Phenotype in horses refers to the observable physical and behavioral traits of an individual horse, which result from the interaction of its genetic makeup and environmental influences. These traits include characteristics such as coat color, height, conformation, and temperament. Phenotypic expression is a focal point in equine breeding and management, as it influences performance, health, and suitability for specific disciplines. Research in this area examines the genetic basis of phenotypic traits, the impact of environmental factors, and the interaction between genetics and environment. This page aggregates peer-reviewed research studies and scholarly articles that explore the genetic determinants, environmental effects, and practical implications of phenotypic traits in horses.
The Journal of heredityMarch 1, 1991
Volume 82, Issue 2 167-169 doi: 10.1093/oxfordjournals.jhered.a111053
Woolf CM.Common white facial and leg markings have a multifactorial mode of inheritance in Equus caballus. Evidence for the complexity of the genetic component is the observation that chestnut (e/e) horses have more extensive white markings than do bay (E/-) horses. Computerized records obtained from the Arabian Horse Registry of America, Inc., were used to determine if heterozygous (E/e) bay horses have more extensive white facial markings than do homozygous (E/E) bay horses. Thirty-five sire families were analyzed. Each sire family consists of a sire, his foals, and the dams of those foals. The facia...
Bowling AT, Millon LV.The phenotypic effects in a yearling Arab filly of a newly described equine autosomal trisomy syndrome for chromosome 30 (65,XX,+30) consisted of small size and severe angular deviation of front legs accompanied by mild polydactyly, but no mental dullness. This case was associated with advanced maternal age. Additional banding studies of a second trisomy case confirmed the assignment to chromosome 26 (64,XX,-26,+t(26q26q)) and evidence of her fertility was presented.
The Journal of heredityJuly 1, 1990
Volume 81, Issue 4 323-331 doi: 10.1093/oxfordjournals.jhered.a110997
Sponenberg DP, Carr G, Simak E, Schwink K.The leopard complex of white spotting patterns in horses consists of the leopard, few-spot leopard, blanket, blanket with spots, varnish roan (or marble), snowflake, frosted, speckled, and mottled patterns. Horses with any of these patterns can produce the other patterns when mated to nonpatterned horses. Twenty-two horses of the Welsh Pony, Noriker, Appaloosa, and Pony of the Americas breeds produced 270 foals in a distribution consistent with a single dominant allele being responsible for the patterns. The symbol for this dominant allele, Lp, is retained from previous work on the leopard pat...
The Journal of heredityJuly 1, 1990
Volume 81, Issue 4 250-256 doi: 10.1093/oxfordjournals.jhered.a110987
Woolf CM.The results of a previous study were compatible with the hypothesis that common white facial markings in the Arabian horse have a multifactorial mode of inheritance. I expanded that study to (1) include the legs and therefore obtain insight into the heritability of common white markings in all peripheral regions (face and legs) of the Arabian horse and (2) investigate the influence of sex and the genotypes that produce the bay and chestnut phenotypes on the variation in common white markings. Both studies were based on computerized data obtained from the Arabian Horse Registry of America, Inc....
Merkt H, Klug E.The rules for the minimal requirements in health and genital potency for stallions formulated by GOTZE (1950) are reformulated, taking into consideration the results achieved by KLUG (1982) and KENNEY (1983). A stallion must be free of phenotypic hereditary faults. Furthermore he has to be in general and genital health and must be fit in both, potentia coeundi and generandi. The figures are based on the examination of thoroughbred and so called "warmblood" stallions. However, they can be adapted to other breeds like draughthorses and ponys.
The Journal of heredityMay 1, 1989
Volume 80, Issue 3 173-178 doi: 10.1093/oxfordjournals.jhered.a110831
Woolf CM.The hypothesis was tested that white facial markings in the Arabian horse show multifactorial inheritance. The hypothesis assumes that (1) alleles at different loci acting in a cumulative manner influence the variation in white facial markings, (2) the amount of whiteness is correlated with the number of genes, and (3) interacting nongenetic factors influence the variation. The study was based on computerized data obtained from the Arabian Horse Registry of America, Inc. The facial region was divided into five areas, and each horse was given a score according to the number of areas with a whit...
