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.
Villegas-Castagnasso EE, Díaz S, Giovambattista G, Dulout FN, Peral-García P.The second exon of equine leucocyte antigen (ELA)-DQB genes was amplified from genomic DNA of 32 Argentine Creole horses by PCR. Amplified DNA was analysed by PCR-restriction fragment length polymorphism (RFLP) and PCR-single-strand conformation polymorphism (SSCP). The PCR-RFLP analysis revealed two HaeIII patterns, four RsaI patterns, five MspI patterns and two HinfI patterns. EcoRI showed no variation in the analysed sample. Additional patterns that did not account for known exon 2 DNA sequences were observed, suggesting the existence of novel ELA-DQB alleles. PCR-SSCP analysis exhibited se...
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...
Kane AJ, Park RD, McIlwraith CW, Rantanen NW, Morehead JP, Bramlage LR.Radiography in presale examinations of TB yearlings has become standard practice in recent years. Objective: To describe the prevalence and distribution of radiographic changes in the fetlocks, carpi, tarsi, stifles and fore feet of Thoroughbred yearlings in central Kentucky when these joints were examined as part of routine pre- and post sale evaluations. Methods: Horses subjected to radiographs included the fore (n = 1127) and hind (n = 1102) fetlocks, carpi (n = 1130), tarsi (n = 1101), stifles (n = 660) and fore feet (n = 300). Radiographic changes were categorised by location and type of ...
Spike-Pierce DL, Bramlage LR.Proximal sesamoiditis has been a common and confusing radiographic diagnosis in Thoroughbred yearling surveys. This study categorised the radiographic appearance of yearling proximal sesamoid bones and determined their effect on the number of races started and earning potential for racing at ages 2 and 3 years. Objective: Yearlings with moderate to severe proximal sesamoiditis have decreased performance at age 2 and 3 years. Methods: Survey radiographs of 487 Thoroughbred yearlings were reviewed. Proximal sesamoid bones were examined and findings placed into 7 categories, 5 of which measured s...
Wilsher S, Allen WR.The normality of equine placentation is essential for fetal health and development. Substantial information exists on the gross morphological status of the placenta but few studies have addressed the problem of degenerative lesions that interfere with placental morphology and placental efficiency. Objective: Degenerative changes in the endometrium with increasing age and parity are reflected in the morphology and density of the placental microcotyledons. Objective: To assess placental efficiency on the basis of foal birthweight as a function of total microscopic area of fetomaternal contact. M...
Nie GJ, Johnson KE, Wenzel JG.Mares were inseminated deep in the uterine horn with 25 million sperm selected by glass wool/Sephadex (GWS) filtration, Percoll separation (PS) or absolute number (AN). Deep-horn insemination using a low-volume, smooth tipped, flexible pipette/catheter delivery system allowed more efficient use of stallion sperm and reduced post-breeding uterine reaction in mares. Mares were pregnant in 15/30, 13/30 and 10/30 cycles for GWS, PS and AN selection methods, respectively. Sperm selection method did not effect pregnancy outcome (P=0.422). However, sperm selected for deep-horn insemination by filtrat...
Rudik SK.The Ukraine is one of the centers of domestication of animals. Many archaeological excavations and chronicles evidence this. The wild horse tarpan was domesticated in Ukraine. There were huge herds of tarpans lived in Ukraine. Tarpans were distinguished for their speed, quality of their hooves (it was very important for the shoeless horses). The last tarpan mare was killed at Ukrainian territory at 1898. In contradistinction to the Eq. Prezewalskii the tarpan was the direct ancestor of the European domesticated horse breeds.
Shin JA, Yang YH, Kim HS, Yun YM, Lee KK.The study was carried out to investigate the genetic polymorphism of the serum proteins of horses in Cheju. They were assigned to three groups; 45 Cheju native horses(CNH), 60 Cheju racing horses(CRH) and 60 Thoroughbreds(TB). We analyzed the phenotypes and gene frequencies of serum proteins which were albumin (Alb), vitamin-D binding protein(GC), esterase (ES), A1B glycoprotein(A1B) and transferrin(TF) loci using horizontal polyacrylamide gel electrophoresis (HPAGE). All of the loci, except A1B in TB, showed polymorphisms and different allelic and phenotypic frequencies in all three groups. E...
