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.
Merkt H, Günzel AR.Embryonic resorption is reported as the main reason for early pregnancy losses in the West German Thoroughbred mare. An analysis of breeding records for the last 11 years showed a resorption rat of 8.4 per cent. Evidence was obtained that these early embryonic losses were associated with too early conception after foaling and with the state of lactation.
Greeves PR, Witherington DH.The difficulties that arise in filling out marking certificates for thoroughbreds are described. The description given on the certificate has to be both written and graphic. A general guide to whorl location is given.
Henneke DR, Kreider JL.Quarter Horse mares (n = 30) and their foals were used in a 2-year study. Objectives of the study were (i) to determine the effects of a treatment regimen, which permitted nursing for four 1-hour periods each day, on the postpartum reproductive performance of the dams, and (ii) to assess the effects of this procedure on the growth and development of foals. Mares in the restricted suckling treatment group showed estrus and ovulated sooner (P less than 0.01) after parturition than did control mares during the first year of the study, but not during the second year. Plasma progesterone concentrat...
Weitkamp LR, Allen PZ.Ancient origin of the equine vitamin D binding protein (Gc) polymorphism is suggested by the finding of two alleles, Gc(F) and Gc(S), in each of three equine subgenera, Equus, Asinus and Hippotigris. The equine Gc and albumin loci are closely linked (lod score = 6). Although no recombinants were observed, the data are not inconsistent with a map distance similar to the 2 centimorgans reported for the human albumin/Gc linkage relationship. Gametic association between the Gc(F) and Alb(F) alleles appears probable in the American Standardbred horse, perhaps as a result of population structure. Si...
Matthews AG.Three major antiprotease components in equine serum were identified and characterised. These were the acidic prealbumin Pr, the homologue of human alpha-1 antitrypsin and 2 protease binding proteins, the acidic prealbumin Xc and alpha-2 macroglobulin, both capable of inhibiting the proteolytic activity of trypsin, but with only limited inhibitory effect on its esterolytic activity. The possible role of these serum antiproteases in the onset of chronic obstructive pulmonary disease (COPD), analogous to the hereditary dysproteinaemia of alpha-1 antitrypsin in man, was investigated. There was no ...
McPherson EA, Lawson GH, Murphy JR, Nicholson JM, Breeze RG, Pirie HM.Breed, age, weight, type of work performed, seasonal onset, poor ventilation and exposure to moulds in the habitat were investigated in relation to the occurrence of chronic obstructive pulmonary disease (COPD). COPD was most commonly detected in showjumping and hacking horses. The older a horse, the more likely it was to become affected although most were 6 to 10 years of age. Of the horses in this sample of the population, which was not a random one, thoroughbred horses were affected least and ponies most often. The high incidence in ponies was related to their more frequent exposure to poor...
Scott EA, McDole M, Shires MH.Sixty-five cases of third phalanx (P3) fracture were retrieved from 20,638 case records at Michigan State University's Veterinary Clinical Center between Feb 1, 1964 and July 1, 1977. The fractures were classified by anatomic location, using a numbering system. Data from case records indicated the most common P3 fracture involved the articular surface of the coffin joint (53 of 65 cases; 81.5%). The greatest occurrence of P3 fracture was in Standardbreds (31 of 65 cases). Thirty-three of the 65 fractures were in geldings of all breeds; 57 of the cases were distributed among racing horses of fo...
Peterman BF, Morton RA.The research explores how different binding ions affect the oxidation speed of horse heart ferrocytochrome c, a protein, by potassium ferricyanide at a constant ionic strength. Studying the Ion Effect […]
Cox JE, Edwards GB, Neal PA.The authors analyse data collected over 23 years from 500 cryptorchid horses. They show that left- and right-sided abdominal cases occur with approximately equal frequency in ponies. Approximately half the right-sided unilateral abdominal cases have the epididymal tail descended while only 20 per cent of the left-sided cases do. These findings are briefly discussed. From their analysis of inguinal cryptorchidism the authors conclude that it is a relatively more complex phenomenon with incidence changing with age as well as breed. Right-sided retention predominates in young ponies, probably bei...
Cermák O.An attempt was made to express the relationship of spermiological characteristics with the fertility on the basis of seasonal variability of the fertility of stallions and of the ejaculate quality. A positive correlation between the activity of spermatozoa and the fertility ensues from the values of correlation coefficients. There is a negative correlation between the fertility and the concentration of citric acid. In the other characteristics, i.e. in the production of spermatozoa, volume of gel substance, pH, ergothioneine concentration, polarographic and hemolytic activity, the correlation ...
Merkt H, Jacobs KO, Klug E, Aukes E.An evaluation of the foaling rate achieved in the Hannoverian breed in Germany between 1815 and 1973 showed that during this period no improvement of the reproductive rate was achieved. The decennial foaling percentage remained within 50--60% except for those decades which included the two World Wars and their aftermaths. The annual foaling percentage remained maximal until the number of mares covered/stallion rose above 80 and it also remained high throughout the reproductive life of the stallion. Only in the oldest stallion (32 years) was there a significant lowering of fertility.
Thompson DL, Pickett BW, Squires EL, Amann RP.Factors affecting testicular measurements in situ and the relationships among the measurements and various reproductive characteristics were studied using data from 48 stallions. Mean values during the breeding season are provided for scrotal width, widths and lengths of individual testes, combined weight of testicular parenchyma, daily sperm production and daily sperm output. Testicular measurements were highly repeatable from day to day and for repeated measurements on a given day; technician provided the largest source of variation in the measurements of a given stallion. Age significantly ...
