity
Australia. This is probably d...
Gupta AK, Chauhan M, Tandon SN.Genetic diversity within the Marwari breed of horses was evaluated using 26 different microsatellite pairs with 48 DNA samples from unrelated horses. This molecular characterisation was undertaken to evaluate the problem of genetic bottlenecks also, if any, in this breed. The estimated mean (-/+ s.e.) allelic diversity was 5.9 (-/+ 2.24), with a total of 133 alleles. A high level of genetic variability within this breed was observed in terms of high values of mean (-/+ s.e.) effective number of alleles (3.3 -/+ 1.27), observed heterozygosity (0.5306 -/+ 0.22), expected Levene's heterozygosity ...
Ijaz A, Ducharme R.Stallion semen was diluted in five different extenders (dimitro-poulus onze (Dimitro's), Kenney's modified tryode (Kenney's), modified INRA82 (INRA82), egg yolk-citrate-taurine (Citrate) and EZ-Mixin) and evaluated for motility after cooling and storage at 5 degrees C for 0, 24, 48, 72 and 96 h. EZ-Mixin extender was used as control while 70 and 100 mM of taurine were added to Dimitro's, Kenney's and INRA82 to study its effect under conditions of storage at 5 degrees C and varying processing modifications. Motility in INRA82 was 57.0, 58.4, 61.1, and 56.1% after 24, 48, 72 and 96 h, respective...
Putnová L, Štohl R.Considering the extensive data sets and statistical techniques, animal breeding embodies a branch of machine learning that has a constantly increasing impact on breeding. In our study, information regarding the potential of machine learning and data mining within a large set of horses and breeds is presented. The individual assignment methods and factors influencing the success rate of the procedure are compared at the Czech population scale. The fixation index values ranged from 0.057 (HMS1) to 0.144 (HTG6), and the overall genetic differentiation amounted to 8.9% among the breeds. The highes...
Drögemüller M, Jagannathan V, Welle MM, Graubner C, Straub R, Gerber V, Burger D, Signer-Hasler H, Poncet PA, Klopfenstein S, von Niederhäusern R....Congenital hepatic fibrosis has been described as a lethal disease with monogenic autosomal recessive inheritance in the Swiss Franches-Montagnes horse breed. We performed a genome-wide association study with 5 cases and 12 controls and detected an association on chromosome 20. Subsequent homozygosity mapping defined a critical interval of 952 kb harboring 10 annotated genes and loci including the polycystic kidney and hepatic disease 1 (autosomal recessive) gene (PKHD1). PKHD1 represents an excellent functional candidate as variants in this gene were identified in human patients with autosoma...
García-Ballesteros S, Varona L, Valera M, Gutiérrez JP, Cervantes I.Ranking trait was used as a selection criterion for competition horses to estimate racing performance. In the literature the most common approaches to estimate breeding values are the linear or threshold statistical models. However, recent studies have shown that a Thurstonian approach was able to fix the race effect (competitive level of the horses that participate in the same race), thus suggesting a better prediction accuracy of breeding values for ranking trait. The aim of this study was to compare the predictability of linear, threshold and Thurstonian approaches for genetic evaluation of...
Trommershausen Bowling A, Clark RS.Gene frequencies at 20 blood group and protein polymorphism loci (A, C, D, K, P, Q, U, Al, Tf, Pi, Xk, Es, Gc, PGD, CA, Cat, PGM, AP, Hb and PHI) are given for seven horse breeds in the United States (Thoroughbred, Arabian, Standardbred, Morgan, Quarter Horse, Paso Fino and Peruvian Paso). These data are used to calculate that the battery of tests is at least 96% effective for recognizing incorrect paternity in these breeds. In addition to paternity testing, these tests can be applied to studies of breed relationships.
Fujiki Y, Rathnam P, Saxena BB.A tentative amino acid sequence of the beta-subunit of equine follicle-stimulating hormone (FSH) was derived from the sequences of tryptic, thermolytic as well as peptic, subtilisin, and chymotryptic peptides. Equine FSH-beta is analogous to human FSH-beta except six amino acid substitutions at positions 12, 16, 21, 62, 108, and 114. The amino acid sequence suggests that the hormone-specific beta-subunits of FSH are similar at the interspecies level, whereas the amino acid sequences of the hormone nonspecific alpha-subunits show variations.
