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Topic:Horse Breeds
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.
Excess of heterozygotes at albumin locus in American Standardbred horses. Data from 5934 matings of American Standardbred horses provided evidence for an excess of heterozygotes at the albumin locus, statistically significant (P less than 0.01) in one mating class (A1-AB stallions x Al-A dams), primarily attributed to an excess of heterozygotes among male offspring.
Pigment types of various color genotypes of horses. 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.
Preliminary evidence for a fourth allele at the phosphohexose isomerase (Phi) locus of horse erythrocytes. 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.
[Endangered domestic animal breeds in German-speaking countries. V. Horses]. Due to motorization the heavy horses, in particular draught horses and carriage horses, were deprived of their "raison d'être". At present therefore, they mostly are found in small livestocks. The past few years they regained some significance through their work in the forests, as an attraction in tourism or somewhere else. In German speaking countries approximately 15 horse breeds must be considered to be threatened in their existence. Breeding history, appearance, use and geographical distribution of 12 of them are discussed in this article.
Subdivision of equine Tf into H1 and H2. Subdivision of equine TfH into two variants, designated H1 (faster) and H2 (slower), has been accomplished by high voltage, thin layer polyacrylamide gel electrophoresis at pH 7.9. Transferrin H1 and H2 have been shown to be controlled by codominant alleles and gene frequencies of the Tf alleles have been determined in the Australian Thoroughbred, Standardbred. Quarter Horse and Arabian Horse breeds.
[Iron and iron-binding capacity in the serum of clinically healthy horses]. Serum iron concentration and iron-binding capacity were determined in 34 respectively 35 clinically healthy horses of different sex, with the age of 3 to 21 years. In the Warm blooded horse, the Half bred, the Haflinger horse, the Heavy horse and the Arabian Haflinger the mean serum iron concentration amounted to 253 +/- 66 micrograms/dl, 202 +/- 87 micrograms/dl, 166 +/- 67 micrograms/dl, 183 micrograms/dl and 366 micrograms/dl, while the iron-binding capacity in the Warm blooded horse, the Half bred, the Haflinger horse, the Thoroughbred, the Heavy horse and the Arabian Haflinger ran up to 4...
Cytochemical analysis of the anionic sites on the membrane of the stallion spermatozoa during the epididymal transit. The structure, relative density, and distribution of anionic sites on the surface of epididymal and ejaculated spermatozoa were studied using polycationic ferritin (CF), colloidal iron hydroxide (CIH), various enzymatic treatments, methylation, and de-acetylation. Macro-molecules containing sugar residues, probably sialic acid, are part of the sperm membrane and show a characteristic distribution and density that is dependent of the sperm region and of its origin. Unlike the spermatozoa of other eutheria examined, the exposure of the stallion spermatozoa to neuraminidase treatment did not prod...
Plasma lysozyme activity of Polish primitive horses under physiological conditions and in experimental fever. The normal level of plasma lysozyme of 9 Tarpane-like horses was 0.922pg/ml. This was
calculated from determinations performed 5 times in a period of 14 months. Observations on the
normal plasma level of lysozyme in the horse revealed marked variations in individual animals, as well
as in the whole group and in the mean values calculated for individual horses. The model for the
subsequent studies was an experimental fever evoked by the administration of E. colz LPS in a dose of
0.1 pg/kg body weight. Blood samples from the jugular vein were taken just before LPS injection, and
then for 8...
Comparison of Ham’s F10 with CO2 or Hepes buffer for storage of equine embryos at 5 C for 24 H. Forty equine embryos collected 7 d post-ovulation were stored at 5 C for 24 h in one of two culture media (n = 20/group): 1) Ham's F10 + 10% heat-treated fetal calf serum (FCS) buffered by gassing with 5% CO2, 5% O2 and 90% N2 and 2) Ham's F10 + 10% FCS with Hepes buffer (25 mM). Embryos cultured in Ham's F10 + CO2 maintained a better quality score and had a larger average increase in diameter (+34.8 micron) than embryos stored in Hepes buffered Ham's F10 (-10.2 micron). Embryos were transferred surgically into recipient mares that ovulated -3 to +1 d in relation to the donor mare. Twenty embr...
Metabolic responses to exercise in the racehorse: changes in plasma alanine concentration. Previous studies in humans have shown that alanine is released from the skeletal muscle in proportion to the work load. We have measured plasma alanine and urea concentrations in well-trained Standardbred and Finnish-bred (cold-blooded) trotters after a graded-intensity exercise and during recovery to study metabolic responses to exercise in this animal model. As controls we measured blood lactate, pyruvate, and glucose concentrations as well as hematocrit values. Metabolic responses to exercise were closely reflected in all these parameters. Plasma alanine increased relatively more than plasm...
Effects of semen fractionation and dilution ratio on equine spermatozoal motility parameters. Two experiments were conducted to examine the effects of semen fractionation and dilution ratio on motility parameters of stallion spermatozoa. In Experiment 1, three ejaculates from each of three stallions were divided into sperm-rich (SR) and sperm-poor (SP) fractions to determine the difference in sperm concentration. Mean sperm concentration in SR fractions (349.5 x 10(6)/ml) was greater (P < 0.001) than that of SP fractions (96.9 x 10(6)/ml). In Experiment 2, three ejaculates from each of two stallions were divided into SR and SP fractions. Fifty percent of the original volume of SR fr...
