Topic:Breed Differences
Breed differences in horses encompass variations in physical characteristics, behavior, and physiological traits among different horse breeds. These differences arise from selective breeding practices aimed at enhancing specific attributes such as speed, endurance, strength, or temperament. Physical attributes can include variations in size, coat color, and conformation, while behavioral traits may involve differences in temperament and trainability. Physiological differences can affect metabolism, disease susceptibility, and performance capabilities. This topic includes peer-reviewed research studies and scholarly articles that explore the genetic, environmental, and historical factors contributing to breed differences, as well as their implications for equine management, health, and performance.
Radioimmunoassay technique for detecting urinary excretion products after administration of synthetic anabolic steroids to the horse. 1. Cross-bred and thoroughbred geldings were injected with veterinary doses of various synthetic anabolic steroids. Urines collected sequentially from treated animals were analysed, following solvent extraction, by radioimmunoassay using 19-[3H]nortestosterone and an antibody raised against a 19-nortestosterone immunogen. 2. Urinary excretion of 19-nortestosterone and/or its cross-reacting metabolites was detectable for various times after administration of different nortestosterone esters, as follows: phenylpropionate (400 mg), greater than 14 days; cyclohexylpropionate (100 mg), greather tha...
A new allele in the prealbumin system of horse serum markers. A family study of an index case in the Arabian breed of horses demonstrated the presence of a new allele in the prealbumin (Pr) system of electrophoretically determined markers in horse serum which, when homozygous, results in the absence of any recognizable zones in the Pr region. The symbol PrO is proposed for this allele which has an estimated frequency in Arabian horses of 0.09.
Genetic polymorphism of the vitamin D binding protein and another post-albumin protein in horse serum. Horizontal polyacrylamide gel electrophoreses, on 10% separation gel, of horse serum revealed polymorphism of the vitamin D binding protein (Gc protein) and another post-albumin protein (Pa). Family data supported the hypothesis that Gc and Pa types were controlled by autosomal codominant alleles. For both Gc and Pa proteins, the homozygous types showed a single fraction while the heterozygous type had two fractions. Pa types were found to be identical to the post-albumin types reported earlier by starch gel electrophoresis. Two Gc alleles, GcF and GcS, and three Pa alleles, Pa D, Pa F and Pa ...
Epidemiologic analysis of oral and pharyngeal cancer in dogs, cats, horses, and cattle. Four hundred sixty-nine oral-pharyngeal malignancies diagnosed in dogs, cats, horses, and cattle and submitted to the Viterinary Medical Data Program between March 1, 1964, and Dec 31, 1974, were analyzed. Of these cases, 84% were in dogs. The most frequent oral-pharyngeal cancer in dogs was melanoma; in cats and horses, it was squamous cell carcinoma. In dogs, the risk of developing melanoma increased more with age than did the risk of developing squamous cell carcinoma and fibrosarcoma. Male dogs had significantly greater risk of developing fibrosarcomas and melanomas than did female dogs. T...
Squamous cell carcinoma in horses. In a review of neoplasm registry records at Kansas State University (1961 through 1971), 58 squamous cell carcinomas were reported in 10 breeds of horses. Mean age of the affected horses was 12.4 years. The head, eye and ocular adnexa accounted for 43.1%, the external male genitalia, 44.8%, and female perineal region, 12.0% of the squamous cell carcinomas, altogether representing 20.2% of 287 neoplasms recorded.
Equine serum lipids: serum lipids and glucose in Morgan and Thoroughbred horses and Shetland ponies. Concentrations of serum phospholipids, triglycerides, total cholesterol, nonesterified fatty acids, and glucose were determined for 9 months (September, 1972, to May, 1973) in 19 fasting horses and ponies (8 Morgan horses, 7 Thoroughbred horses, and 4 Shetland Ponies). Morgan horses had higher concentrations of total lipid than did Thoroughbreds, although the relative proportions of each type of lipid were similar in the 2 breeds. Shetland Ponies had higher nonesterified fatty acid and lower glucose concentrations than did either breed of horse. In both breeds of horses, concentrations of seru...
Equine serum lipids: serum lipoprotein profiles of Morgan and Thoroughbred horses. The serum of lipoproteins of 10 Morgan and 8 Thoroughbred horses were examined by 2 methods of polyacrylamide gel electrophoresis. A significant breed difference in the beta-lipoprotein to alpha-lipoprotein ratio was seen in gradient slab electrophoresis. A breed difference in the number of peaks, but no difference in beta-lipoprotein to alpha-lipoprotein ratio, was found in disc gel electrophoresis. These results have been correlated to indicate differences in charge of alpha-lipoprotein components and in size of beta-lipoprotein components between these 2 breeds of horses.