Sato T, Itou T, Sakai T.The complete coding region sequence of equine muscle-type phosphofructokinase (ePFKM) was obtained from skeletal muscle of a thoroughbred horse. The deduced amino acid sequence of ePFKM showed 97%, 96%, 96%, 96% and 95% identity to canine, human, mouse, rabbit and rat PFKM, respectively. The amino and carboxyl terminal halves of ePFKM presented a structure of tandem repeat, as other mammalian PFKMs. As the amino acid residues constituting various ligand-binding sites were also conserved, it is thought that ePFKM has enzymatic activity similar to PFKM in other mammals.
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...
Marchal R, Caillaud M, Martoriati A, Gérard N, Mermillod P, Goudet G.The aim of this study was to investigate the role of growth hormone (GH) on in vitro cumulus expansion and oocyte maturation in equine and porcine cumulus-oocyte complexes (COCs), and to approach its way of action. Equine COCs were cultured in a control medium (TCM199, 5 mg/ml BSA, 1 microg/ml estradiol, and antibiotics) supplemented with either 0.5 microg/ml equine GH or 5 microg/ml equine LH. Porcine COCs were cultured in a basal medium (TCM199 with 570 microM cysteamine) supplemented with 0, 0.1, 0.5, or 1 microg/ml porcine GH or in a control medium (basal medium with 10 ng/ml epidermal gro...
Guérin G, Bailey E, Bernoco D, Anderson I, Antczak DF, Bell K, Biros I, Bjørnstad G, Bowling AT, Brandon R, Caetano AR, Cholewinski G, Colling D....A low-density, male-based linkage map was constructed as one of the objectives of the International Equine Gene Mapping Workshop. Here we report the second generation map based on testing 503 half-sibling offspring from 13 sire families for 344 informative markers using the CRIMAP program. The multipoint linkage analysis localized 310 markers (90%) with 257 markers being linearly ordered. The map included 34 linkage groups representing all 31 autosomes and spanning 2262 cM with an average interval between loci of 10.1 cM. This map is a milestone in that it is the first map with linkage groups ...
Kavak A, Lundeheim N, Aidnik M, Einarsson S.Evaluation of testicular measurements and daily sperm output (DSO) yields valuable information for predicting the reproductive capacity of stallions. The present study evaluated testicular measurements (height, length, width and circumference) and DSO of eight Tori and eight Estonian breed stallions. One ejaculate of semen was collected daily for 10 subsequent days from each stallion. The gel-free volume of semen was measured with a graduated glass cylinder and the sperm concentration was assessed with a Chorjajev chamber. The volume of gel-free fraction was multiplied by the sperm concentrati...
van den Hoven R, Zappe H, Zitterl-Eglseer K, Jugl M, Franz C.The effects of an oral preparation containing an extract of thyme and primula (Bronchipret; Bionorica) on the lung function of five horses suffering heaves were determined in a longitudinal study. The horses accepted the product well. The plasma concentrations of the marker substance, thymol, indicated that at least one of the substances in the extract had been absorbed from the gastrointestinal tract. The compliance, pulmonary pressure and airway resistance of the horses' lungs were all significantly improved after one month of treatment However, the severity of their clinical signs and their...
Curik I, Zechner P, Sölkner J, Achmann R, Bodo I, Dovc P, Kavar T, Marti E, Brem G.While the negative effects of inbreeding and reduced heterozygosity on fecundity and survival are well established, only a few investigations have been carried out concerning their influence on morphological traits. This topic is of particular interest for a small and closed population such as the Lipizzan horse. Thus, 27 morphological traits were measured in 360 Lipizzan mares and were regressed on the individual inbreeding coefficients, as well as on the individual heterozygosity and mean squared distances (mean d(2)) between microsatellite alleles within an individual. Both individual heter...
