Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Relationship between colloid osmotic pressure and plasma protein concentration in cattle, horses, dogs, and cats. The relationship between colloid osmotic pressure (COP) and protein concentration was investigated for purified proteins and plasma samples obtained from cattle, horses, dogs, and cats. At equivalent concentrations, bovine albumin exerted a COP that exceeded that of gamma-globulins by a mean factor of 4.4. Similar relationships between COP and protein were observed in the other species. Consequently, for a given total protein concentration, COP was dependent on the albumin/gamma-globulins ratio. A commonly used nomogram for estimating COP from protein concentration, the Landis-Pappenheimer equ...
Developmental regulation of class I major histocompatibility complex antigen expression by equine trophoblastic cells. Between days 36-38 of pregnancy equine trophoblastic cells of the chorionic girdle migrate and form endometrial cups. Just prior to invasion, the chorionic girdle cells express high levels of polymorphic, paternally inherited, major histocompatibility complex (MHC) class I antigens. Their descendents, the mature, invasive trophoblast cells of the endometrial cups, however, express low or undetectable levels of MHC class I antigens by day 44 of pregnancy. Experiments with MHC compatible pregnancies, the study of residual chorionic girdle cells that had failed to invade the endometrium and remai...
Isolation, propagation, and cryopreservation of equine articular chondrocytes. Equine articular chondrocytes were isolated from explant cartilage cultures by digestion in a 0.075% collagenase solution for 15 to 19 hours. Cartilage from late-term fetal and neonatal foals resulted in mean chondrocyte yield of 51.99 x 10(6) cells/g of cartilage (wet weight), compared with a yield of 17.83 x 10(6) cells/g for foals 3 to 12 months old. Propagation of chondrocytes in monolayer and 3-dimensional culture was accomplished, using Ham's F-12 as the basal medium, with supplements of fetal bovine serum (10%), ascorbic acid, alpha-ketoglutarate, and L-glutamine. The medium was buffere...
Histological features of the dorsal cortex of the third metacarpal bone mid-diaphysis during postnatal growth in thoroughbred horses. The dorsal cortex of the equine third metacarpal mid-diaphyseal bone was characterised during growth by the histological and microradiographic examination of specimens from 30 horses ranging in age from 2 months to 8 y. Bone from horses aged less than 6 months was characterised by rapid periosteal apposition of circumferential trabeculae of woven bone that were next connected by radial trabeculae to the parent cortex. Deposition of lamellar bone on the inner trabecular surfaces resulted in rows of primary osteons. Replacement of primary bone occurred only after 4 months of age and preferential...
Visual acuity in the horse. We assessed the ease with which horses could learn visual discriminations and measured their resolution acuity. We trained three horses to press their noses against one of two large wooden panels to receive a small food reward. Following training on a series of two-choice discrimination tasks, resolution acuity was measured. Although there was some variability between animals, the best acuity obtained was 23.3 c deg-1. Within the margin of error imposed by limited anatomical data, the obtained values are consistent with predictions based on retinal ganglion cell density estimates and posterior...
Use of a semi-quantitative sweat test in thoroughbred horses. A practical test for evaluating the sweating response to various concentrations of the specific beta 2 agonist, salbutamol sulphate, is described. The results of performing this test on horses (n = 54) considered to be "free sweaters", horses (n = 6) that showed signs of heat stress following exercise, and horses with complete anhidrosis (n = 2) are presented. The results indicate that intradermal injections of 0.1 ml of salbutamol sulphate at dilutions of 10(-7) or less are suitable stimuli to elicit a visually detectable local sweating in horses with a normal sweating response. Horses that o...
Reduction and reoxidation of equine gonadotropin alpha-subunits. Ovine (o) and equine (e) LH alpha-subunits were reduced and reoxidized using conditions known to be effective for bovine and human alpha-subunits. The major product of oLH alpha refolding was alpha-subunit monomer. In contrast, eLH alpha formed a 121,000 mol wt aggregate. Monomeric eLH alpha was recovered, but in greatly reduced yield. To test the effects of carbohydrate variation on the aggregation of equine alpha-subunits, all of the equine gonadotropin alpha-subunits (eFSH alpha, eCG alpha, eLH alpha, and free alpha-subunit) were reduced and reoxidized. In each case, the major product was t...
The inhibitory effect of furosemide on the contractile response of equine trachealis to cholinergic nerve stimulation. The effects of furosemide on the responses of equine trachealis muscle with and without epithelium to electrical field stimulation (EFS) and exogenous acetylcholine (ACh) were investigated in organ baths. Tissues were pretreated with guanethidine and the parameters used for EFS were those previously demonstrated to activate postganglionic cholinergic neurons. In tissues with intact epithelium, furosemide (100 microM) shifted the frequency-response curve to the right. In the preparations without epithelium, furosemide did not affect the response to EFS. Neither in epithelium-on nor in epitheliu...
