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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.
Chronic administration of therapeutic levels of clenbuterol acts as a repartitioning agent. The purpose of this study was to examine the effect of therapeutic levels of clenbuterol, with and without exercise training, on body composition. Twenty-three unfit Standardbred mares were divided into four experimental groups: clenbuterol (2.4 microg/kg body wt twice daily) plus exercise (ClenEx; 20 min at 50% maximal oxygen consumption 3 days/wk; n = 6), clenbuterol only (Clen; n = 6), exercise only (Ex; n = 5), and control (Con; n = 6). Rump fat thickness was measured at 2-wk intervals by using B-mode ultrasound, and percent body fat (%fat) was calculated by using previously published meth...
Thermal unfolding of monomeric and dimeric beta-lactoglobulins. The thermal stabilities of dimeric bovine beta-lactoglobulin and monomeric equine beta-lactoglobulin were investigated at neutral pH by means of differential scanning calorimetry, circular dichroism, tryptophan fluorescence, and by binding of an hydrophobic probe. Differential scanning calorimetry showed the presence of two structural domains with different thermal stabilities in both proteins. Thermodynamic analysis of the calorimetric signal revealed that the two domains unfold independently according to a mechanism where an equilibrium step is followed by an irreversible transition. The spe...
Equine rhinitis B virus: a new serotype. Equine rhinovirus serotype 3 isolate P313/75 was assigned, with an unclassified genus status, to the family PICORNAVIRIDAE: The sequence from the 5' poly(C) tract to the 3' poly(A) tract of P313/75 was determined. The sequence is 8821 bases in length and contains a potential open reading frame for a polyprotein of 2583 amino acids. Sequence comparison and phylogenic analysis suggest that P313/75 is most closely related to the prototype equine rhinitis B virus (ERBV) strain P1436/71, formerly named equine rhinovirus type 2. A high degree of sequence similarity was found in the P2 and P3 regions...
Use of the flexion test of the distal forelimb in the sound horse: repeatability and effect of age, gender, weight, height and fetlock joint range of motion. The flexion test of the distal limb is a commonly used clinical tool in both lame and sound horses. In the latter use it is given some predictive value. In recent studies it has been shown that examiner-related factors (force, time) may strongly influence the outcome of the test. In the present study, the possible influences of a number of horse-related factors and short- and long-term repeatability were investigated. Flexion tests were performed by the same researcher in 100 clinically sound horses under standardized conditions. The outcome of the test was scored on a 9-point semiquantitative...
The action of mercury on cell membranes. The action of mercuric chloride and methyl mercuric chloride on the membrane lateral domain organization of bovine, equine, and canine erythrocytes was studied. Electron paramagnetic resonance (EPR) spectra of spin-labeled erythrocytes were analyzed with respect to their lateral domain structure. Continuous alteration of the membrane domain populations revealed that mercuric compounds affect the membrane via the evolution of toxic events in the cells.
“Equine basal cell tumors: 6 cases (1985-1999)”. Basal cell tumors are rare benign tumors in horses. Over a 15-year period, 6 horses were diagnosed with basal cell tumors. The tumors were well-circumscribed. freely moveable, firm, raised papules, nodules, or masses that ranged from 0.6 to 5 cm in diameter. Five of the 6 tumors were ulcerated. Based on gross appearance, the tumors were diagnosed as sarcoids, and 1 was diagnosed as a melanoma. The range of age of affected horses was 6-26 years. The tumors were identified clinically 1 week to 3 years before excision. In 4 horses for which information was available, complete surgical excision wa...
A structural and immunological study of chorionic gonadotrophin production by equine trophoblast girdle and cup cells. Equine chorionic gonadotropin (eCG) production by the fetally derived endometrial cups appears to be necessary for the establishment and maintenance of normal equine pregnancy. Starting at about the 27th day of pregnancy, an equatorial band of trophectodermal cells on the surface of the spherical conceptus forms the chorionic girdle. This girdle consists initially of flat trophectodermal epithelium which corrugates into folds as the cells proliferate. The folds are then pressed against the uterine epithelium by expansion of the conceptus. The cells on the apices of the folds become binucleate ...
