Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Physiology
The physiology of horses encompasses the study of the biological functions and processes that occur within the equine body. This includes the examination of various systems such as the cardiovascular, respiratory, musculoskeletal, digestive, and nervous systems. Understanding equine physiology is essential for comprehending how horses adapt to different environmental conditions, perform physical activities, and respond to health challenges. Research in this field often focuses on the mechanisms of energy metabolism, thermoregulation, and muscle function during exercise, as well as the physiological responses to stress and disease. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine physiology, providing insights into the biological processes that support the health and performance of horses.
Corpus spongiosum penis pressure and penile muscle activity in the stallion during coitus. A needle-tipped catheter or subminiature pressure transducer was implanted in the corpus spongiosum penis (CSP) of Shetland Pony stallions to determine pressure during coitus. Electrodes for monitoring the electromyographic (EMG) activity were implanted in the ischiocavernosus (IC) and bulbospongiosus (BS) muscles. The mean peak CSP pressure recorded with the catheter was 762 mm of Hg, and with the subminiature pressure transducer, it was 994 mm of Hg. The simultaneous occurrence of the CSP pressure peaks and bursts of BS muscle activity indicated that these muscles were the likely source of e...
Prolonged perfusion with a membrane oxygenator in awake ponies. Prolonged extracorporeal membrane oxygenation (PEMO) was performed in 6 adult ponies with the membrane oxygenator in vein-to-artery bypass circuit. A flow rate equal to 46 per cent of control cardiac output was diverted through the PEMO circuit of 10 to 24 hours. Three of the 6 ponies were perfused for at least 20 hours and developed no complications. Immediately following initiation of PEMO, left ventricular output decreased; however, in the interval between 6 and 24 hours, left ventricular output was increased above control levels. Aortic pressure and left ventricular work were markedly elev...
Cyclic changes in ionic composition of digesta in the equine intestinal tract. Effects of diet and time after feeding on osmolality and inorganic ion content of gastrointestinal digesta were studied in 24 ponies. Animals, fed either a conventional or a low-protein, high-cellulose diet, were sacrificed 2, 4, 8, or 12 h after a meal. Animals fed the conventional diet showed cyclic variations in the ionic composition and osmolality of digesta with time after feeding. The most marked variations were seen in the contents of the stomach and small colon. However, results also indicated a cyclic appearance and disappearance of Na in large intestinal contents that correlated with...
Equine laminitis of alimentary origin: an experimental model. Acute alimentary form of laminitis was uniformly induced in 11 of 12 horses by administration of a starch and wood flour gruel and could be graded by previously established (Obel) and presently defined criteria. The experimentally induced laminitis was similar to naturally occurring laminitis, as determined on the basis of lameness severity and vital signs. Packed cell volume, leukocyte count, and total protein were significantly increased (P smaller than 0.05) at 24 and 40 hours after administration of gruel. Arterial systolic and diastolic pressures increased, central venous pressure decreas...
Symposium on back problems in the horse. (2) The diagnosis of diseases of the horse’s back. A description of some of the clinical features of low back pain in the horse has been given and a number of methods for assisting diagnosis considered. As well as a complete clinical examination both at rest and during exercise, a useful diagnostic aid in some chronic cases was the injection of local anaesthetic into the interspinous spaces. A laboratory examination, including haematological and biochemical profiles, was undertaken in all cases. The serum enzymes GOT and CPK were particularly valuable as an aid to diagnosis in atypical tying-up. A technique for radiography of the vertebral col...
An examination of octanol and octanal metabolism to octanoic acid by horse liver alcohol dehydrogenase. The kinetics of the horse liver alcohol dehydrogenase (alcohol: NAD+ oxidoreductase EC 1.1.1.1) catalyzed metabolism of octanol and octanal to octanoic acid have been examined. On incubation of octanol with horse liver alcohol dehydrogenase in the presence of NAD+, NADH as well as octanal and octanoic acid were seen as the initial products. However, on continued incubation, the octanal concentration progressively decreased to where only negligible quantities were present in the incubation after 10 min. The production of NADH was biphasic. An initial phase was followed in about 2 min with a slo...
