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.
Hereditary lethal arthrogryposis (“muscle contracture”) in horses. In 4 female foals of the Norwegian horse breed, "Fjord Horse", congenital arthrogryposis of the limbs are described. The disorder was mainly limited to the hind limbs and associated with polydactylia and partly with brachygnathia superior and cleft palate. The defective foals were paternal halfsisters of 4 normal foals (1 female + 3 males), sired by the stallion "Bingo" 1804, which was phenotypically quite normal. The disorder being lethal, is possibly caused by a sex-limited or a strongly sex-influenced dominant gene.
Twinning in mares: A survey of veterinarians and analyses of theriogenology records. Responses of 22 veterinarians to a questionnaire and the records of three brood-mare farms were examined to obtain information on twinning. The incidence rates of multiple ovulations on the three farms were 9%, 11%, and 22%. The multiple ovulation rate was reduced 42-67% in foaling mares compared to barren and maiden mares. Multiple ovulations were significantly more frequent in Thoroughbreds (19%) than in Quarter Horses (9%) and Appaloosas (8%). Both the questionnaire and the farm records indicated a high degree of repeatability of multiple ovulations and twin pregnancies within mares and wit...
A linkage group composed of three coat color genes and three serum protein loci in horses. The equine coat color genes chestnut (e) and roan (Rn) have been tested for linkage to 15 protein and blood group loci. Data showing close or fairly close linkage to the serum albumin locus (Al) and loose linkage to the serum esterase locus (Es) for both e and Rn are presented. This means that three coat color genes (To, e and Rn) and three serum protein loci (Al, Gc, and Es) are linked in the same linkage group. The gene order can tentatively be written Al, Gc, Rn, To-e-Es. The implications of the results for studies on coat color inheritance in horses are discussed. The possibility of using ...
[ECG similarities in the parents and offspring of thoroughbred horses]. The ECG characters were studied in two sires (Manrico and Infernal) and their 26-membered set of progeny as well as in one mare (Victoire) and her five daughters. The confer of some ECG characters from the sire's side as well as from the mare's side to the offspring was demonstrated. The consistency of some ECG characters was particularly obvious in externally dominant Manrico sire and his offspring as well as in the breeding mare and her five daughters (inclination of the electric cardiac axis, intrinsicoid deflexion lag, P wave shape, deep S in the 3rd connection).
Blood gas and acid–base status in spontaneously delivered, term-induced and induced premature foals. Six spontaneously delivered foals, 8 Thoroughbred foals induced at term with fluprostenol and 17 Pony foals induced prematurely with fluprostenol and oxytocin at a gestational age of 270 to 330 days were studied to determine PO2, PCO2, pH, base excess and HCO3 values in arterial blood between birth and 7 days of age. The Pony foals were subdivided into those that survived greater than 24 h (N = 9) and less than 9 h (N = 8). Blood gas and acid base values in the term-induced foals were similar to those in spontaneously delivered foals. The induced premature foals surviving greater than 24 h had...
[Purification of alpha-1,4 leads to 1,4-glucosyltransferase from horse blood serum]. The purification of alpha-1,4-1,4-glucosyltransferase from the equine serum is presented. Ion-exchange chromatography on DE-11, DE-32 and CM-32 celluloses was applied in the successive steps of isolation. Gel-filtration on Bio-Gel P-200 was the last step of purification; it gave the protein which was homogeneous on disc polyacrylamide gel electrophoresis. The purification degree was of the order 2100 at about 40% yield.
Characteristics and fertility of stallion semen. A study of stallion fertility was conducted on commercial studs in eastern Australia over 4 breeding seasons (1974/75-1977/78). Data from 47 stallions (66 stallion seasons) aged 2-26 years and representing 7 breeds and 1664 mares were used to relate seminal characteristics to fertility. Percentage pregnancies per service was the most sensitive measure of fertility with stallions on commercial studs. Breed and age of stallion, breeding season and the referral status of the stallion ('suspect' or 'normal') had significant (P less than 0.01) effects on fertility. The semen characteristics that we...
The repeatability of seminal characteristics of stallions. Fifteen seminal characteristics were measured in ejaculates from 4 laboratory stallions and from 164 commercial stud stallions. Complete field and laboratory data were available from 536 and 531 ejaculates, respectively. These were obtained over 4 breeding seasons (1974/75-1977/78) and 9 breeds were represented. Stallions at commercial studs produced 1-13 ejaculates at intervals of approximately 4 weeks and ranging from 1 h to 1 year apart. Intra-class correlations or 'repeatability' of each seminal characteristic were calculated. Significant between-stallion variation occurred in all characte...
Epidemiological and bacteriological studies of Corynebacterium equi isolates from Californian farms. Soil samples were collected from 6 horse breeding establishments in California and cultured for Corynebacterium equi. Only 3 of the farms had a history of the occurrence of pneumonia caused by C. equi. One farm had experienced an outbreak in 5 out of 6 foals just before soil sampling. Soil isolates were identified as C. equi on the basis of physical and biochemical characteristics found to be consistent with isolates of equine origin. C. equi was found in many soil samples within endemic areas where greatest concentrations were obtained in places accessible to horses. On non-endemic farms, onl...
Effects of washing on the bacterial flora of the stallion’s penis. Six stallions were subjected to extensive cleansing of the penis and prepuce with water, Ivory Soap and water, or Betadine surgical scrub and water. The stallions were all washed for 14 days, and then allowed 14 days respite. This pattern of washing and resting was repeated consecutively. Swabs were taken from all 7 stallions twice weekly and semen was collected once a week for bacteriological examination. All forms of cleansing altered the bacterial flora of the stallion's penis; the Ivory Soap tended to encourage the replacement of the normal flora with coliform organisms, while Betadine fav...