Juneja RK, Sandberg K, Kuryl J, Gahne B.Two-dimensional agarose gel (pH 8.6)-horizontal polyacrylamide gel (pH 9.0) electrophoresis of horse serum samples, followed by general protein staining, revealed genetic polymorphism of an unidentified protein tentatively designated serum protein 3 (SP3). The SP3 fractions appeared distinctly when a 14% concentration of acrylamide was used in the separation gels. The 2-D mobilities of SP3 fractions were quite similar to that of albumin. Family data were consistent with the hypothesis that the observed SP3 phenotypes were controlled by four co-dominant, autosomal alleles (D, F, I, S). Evidence...
Rozhkov IuI, Okhapkin SK, Vorob'ev EG, Bezenko SP, Galimov IR.A stabilizing selection which is made in cattle according to phenotypic characters affects simultaneously a genetic character--the level of individual heterozygosity++. As a result animals with mean (modal) level of heterozygosity++ have the least probability of elimination. Similarly, the driving selection in pigs and horses leads to a change in both phenotypic characters and genetic character, the level of individual heterozygosity++. In this case the most heterozygous animals have the least probability of elimination.
Kent MG, Schneller HE, Hegsted RL, Johnston SD, Wachtel SS.The XY Sex Reversal Syndrome of the horse is a condition associated with female or intersexual development in genetic males. In our previous study, 38 sex reversed XY mares were classified according to behavior, gross clinical phenotype, gonadal status, and H-Y phenotype. Four classes were described, ranging from potentially fertile female (Class I) to virilized intersex (Class IV). In the present study, serum testosterone concentrations were measured in 29 sex-reversed XY mares, 3 normal mares and 3 normal stallions. Serums were obtained during the breeding season (March-August), and were sto...
Kent MG, Shoffner RN, Hunter A, Elliston KO, Schroder W, Tolley E, Wachtel SS.An inherited genetic disorder causes XY embryos of the horse to develop as mares. On the basis of our study of 38 such mares, we have identified four grades or classes of XY sex reversal according to this scheme: class I, nearly normal female, of which some are fertile; class II, female with gonadal dysgenesis, normal mullerian development; class III, intersex mare with gonadal dysgenesis, abnormal mullerian development, enlarged clitoris; class IV, virilized intersex characterized by high levels of testosterone. In general, class I and class II mares were typed H-Y antigen-negative whereas cl...
The Journal of heredityMarch 1, 1988
Volume 79, Issue 2 100-106 doi: 10.1093/oxfordjournals.jhered.a110461
Woolf CM, Swafford JR.The ultrastructural imaging of melanocytes coupled with analyses to detect sulfur-containing melanosomes by energy-dispersive X-ray spectroscopy were used to test the hypothesis that the yellowish-red and black pigments found in Arabian horses result from pheomelanogenesis and eumelanogenesis, respectively. These procedures detected pheomelanosomes in follicles at the base of hairs in chestnut horses and eumelanosomes in follicles at the base of hairs in black horses. By analyzing tissue obtained by skin biopsy, these procedures also demonstrated that skin melanocytes in a chestnut horse produ...
Sponenberg DP, Ito S, Eng LA, Schwink K.Hair samples of various colors of horses were analyzed for content of both eumelanin and pheomelanin by a procedure using high performance liquid chromatography. The results are in accord with generally accepted genetic hypotheses accounting for the various colors. However, the results support the hypothesis that the chestnut/sorrel group of colors is conditioned by the extension locus, not the brown locus. The results also indicate that the brown locus is a likely contributor to some rare color phenotypes.
Bowling AT, Wictum E.A fourth allele at the horse erythrocyte phosphohexose isomerase (Phi) locus was proposed to account for phenotypes observed after starch gel electrophoresis and enzymatic staining of red cell lysates from American Saddlebred and Tennessee Walking Horse breeds. The gene was rare, having an estimated frequency of 0.009 in 949 Saddlebreds tested.
Bowling AT, Scott AM, Flint J, Clegg JB.Four minor haplotypes that produce abnormal haemoglobin phenotypes in horses have been characterized. Two of them, AIIb and V, are copy number variants with, respectively, one and three alpha genes instead of the normal complement of two. The AIIa and C haplotypes, on the other hand, each have two alpha genes but, as a result of probable gene conversions, they now encode identical, though haplotype specific, globins. Two out of 60 unrelated and phenotypically normal horses studied had an unusual triplicated rearrangement in the embryonic zeta-gene locus. Each of these variants appears to have ...
