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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.
PCR-RFLP analysis of the cytochrome b gene in horse mitochondrial DNA. The mitochondrial DNA sequence of cytochrome b gene in a Thoroughbred horse was determined. By comparing DNA sequences between the Thoroughbred and published sequence data (two horses and one Grevyi zebra), polymerase chain reaction (PCR) primers were designed for amplification of a 590 bp DNA fragment in the cytochrome b gene, and PCR-restriction fragment length polymorphism (RFLP) analysis was studied in 140 horses of six breeds using three restriction enzymes (AciI, BamHI, RsaI). Two morphs were found using each of the three enzymes. By combining three enzymes morphs, the 140 horses examine...
Seminal plasma affects membrane integrity and motility of equine spermatozoa after cryopreservation. Effects of seminal plasma on post-thaw motility and membrane integrity of cryopreserved horse spermatozoa were investigated. Carboxyfluorescein diacetate staining was used for the assessment of sperm membrane integrity. Adding 30% of seminal plasma from stallions with high post-thaw sperm motility to ejaculates from stallions with low post-thaw sperm motility increased progressive motility from 24.0 +/- 1.6 to 34.5 +/- 1.9% (P < 0.05) and membrane integrity from 27.0 +/- 2.1 to 34.3 +/- 2.3% membrane-intact spermatozoa (P < 0.05). Conversely, the addition of seminal plasma from stallions...
Quantification of normal head morphometry of stallion spermatozoa. The heads of stallion spermatozoa were analysed by computer automated sperm head morphometry and the morphometric values of the major subpopulations of sperm heads were assessed. The criteria for normal dimensions of stallion sperm heads are proposed based on the analysis of these measurements. Semen samples were collected from 10 fertile and 10 subfertile stallions, processed by a standard method, smeared onto microscope slides and stained using haematoxylin. At least 200 properly digitized sperm heads were analysed from each stallion. The measurements for length, width, area, perimeter and w...
SDS-PAGE characterization of the proteins in equine seminal plasma. The aims of this project were to document the protein profile of equine seminal plasma and determine the variability between stallions in the relative composition of proteins in the ejaculate. A single ejaculate was obtained from 14 stallions of varying breed and age. The gel fraction was removed by an in-line filter. The semen was centrifuged and the supernatant seminal plasma aspirated without disturbing the sperm pellet. The seminal plasma was recentrifuged and stored in cryovials at -70 degrees C. Samples were thawed, recentrifuged, assayed for protein concentration (BCA protein assay), di...
Intraosseous epidermoid cyst in a horse. A 21-year-old female American Saddle Horse with a prominent swelling on the ventral aspect of the right hemimandible and radiographic evidence of a bone cyst was examined. The cyst cavity was surgically explored and was found to contain mucinous fluid and sheets of keratin. Microscopically, the cyst was lined by well-differentiated squamous epithelium characterized by various degrees of hyperkeratosis and parakeratosis. The stromal component varied from scant areas in which epithelium was closely apposed to bone to wide regions of dense connective tissue that contained fragments of keratin sur...
Characterisation of proteins in the seminal plasma of stallions, geldings and supplemented with testosterone. The major proteins in stallion seminal plasma were characterised by two-dimensional polyacrylamide gel electrophoresis, and compared with the patterns of proteins in normal geldings (castrated males) and geldings supplemented with testosterone. The major proteins or groups of proteins identified according to their approximate relative molecular weight in kilodaltons (kDa) and apparent isoelectric point (pl) were: 1) 60 kDa. pl 7; 2) 23 kDa, pl 4-5; 3) 25-30 kDa, pl 5.5-6; 4) 23 kDa, pl 7-8; and 5) 15-20 kDa, pl 6-7.5. Protein groups 1 and 2 were more prominent in the seminal plasma from the st...
Allergens of horse dander: comparison among breeds and individual animals by immunoblotting. Some patients who are allergic to horses have reported that they can tolerate certain breeds, and the presence of breed-specific allergens has been suggested. Breeders and patients with asthma have claimed that Bashkir horses are nonallergenic. We used sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting to determine IgE-binding profiles of extracts of dander obtained from horses of several breeds. We found considerable inter-breed and within-breed variation but no breed-specific allergens. Danders from all breeds investigated contained the most important allergens, and ...
In vitro induction of acrosome reactions in stallion spermatozoa by heparin and A23187. The ability of the glycosaminoglycan, heparin, and the calcium ionophore, A23187, to induce acrosome reaction in equine spermatozoa was assessed using semen from 3 warmblood stallions of known high fertility. After collection of semen, the spermatozoa were washed and incubated in vitro with heparin or A23187. Incubation periods were 0, 4, 6 or 8 h with 0, 1, 10 or 100 microg/ml heparin or 0, 10, 30 or 60 min with 0, 0.01, 0.1, 1 or 10 microM A23187, respectively. Acrosome reactions were determined by staining the spermatozoa with naphthol yellow S plus erythrosin B, and sperm viability was ass...
Cryopreservation of equine embryos. Principles and procedures for cryopreservation of equine embryos are described. Embryos less than 250 microM in diameter can be cryopreserved successfully if glycerol is used as the cryoprotectant. Cooling is takes place in such a way that most of the water leaves the cells before intracellular ice forms, and glycerol is removed after thawing without undue osmotic swelling of cells. Vitrification procedures also show promise for small embryos. Satisfactory procedures for cryopreserving embryos of more than 250 microM in diameter are not yet available.