Comparison of receptor properties of erythrocyte membrane glycoproteins. Membrane glycoproteins from horse, sheep, goat and bovine erythrocytes were solubilized and purified. These glycoproteins could be placed in three groups based on their degrees of glycosylation: The major bovine erythrocyte glycoprotein (BGII) had 77% sugar, the minor bovine glycoprotein (BGI) had 27% sugar and the others had approximately 50% sugar. Four of the glycoproteins aggregated in a uniform way in aqueous solution--one, BGII, did not. Four had similar subunit sizes of 25-34,000 daltons, but BGII was larger--55,000 daltons. Receptor functions (for plant and invertebrate lectins, antibo...
Genetics of Standardbred stallion reproductive performance. Reproductive performance of 10 Standardbred stallions was related to the probability that the embryo resulting from a given mating would be heterozygous for transferrin or plasma esterase. Fertility, measured by foaling rate per insemination or by foaling rate per year, showed a highly significant regression on the probability of offspring heterozygosity for transferrin and, to lesser extent, for esterase. Substantial differences between stallions in the slope of the regression line and no deficiency of foals homozygous for either protein suggests that the relationship to fertility is indirect...
Pancreatic beta cell function in the neonatal foal. Plasma concentrations of insulin and glucose were measured in Pony and Thoroughbred foals at birth and at intervals thereafter for up to 7 days. The plasma concentrations of insulin in foals of both breeds at birth were 11.2 +/- 2.5 microU/ml (N = 6) and 13.5 +/- 1.5 microU/ml (N = 16) respectively. These values were similar to those obtained for foals in utero but were significantly less than those in adult animals. There was little variation in the plasma concentrations of insulin and glucose during the first 2 h of life and both concentrations tended to rise in the next 24-48 h. Although th...
Fertility of stallions with abnormalities of the sperm acrosome. During a 2-year period, 7 stallions were identified as having ejaculated spermatozoa characterized by a high incidence (27-74%) of acrosomal abnormalities. The most frequent abnormality of the acrosome was the 'knobbed sperm' defect which was observed in nigrosin--eosin, Giemsa, and haematoxylin and eosin stained semen smears under light microscopy, in buffered formal--saline and in glutaraldehyde-fixed wet mounts under phase contrast and differential interference microscopy, and in glutaraldehyde-fixed spermatozoa with electron microscopy and scanning electron microscopy. The defect was visib...
Melatonin rhythms in Pony mares and foals. Melatonin concentrations in intact (N = 3) and sham-operated (N = 3) mares during March were greater (P less than 0 . 05) during the night than during the day, but this pattern was not seen in 3 mares from which the superior cervical ganglia had been removed bilaterally. When 4 Pony mares were exposed to a photoperiod of 10L:14D for 3 weeks and then to continuous darkness (0L:24D) for another 3 weeks, melatonin levels were greater (P less than 0 . 05) at the end of the 0L:24D period than during the earlier period and still displayed rhythmic fluctuations but were no longer co-ordinated with eq...
Influence of bacterial products on the motility of stallion spermatozoa. Sterile filtrates were prepared from equine isolates of Klebsiella pneumoniae (genitalium), Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli, Streptococcus zooepidemicus, Streptococcus equisimilis, Actinobacillus equuli, and Corynebacterium equi and mixed individually with extended stallion semen. When diluted in the extended semen the filtrates represented bacterial populations of 0.5 x 10(6), 1 x 10(6), 2 x 10(6) and 4 x 10(6) cells/ml. pH values were recorded for each filtrate. Specimens were monitored for percentage motile spermatozoa at 30-min intervals until they reached 10% o...
Transuterine migration of the fetus in the mare between day 42 and parturition. A total of 2187 Thoroughbred and Standardbred mares was examined over a 4-year period to determine the location of the fetus at 42 days, the location of the previous fetus as determined by examination 5-15 days after foaling, and pregnancy location the next season. Maiden mares showed 44 and 56% of pregnancies in the left and right horns respectively. No transuterine migration was observed in 139 maiden mares examined after their first foal. Lactating mares showed 62% implantations and full-term pregnancies on one side of the uterus with the next season's pregnancy being in the opposite uterin...
Some aspects of tissue maturation in fetal and perinatal foals. Collagen, elastin and structural glycoprotein content of the lungs of 38 fetal and neonatal foals, 8 of which were showing dysmaturity or convulsive syndrome, were measured by standard biochemical means. Glycoprotein content showed little or no change between 100 and 340 days of gestation; elastin remained constant from 100 to about 260 days when there was an exponential increase up to the time of birth, while collagen content rose linearly from 100 days to birth. In dysmature animals there was significantly less collagen in the lungs at birth but the difference in elastin content between the ...
Influence of prostaglandin F2 alpha on sperm production and seminal characteristics of the stallion. Six mature stallions were used to test the effect of prostaglandin F2 alpha (PGF2 alpha ) on sperm production and seminal characteristics. Semen was collected from each stallion twice weekly 1 hr following a 10 mg intramuscular injection of PGF2 alpha or a sham injection. A switchback design was used so that three stallions received PGF2 alpha and three served as controls during the first 9 weeks (period 1). Treatment regimens were reversed during the second 9 weeks (period 2). Treatment of stallions with PGF2 alpha resulted in an increase (P less than .05) in gel free seminal volume and a dec...