Weitkamp LR, MacCluer JW, Guttormsen SA, King RH.The transmission ratios of alleles at 12 protein marker loci were computed individually for American Standardbred stallions in a genealogy of 5392 phenotyped horses. Over all loci there was significant gene transmission distortion for trotting stallions (p = 0.0019) but not for pacing stallions (p = 0.99). The transmission distortion was due to sire-specific effects (p = 0.0024) and not to increased transmission of one or the other allele of a given heterozygous genotype (p = 0.21). Individual-specific, non-random transmission of homologous chromosomes may provide a mechanism for selection to ...
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 ...
Antczak DF, Bailey E, Barger B, Guerin G, Lazary S, McClure J, Mottironi VD, Symons R, Templeton J, Varewyck H.The Third International Workshop on Lymphocyte Alloantigens of the Horse was held on 25-27 April 1984 in Kennett Square, Pennsylvania. Twelve laboratories from five countries participated. The principal purpose of this Workshop was to determine the phenotypic and gene frequencies of the 10 equine lymphocyte antigens (ELA) and a non-ELA lymphocyte antigen, ELY-2.1, in several breeds of horse. A total of 86 alloantisera characterized in previous workshops were tested against lymphocytes from 1179 horses. In addition, several experimental antisera were also tested against the same panel of lympho...
Kay PH, Dawkins RL, Bowling AT, Bernoco D.Plasma or serum samples from 12 Arabian and 181 standardbred horses have been typed using an immunofixation technique to determine electrophoretic polymorphism of equine third complement component (C3). Six distinctly different electrophoretic patterns of equine C3 have been recognized thus far. SDS PAGE analysis of equine C3/anti C3 complexes revealed that the submolecular structure comprised an alpha chain and beta chain of molecular weights approximately 118,000 and 63,000 daltons respectively. The molecular weights of the alpha and beta chains were similar in all electrophoretic variants t...
Kent MG, Shoffner RN, Buoen L, Weber AF.The XY sex-reversal syndrome occurs when a phenotypic mare is born that has the karyotype of a stallion. The syndrome is manifested by both genotypic and phenotypic heterogeneity. The sex-reversed genetic condition occurs frequently within certain pedigrees where XY females have been found and can be readily detected by chromosome karyotyping. The phenotypic spectrum ranges from the feminine mare with a reproductive tract that is within normal limits to the greatly masculinized mare. Pedigree analysis suggests that there are two modes of inheritance: (1) an X-linked recessive or autosomal sex-...
Rando A, Di Gregorio P, Masina P.Horse DNA samples digested with PstI and probed with the rabbit beta 1 globin gene show three phenotypes determined by one fragment of variable length (about 5.1 or 3.3 kb). Family data demonstrate that these fragments segregate as Mendelian alleles. The frequencies of the two alleles are 0.66 for the 3.3-kb fragment and 0.34 for the 5.1-kb one. Another polymorphism has been detected with BamHI. Again three phenotypes determined by two alleles (fragments of 7.5 and 3.8 kb) have been observed. Allelic frequencies of the 7.5- and 3.8-kb fragments are 0.24 and 0.76 respectively. The two polymorph...
Halnan CR.From the standpoint that cytogenetic screening in mares is seldom necessary as an aid to diagnosis of the gonadal dysgenesis syndrome, a series of double-blind trials were conducted to test the proposal that present practice failed to explore the potential for cytogenetics in clinical practice. It was demonstrated that diagnoses of infertility might be made where mares were found to be of normal phenotype by clinical examination. Such mares were found to be gonosmic mosaics. One stallion had a polymorphism of the X chromosome and had poor conception rates. It was demonstrated that the true val...
Hitchcock PJ, Brown TM, Corwin D, Hayes SF, Olszewski A, Todd WJ.Examination of recently isolated cultures of three strains of Contagious Equine Metritis Organism grown on specially formulated, serum-free, clear typing medium revealed the presence of numerous colonial opacity variants. These colonies were prepared by a number of fixation and staining techniques and examined by scanning and transmission electron microscopy. Opaque and transparent phenotypes produced copious amounts of extracellular material compared with intermediate-opacity phenotypes which produced little or none. Also unique to intermediate colonies were numerous thin intercellular strand...