Intracellular calcium concentration in equine spermatozoa attached to oviductal epithelial cells in vitro. Interaction of spermatozoa with oviductal epithelial cells (OEC) in the oviductal isthmus prolongs the life span of spermatozoa. The hypothesis that the interaction of equine spermatozoa with OEC affects their intracellular calcium concentration ([Ca2+]i) was tested in a sperm-OEC coculture model. Changes in [Ca2+]i in spermatozoa loaded with the fluorescent calcium indicator indo-1 acetoxymethylester (AM) were determined for spermatozoa attached to OEC or to Matrigel, as well as for free-swimming spermatozoa incubated without oviductal epithelium. [Ca2+]i was determined before incubation and ...
Analysis of stallion semen and its relation to fertility. This article describes some of the basic methodology for conducting stallion semen evaluations. Not all of these assays will likely be conducted on every semen sample collected. Routine evaluations should include determination of semen volume, sperm concentration, and an estimation of the percentage of progressively motile sperm, at a minimum. Other assays can be used if a seminal problem is discerned at the beginning of the breeding season or after a stallion has recovered from an illness or injury. Additionally, laboratory assays are particularly important to conduct on cryopreserved spermat...
Cryopreservation of stallion spermatozoa. The main advantage to using frozen semen in any breeding program is faster genetic gain for the inherited trait desired. Milk production of dairy cows doubled (from 26,000 to 52,000 kg of milk/cow per year) between 1950 and 1980, because the dairy industry was using semen only from bulls with the greatest genetic potential for milk production. This genetic gain could have been achieved without the use of frozen semen; however, the time required to achieve that same genetic progress would have been lengthened exceedingly. Fertility rates using frozen stallion spermatozoa are not equal to that o...
Cloning and sequencing of an equine insulin-like growth factor I cDNA and its expression in fetal and adult tissues. A cDNA for equine insulin-like growth factor I (IGF I) has been isolated by reverse transcriptase-polymerase chain reaction and subsequently sequenced. The sequenced fragment contained 465 bp including the coding regions for the signal peptide, the entire mature protein, and 4 amino acids into the E-peptide. Like its human counterpart, the mature equine IGF I peptide contains 70 amino acids and was 100% homologous between horse and man. The 49-amino-acid signal peptide had the threonine in position 26 of the human signal peptide substituted by isoleucine. The nucleotide homology across the ent...
Familial basis of exertional rhabdomyolysis in quarter horse-related breeds. To trace pedigrees from affected horses, identify likely contributing founder horses, and determine the conditional probability of founder genotypes. Methods: Muscle biopsy records from the Neuromuscular Disease Laboratory at the University of California-Davis and the University of Minnesota were searched to identify horses with a polysaccharide storage myopathy and exercise intolerance/rhabdomyolysis. Pedigrees containing 5 to 6 generations were obtained where possible. Methods: 13 Quarter Horses, 4 American Paint Horses, 3 Appaloosas, and 3 Quarter Horse crossbreds (16 mares, 4 geldings, and...
Actinobacillus suis septicaemia in two foals. A 24-hour-old Hackney ony filly developed signs of weakness, depression and a poor suck reflex, with harsh lung sounds over both fields, and a 48-hour-old Arabian colt from a normal birth which had sucked vigorously developed loose stools and became depressed, weak and anorectic. Both foals had serum IgG concentrations greater than 800 mg/dl, but each had a severe neutropenia with a left shift, and blood cultures from both of them yielded Actinobacillus suis. The A suis isolates had different antimicrobial susceptibility patterns and, in the case of the Arabian, the isolate was resistant to co...
Nucleotide sequence of exons 5 to 9 of the p53 tumour-suppressor gene of the horse (Equus caballus). An evolutionary conserved 1.3 kb fragment corresponding to the horse p53 tumour suppressor gene was PCR amplified, cloned and the nucleotide sequence determined. The p53 fragment encoded exons 5 to 9 and the intervening introns. The nucleotide sequence and the predicted aminoacid sequence showed a high level of homology with human and donkey p53 sequences.
Effect of timing of frozen semen insemination on pregnancy rate in mares. Thirty-four mares were inseminated with frozen semen from one stallion during 2 oestrous cycles, every 48 h until ovulation took place and within 12 h after ovulation. Semen was frozen using the Colorado method. The insemination dose was from 200 to 400 x 10(6) progressively motile spermatozoa. Ovaries were examined every 12 h to determine time of ovulation. Examination for pregnancy was carried out using ultrasonography, 15 days after ovulation. Thirty-five per cent of mares inseminated < 24 h and 23% of mares inseminated between 24-48 h before ovulation were pregnant (p = 0.388). The preg...
Cytofluorescent assay to quantify adhesion of equine spermatozoa to oviduct epithelial cells in vitro. To facilitate the study of interactions between equine spermatozoa and homologous oviduct epithelial cells, we developed an assay to count labelled spermatozoa bound to oviduct epithelial cell (OEC) monolayers and used the assay to compare the binding ability of spermatozoa from different stallions. Washed spermatozoa from three stallions were incubated with the fluorochrome Hoechst 33342 (5 micrograms/ml) for 1 min. Spermatozoa were then layered over confluent monolayers of oviduct epithelial cells in 2 cm2 culture wells. Coculture treatments comprised five concentrations of spermatozoa (10(5...
The effect of arthritis in the carpal joint on performance in Norwegian cold-blooded trotters. The purpose of this study was to evaluate the impact of arthritis of the carpal joint on performance of Norwegian cold-blooded trotters. Two performance variables were used in the analyses. The first was the start status, for which horses that had started in one or more races within a certain age received the value 1, and horses that had not raced were correspondingly assigned the value 0. The second variable was the accumulated, transformed and standardized earnings (ATSE), which is the power transformation of earnings (earnings .2, with unraced horses assigned a value of zero) expressed as a...
