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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 placental cup cells show glycan expression distinct from that of both chorionic girdle progenitor cells and early allantochorionic trophoblast of the placenta. Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine girdle and cup cells, and associated endometrial glands, have been investigated from 37 to 67 days gestation. Results were compared with the glycosylation of the 50-day allantochorionic trophoblast of the established equine placenta that will later form the microcotyledons. The differentiated cup cells, which secrete equine chorionic gonadotropin (eCG), showed a pattern of glycosylation that was distinct both from the progenitor girdle cells and the allantochorionic trophoblast, with granules that bo...
[O,O-dialkyl-S-bromomethylthiophosphates–inhibitors of mammalian choline- and carboxyl esterases: structure-activity relationship]. The interaction kinetics of potential pesticides, O,O-dialkyl S-bromomethylthiophosphates (RO)2P(O) SCH2Br (R = Et, i-Pr, n-Pr, n-Bu, or n-Am) with acetylcholinesterase, butyryl cholinesterase, and carboxyl esterase from warm-blooded animals was studied. All the compounds irreversibly inhibit these esterases, with k1 (M-1 min-1) being 1.8 x 10(4) - 1.9 x 10(6) for acetylcholinesterase, 2.0 x 10(6) - 4.1 x 10(7) for the more sensitive butyryl cholinesterase, and 2.3 x 10(7) - 2.3 x 10(8) and higher for the most sensitive carboxyl esterase. By using the Hansch and Kubinyi technique of multiple r...
Effects of feeding frequency and voluntary salt intake on fluid and electrolyte regulation in athletic horses. The effect of feeding frequency and voluntary sodium intake (VSI) on fluid shifts and plasma aldosterone concentration (PAC) were studied at rest and after exercise in six athletic horses. The horses were fed twice a day (2TD) and six times a day (6TD) for 25 days for each protocol, according to a changeover design. VSI was measured by weighing each horse's salt block daily. Feeding 2TD or 6TD caused no major alterations in fluid shifts, but in the 2TD treatment there was a postprandial increase in plasma protein concentration and osmolality that lasted <1 h. PAC and VSI were not affected b...
The influence of betaine on untrained and trained horses exercising to fatigue. Because exercise fatigue has been associated with the accumulation of lactic acid, factors that influence lactate metabolism during exercise can potentially enhance performance. The objective of this study was to examine the effects of supplemental betaine on eight mature Thoroughbred horses before and after 8 wk of conditioning. The effects of betaine were tested in two cross-over design experiments, allowing each horse to receive both the control and betaine treatments at each fitness level. Ingestion of 80 mg of betaine/kg of BW for 14 d before exercise testing did not alter plasma lactate,...
Ultrasonographic evaluation of equine tendons: a quantitative in vitro study of the effects of amplifier gain level, transducer-tilt, and transducer-displacement. The objective of the in vitro experiments described in this paper was to quantify the effects of some instrumental variables on the quantitative evaluation, by means of first-order gray-level statistics, of ultrasonographic images of equine tendons. The experiments were done on three isolated equine superficial digital flexor tendons that were mounted in a frame and submerged in a waterbath. Sections with either normal tendon tissue, an acute lesion, or a chronic scar, were selected. In these sections, the following experiments were done: 1) a gradual increase of total amplifier gain output su...
Back problems. Neuroanatomy and neurological examination. Components of the equine nervous system are described including classical anatomy and newer sensory innervation maps that are useful for localizing lesions to and within the nervous system. The key components in a neurological examination that help differentiate primary neurologic disease from musculoskeletal disorders are explained. Gait deficits associated with neurologic dysfunction are listed as well as diagnostic aids and an overview of differential diagnoses.
Tack and saddle fit. Examining the fit of the saddle is perhaps the most important aspect of examining a horse with a suspected back problem. If the back problem is corrected and a poorly fitting saddle is placed on the back, the problems will return. An ill-fitting saddle contributes to direct and compensatory lower leg lameness making it even more imperative to correct the fit. A correctly fitting saddle enhances both the horse and rider's ability to perform with accuracy, lightness, and freedom of movement.
Osseous spinal pathology. Pathologic changes have been observed at the spinous processes, intervertebral articulations, and sacroiliac joints in horses. Varying severity of degenerative articular changes are found in many articular processes, intertransverse, lumbosacral, and sacroiliac joints. Pathologic lesions tend to affect multiple vertebral locations within a specimen. Further studies need to be conducted to evaluate the clinical significance of the numerous vertebral and pelvic pathologic findings found in a sample of Thoroughbred racehorses that died because of unrelated injuries. Increased knowledge of osseous...
Back problems. Chiropractic evaluation and management. A thorough knowledge of equine spinal anatomy, biomechanics, and potential pathology is required to understand the principles and theories behind chiropractic and to apply its techniques properly. Chiropractic provides additional diagnostic and therapeutic means that may help equine practitioners to identify and treat the primary cause of lameness or poor performance. Specialized training in the evaluation and treatment of vertebral joint dysfunction and neuromusculoskeletal disorders places chiropractic in the forefront of conservative treatment of spinal-related disorders. Nevertheless, limi...