Didkowski S, Kaminski M, Kerjan P, Tomaszewska-Guszkiewicz K, Zurkowski M.By the method of precipitation with Rivanol (2-ethoxy-6,9-diaminoacridine lactate) and ammonium sulphate followed by chromatography on DEAE cellulose three genetic variants of transferrin were purified from equine serum: D, M and R. Their molecular mass determined in this study was 80 000, and it was identical for all three variants, which differed slightly in their amino acid composition. The protein level was determined in the serum of 535 two-year-old thoroughbred English horses by the method of rocket immunoelectrophoresis using antibodies obtained against three transferrins. The individua...
Osterhoff DR, Groenewald J.By using isoelectric focusing in thin agarose slab gels 1049 Thoroughbred, 82 Nooitgedachter, 45 Percheron and 244 horses of other breeds were examined. The numbers of other Equidae tested were 107 donkeys, 50 mules, 4 common zebras (Equus burchelli boehmi) and 8 mountain zebras (Equus zebra hartmannae). Phenotypic data are presented for all tested animals and gene frequencies are calculated for the horses.
Juneja RK, Andersson L, Sandberg K, Gahne B, Adalsteinsson S, Gunnarsson E.Two-dimensional agarose gel (pH 8.6)-horizontal polyacrylamide gel (pH 9.0) electrophoresis of horse serum proteins revealed genetic polymorphism of ceruloplasmin (Cp) and two unidentified serum proteins tentatively designated serum protein 1 (SP1) and serum protein 2 (SP2). Family data were consistent with the hypothesis that the observed Cp and SP1 phenotypes were each controlled by two codominant, autosomal alleles. The three common SP2 phenotypes were shown to be controlled by two codominant, autosomal alleles. Population data and limited family data indicated the occurrence of two additio...
Antczak DF, Bright SM, Remick LH, Bauman BE.A genetic system controlling lymphocyte alloantigens of the horse is described. Alloantisera to paternal histocompatibility antigens induced as a result of pregnancy in mares were used in an antibody-mediated complement-dependent microcytotoxicity assay to define 15 Equine Leukocyte Antigen (ELA) specificities using cluster analysis. In this study 369 sera were screened for alloantibody using lymphocytes from 10 randomly selected, unrelated horses. A high proportion (83%) of these sera were found to be positive for antibody to lymphocyte alloantigens. After initial cluster analysis, 120 of the...
Bouquet Y, Van Zeveren A, Van de Weghe A, Mériaux JC.The inheritance of a new D system red cell antigen, factor 22, is described. It has also been possible to discriminate more efficiently between D system phenogroups enabling genotypes to be identified from phenotypes in the majority of cases. This improves the accuracy of animal identification and gene frequency estimates.
Ek N.Selected transferrin phenotypes from 14 horses were investigated by antigen-antibody crossed electrophoresis. Horse sera were subjected to starch gel electrophoresis followed by right angle electrophoresis in agarose gels containing rabbit produced anti-horse transferrin. This technique gave an additional zone in the front as compared with 2 transferrin zones seen after ordinary starch gel electrophoresis. Comparisons of transferrin concentrations in horse sera were performed by an immunodiffusion technique. Values were related to a chosen reference serum. A total of 372 horses (210 Norwegian ...
Braend M, Romagnoli A.Starch gel electrophoresis of 55 donkey serum samples revealed three prealbumin (Pr) phenotypes temporarily designated Pr M, Pr MT and Pr T. The distribution was in agreement with a genetic theory of two codominant alleles of frequencies, PrM = 0.87 and PrT - 0.13. Variation was also observed for proteins migrating with the same rate as the Xh zones in the horse.
Ek N, Braend M.Comparisons of Pr protein amounts in horse sera have been performed using .’s (1965) immunodiffusion technique. Relative values against a chosen standard of 100 % were determined for a total of 435 horses. There was considerable variation between horses, the highest Pr value being 125 and the lowest 50 % of the standard. In animals of the same Pr phenotype the mean Pr values were significantly higher (P < 0.001) in foals than in mares. In Norwegian Trotter horses the Pr value of Pr NN animals was significantly higher than that of Pr SS phenotypes, whereas the mean Pr values of Pr SS was sig...