Species variability in the modification of erythrocyte surface proteins by enzymatic probes. Bovine and equine erythrocytes have been studied by three different surface modification techniques to investigate the accessibility of the surface components to the external medium. Lactoperoxidase labeling of equine erythrocytes results in a significant labeling of only one membrane component, a 100 000-mol.wt polypeptide corresponding to the membrane-spanning Component III of human erythrocytes. The major sialoglycoprotein of the equine erythrocyte is not labeled. This is in contradistinction to the situation for human and bovine cells, where both components are labeled. The equine membrane...
Digestive physiology of the horse. Recent studies on the digestive physiology of the horse are reviewed. It was suggested that the small intestine is the primary site of digestion and absorption of protein, soluble carbohydrates, most minerals, fats, fat soluble and water soluble vitamins. The large intestine is the primary site of fibre digestion and net water absorption. Significant amounts of phosphorus are also absorbed from the large intestine. Many factors such as rate of passage, processing of feeds, level of intake, work and maturity of plant may influence digestive ability.
[Sterols of horse erythrocytes]. Sterols of the whole erythrocytes, hemoglobin, membranes and their protein fractions were studied. Erythrocytes and their components were established to contain, besides cholesterol, other substances of the sterol nature. Cholesterol, 7-dehydrocholesterol and other substances of the cholesterol series are practically completely linked with the lipoproteid fractions of the erythrocyte membrane whereas all sterols found in the native erythrocytes in negligible amounts are bound with hemoglobin.
Histological development of the thymic and intestinal lymphoid tissue of the horse. The basic components of the immune system, and the defence mechanisms in the gastrointestinal tract, are briefly reviewed. Histological studies in 84 equine foetuses showed that lymphoid cells begin populating the thymic primordium at 11-12 weeks, the mesenteric lymph nodes at 13 weeks, the spleen at 25 weeks and the intestinal lamina propria at 13-14 weeks' gestation. Lymphocytes were seen in the intestinal epithelium very early in gestation. Histological signs of response to antigenic stimulation were seen in five foetuses, indicating that the horse is likely to be capable of mounting an imm...
Surface receptors on neutrophils and monocytes from immunodeficient and normal horses. Surface receptors on peripheral blood neutrophils and monocytes from normal and immunodeficient horses have been studied. Sheep erythrocytes (SRBC) coated with IgG, IgM, and complement but not IgG(T), readily bound to normal equine monocytes and neutrophils. More than 4000 molecules of IgG were required to sensitize each SRBC for adherence to monocytes, and more than 12,000 molecules were required for adherence to neutrophils. Young horses with a severe combined immunodeficiency had an almost total absence of lymphocytes, but normal numbers of monocytes and neutrophils. The number of receptors...
Mercuri-nitrophenol as a reporter group for the conformational change of hemoglobin. One mole of horse hemoglobin tetramer reacts with 2 moles of 2-chloromercuri-4-nitrophenol (MNP) at beta 93 cysteine. The difference spectra between NMP-bound hemoglobin and hemoglobin, measured with the aid of ascorbic acid and ascorate oxidase [EC 1.10.3.3] as deoxygenation reagents, indicate that the pK of the phenolic hydroxyl group of MNP increases by 0.6 to 0.8 pH unit on deoxygenation of the hemoglobin. The Hill constant of the modified hemoglobin changes with pH. It decreases from about 2.4 at pH 6.8 to about 1.0 at pH 9.0 This effect of the reagent is interpreted as inherent to the re...
Carbohydrate digestion and absorption in the equine small intestine. Dietary carbohydrates, which constitute a most important source of equine nutrition, are digested and absorbed by a series of complex processes principally in the small intestine, beginning with intraluminal starch hydrolysis by the action of pancreatic amylase. The continuous secretion of a copious volume of pancreatic juice, low in enzyme activity, presumably releases sufficient oligosaccharides for further hydrolysis at the intestinal cell surface by brush border enzymes. Active carrier mediated mechanisms then transport the final hexose products across the intestinal cell for uptake in the...
Effects of fasting on hepatic function in ponies. Hepatic function was measured, using sulfobromophthalein sodium (BSP) in fed and fasted ponies. In the 1st experiment, single injections of BSP were administered, and the rate of removal of BSP from plasma was determined. Fasting decreased the rate of BSP removal from plasma, as indicated by increased half-time (t 1/2). In the 2nd experiment, BSP was infused for 5 hours, and its clearance from plasma was determined. Fasting decreased BSP clearance. In the 3rd experiment, BSP was infused consecutively at 2 dose rates, and maximal excretion and hepatic storage were determined. Although fasting d...