Quantitative analysis of computer-averaged electromyographic profiles of intrinsic limb muscles in ponies at the walk. The function of several intrinsic muscles of the fore-and hind limbs of 5 ponies walking normally was evaluated via surface electromyography. Electromyographic signals were band-pass filtered, rectified, linear enveloped, and standardized to the stride duration. Mean data from the muscles of the left and right limbs that were obtained from at least 30 strides in 2 recording sessions were recorded as electromyographic signals-time curves. The timing of muscle activity was determined from these graphs. On the basis of the major peaks in the electromyographic signal, muscle functions were identif...
Regulation of matrix metabolism in equine cartilage explant cultures by interleukin 1. Explant cultures were set up, using articular cartilage obtained from metatarsophalangeal joints of 11 horses. Explants from 2 horses were used to determine culture conditions appropriate for tissue viability. The cartilage explants maintained steady-state metabolism of proteoglycans during a 13-day evaluation period. The metabolic response of equine articular cartilage to incubation with recombinant human interleukin 1 (0.01 to 100 ng/ml) was studied, using cartilage obtained from the remaining 9 horses, age of which ranged from 3 months to 20 years. Interleukin 1 induced a dose-dependent rel...
Characterization of lipoprotein lipase activators from equine plasma. Equine plasma lipoproteins were fractionated into VLDL, LDL-1, LDL-2 and HDL by density gradient ultracentrifugation. From each lipoprotein fraction, five apo C like peptides of approx. M(r) 1400, 10000, 9500, 9000 and 8000 were detected by SDS-polyacrylamide gel electrophoresis. After partial purification by Sephadex G-75, one fraction, showing a strong activation of lipoprotein lipase, was further purified by Mono Q anion exchange column. Two of the apo C like peptides (M(r) 10000 and 8000) activated the bovine milk lipoprotein lipase in vitro; only one (M(r) 9500) inhibited the lipolytic ac...
Measurement of muscle surface capillary blood flow by laser Doppler flowmetry. Muscle surface capillary blood flow was measured in the biceps femoris and lateral head of the triceps brachii muscles in six horses before and during halothane anesthesia by using laser Doppler flowmetry. During 90 minutes of anesthesia, muscle surface capillary blood flow was reduced to 20% to 40% of preanesthetic values. Muscle surface capillary blood flow tended to be lower in dependent muscles than in nondependent muscles, and this disparity was greater in the forelimbs than in the hind limbs.
Comparison of antibody and cell-mediated immune responses in horses following feeding of a novel dietary antigen, ovalbumin, and rotavirus. Adult ponies which were fed ovalbumin (OVA) daily for 2 weeks had significantly greater serum anti-OVA IgG (P = 0.001) and antigen specific lymphocyte responses (P = 0.031) after intramuscular injection with OVA given with saponin than control ponies which had not been fed the antigen. This suggests that, despite the lack of evidence of B- or T-cell activation in peripheral blood during the period of OVA feeding, the animals were primed for an active secondary immune response. Adult ponies were challenged with equine rotavirus, strain H-2, but no statistically significant differences were foun...
Effects of high-intensity exercise on plasma catecholamines in the thoroughbred horse. In Study 1, a single speed test of 6 to 12 m/sec was performed for 2 mins at an incline of 5 degrees on a high-speed treadmill (single-step test). Only one speed was performed per session and blood samples were taken before and after the test. In Study 2 horses cantered for 1 min at increasing speeds of 6 to 13 m/sec on an incline of 3 degrees (multiple-step test). Blood samples were taken before exercise, throughout the test and during recovery. In the single-step test plasma concentrations of adrenaline and noradrenaline both increased at speeds of 9 m/sec, as did blood lactate. Mean concent...
Taurine content and distribution in equine skeletal muscle. Taurine (TAU) is found in large but variable amounts in the skeletal muscles of many species. It has been reported that slow twitch muscles in the rat exhibit higher TAU levels than fast twitch muscles. Variation in muscle taurine content may be attributable to differences in the fibre type composition of different muscles. TAU content (mmol kg-1 dry muscle) and percentage type-1, type-2A, and type-2B fibre section area (f.s.a.) were measured in muscle samples taken from up to six sites in the middle gluteal muscle of four horses and one pony at post mortem and in biopsy samples taken from twe...
Functional significance of the morphology and micromechanics of collagen fibres in relation to partial rupture of the superficial digital flexor tendon in racehorses. The high incidence of partial rupture of the superficial digital flexor tendor in the equine athlete represents a major cause for concern in the racing industry. Frequently, the lesion is localised to the central core of the tendon. This study tested the hypothesis that the site specific structural failure results from differences in the collagen fibre morphology and associated micromechanics between central and peripheral regions of the tendon. Bundles of collagen fibres were dissected from central and peripheral sites in the mid-metacarpal region of the tendon. Crimp morphology was quantifie...
