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Topic:Equine Science
Equine Science encompasses the study of horses and their management, health, and performance. This field integrates various scientific disciplines such as biology, genetics, nutrition, physiology, and veterinary medicine to understand and improve the well-being and capabilities of horses. Areas of focus include equine anatomy, reproduction, behavior, and disease prevention. Research in equine science aims to enhance horse care, optimize training and performance, and address health challenges. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine science, providing insights into the latest advancements and methodologies in the field.
Equine oocyte competence for nuclear and cytoplasmic in vitro maturation: effect of follicle size and hormonal environment. Equine oocyte competence after in vitro maturation (IVM) was investigated in terms of the diameter of the follicle of origin and the stage of the estrous cycle, with three criteria of maturation: nuclear stage after DNA Hoechst staining, meiotic spindle morphology after tubulin immunocytochemical staining, and cortical granule localization after lectin labeling. Seven successive in vivo ultrasound-guided follicular punctures were performed on 10 cyclic saddle mares, alternatively at the end of the follicular phase (after induction of ovulation with a gonadotropin injection) and in midluteal ph...
Surgery of the small intestine. Although earlier reports describe a poor prognosis for small intestinal surgery in the horse, there is growing evidence that the short-term survival rate can exceed 80%. In addition to advancements in surgery and aftercare, early referral contributes considerably to the improved prognosis. Surgical procedures that restore anatomic and physiologic continuity to close to normal can minimize postoperative complications. Jejunojejunostomy carries a better prognosis than jejunocecostomy, probably because the latter involves anastomosis between two intestinal segments with dissimilar functions. Care...
Colopexy. Colopexy is a surgical procedure designed to create an adhesion from the ventral colon to the body wall to prevent recurrence of large colon volvulus or displacement, and is a useful technique to prevent recurrence of this disease. Colopexies usually are reserved for broodmares, because this is the population of horses that is most predisposed to recurrence of large colon volvulus.
Detection of equine arteritis virus in the semen of carrier stallions by using a sensitive nested PCR assay. A nested PCR, developed for the detection of equine arteritis virus (EAV) in semen, detected less than 2.5 PFU of EAV per ml of naturally infected seminal plasma. Based on results from testing 88 semen samples from 70 stallions, the sensitivity and specificity of the test were 100 and 97%, respectively.
[Separation techniques ro achieve vital and reproduction competent equine spermatozoa populations–a survey]. Equine ejaculates are significantly characterized by widely varying parameters especially in those of practical relevance for equine Al. Therefore it is of interest for practical purposes to get subpopulations of concentrated, vital, and competent spermatozoa from the origin ejaculates. Special preparation of the donor stallions will stabilize sperm output. Fractionated semen collection from stallions supplies sperm enriched seminal fractions very useful to work with further in semen preservation. Most important to achieve a concentrated sperm subpopulation are semen manipulations post ejacula...
Hydrolysis of extracellular adenine nucleotides by equine epidydimal spermatozoa. Ectoenzymic activities capable of hydrolyzing ATP sequentially to adenosine are present on equine epidydimal spermatozoa membranes. Kinetic parameters for ATPase, ADPase and 5'-nucleotidase were obtained by analysis of progress reactions curve when ATP, ADP and AMP were supplied as initial substrates. These values are not different from those found when the substrates were supplied from the preceding reactions. Feed-forward inhibition on 5'-nucleotidase by ATP/ADP was taken into account to fit simulated data to the experimental results. None of the substrates supplied by the preceding reaction...
Alpha-adrenoceptors in equine digital veins: evidence for the presence of both alpha1 and alpha2-receptors mediating vasoconstriction. Rings of equine digital vein examined under conditions of isometric tension recording constricted to alpha-adrenoceptor agonists with an order of potency of 5-bromo-6-[2-imidazolin-2-yl-amino]-quinoxaline bitartrate (UK 14304) = noradrenaline > 6-Allyl-2-amino-5,6,7,8-tetrahydro-4H-thiazolo-(4,5-d) azepine (BHT-920) > phenylephrine > dopamine > methoxamine. The maximum force generated was greatest for the non-selective agonist noradrenaline and lowest for the alpha2-selective agonist BHT-920 with the other agonists between these two extremes. Selective inactivation of alpha1-adreno...
FISH mapping of the IGF2 gene in horse and donkey-detection of homoeology with HSA11. Three genomic subclones derived from a phage clone containing the equine IGF2 gene were used to FISH map the gene on horse (ECA) and donkey (EAS) metaphase chromosomes. The gene mapped on ECA 12q13 band and is the first locus mapped to this horse chromosome. In donkey the gene mapped very terminal on the long arm of one small submetacentric chromosome that shows almost identical DAPI-banding pattern with ECA12. This is the first locus mapped in donkey genome. Cross species chromosome painting of equine metaphase chromosomes with human Chromosome (Chr) 11-specific probe showed homoeology of thi...