Spinal ligament pathology. Young elite athletes, particularly horses used for jumping, are at a relatively high risk for injury to the ligaments associated with the axial skeleton. Extreme back flexion appears to be a contributing factor to ligament damage. Back pain due to injury of the ligaments of the axial skeleton has often been considered to be secondary to lower limb injury, to the extent that a separate definitive diagnosis, treatment, and prognosis were unnecessary. Diagnostic imaging, ultrasound in particular, has demonstrated ligamentous damage that can be the limiting factor in return to previous athletic us...
Back problems. Historical perspective and clinical indications. This article is presented as an introduction to the complex subject of back pain and its management in horses. It considers some of the historical perspectives and deals with some of the limiting factors when attempting to evaluate back pain. The clinical indications of a back problem are considered, as is the important distinction of primary versus secondary back pain. Finally, a list of considerations capable of causing back pain and impaired performance is included.
Immunolocalisation of oxytocin in the equine ovary. Oxytocin has been identified in the ovaries of many species
including ruminants (Wathes and Swann 1982; Rodgers et al.
1983), pigs (Jarry etal. 1990), sub-human primates (Khan-Dawood
1998), rats (Ho and Lee 1992) and women (Schaeffer et al. 1984).
In these species ovarian oxytocin has several roles, including
control of luteal regression (Fht and Sheldrick 1983) and possibly
luteinisation (Aladin Chandrase.kher and Fortune 1990; Eispanier et
al. 1997), and involvement in ovulation (viggiano et al. 1989).
In the mare, circulating oxytocin is reported to be high in
oestrus and early dio...
Three dimensional structure of the distal condyles of the third metacarpal bone of the horse. This study examined the three-dimensional (3D) microarchitecture of regions of the equine third metacarpal bone (McIII) commonly involved in distal condylar fractures. Limbs were obtained from Thoroughbred horses (neonates to age 24 years) destroyed for inoperable fractures and a variety of other conditions. Beams, blocks and sections were cut in the principal axes, some embedded in PMMA and others examined unembedded. Several methods were used to study the 3D structure, including conventional and confocal optical microscopy, scanning electron microscopy (SEM) and radiography. The mineralised ...
Structural variation of the distal condyles of the third metacarpal and third metatarsal bones in the horse. This study examined 3-dimensional (3D) distribution of sectors with contrasting density in the equine third metacarpal (McIII) and third metatarsal (MtIII) bones with a view to explaining the aetiology of distal condylar fractures. Macroradiography and computed tomographic (CT) imaging were used in the nondestructive study of bones obtained from horses, most of which were Thoroughbreds in race training. Distal condylar regions of McIII and MtIII were also studied in microradiographs of 100 microm thick mediolateral sections cut perpendicular to the dorsal and palmar/plantar articular surfaces....
Ocular manifestations of equine motor neuron disease. The characteristics of the ocular manifestations of equine motor neuron disease (EMND) are described. Forty-two horses with histories, clinical signs and necropsies compatible with EMND were the subjects of this study. Ophthalmoscopic lesions that varied in severity were found in 40 of 42 horses and appeared as a distinct pigmented reticulated pattern at the tapetal-nontapetal junction or throughout the fundus, depending upon severity. The pattern colours ranged from yellow brown to black. Areas of hyperreflectivity formed mosaic patterns in the tapetal fundus. ERG B-wave amplitudes were usual...
Lack of local anaesthetic efficacy of fentanyl in the abaxial sesamoid block model. Fentanyl and other opioid drugs have their effect in the central nervous system; however, activity at peripheral sites has also been demonstrated. Pain-suppression activity at peripheral sites raises the possibility of skilled individuals producing local anaesthetic effects with small doses of opioid drugs that would be difficult to detect forensically and could be used to affect the outcome of a race. Therefore, the local pain-suppression effect (peripheral nerve inhibition) of fentanyl was tested using an abaxial sesamoid block/hoof withdrawal model. With this model, fentanyl did not produce...
Metabolic effects of nitric oxide synthase inhibition during exercise in the horse. The effect of nitric oxide synthase (NOS) inhibition during exercise on lactate production was investigated in five Thoroughbred horses. A standard exercise test (SET), consisting of three canters (approximately 55 per cent VO2max), with walking and trotting between each canter, was performed twice (control and test, in random order) by each horse. Nphi-nitro-L-arginine methyl ester (L-NAME; 20 mg kg-1), a competitive inhibitor of NOS, induced a significant increase (P < 0.05) in plasma lactate [5.7 (2.9) vs 11.8 (3.8) mmol L-1], which continued to increase despite administration of L-argin...
Identification of a new aspartic proteinase expressed by the outer chorionic cell layer of the equine placenta. The pregnancy-associated glycoproteins (PAGs) are placental antigens that were initially characterized as pregnancy markers in the maternal circulation of domestic ruminant species. They are members of the aspartic proteinase gene family, having greatest sequence identity with pepsinogens. However, some are not capable of functioning as enzymes. The PAGs are associated with a large gene family within the Artiodactyla order (cattle, camels, pigs). So far, no members of this family have been characterized in species outside this order. This report describes the cloning and initial characterizati...