Effects of exercise on the diameter of collagen fibrils in the central core and periphery of the superficial digital flexor tendon in foals. To determine the effects of exercise on collagen fibril diameter distribution in the superficial digital flexor tendon (SDFT) of foals. Methods: 43 Dutch Warmblood foals. Methods: From 1 week until 5 months of age, group-1 foals (n = 14) were housed in stalls and not exercised, group-2 foals (14) were housed in stalls but were exercised, and group-3 foals (15) were maintained at pasture. Biopsy specimens were collected from the SDFT at 2 months, and 8 foals in each group were euthanatized at 5 months. Remaining foals were housed together in a loose stall and paddock until euthanatized at 11 mo...
Model formulation and determination of in vitro parameters of a noninvasive method to calculate flexor tendon forces in the equine forelimb. To describe a method to calculate flexor tendon forces on the basis of inverse dynamic analysis and an in vitro model of the equine forelimb and to quantify parameters for the model. Methods: 38 forelimbs of 23 horses that each had an estimated body mass of > or = 500 kg. Methods: Longitudinal limb sections were used to determine the lines of action of the tendons. Additionally, limb and tendon loading experiments were performed to determine mechanical properties of the flexor tendons. Results: The study quantified the parameters for a pulley model to describe the lines of action. Furthermo...
Sensitivity analysis and application to trotting of a noninvasive method to calculate flexor tendon forces in the equine forelimb. To test the sensitivity to measurement and modeling errors of a method for noninvasive calculation of flexor tendon forces in the equine forelimb and to calculate tendon forces for Dutch Warmblood horses during trotting. Methods: A normative set of kinematic and ground-reaction force (GRF) data obtained from horses during trotting in another study. Methods: Forces in the flexor tendons were calculated from the data set before and after addition of fixed relative and absolute errors. Amount of error was based on normal accuracy of the variables. A similar analysis was performed for a measure of...
The acrosomic reaction in stallion spermatozoa: inductive effect of the mare preovulatory follicular fluid. In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In ...
Influence of epidermal growth factor on mammalian oocyte maturation via tyrosine-kinase pathway. Epidermal growth factor (EGF) has been reported to promote different functions in mammalian ovaries, including oocyte maturation. The aim of the present study was to establish: that EGF influences oocyte maturation in ovine and equine, that a tyrosine kinase-dependent intracellular mechanism mediates EGF effect and, that EGF-R receptor is detectable in ovarian follicles by immunohistochemistry methods. Selected ovine and equine oocytes were aspirated from 2-5 mm (ovine) or 25 mm (equine) follicles and cultured in TCM 199 for 22 (ovine) or 36 hours (equine). They are then subjected to culture w...
Influence of epidermal growth factor on mammalian oocyte maturation via tyrosine-kinase pathway. Epidermal growth factor (EGF) has been reported to promote different functions in mammalian ovaries, including oocyte maturation. The aim of the present study was to establish: that EGF influences oocyte maturation in ovine and equine, that a tyrosine kinase-dependent intracellular mechanism mediates EGF effect and, that EGF-R receptor is detectable in ovarian follicles by immunohistochemistry methods. Selected ovine and equine oocytes were aspirated from 2-5 mm (ovine) or 25 mm (equine) follicles and cultured in TCM 199 for 22 (ovine) or 36 hours (equine). They are then subjected to culture w...