Janett F, Thun R, Bettschen S, Burger D, Hassig M.The objective of this study was to investigate seasonal changes of semen quality parameters in Franches-Montagnes stallions and to compare the freezability of ejaculates collected in autumn and winter. Experiments were performed using 15 stallions from the National Stud Farm in Avenches (Switzerland). Ejaculates were collected and evaluated every month during 1 year as well as cryopreserved in autumn and winter (September to February). In fresh semen the gel-free volume, concentration, motility and morphology (normal sperm, major defects, vacuoles and acrosome defects) were evaluated and in fr...
López-Sanromán FJ, Cruz JM, Santos M, Mazzini RA, Tabanera A, Tendillo FJ.To evaluate the local analgesic effect of ketamine in a palmar digital nerve block at the base of the proximal sesamoid (abaxial sesamoid block) in horses. Methods: 36 mature healthy Andalusian horses. Methods: Horses were randomly assigned to 4 groups of 9 horses each and received an abaxial sesamoid block in a randomly chosen forelimb with 1 of the following: saline (0.9% NaCl) solution, 1% ketamine solution, 2% ketamine solution, or 3% ketamine solution. To determine analgesia, the radiant heat lamp-hoof withdrawal model was used as a noxious thermal stimulus. Before each nerve block, basel...
Beekley MD, Ideus JM, Brechue WF, Kearns CF, McKeever KH.The purpose of this study was to examine changes in myosin heavy chain (MHC) composition due to chronic clenbuterol administration with or without exercise in mares. Unfit Standardbred mares (aged 10+/-3 years) were divided into four groups: clenbuterol (2.4 micro/kg BW twice daily) plus exercise (3 days/week for 20 min at 50% VO(2max); CLENEX; n=6), clenbuterol only (CLEN; n=6), exercise only (EX; n=5), and control (CON; n=6). Muscle biopsies were obtained from gluteus medius muscle before and after the eight-week training/administration period. MHC composition was determined via SDS gel elec...
Chowdhary BP, Raudsepp T, Kata SR, Goh G, Millon LV, Allan V, Piumi F, Guérin G, Swinburne J, Binns M, Lear TL, Mickelson J, Murray J, Antczak DF....A first-generation radiation hybrid (RH) map of the equine (Equus caballus) genome was assembled using 92 horse x hamster hybrid cell lines and 730 equine markers. The map is the first comprehensive framework map of the horse that (1) incorporates type I as well as type II markers, (2) integrates synteny, cytogenetic, and meiotic maps into a consensus map, and (3) provides the most detailed genome-wide information to date on the organization and comparative status of the equine genome. The 730 loci (258 type I and 472 type II) included in the final map are clustered in 101 RH groups distribute...
Sieme H, Martinsson G, Rauterberg H, Walter K, Aurich C, Petzoldt R, Klug E.The objective of this research was to improve the techniques in processing chilled and frozen-thawed horse semen. In a preliminary experiment (Exp. I), different techniques for sperm selection and preparation [Swim-up, Glass wool (GW) filtration, Glass wool Sephadex (GWS) filtration; Percoll] were tested for their suitability for equine spermatozoa and results were compared with the routine procedure by dilution (Exp. I). In the main experiment (Exp. II), two sperm preparation techniques (GWS, Leucosorb) refering to the results of Exp. I and a previous study of our group (Pferdcheilkunde 1996 ...
Seltenhammer MH, Simhofer H, Scherzer S, Zechner R, Curik I, Sölkner J, Brandt SM, Jansen B, Pehamberger H, Eisenmenger E.Equine melanomas occur most commonly in grey horses at age 5 years or more. Generally, benign and malignant melanomas are distinguished by microscopy, but a more distinct classification would be helpful. Objective: The objectives of this study were to gain further evidence concerning the occurrence of melanotic tumours, and to evaluate the impact of heredity on melanoma development. Methods: A clinical study was conducted on a defined population of 296 grey horses of Lipizzaner breed. Individuals were classified according to their stage of disease using a 0-5 scale. Heritability was estimated ...
Milenkovic D, Chaffaux S, Taourit S, Guérin G.Epidermolysis bullosa (EB) is a heterogeneous group of inherited diseases characterised by skin blistering and fragility. In humans, one of the most severe forms of EB known as Herlitz-junctional EB (H-JEB), is caused by mutations in the laminin 5 genes. EB has been described in several species, like cattle, sheep, dogs, cats and horses where the mutation, a cytosine insertion in exon 10 of the LAMC2 gene, was very recently identified in Belgian horses as the mutation responsible for JEB. In this study, the same mutation was found to be totally associated with the JEB phenotype in two French d...