Exercise modifies the age-related change in crimp pattern in the core region of the equine superficial digital flexor tendon. One of the current concepts with regard to equine superficial digital flexor tendonitis is that cumulative subclinical microscopic damage weakens the structure, predisposing the tendon to partial or complete rupture. This microtrauma is likely to affect the waveform or crimp of the collagen fibrils, which are the units of tensile strength. Collagen fibril crimp morphology characteristics were determined in superficial digital flexor tendons of 18 horses presented for necropsy. Horses were separated into exercised (n = 9) and non-exercised groups (n = 9), based on recent function. Five of the e...
Variations of equine urinary volatile compounds during the oestrous cycle. Equine urine was analysed by capillary gas chromatography. The volatile profiles from oestrous and dioestrous samples were compared to establish any qualitative or quantitative difference that may have potential value in olfactory communication. Forty-five different volatile compounds were detected. Of these, 17 major compounds were common to all chromatograms. The chemical profile of oestrous urine was distinguished by the presence of a unique peak that was not present in dioestrous samples. Numerous constituents exhibited endocrine dependence: while the concentrations of seix peaks increased...
Estrogen concentrations in semen of the stallion. Large amounts of estrogens are secreted by the tests of the mature stallion. In a recent study by Claus et al. [Claus, Dimmick, T., Gimenez, T., Hudson, L.W., 1992. Estrogens and prostaglandin F2 alpha in the semen and blood plasma of stallions. Theriogenology 38, 687-693.], it was stated that high levels of estrogens were also present in semen. As a preliminary step to study possible implications for fertility in the stallion, we have measured estrone sulphate (E1S), the principal estrogen in blood, in both seminal plasma and spermatozoa. Semen was collected from four Standardbred stallions a...
Muscarinic signaling pathway for calcium release and calcium-activated chloride current in smooth muscle. We investigated the muscarinic activation of Ca(2+)-activated Cl- currents [ICl(Ca)] in voltage-clamped equine tracheal myocytes. The threshold of cytosolic free Ca2+ concentration ([Ca2+]i) required for activation of ICl(Ca) was 202 +/- 22 nM, and full activation of the current occurred at 771 +/- 31 nM. Hexahydro-sila-difenidol (M3 antagonist) inhibited the methacholine-induced phasic [Ca2+]i increase and ICl(Ca) in a concentration-dependent manner, whereas methoctramine (M2 antagonist) only slightly attenuated the [Ca2+]i increase and ICl(Ca) (14.8 and 21.4%, respectively), consistent with ...
Assessment of viability and mitochondrial function of equine spermatozoa using double staining and flow cytometry. An objective double-staining method was developed to evaluate viability and mitochondrial function of stallion spermatozoa using flow cytometry. Sperm viability was assessed by propidium iodide (PI) exclusion, and mitochondrial function was measured by the intensity of rhodamine 123 (R123) fluorescence. Flow cytometry estimates of sperm viability measured by PI were equivalent (P > 0.05) to estimates made using Hoechst 33258 stain and fluorescent microscopy (% dead: 25 +/- 2.4 vs 21.5 +/- 3.5). The use of both PI and R123 was validated by addition of various proportions of freeze-shocked (m...
Ageing draft and trotter horses by their dentition. The accuracy of ageing horses by their dentition was assessed by comparing the dental features with the known dates of birth of 212 trotter horses and 189 Belgian draft horses. The horses ranged in age from two to 25 years. In both breeds it was observed that the shedding of the incisors and the appearance of the dental stars were the most reliable features for age determination. In young animals, the dental configuration was similar in both breeds. With increasing age the incisor teeth of draft horses were more liable to abrasion than those of trotter horses. The sequential changes in appeara...
Modeling study of compensatory head movements in lame horses. To study the role of head movements in lame horses. Methods: 11 Dutch Warmblood horses. Methods: A 2-segment 2-dimensional inverse dynamic model of trotting horses was developed: trunk and head/neck segment joined in a neck joint. Model input consisted of averaged segmental inertial properties and averaged kinematic data, taken from 11 horses, trotting on a treadmill (3.5 m/s) in 3 conditions of induced lameness: sound, mildly lame, and moderately lame. Dynamic and static effects were analyzed. Results: Dynamic effects were found to be considerably larger than static effects. In the moderately...
Regional differentiation of the blood-epididymis barrier in stallion (Equus caballus). The occurrence, localization and ultrastructural characteristics of a blood-tissue barrier throughout the stallion proximal seminal excurrent duct system were studied by the exclusion of electron-dense tracers and freeze-fracture techniques. Striking differences were observed in the distribution of lanthanum tracer and in the geometrical organization of the zonulae occludentes along the ductus efferentes, epididymides and vas deferens. The zonulae occludentes domain, the principal structural component of the blood-epididymis barrier, differed in permeability, width and strand numbers along the...
Comparative study between pony mares and ewes evaluating gonadotrophic response to administration of gonadotrophin-releasing hormone. This study compared equine and ovine LH secretory responses to GnRH treatment. Dioestrous mares and ewes were challenged with continuous GnRH for 15 h. Mares that received constant GnRH (110 micrograms h-1) had sustained LH secretion (P < 0.01), whereas LH concentrations in ewes treated with continuous GnRH (25 micrograms h-1) initially increased, then declined and remained low, suggesting GnRH receptor desensitization or downregulation. In addition, progesterone-primed, ovariectomized mares and ewes were challenged with pulsatile or continuous GnRH for 5 days. Plasma LH concentrations were...