Administration of bovine, porcine and equine growth hormone to the horse: effect on insulin-like growth factor-I and selected IGF binding proteins. This study investigated the biochemical effects of administration of three types of recombinant growth hormone (GH; somatotropin) to the Thoroughbred horse. Equine or bovine or porcine GH was administered at a recommended dosage to 3-5-year old Thoroughbred geldings, for up to 21 days. It was shown that, in addition to equine GH, bovine and porcine GH were active in the horse; however, porcine GH caused injection-site reactions that were so serious that administration had to be terminated. The concentrations of a range of GH-related serum protein markers were determined before, during and afte...
The effects of ph, osmolarity and urine contamination on equine spermatozoal motility. Urospermia has been reported as a cause of infertility in numerous species. The detrimental effects of urine on spermatozoa are due, at least in part, to changes in pH and osmolarity. Semen was collected and subjected to conditions of varying pH (Experiment 1), of varying osmolarity (Experiment 2), and various quantities and concentrations of urine (Experiment 3) and effects on motility were recorded. Finally, semen was contaminated with urine and then either of 2 semen extenders was added, with or without centrifugation, in an attempt to alleviate the detrimental effect of urine on motility (...
Immortalization of equine trophoblast cell lines of chorionic girdle cell lineage by simian virus-40 large T antigen. Immortalized cell lines have many potential experimental applications including the analysis of molecular mechanisms underlying cell-specific gene expression. We have utilized a recombinant retrovirus encoding the simian virus-40 (SV-40) large T antigen to construct several immortalized cell lines of equine chorionic girdle cell lineage - the progenitor cells that differentiate into the equine chorionic gonadotropin (eCG) producing endometrial cups. Morphologically, the immortalized cell lines appear similar to normal chorionic girdle cells. Derivation of the immortalized cell lines from a cho...
A reduction in interstitial cells of Cajal in horses with equine dysautonomia (grass sickness). Equine dysautonomia (grass sickness) is a common, frequently fatal disease of horses characterised by dysfunction of the gastrointestinal tract. Interstitial cells of Cajal are the c-Kit-immunoreactive cells responsible for the generation of pacemaker activity in gastrointestinal smooth muscle. Impairment of this pacemaker action has been implicated in several motility disorders in humans and laboratory mammals. The aim of this study was to test the hypothesis that changes in interstitial cells of Cajal may be involved in the pathophysiology of the intestinal dysfunction observed in equine gra...
Muscle glycogen depletion and subsequent replenishment affect anaerobic capacity of horses. The purpose of this study was to determine the effect of muscle glycogen depletion and subsequent replenishment on anaerobic capacity of horses. In a blinded crossover study, seven fit horses performed glycogen-depleting exercise on two occasions. Horses were infused after glycogen-depleting exercise with either 6 g/kg body wt of glucose as a 13.5% solution in 0.9% NaCl (Glu) or with 0.9% NaCl (Sal) of equivalent volume. Subsequently, horses performed a high-speed exercise test (120% of maximal rate of oxygen consumption) to estimate maximum accumulated oxygen deficit. Replenishment of muscle ...
Genetic variation in the feral horses of the Namib Desert, Namibia. Genetic variation at 7 blood-group and 10 biochemical genetic loci was examined in 30 horses from a feral herd from the Namib Desert of Namibia, Africa. The observed genetic variability was extremely low compared with that found in domestic horse breeds. The low variation was most probably a result of recent small population size and a small founding population size. Genetic comparison of the Namib horses, which were of unknown origins, to domestic horse breeds, showed that the Namib horses had the highest genetic similarity to Arabian type horses, although they did not closely resemble this t...
A partially unfolded state of equine beta-lactoglobulin at pH 8.7. The urea-induced unfolding transition of equine beta-lactoglobulin was studied at pH 8.7 using circular dichroism (CD), ultracentrifugation, and gel filtration chromatography. The unfolding transition curves showed that at least one intermediate accumulates at moderate concentrations of urea. Furthermore, analytical ultracentrifugation experiments indicated that the intermediate forms a dimer. Thus, the urea-induced unfolding transition was measured by CD at various protein concentrations and was analyzed by a model assuming the four conformational states (the native, intermediate, dimeric int...