Characterization of equine zona pellucida glycoproteins by polyacrylamide gel electrophoresis and immunological techniques. This study was designed to explore the composition of the equine zona pellucida (EZP) by one- and two-dimensional polyacrylamide gel electrophoresis (1D- and 2D-PAGE), silver staining and immunoblotting techniques. Antral follicles palpable on frozen-thawed equine ovaries were aspirated with a needle and syringe, and the resultant follicular fluid, cellular material and oocytes were pooled. Oocytes were placed in Petri dishes, moved by narrow-bore pipette to droplets of phosphate-buffered saline (PBS) and mechanically cleaned of cumulus cells. The EZP from these collected oocytes was solubiliz...
Measurement of tracheal static pressure in exercising horses. A nasotracheal catheter for measuring tracheal static pressure in exercising horses was designed according to aerodynamic engineering principles. Small ports near the end of the catheter transmitted pressure fluctuations to the recording apparatus. Accuracy was determined by the size, number, and location of pressure sensing holes on the catheter, and by the position of the catheter in the trachea. The catheter had adequate frequency response to 33 Hz, was insensitive to movement artifacts, was easily introduced, was tolerated well by horses, and resulted in small ventilatory impairment at max...
Effect of dietary biotin supplement on equine hoof horn growth rate and hardness. Over a 10-month period, 24 randomly selected riding horses were fed various amounts of biotin. Statistically significant improvements in growth rates and hardness of hooves were produced by biotin supplementation. Greater growth rates and hardness were achieved at a daily dose of 15 mg than at 7.5 mg. Increased hoof hardness was greatest in the hoof quarters and toe. No ring formation occurred in hooves of horses fed biotin intermittently.
A kinematic and strain gauge study of the reciprocal apparatus in the equine hind limb. Hind limb kinematics were recorded in five horses at walk and trot using an opto-electronic CODA-3 system. Simultaneously, in vivo strain in the completely tendinous peroneus tertius muscle was registered by implanted mercury-in-silastic strain gauges. The origin-insertion length patterns of the peroneus tertius were calculated from raw kinematic data and from data corrected for the error caused by skin displacement, and compared with the directly measured strain. The strain patterns calculated from externally measured kinematic data appeared to be in accordance with the directly measured stra...
Additive and synergistic pharmacologic inhibition of equine fibrinoligase (factor XIIIa*-like) biochemical activity. A selected group of pharmaceutical compounds were evaluated for the ability to inhibit the biochemical activity of fibrinoligase (coagulation factor XIIIa*) in pooled equine plasma. Criteria for the pharmaceuticals selected were based on the mechanism of the transglutamination biochemical reaction mediated by coagulation factor XIIa*. These criteria were complemented by recognition of the molecular configuration and chemical composition of amino acid residue side chains involved in the process of covalent fibrin monomer polymerization (cross-linking, transglutamination) mediated by this enzyme...
Anatomy of the prepubic tendon in the horse, cow, sheep, goat, and dog. Analyses of the fibers in the prepubic tendon of the horse and ruminants have shown that it is composed of the crossed and uncrossed tendons of origin of the pectineus muscles, the pelvic tendons of the rectus and obliquus abdominis muscles, and the tendons of origin of the cranial parts of the gracilis muscles. Pelvic attachments of the linea alba and the yellow abdominal tunic are incorporated in it. It is not a transverse ligament, and it is not homologous to the human superior (cranial) pubic ligament. The dog differs in 4 respects: (1) the pectineus tendons do not cross, but each originat...
Distribution of coronary collateral blood flow at different levels of collateral growth in conscious ponies. Coronary collateral growth was stimulated in chronically instrumented conscious ponies by a previously validated intermittent coronary occlusion method. Changes in regional myocardial function (sonomicrometry) and reactive hyperemia (Doppler method) were used to monitor collateral growth and to program measurements of regional myocardial blood flow (microsphere method). A serial analysis of the transmural and lateral distributions of collateral blood flow was performed at the native and three superimposed levels of collateral growth. Results in nine animals undergoing an average of 553 +/- 188...
Ultrastructure of cilia in horses. This paper presents some ultrastructural details of cilia from the ciliated tracheal epithelium of healthy horses. By using a new fixation method, the Authors were able to describe minute details, some of which have been only rarely observed in other species and mostly by means of the freeze-etch technique (i.e. electron dense particles of ciliary necklace). The Authors justify the need to investigate the ultrastructural details of cilia in various species since the minute morphological differences might be functionally significant.