Equine serum lipids: lipid composition and electrophoretic mobility of equine serum lipoprotein fractions. The serum lipoprotein fractions from 5 Morgan and 5 Thoroughbred horses were isolated by preparative ultracentrifugation, chemically analyzed for lipid composition, and studied by 2 methods of polyacrylamide gel electrophoresis to determine electrophoretic mobility. Breed differences were not seen in the relative percentages of the lipid classes found in the various fractions. Normally, horses, like most animals, carry the majority of their lipid in high-density lipoproteins. Electrophoretically, the only difference seen between breeds occurred on disc electrophoresis where the extra band, whi...
Empyema of the equine paranasal sinuses. A survey of 28 cases of chronic purulent infection of the sinuses in the horse showed a relationship between incidence and age, and a probable relationship with breed. Dental disease was apparently the cause of half the cases. The conventional treatment of trephination followed by irrigation with antiseptic solutions resulted in freedom from recurrence of the disease for over 1 year in 17 of the 28 horses. Antibiotic therapy appears to be useless in chronic empyema. The prognosis is adversely affected by the development of facial swelling, a sign seen usually only in long-standing cases.
Serum levels of the immunoglobulins IgG and IgG(T) in horses. Levels of the immunoglobulins IgG and IgG(T) in serum in Norwegian horses of the breeds “Døle” and “Fjord” were determined by the quantitative radial immunodiffusion test. No significant differences were apparent between the 2 Norwegian breeds. The immunoglobulin levels were approximately in the same range as previously reported for Shetland ponies. Immunoglobulins could not be detected in the newborn foal. As early as 24 hrs. after birth the mean immunoglobulin level was within the adult range. After a drop during the first month of life, the immunoglobulins increased. IgG(T) rose mo...
Genetic Control of Albumin Phenotypes in Horses. By means of a starch-gel technique suggested by Kristjansson, 3 albumin phenotypes A, AB and B are demonstrable in the serum of horses. As indicated by data on the inheritance of these phenotypes and by a gene-frequency analysis of the distribution of the phenotypes in 2 breeds of horses, the results are consistent with the interpretation that the 3 phenotypes are controlled by a pair of codominant, autosomal alleles. These 3 phenotypes can be diagnosed by examining either the albumin region or the post-albumin region of the gels. Hence, diagnosis in one region serves as an independent check o...
Population Genetic Analysis of the Estonian Native Horse Suggests Diverse and Distinct Genetics, Ancient Origin and Contribution from Unique Patrilines. The Estonian Native Horse (ENH) is a medium-size pony found mainly in the western islands of Estonia and is well-adapted to the harsh northern climate and poor pastures. The ancestry of the ENH is debated, including alleged claims about direct descendance from the extinct Tarpan. Here we conducted a detailed analysis of the genetic makeup and relationships of the ENH based on the genotypes of 15 autosomal short tandem repeats (STRs), 18 Y chromosomal single nucleotide polymorphisms (SNPs), mitochondrial D-loop sequence and lateral gait allele in DMRT3. The study encompassed 2890 horses of 61 b...
Retrospective study of factors affecting multiple ovulations, embryo recovery, quality, and diameter in a commercial equine embryo transfer program. In this study, 198 donor mares of different breeds, ages, and reproductive category were inseminated with fresh, cooled and frozen or frozen and cooled semen at the embryo transfer station or in private artificial insemination centers during 10 breeding seasons. The results of this activity were retrospectively analyzed by Pearson Chi-square test and logistic regression to evaluate factors affecting multiple ovulations, embryo recovery, embryo quality, and embryo diameter. Out of the 661 cycles, 937 ovulations were recorded (mean ovulations/cycle: 1.42 ± 0.58). Ovulation rate and incidence of...
The American Quarter Horse: population structure and relationship to the thoroughbred. A breed known for its versatility, the American Quarter Horse (QH), is increasingly bred for performance in specific disciplines. The impact of selective breeding on the diversity and structure of the QH breed was evaluated using pedigree analysis and genome-wide SNP data from horses representing 6 performance groups (halter, western pleasure, reining, working cow, cutting, and racing). Genotype data (36 037 single nucleotide polymorphisms [SNPs]) from 36 Thoroughbreds were also evaluated with those from the 132 performing QHs to evaluate the Thoroughbred's influence on QH diversity. Results s...
Differences in extracellular matrix proteins between Friesian horses with aortic rupture, unaffected Friesians and Warmblood horses. Unlike in Warmblood horses, aortic rupture is quite common in Friesian horses, in which a hereditary trait is suspected. The aortic connective tissue in affected Friesians shows histological changes such as medial necrosis, elastic fibre fragmentation, mucoid material accumulation and fibrosis with aberrant collagen morphology. However, ultrastructural examination of the collagen fibres of the mid-thoracic aorta has been inconclusive in further elucidating the pathogenesis of the disease. Objective: To assess several extracellular matrix (ECM) components biochemically in order to explore a pos...