Parés-Casanova PM.Morphological integration and modularity are concepts that refer to the covariation level between the components of a structure. Morphological modules are independent subsets of highly correlated traits. The horse skull has been studied as a whole functional structure for decades, but the integrative approach towards quantitative examination of modules is scarce. We report here the first evaluation of cranial modularity in the horse at basal level. For this, we studied the modularity hypothesis for splanchnocranium and basicranium modules in the horse, two phenotipic regions under local influe...
Ciosek J, Kimes A, Vinardell T, Miller DC, Antczak DF, Brooks S.Valued for their temperament, beauty, athletic ability, and exhibition in the show ring, Arabian horses are an important component of the horse industry. Juvenile idiopathic epilepsy (JIE), a seizure disorder, is most often reported in Arabian foals from birth to 6 months of age. Affected foals exhibit tonic-clonic seizures lasting as long as 5 min and risking secondary complications like temporary blindness and disorientation. Some foals outgrow this condition, while others die or suffer lifelong complications if not treated. Previous work suggested a strong genetic component to JIE and propo...
Han H, Mao C, Chen N, Lan X, Chen H, Lei C, Dang R.Kit gene is a genetic determinant of horse white coat color which has been a highly valued trait in horses for at least 2,000 years. Single nucleotide polymorphisms (SNPs) in Kit are of importance due to their strong associations with melanoblast survival during embryonic development. In this study, a mutation analysis of all 21 Kit exons in 14 Chinese domestic horse breeds revealed six SNPs (g.91214T>G, g.143245T>G, g.164297C>T, g.170189C>T, g.171356C>G, and g.171471G>A), which located in 5'-UTR region, intron 6, exon 15, exon 20, intron 20, and exon 21 of the equine Kit gene, respectively. S...
Xie FY, Feng YL, Wang HH, Ma YF, Yang Y, Wang YC, Shen W, Pan QJ, Yin S, Sun YJ, Ma JY.Prior to the mechanization of agriculture and labor-intensive tasks, humans used donkeys (Equus africanus asinus) for farm work and packing. However, as mechanization increased, donkeys have been increasingly raised for meat, milk, and fur in China. To maintain the development of the donkey industry, breeding programs should focus on traits related to these new uses. Compared to conventional marker-assisted breeding plans, genome- and transcriptome-based selection methods are more efficient and effective. To analyze the coding genes of the donkey genome, we assembled the transcriptome of donke...
Lee J, Shin D, Kim H.Thoroughbred horses have been bred exclusively for racing in England for a long time. Additionally, because horse racing is a global sport, a healthy leisure activity for ordinary citizens, and a high-value business, systematic racehorse breeding at the population level is a requirement for continuous industrial development. Therefore, we established genomic evaluation system (using prize money as horse racing traits) to produce spirited, agile, and strong racing horse population. Methods: We used phenotypic data from 25,061 Thoroughbred horses (all registered individuals in Korea) that compet...
Rozhkov IuI, Okhapkin SK, Vorob'ev EG, Bezenko SP, Galimov IR.A stabilizing selection which is made in cattle according to phenotypic characters affects simultaneously a genetic character--the level of individual heterozygosity++. As a result animals with mean (modal) level of heterozygosity++ have the least probability of elimination. Similarly, the driving selection in pigs and horses leads to a change in both phenotypic characters and genetic character, the level of individual heterozygosity++. In this case the most heterozygous animals have the least probability of elimination.
Lewczuk D, Metera-Zarzycka E.Many horse breeds in the world are reserved as genetic resources; however, their characteristics seem to be insufficiently clarified, especially in terms of horse performance. Two jumping ability evaluation methods have been used to compare different types of performance breeds and on this basis their applicability for precision phenotyping has been determined. Methods: Jumping data of 186 young Polish Warmblood stallions (27 with an endangered status) bred for sport and multipurpose use was collected during their performance tests organised under identical environmental conditions following t...
Méténier L, Kaminski M.Immunochemical and enzymatic analyses of horse serum carboxylesterase were carried out with respect to the existence of a silent gene. Sera with positive phenotypic expression of esterase, both heterozygotes and presumed homozygotes, were compared with:--sera with positive phenotypic expression but genotypically +/O;--sera with a negative phenotypic expression, i. e. genotypically O/O;--sera of natural +/O "hemi-zygotes": mules (donkey lacking the esterase);--positive sera heated at 60 degrees C;--positive sera after specific inhibition of enzymatic activity. Titration by immunocompetition has...