Causes of natal dispersal and emigration and their effects on harem formation in Misaki feral horses. Misaki feral horses were separated into 2 herds and the difference between dispersal from natal group (natal dispersal) and dispersal from natal area (natal emigration) was studied. The causes of dispersal and emigration and their effects on harem formation were studied 1979-1994. The number of horses ranged from 73 (mature males: 8, mature females: 26, young males: 8, young females: 3, colt foals: 6, filly foals: 10 and geldings: 12) in 1979 and 86 (mature males: 14, mature females: 37, young males: 12, young females: 7, colt foals: 5, filly foals: 7 and geldings: 4) in 1994 when the present ...
Disruption of sphingolipid metabolism and induction of equine leukoencephalomalacia by Fusarium proliferatum culture material containing fumonisin B(2) or B(3). Fumonisin B(1), B(2), and B(3) are inhibitors of ceramide synthase, a key enzyme in the pathway for de novo sphingolipid biosynthesis. Corn, naturally contaminated with either predominantly fumonisin B(1) or pure fumonisin B(1), has been shown to cause equine leukoencephalomalacia (ELEM). It has been hypothesized that fumonisin-induced disruption of sphingolipid metabolism is an early event in the development of ELEM. Recently, it was shown that Fusarium proliferatum corn culture diets containing predominantly fumonisin B(2), but not diets which were predominantly fumonisin B(3), at 75 ppm (0....
Expression and localization of relaxin in the ovary of the mare. Immunoreactive, chromatographic and molecular techniques were used to study the expression of relaxin in mare ovaries at different stages of the oestrous cycle. Relaxin in follicular fluid ranged from 1.6 to 2.5, from 1.4 to 5.2, from 1.2 to 6.7 and from 1.0 to 3.5 ng ml-1 in small ( 2 3 4 cm) follicles, respectively, and total content of fluid relaxin per follicle increased (P < 0.05) with follicular size. When subjected to reverse phase HPLC analysis, follicular fluid yielded absorbance profiles corresponding closely to those of purified relaxin, and immunoreactive peaks in follicular f...
[Spontaneous and manual embryo reduction in mares: a twin prevention programme]. Data from the literature and own data for 67 twin pregnancies were used to establish the factors essential to the decision on how to treat twins at different gestational ages. Spontaneous (natural) reduction was compared with manual embryo reduction. Manual embryo reduction is always indicated when a twin is diagnosed before day 16 after ovulation. Thereafter, the type of fixation is the main determinant. Manual embryo reduction is always first choice for bilateral and unilateral non adjacent embryos and must be applied as early as possible. The change of natural reduction up to day 30, is hig...
Abdominal surgery in foals: a review of 119 cases (1977-1994). The case records of 119 young horses (all less than age one year) that underwent an exploratory celiotomy during a 17 year period were examined to determine the surgical findings, short- and long-term outcome, and prevalence of small intestinal disease compared to previous reports in the mature horse. Physical and laboratory values were compared for long-term survivors vs. nonsurvivors and the frequency of post operative intra-abdominal adhesions was determined. The most common cause for exploratory celiotomy was small intestinal strangulation, followed by enteritis and uroperitoneum. Six hors...
An empirical study of the impact of complexity on participation in horserace betting. The aim of the research reported in this paper was to explore empirically whether levels of participation in horserace betting are affected by the complexity of the betting task. The study employed a systematic random sample of 1161 betting decisions made in UK offcourse betting offices during 1987. The research was conducted in a naturalistic setting where it was possible to grade complexity and to measure levels of participation. Complexity was defined in terms of both the number of alternatives in the decision-maker's choice set (number of horses in a race) and the complexity of the attribu...
Development and validation of a series of three-dimensional finite element models of the equine metacarpus. Three-dimensional finite element (FE) models of the left metacarpi of five adult horses were developed from quantitative computed tomography data, using the algorithms of Keyak et al. (1990, J Biomed. Engng 12, 389-397). The metacarpi were then equipped with 12 rosette strain gauges and loaded non-destructively in a mechanical testing machine. The bones and the models were loaded in axial compression, with the load evenly distributed across the distal row of carpal bones, and with a point load placed mediad to the sagittal midline, to a load equivalent to three times body weight (-15 kN); and ...
Cellular heterogeneity in cathepsin D distribution in equine articular cartilage. The distribution of cathepsin D in normal equine growth cartilage has been examined immunocytochemically using an antiserum raised against human cathepsin D. The cross-reactivity and specificity of the antiserum for equine cathepsin D was confirmed, and its lysosomal localisation was demonstrated in horse skin fibroblasts by confocal scanning microscopy. Cultured horse chondrocytes were heterogenous in their expression of cathepsin D. Heterogeneity of distribution of the enzyme was also seen in chondrocytes in cartilage from different anatomical sites. A high level of cathepsin D was observed ...