Definition of 15 equine leucocyte antigens. Fifteen equine leucocyte antigens were defined by absorption and titration analysis of alloantisera obtained by natural sensitisation through pregnancy and by planned experimental immunisation. Definitive sera were tested on the cells of 90 unrelated horses and members of eight equine families. The family data suggested that 13 specificities were coded by a single locus (first locus) and one specificity (Eq 14) was coded by a second linked locus. The remaining specificity (Eq 7) was controlled by a third locus unlinked to the first or second loci. Tests on the cells of unrelated horses showed ...
Induction and characterization of acrosome reaction in equine spermatozoa. Equine spermatozoa were incubated in a chemically defined medium for 8 hours. The medium preserved spermatozoal viability, as assessed by total spermatozoal motility, progressive spermatozoal motility, and spermatozoal exclusion of eosin stain. Effects of time and divalent cation ionophore, A23187, on the occurrence and character of the spermatozoal acrosome reaction were determined. Two light microscopic assays, a triple-stain technique and a chlortetracycline fluorescence assay, were calibrated with transmission electron microscopy for detection of the acrosome reaction. Incubation time and ...
Gene conversions in the horse alpha-globin gene complex. The sequences of the linked alpha 2- and alpha 1-globin genes of the equine BI and BII haplotypes are greater than 99% identical within a 1.2-kb region extending from approximately 75 bp upstream of the putative cap site to a point approximately 150 bp 3' to the poly A addition signal. Differences between the alpha 2 and alpha 1 genes that are common to both haplotypes indicate that a major gene conversion occurred approximately 12 Myr ago and that this has been followed by shorter, more localized, conversions. Interhaplotype (allelic) comparisons at the alpha loci suggest that the BI and BII ...
The amino acid sequence of an amyloid fibril protein AA isolated from the horse. The amino acid sequence of the amyloid fibril protein AA from horse was established from characterization of cyanogen bromide fragments, tryptic peptides, and a peptide derived from a digest with Staphylococcus aureus V8 proteinase. The protein was found to consist of 80 amino acid residues. Sequence homologies with protein AA from other species were very striking, and revealed an insertion of two amino acid residues between positions 72 and 73. In position 44, two amino acid residues were found which provide further evidence for a polymorphism in the amyloid fibril protein AA.
Equine linkage group II: phase conservation of To with AlB and GcS. Blood type analysis of 29 foals in a paternal half-sib family verified linkage of five LGII loci (Es, E, To, Gc, Al). Population and parentage data from other tobiano-spotted horses suggested conservation of a tightly linked (To:GcS:AlB) marker complex.
Calmodulin-mediated adenylate cyclase from mammalian sperm. Calmodulin (CaM), the calcium binding protein that modulates the activity of a number of key regulatory enzymes, is present at high levels in sperm. To determine whether CaM regulates adenylate cyclase in mammalian sperm, the actions of EGTA and selected CaM antagonists on a solubilized adenylate cyclase from mature equine sperm were examined. The activity of equine sperm adenylate cyclase was inhibited by EGTA in a concentration-dependent manner with a half-maximal inhibitory concentration (IC50) of 2 mM. Equine sperm adenylate cyclase was also inhibited in a concentration-dependent manner by...
Isolation and characterization of two protamines St1 and St2 from stallion spermatozoa, and amino-acid sequence of the major protamine St1. Two protamines, St1 and St2, were isolated from stallion sperm nuclei, where they represent about 75 and 25%, respectively, of the total basic protein complement. The primary structure of protamine St1 (49 residues; Mr approximately equal to 6600) has been determined. The structure of this protamine is compared to the amino-acid sequence of other mammalian protamines already known.
Time-related responses of spontaneously breathing, laterally recumbent horses to prolonged anesthesia with halothane. Cardiovascular and respiratory functions were serially evaluated in ten healthy, fasting, spontaneously breathing, laterally recumbent adult horses during five hours of constant 1.06% alveolar halothane (equivalent to 1.2 times the minimum alveolar concentration for horses). Mean carotid arterial pressure was about 25% higher after one hour of constant-dose halothane than after 30 minutes of constant-dose (P less than 0.05), and remained increased throughout the study. Mean carotid arterial pressure peaked after 90 minutes, and was about 30% higher than at 30 minutes. Total peripheral vascular...
Serum retinol, 25-hydroxyvitamin D and alpha-tocopherol of racing trotters in Finland. Serum levels of retinol, 25-hydroxyvitamin D2, 25-hydroxyvitamin D3 and alpha-tocopherol were determined by high performance liquid chromatography from 142 Standardbred and Finnish Coldblooded Trotters aged three to 15 years. Blood samples were collected during January and July. Serum levels of retinol and alpha-tocopherol were about a third of those in man, with summer values indicating an increase in most horses. The relatively low serum concentrations of 25-hydroxyvitamin D and alpha-tocopherol suggest that during the winter season a deficiency of these vitamins may occur in horses in north...
Aromatization of 19-norandrogens by equine testicular microsomes. In the stallion testis, aromatase activity was localized in the microsomal fraction. Androgen aromatization occurred through the loss of 1 beta,2 beta hydrogen atoms and appeared to involve free sulfhydryl groups. A single enzyme system seemed to aromatize androgen and norandrogen at the same rate while having a much lower affinity for norandrogens.