Dierks C, Sieme H, Piechotta M, Lehner S, Merkt JC, Uphaus H, Klug E, Distl O.A female thoroughbred successful in horse racing was positively tested for high testosterone values. This horse neither showed stallion-like-behaviour nor signs of ambiguous external genitalia. The karyotype of this horse was 2n = 64,XY and the sex-determining region of Y (SRY) PCR was positive. Hair samples tested for naturally testosterone revealed values normal for stallions, and tests for eight synthetic testosterone esters remained negative. The phenotype, ultrasonographic examination, hormone status, cytogenetic evaluation and molecular diagnostics lead to the diagnosis of an XY testicul...
Krüger B, Siesenop U, Böhm KH.In 1993 and 1994 a highly increased occurrence of equine dermatophilosis was observed, and a study was initiated to determine phenotypic heterogeneity among 120 clinical isolates using biochemistry, antibiotic resistance profiles, membrane protein profiles and Western blotting. The biochemical examinations contained 1% equine serum in medium. Moreover, the API ZYM-test from bioMérieux was used. The biochemical reactions were suited to identify Dermatophilus congolensis but did not allow a differentiation among the various isolates. Antibiotic resistance in one or more isolates was observed ag...
Didkowski S, Kaminski M, Kerjan P, Tomaszewska-Guszkiewicz K, Zurkowski M.By the method of precipitation with Rivanol (2-ethoxy-6,9-diaminoacridine lactate) and ammonium sulphate followed by chromatography on DEAE cellulose three genetic variants of transferrin were purified from equine serum: D, M and R. Their molecular mass determined in this study was 80 000, and it was identical for all three variants, which differed slightly in their amino acid composition. The protein level was determined in the serum of 535 two-year-old thoroughbred English horses by the method of rocket immunoelectrophoresis using antibodies obtained against three transferrins. The individua...
Kent MG, Schneller HE, Hegsted RL, Johnston SD, Wachtel SS.The XY Sex Reversal Syndrome of the horse is a condition associated with female or intersexual development in genetic males. In our previous study, 38 sex reversed XY mares were classified according to behavior, gross clinical phenotype, gonadal status, and H-Y phenotype. Four classes were described, ranging from potentially fertile female (Class I) to virilized intersex (Class IV). In the present study, serum testosterone concentrations were measured in 29 sex-reversed XY mares, 3 normal mares and 3 normal stallions. Serums were obtained during the breeding season (March-August), and were sto...
Watanabe R, Huruta H, Ueno Y, Nukada T, Niwa H, Shinyashiki N, Kano R.Trichophyton equinum is a zoophilic dermatophyte that is frequently isolated from horse dermatophytosis and rare infections in humans. In the present study, molecular and physiological testing were performed on T. equinum isolates from dermatophytoses of Japanese racehorses to assess genotype and phenotype patterns of these strains. Comparative nucleotide sequence analysis showed that internal transcribed spacer (ITS) region sequences amplified from all Japanese isolates were 99.5% identical to T. equinum reference strains. ITS sequences amplified among the isolates were 100% (BT2) showed that...
Kniazev SP, Reissmann M, Wagner HJ, Kuraĭ MV, Samovolov NV.Results of the first in Russia survey of the gene pool of the breeding nucleus of the Russian population of thoroughbred horses by means of PCR analysis of the E (Extension) locus MC1R gene mutations are presented. The data on the structure of breeding populations from the leading stud farms Voskhod and Oros with regard to color phenotypes as well as genotype and allele frequencies are presented. The population structure parameters are discussed with respect to possible specific features of microevolution processes.
Maĭboroda SN.Study of the variability and heritability of sprightliness and exterior characteristics which are the constituent factors of capacity for work of trotting horse breed, permits predicting and planning the direction of selection work in the breed, and determining the efficiency of animals selection according to phenotype. To increase the level of capacity for work of Orloff trotting horse breed, according to the paper data, more consideration should be given to correctness of the exterior, as a biomechanical basis of the horse motion.