Turner RM, McDonnell SM.Significant amounts of alkaline phosphatase (AP) activity have been found in semen plasma from numerous species. In species in which the majority of semen plasma AP (SPAP) activity originates from the epididymis and testicle, SPAP activity can be used clinically as a marker to differentiate testicular origin azoospermia or oligospermia from ejaculatory failure. Information on SPAP activity in stallions to date has been limited. In this study, a standard clinical chemistry analyzer was used to determine AP activity in pre-ejaculatory fluid and ejaculates from groups of normal stallions. Additio...
Aurich JE, Kranski S, Parvizi N, Aurich C.This study investigated the regulation of growth hormone (GH) release in stallions and tested the hypothesis that the somatotrophic axis influences testicular function. Basal plasma GH concentrations, effects of an experimental decrease of GH release on testicular function and an opioidergic regulation of GH release were investigated in Shetland stallions (n=6). No seasonal variations in plasma GH concentrations were found over a 12-month period. Treatment with the somatostatin analogue octreotid (100mg twice daily over 10 days) caused a decrease in semen motility from 38.7+/-8.4% progressivel...
Lenasi T, Rogelj I, Dovc P.Here we report the entire cDNA sequences for equine alphaS1-, beta- and kappa-casein. Based on interspecies comparison, nine exons were found in equine beta-casein and five in kappa-casein. In equine alphaS1-casein cDNA the exon 5 was missing, which resulted in the total of 18 exons instead of 19 theoretically possible exons in alphaS1-casein cDNA. Comparison of DNA sequences representing exon 5 in other species with corresponding equine genomic region confirmed the presence of cryptic exon in horse genomic DNA. Equine alphaS1-casein mRNA was present in three forms in the lactating mammary gla...
Marti E, Binns M.This research study discusses the importance of creating a gene map for horses to enhance understanding of horse genetics, improve selective breeding methods, and aid in the diagnosis and treatment […]
Escribano BM, Agüera EI, Rubio MD, Santisteban R, Vivo R, Agüera S, Tovar P.We hypothesized that the information obtained from a discriminant analysis could be used to objectively discriminate horses untrained from early ages, in agreement with certain physiological characteristics. In the biopsies of 24 Spanish Pure Bred horses (1.5-3 years old) before and after a standardized exercise test (SET; 4-7 m/s with a change of velocity of 1m/s every 2 min) muscle enzymes, substrate and metabolites were determined. Also, diverse plasma and blood parameters were considered. Three pre-exercise groups (A1: six horses; A2: seven horses and A3: eleven horses) and two post-exerci...
Gerhards H, Werry H, Deegen E, Köstlin RG.Coloboma and ectopia of the crystalline lens are rarely encountered or diagnosed congenital defects of the equine eye. The clinical and ophthalmoscopic features of a congenital coloboma of the lens in a 3 year old Hanoverian stallion and of an ectopic lens in a 6-month old Hanoverian filly are described and depicted. In the stallion, the lens coloboma was associated with a partial coloboma of the zonules, and in the filly, the ectopic lens was small and spherical (microphakia, spherophakia) and associated with syneresis of and small floaters in the vitreous. Although it cannot be excluded that...
Medica P, Fazio E, Cravana C, Ferlazzo A.The aim of this study was to investigate thyroid hormone levels in horses stabled in two different locations on the island of Sicily. The study was carried out on a total of 72 clinically healthy Sanfratellano horses ranging in age from 5 to 9 years and weighing 585 ± 40 kg. The results showed higher thyroxine values (P < 0.02) in horses stabled in an endemic goitre area (group II) than those observed in horses in a non-endemic area (group I). Unexpectedly, the T(4)/T(3) and the fT(4)/fT(3) rations were both lower in group I than in group II. The percentages of fT(4) to T(4) and of fT(3) to T...