Estimation of the probability for exceeding thresholds of urine specific gravity and plasma concentration of furosemide at various intervals after intravenous administration of furosemide in horses. To estimate the probability of concurrently exceeding thresholds for plasma concentration of furosemide and urine specific gravity after IV administration of furosemide in horses. Methods: 12 mature healthy Thoroughbred (n = 6) or Quarter Horse (6) mares. Methods: Venous blood was collected from each horse prior to and 0.25, 0.5, 0.75, 1, 2, 3, 4, 4.5, 5, and 6 hours after IV administration of 250 mg (first experiment) or 500 mg (second experiment) of furosemide. Urine was collected hourly between 1 and 6 hours after administration of furosemide at both doses. Concentrations of furosemide were...
Voluntary limb-load distribution in horses with acute and chronic laminitis. To compare limb-load distribution between horses with and without acute or chronic laminitis. Methods: 10 horses with carbohydrate-induced acute laminitis, 20 horses with naturally occurring chronic laminitis, and 20 horses without foot abnormalities (controls). Methods: Limb-load distribution was determined, using a custom-designed system that allowed simultaneous quantification of the mean percentage of body weight voluntarily placed on each limb (ie, mean limb load) and the SD of the mean load over a 5-minute period (ie, load distribution profile [LDP]). Load distribution profile was used a...
Morphologic stages of the equine embryo proper on days 17 to 40 after ovulation. To describe the gross and histologic changes that develop in the equine embryo proper (ie, the portion of the embryo that becomes the fetus) from days 17 to 40 after ovulation and to compare the external features of equine embryos with those of porcine, ovine, and human embryos. Methods: 34 embryos collected from mixed-breed pony mares. Methods: External features for each embryo proper, including length, number of branchial arches, growth of appendages, face and head features, and body features, were examined, using a dissecting microscope, for embryos collected on days 17 to 40. Internal feat...
The effects of treadmill inclination and speed on the activity of three trunk muscles in the trotting horse. The purpose of this study was to evaluate the effects of speed and slope on the activity of trunk muscles. The electromyographic (EMG) activity of the splenius (Sp), longissimus dorsi (LD) and rectus abdominis (RA) muscles was recorded with surface electrodes during treadmill locomotion at trot for different combinations of speed (3.5 to 6 m/s) and slope (0 to 6%). Raw EMG signals were processed to determine activity duration, onset and end and integrated EMG (IEMG). For the 3 muscles investigated, onset and end of activity were obtained earlier in the stride cycle when speed increased. A long...
Genetic diversity in Spanish donkey breeds using microsatellite DNA markers. Genetic diversity at 13 equine microsatellite loci was compared in five endangered Spanish donkey breeds: Andaluza, Catalana, Mallorquina, Encartaciones and Zamorano-Leonesa. All of the equine microsatellites used in this study were amplified and were polymorphic in the domestic donkey breeds with the exception of HMS1, which was monomorphic, and ASB2, which failed to amplify. Allele number, frequency distributions and mean heterozygosities were very similar among the Spanish donkey breeds. The unbiased expected heterozygosity (H(E)) over all the populations varied between 0.637 and 0.684 in t...
A study of an electrodiagnostic technique for the evaluation of equine recurrent laryngeal neuropathy. The electrodiagnostic measurement of the thoracolaryngeal reflex (TLR) ('slap test') latency was compared to 5 other diagnostic techniques used for evaluation of laryngeal function, namely laryngeal muscle palpation, resting and immediately postexercise endoscopic examinations, and palpable and endoscopic responses to the TLR. Compared to resting endoscopy, the electrodiagnostic measurement of TLR latency was not found to be an accurate test for the evaluation of recurrent laryngeal neuropathy (RLN), nor was laryngeal muscle palpation or the endoscopic response to the TLR. Twenty-five (71%) of...