The Journal of heredityAugust 4, 2021
Volume 112, Issue 5 443-446 doi: 10.1093/jhered/esab037
Hammons V, Ribeiro L, Munyard K, Sadeghi R, Miller D, Antczak D, Brooks SA.Chestnut coat color in horses is determined by a missense mutation within the MC1R gene. However, the intensity of the chestnut color can vary widely within individuals possessing this genotype. Here, we investigated this variation using standardized photographs of 96 horses. Each horse was ranked lightest to darkest within the cohort for phenotype by 3 blinded observers. A genome-wide association study utilizing the relative shade ranking as the phenotype and using 268 487 single-nucleotide polymorphisms (SNPs) genotyped using the Affymetrix Equine 670k array identified a single significantly...
Christensen H, Hommez J, Olsen JE, Bisgaard M.To investigate if taxon 42 of Bisgaard isolated from pigs represents genuine [Pasteurella] caballi, which was previously only isolated from horses. Results: A total of 15 field isolates from horses and pigs from five different countries representing three continents were subjected to extended phenotypical characterization. Although minor differences were observed between taxon 42 and [P.] caballi, these differences did not allow phenotypic separation. Ribotyping based on HindIII digestion showed five profiles based on nine band positions. One [P.] caballi strain and two taxon 42 strains shared...
Oda D, Onogi A.The inheritance of racing performance in Thoroughbreds is of interest to breeders and geneticists. Therefore, the genetic parameters of racing performance have been investigated in various populations of Thoroughbreds. However, the predictability of the racing performance of a racehorse has not been assessed well. In this study, we built mixed-effects models for Japanese Thoroughbreds and assessed their predictability of racing performance. We used the average velocity as an index of racing performance and treated each category of racecourse and distance as different traits. Model selection us...
Brandon RB, Giffard JM, Bell K.Single nucleotide polymorphisms (SNPs) in exons 13, 15 and 16 of equine transferrin for common, rare and mutant variants were investigated. Compared with previous work a further 13 SNPs have been identified, allowing for the two previously identified clades to be subdivided into 11 groups. A combination of one or more of eight SNPs can be used to classify the equine variants into these 11 groups, since most are co-inherited. Putative sites of glycosylation in exons 13 and 16 showed no polymorphism, suggesting that presence or absence of sugar moieties does not lead to electrophoretic variation...
Lopez BS, Hurley DJ, Giancola S, Giguère S, Felippe MJB, Hart KA.The impact of culture conditions on equine monocyte-derived dendritic cells (MoDC) generation has not been fully characterized. We hypothesized that 1) MoDC could be cultured in a commercially available serum-free medium (AIM-V); and 2) that differential culture conditions would influence MoDC viability, yield and phenotype. MoDC generated from adult horses were cultured under variable conditions in a series of experiments. Viability was assessed using trypan blue and propidium iodide staining. Yield was determined by manual hemocytometer counting. Phenotype was assessed by flow cytometric ana...
Gossett CL, Guyer D, Hein J, Brooks SA.White spotting is an iconic feature of the American Paint Horse. The American Paint Horse Association (APHA) is dedicated to recording pedigree and performance of this stock-type breed, while preserving its distinctive coat color and conformation. Here, the depigmented proportion of the coat (% white coat) was measured using digital photograph analysis of 1195 registered American Paint Horses. Genotypes for nine white-spotting polymorphisms commonly found in Paint Horses, and two pigment-producing loci and genes, were also provided by the APHA. White-coat percent significantly increased in h...
Powers A, Peek SF, Reed S, Donnelly CG, Tinkler S, Gasper D, Woolard KD, Finno CJ.Equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM) is a neurodegenerative disease that primarily affects young, genetically predisposed horses that are deficient in vitamin E. Equine NAD/EDM has not previously been documented in Gypsy Vanner horses (GVs). Objective: To evaluate: (1) the clinical phenotype, blood vitamin E concentrations before and after supplementation and pedigree in a cohort of GV horses with a high prevalence of neurologic disease suspicious for eNAD/EDM and (2) to confirm eNAD/EDM in GVs through postmortem evaluation. Methods: Twenty-six GVs from 1 fa...
Rodríguez M, Quiroga J, Cortés B, Morán G, Henríquez C.Tamoxifen (TAM) is widely utilized in the prevention and treatment of human breast cancer and has demonstrated the potential to modulate the immune response. It has been proposed as a therapeutic tool for immune-mediated diseases. TAM has been investigated as a possible treatment for asthma-like conditions in horses, revealing specific impacts on the innate immune system. While the effects of TAM on equine neutrophils are well-documented, its influence on lymphocytes and the modulation of the immune response polarization remains unclear. This study employed peripheral blood mononuclear cells ...