Rumbaugh GE, Adamson PJ.Blood was collected from healthy Quarter Horse and Appaloosa foals at birth and at intervals until 18 weeks of age and then was processed in an automated system for serum chemical analysis, grouping the results by age. The test values were markedly different from those normally expected in adult horses. The greatest differences were in alkaline phosphatase, lactate dehydrogenase, glucose, and total bilirubin measurements. It was concluded that serum biochemical test results be compared with age-specific normal values before diagnoses are made in cases of illness.
Yoshihara T, Kikuchi M, Akiba Y, Horiguchi M, Takasu M, Tozaki T.The Taishu horse in Tsushima is one of eight Japanese native breeds. The breed is on the verge of extinction due to a rapid decrease in numbers since the 1960s owing to motorization in Japan. In this study, we aimed to confirm the pedigree information of 52 horses by genotyping 31 microsatellites in order to avoid inbreeding. Parentage verification failed to identify genetic contradictions among trios (sires, dams, and foals) registered with the Japan Equine Affairs Association (JEAA). Pedigree information registered at the JEAA was obtained and adequately understood. Additionally, the genetic...
Gill JJ, Kempski HM, Hallows BJ, Warren AM.IT is well known that chromosomal abnormalities are
frequently associated with infertility in the mare (Table 1). The
most commonly reported abnormality is 6 3 x 0 which can
occur in a mosaic or non-mosaic form. Various other
aneuploidies of the sex chromosomes have been reported but
the 6SXXX genotype appears to be rare. Chandley et a1 (1975)
and Chandley (1984) have reported two 65XXX animals and
Walker (1979) a 64XW6SXXW6SXXY one.
This paper reports a mosaic 64XXh5XXX animal and
emphasises the need for more cytogenetic analysis in the
horse.
Ruohoniemi M, Ahtiainen H, Ojala M.Ossification of the cartilages in the foot is common in coldblooded horses, but prevalence as well as ossification pattern varies between breeds; research on estimation of heritability for the condition has been limited. Objective: Our purpose was to calculate estimates of 1) heritability for ossification parameters of the cartilages in the front feet of the Finnhorse and 2) genetic correlations between the different ossification parameters. Methods: Estimates of heritability for different ossification parameters of the cartilages in the front feet and of genetic correlations between different...
Smith MR, Stevens KB, Durham AE, Marr CM.Liver disease is fairly common in horses and, although previous literature suggests that fatality rates are high, impressions gained from current clinical practice suggest that this is no longer the case. Objective: A case-control study was undertaken in 2 hospitals to investigate whether age, gender or breed type predisposed horses to developing hepatic disease, with the additional aim of determining whether these factors and disease category had any effect on outcome. Methods: Eighty-eight cases were identified by review of computerised archives at 2 hospitals. Three cases admitted immediate...
Cothran EG, Long YG.A new D blood group phenogroup consisting of the specificities adeo was observed in a stallion family of Caspian ponies from Iran. An additional six undescribed genetic variants were seen in a total of 82 Iranian horses. This result suggests extensive new genetic variation may be present in domestic horses from geographic regions that have not yet received scientific attention.
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...
Wolgien D, Keller H.The anesthesia routine in the horse is briefly explained. 35 postanesthetic complications resulted from the total of 4364 cases of anesthesia. They are evaluated by means of the duration of anesthesia, the time of paresis, the exemplary courses of enzymes as well as the distribution of race and sex and their ratio towards all cases of anesthesia. Finally a list of demands concerning the operative and postoperative phases is compiled to minimize postoperative myositis (PAM) and lameness (PAL).
Ayala I, Gutierrez C, Benedito JL, Hernández J, Castillo C, López Alonso M, Miranda M, Montes A.This investigation was undertaken to determine values of electrocardiographic parameters in Spanish-bred horses at different stages of growth. The study was carried out on 179 healthy Spanish-bred (Andalusian) horses (98 females and 81 males), which were aged between 1 month and 17 years. The ECGs showed P waves of different configurations. The bifid shape deflection of the P wave was generally more frequent than the simple one in animals from 6 months of age. The first component of bifid P waves (P1) did not vary in a statistically significant way with increasing age, showing a mean value of ...