Field exercise testing for assessing fitness in French standardbred trotters. This review considers standardized exercise testing which is, routinely used for French Trotters in the field. Track testing provides a more limited range of measurements than treadmill testing, but has the advantage of being performed in the horse's natural environment. Various measurements such as heart rate during exercise and blood lactate concentration after exercise may be measured on the track and lead to the calculation of physiological variables such as V200 (velocity corresponding to a 200 bpm heart rate) and V4 (velocity corresponding to a 4 mmol/L blood lactate concentration). V4 i...
Modulation of allospecific CTL responses during pregnancy in equids: an immunological barrier to interspecies matings? Maternal immune recognition of the developing conceptus in equine pregnancy is characterized by the strongest and most consistent alloantibody response described in any species, a response directed almost exclusively against paternal MHC class I Ags. This work investigated the cellular immune response to paternal MHC Ags in pregnant and nonpregnant horses and donkeys, and in horses carrying interspecies hybrid mule conceptuses. We observed profound decreases in classical, MHC-restricted, CTL activity to allogeneic paternal cells in peripheral blood lymphocytes from both horse mares and donkey ...
Exercise in the heat: thermoregulatory limitations to performance in humans and horses. This paper reviews the limits to exercise imposed by increases in ambient, hypothalamic, and contracting skeletal muscle temperature in humans and horses. Like humans, horses frequently compete in hot environments, yet their high mass-specific rate of heat production and low mass-specific surface area for heat dissipation places them at a great disadvantage compared to humans. Exercise in hot conditions increases the rate of body heat storage and reduces the time required to reach a critical hypothalamic temperature that results in voluntary fatigue. This critical temperature appears to be ass...
Concentrations of macro- and micro-elements in the milk of pasture-fed thoroughbred mares. To determine the changes in Ca, P, Mg, Na, K, S, Cu, Fe and Zn concentrations of milk during the lactation in pasture-fed Thoroughbred mares and then calculate the dietary mineral requirements of the sucking foal and the lactating mare. Methods: Milk was sampled on days 1, 3, 7, 14, 21, 28 and at various times between 55 to 65, 85 to 95 and 135 to 150 days after parturition from 21 pasture-fed mares. The concentrations of macro- and micro-elements in the milk were determined by inductively coupled plasma emission spectrometry. Results: Concentrations (mg/L) of these elements were highest in co...
Molecular dynamics simulation of alpha-lactalbumin and calcium binding c-type lysozyme. Alpha-lactalbumins (LAs) and c-type lysozymes (LYZs) are two classes of proteins which have a 35-40% sequence homology and share a common three dimensional fold but perform different functions. Lysozymes bind and cleave the glycosidic bond linkage in sugars, where as, alpha-lactalbumin does not bind sugar but participates in the synthesis of lactose. Alpha-lactalbumin is a metallo-protein and binds calcium, where as, only a few of the LYZs bind calcium. These proteins consist of two domains, an alpha-helical and a beta-strand domain, separated by a cleft. Calcium is bound at a loop situated at...
V(O2) recovery kinetics in the horse following moderate, heavy, and severe exercise. At the onset of exercise, horses exhibit O2 uptake (VO2) kinetics that are qualitatively similar to those of humans. In humans, there is a marked dissymmetry between on- and off-kinetics for VO2. This investigation sought to formally characterize the off-transient (recovery) VO2 kinetics in the horse within the moderate (M), heavy (H), and severe (S) exercise domains. Six horses were run on a high-speed treadmill at M, H, and S exercise intensities (i.e., that speed which yielded approximately 50, 85, 100% peak VO2, respectively, on the maximal incremental test). The time courses for the recov...
Extraction of equine chorionic gonadotrophin from pregnant mare plasma by direct adsorption on chromatographic media. Equine chorionic gonadotrophin (eCG) is a hormone of practical value in veterinary medicine and animal production. Here we report a novel preparation procedure based on its direct adsorption onto anionic-exchange resins in a batch-wise mode. The active plasma is previously conditioned to reduce pH and ionic strength to required levels. After the adsorption stage, a 90% recovery of the initial eCG is achieved, with a concentration factor of about 50 and an enrichment factor around 500, with high preservation of biological activity. Further purification is carried out by cation-exchange column c...
The effect of motilin on the regulation mechanism of intestinal motility in conscious horses. Laparotomy was performed on seven thoroughbreds to attach a force transducer to the proximal jejunum, distal jejunum, and ileum, as well as to the serous membrane of the cecum. Following observation of intestinal motility in conscious horses, they were intravenously injected with motilin (0.6 microgram/kg) to examine its effect on intestinal motility. Strong contractions peculiar to horses were observed in small intestine. Further, motilin caused strong contractions in the proximal jejunum. The results suggested the involvement of motilin in the regulation mechanism of intestinal motility.