Van Mol B, Oosterlinck M, Janssens S, Buys N, Pille F.Various environmental and genetic risk factors are linked to the pathogenesis of equine osteochondrosis and osteochondral fragments in the fetlock joint. Therefore, a scoping review was conducted to describe current evidence linking genetic factors and environmental factors of these osteochondral disorders. This article constitutes the first part of this scoping review and focuses on environmental factors, with the second part addressing genetic factors. To identify potentially relevant papers online bibliographical databases PubMed and Web of Science were utilised, supplemented with articles ...
Bussiman F, Alves AAC, Richter J, Hidalgo J, Veroneze R, Oliveira T.Gait scores are widely used in the genetic evaluation of horses. However, the nature of such measurement may limit genetic progress since there is subjectivity in phenotypic information. This study aimed to assess the application of machine learning techniques in the prediction of breeding values for five visual gait scores in Campolina horses: dissociation, comfort, style, regularity, and development. The dataset contained over 5000 phenotypic records with 107,951 horses (14 generations) in the pedigree. A fixed model was used to estimate least-square solutions for fixed effects and adjusted ...
Van Mol B, Janssens S, Oosterlinck M, Pille F, Buys N.Equine osteochondrosis and osteochondral fragments in the fetlock joint are linked to various environmental and genetic risk factors. To assess the scope of the literature linking these risk factors to the development of these osteochondral disorders, while identifying knowledge gaps and challenges to guide future research, a scoping review was performed. This article constitutes the second part of this scoping review and focuses on genetic factors, with the first part addressing environmental factors. To identify potentially relevant papers, online bibliographical databases PubMed and Web of ...
Van Cauter R, Caudron I, Lejeune JP, Rousset A, Serteyn D.Osteochondral fragments within equine joints are commonly encountered and may predispose to lameness and limitation to sport purposes. Factors leading to this condition include genetic, nutritional and environmental conditions. However, few studies have evaluated the impact of conformation traits and their correlation with osteochondrosis. This study, based on the radiographic screenings of young horses born in Wallonia (266 individuals, 532 forelimbs), evaluated the correlation between foot, fetlock conformations of the front limb, height at the withers and presence of osteochondral fragments...
Pepper B, North E, Foster M, Culwell J, Nicodemus MC, Cavinder C, Harvey K, Williams T.Registration numbers for the Palomino Horse Breeders of America (PHBA) have risen with the assistance of new registration guidelines. These changes in guidelines allowed for registration of any horse with a palomino body color, including those with unknown pedigrees. While this promoted registry growth, documenting the breed's orgins from those known pedigrees making up the breed's foundation is important with the introduction of unknown pedigrees. This can be accomplished using pedigree tracing, which is of particular value for color registries as the study of coat color patterns is plagued w...
Yoshihara T, Tozaki T, Nakaya S, Takasu M, Kawate K, Furukawa R, Kikuchi M, Isihge T, Nagata SI, Kakoi H, Hobo S.The Taishu horse is a native Japanese breed threatened with extinction. It is important to genotype the causative genes of rare phenotypes in endangered breeds because unique genetic traits might be lost unless a breeding strategy for conservation is constructed. In the present study, nine single-nucleotide variants and three indels of nine genes related to coat color, body composition, and gait were genotyped in 56 Taishu horses. Of these, only three genes were polymorphic. The observed coat color phenotypes coincided with the estimated phenotype from the genotypes, whereas black horses showe...
Liu YK, Fu WW, Wang ZY, Pei SW, Li KH, Wu WW, Le MZ, Yue XP.Chakouyi (CKY) horses from the Qinghai‒Xizang Plateau are well known for their unique lateral gaits and high-altitude adaptation, but genetic mechanisms underlying these phenotypes remain unclear. This study presents a comparison of 60 newly resequenced genomes of gaited CKY horses with 139 public genomes from 19 horse breeds. Population structure analyses (admixture, PCA, and neighbor-joining tree) reveal a close genetic relationship between CKY and other highland breeds (Tibetan and Chaidamu horses). Compared with other Chinese breeds, CKY horses present reduced nucleotide diversity (θπ)...