Bielański W, Kaczmarski F.Semen samples were collected from 3 fertile stallions by means of an 'open' artificial vagina and examined under scanning and transmission electron microscopy. The stallion spermatozoon has many features in common with that of other mammals but differs specifically in that it has an asymmetric head, an abaxial position of the tail and an acrosome of small volume. The presence of microtubules in the neck is also a characteristic of stallion spermatozoa.
Peaker M, Rossdale PD, Forsyth IA, Falk M.Small samples of mammary secretion were taken for analysis from Thoroughbred mares during the last 3 weeks of pregnancy up to the time of foaling. The concentrations of sodium and chloride decreased while those of lactose, potassium, citrate, phosphate, calcium, magnesium and protein increased. The time-course of these changes showed marked variation between animals. The concentration of whey proteins began to increase about 10 days before parturition. The appearance of the secretion and the size of the mammary glands increased in the last few days of pregnancy. It is suggested that the concen...
Squires EL, Pickett BW, Amann RP.Five ejaculates were collected at hourly intervals from 32 sexually rested stallions. Gel volume, total seminal volume, sperm concentration and spermatozoa per ejaculate declined (P less than 0.01) from the first to the second or third ejaculate. Gel-free seminal volume or percentage of motile spermatozoa did not vary (P less than 0.05) among ejaculates. Ejaculates from 2- to 3-year-old stallions contained less volume and fewer spermatozoa than those from 9- to 16-year-old stallions. Regardless of the stallion's age the first, first 2, first 3 and first 4 ejaculates represented 50, 74, 86 and ...
Berndtson WE, Hoyer JH, Squires EL, Pickett BW.The effect of exogenous testosterone on sperm production, seminal quality and libido was studied in 24 stallions. Based on pretreatment data, a stallion was assigned to 1 of 3 groups each containing 8 animals. One member of each group received 0 (Group 1), 50 (Group 2), or 200 micrograms (Group 3) testosterone propionate per kg body weight every 2 days for 88 days. The lower dose of testosterone had no significant effect on most of the parameters studied: the higher dose depressed total scrotal width at Day 90 post-treatment (P less than 0.01), total spermatozoa ejaculated between Days 60 and ...
Bowling AT, Dileanis S.The C3 polymorphism of equine serum or plasma revealed by agarose gel electrophoresis can be diagnosed with protein stain following acid protein fixation. In addition to the three alleles previously described (C31, C32, C33), a fourth allele (C34) was found. Population data for 25 domestic breeds and Equus przewalskii are presented.
Carnevale EM.Vitrification can be used successfully to cryopreserve equine embryos. Embryos for vitrification should be collected from donor mares' uteri when they are 300 mm or less in diameter, however,and at the morula or early blastocyst stage of development. No special equipment is required for vitrification; the straw containing the embryo is exposed to vapor for 1 minute before plunging it into liquid nitrogen. Warming of the straw requires no special equipment,and the embryo can be transferred directly from the straw into a recipient's uterus. Vitrification has been repeatedly successful when the p...
Marteniuk JV, Carleton CL, Lloyd JW, Shea ME.To determine whether sex of fetus, sire, month of conception, or year of foaling was associated with duration of gestation in mares. Methods: Epidemiologic retrospective cohort study. Methods: 500 foalings for 296 Standardbred mares. Methods: Data for reproductive events from 1986 to 1992 were analyzed. Analyses were conducted to determine whether duration of gestation was associated with sex of fetus, sire, month of conception, or year of foaling. Results: Mean duration of gestation was 343.3 days and was significantly greater for colt fetuses (344.4 days) than for filly fetuses (342.2 days)....
Hammons V, Brooks SA, Wickens C.Genetic testing offers precise and accurate data to horse owners concerning their horse's health and offers potential economic value increases of foal crops via genome-assisted selection. Despite availability of at least 96 commercially available markers, fewer than 20 are commonly used. This project seeks to identify the barriers to the incorporation of genomic tools in diverse equine operations. Based on studies examining public opinion of human medical testing, we expected that lack of genetic education and few industry requirements for testing may contribute to neutral or negative opinions...
Weaver MP, Wilant L.A postal survey of the owners of Clydesdale horses in the UK and USA was conducted to obtain information on tarsocrural effusion ('bog spavin') as an indicator of osteochondrosis from 935 horses. Additional information requested included details of how this condition was investigated and treated. The reported tarsocrural effusion incidence was 10 per cent. The majority of respondents believed the condition to be of concern to Clydesdale owners, but only a minority were aware of the implications of tarsocrural effusion, suggesting that owner education would be of benefit.
Bowling AT, Nickel LS.Family data from Paso Fino horses support the existence of a new allele (Aabdf) in the A system of red cell alloantigens. Considering breeds throughout the world, the A system now consists of 13 alleles defined by reagents which serologically detect seven factors.
Blanchard TL, Thompson JA, Love CC, Brinsko SP, Ramsey J, O'Meara A, Varner DD.Records (years 2005-2007) were analyzed from a Thoroughbred stud farm in central Kentucky. Data from all breeding cycles of foaling mares were tabulated (3184 cycles of 2003 foaling mares bred between 7 and 163 days postpartum). A multiple logistic regression model employing Bayesian statistics was used to adjust for factors that significantly affected outcome; odds ratios (ORs) for pregnancy rate, pregnancy loss rate, and foaling rate were determined to examine the influence of day of postpartum breeding on these parameters. Mares bred before Day 22 (Day 0 = day of foaling) postpartum had a d...