Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Calcium
Calcium is a mineral that is essential for various physiological processes in horses, including bone development, muscle function, and nerve transmission. It is a critical component of the equine diet and is involved in maintaining skeletal integrity and supporting metabolic functions. Calcium levels in horses are regulated through dietary intake, absorption in the gastrointestinal tract, and hormonal control mechanisms involving the parathyroid hormone and vitamin D. Imbalances in calcium levels can lead to health issues such as metabolic bone disease or hypocalcemia. This page compiles peer-reviewed research studies and scholarly articles that explore the metabolism, dietary requirements, and health implications of calcium in equine nutrition and physiology.
Increased sensitivity of a rotavirus serotyping enzyme-linked immunosorbent assay by the incorporation of CaCl2. The sensitivity of a rotavirus serotyping enzyme-linked immunosorbent assay (ELISA) was improved by the addition of 0.5 mM CaCl2 to the washing buffer and reagent diluent. Twenty-nine of 63 (46%) previously untyped bovine and equine faecal rotavirus samples were serotyped in the modified assay. A differential response to Ca2+ ions was noted for different G-serotypes suggesting that serotyping assays performed without the inclusion of CaCl2 in the assay buffers may produce biased results.
Exercise induced alterations in the serum muscle enzymes, erythrocyte potassium and plasma constituents following feed withdrawal or furosemide and sodium bicarbonate administration in the horse. Six thoroughbreds were used in each of three trials to examine the effect of potassium depletion on exercise-associated muscle damage. Horses were exercised after a control period (Treatment 1), a 72-hour fast (Treatment 2), and furosemide and sodium bicarbonate (Treatment 3). During the preexercise period, feed withdrawal for 72 hours caused decreases in body weight, plasma sodium, chloride, and serum calcium. There were no changes in plasma potassium, erythrocyte potassium, or serum creatine phosphokinase (CK) activity. Furosemide and sodium bicarbonate administration resulted in a decrease ...
Renal clearance, urinary excretion of endogenous substances, and urinary diagnostic indices in healthy neonatal foals. Urine (U) and serum (S) were obtained every 2 hours during a 12- or 24-hour period from eight healthy 96-hour-old pony or horse foals. Dams' milk samples were obtained concurrently. Urine volume was measured during this 12- or 24-hour period. The mean amount of urine produced was 148 +/- 20 ml/kg/day. Baseline urinalyses were evaluated on all foals at two days of age, before any manipulation. Urine generally was dilute (less than 1.008) but the specific gravity was as high as 1.027 in one normal foal. Continuous (12 or 24 hour) urinary catheterization resulted in bacteriuria but not white bloo...
Circadian rhythms of osteocalcin in equine serum. Correlation with alkaline phosphatase, calcium, phosphate and total protein levels. The purpose of the study was to determine whether there were circadian variations in serum osteocalcin in normal horses and to determine whether it was important to regulate the time of blood sampling in clinical investigations. Osteocalcin or bone Gla-protein (BGP), alkaline phosphatase, total calcium, phosphate and total protein were studied over a 24 h period. Blood samples were taken every 60 min from nine adult Standardbred horses. There was a correlation between serum levels of alkaline phosphatase (r = 0.3, p less than 0.01), phosphate (r = 0.42, p less than 0.01) and serum osteocalcin ...
Variations in structural and functional changes of stallion spermatozoa in response to calcium ionophore A23187. Three experiments were conducted to assess the structural and functional changes of stallion spermatozoa in response to the calcium ionophore A23187, and to determine individual variation between stallions. In Experiment 1, changes in the acrosome of spermatozoa exposed to 7.14 microM A23187 for fixed times between 0 and 120 min were examined. There was a steady increase with time in the number of spermatozoa undergoing the acrosome reaction although the rate of increase differed between stallions. Sperm motility decreased sharply when incubation was extended beyond 30 min. In Experiment 2, th...
Effects of placental pathology on maternal plasma progestagen and mammary secretion calcium concentrations and on neonatal adrenocortical function in the horse. Between 1985 and 1990, 25 Thoroughbred mares were classified as having an abnormal pregnancy on the basis of precocious signs of impending parturition. Throughout the remainder of their pregnancies, plasma progestagen and mammary secretion calcium concentrations were monitored. After parturition, evidence of placental pathology was recorded and their foals were assessed with regard to adrenocortical function and behaviour. Seven pony mares were used to establish a model of placental pathology and, following induced placental separation, were subjected to the same protocol. Control animals cons...
Yield and composition of milk from lactating mares: effect of lactation stage and individual differences. The yields and composition of milk from nursing mares were studied during the first two months of lactation in 11 mares of heavy breeds (784 kg). Daily yield increased from 21.7 to 24.6 kg between weeks 1 and 8 of lactation. Fat, protein, gross energy and Ca concentrations significantly decreased when lactose content increased during this period. Individual variations were higher for yield than for composition. Casein, whey protein and non-protein N (56, 34 and 10% of crude protein, respectively) and amino acid composition did not vary between weeks 1 and 8 of lactation.
Crystallization of a calcium-binding lysozyme from horse milk. Crystals of the calcium-containing lysozyme from horse milk have been grown by precipitation with sodium phosphate. The crystals are orthorhombic space group P2(1)2(1)2(1) with cell dimensions a = 53.2, b = 57.1, and c = 38.2 A and contain a single molecule in the asymmetric unit. The crystals are suitable for high resolution x-ray structural analysis.
Failure of pH to predict ionized calcium percentage in healthy horses. Blood, serum, and plasma total calcium concentrations and plasma and serum ionized calcium concentrations were anaerobically determined by use of a calcium-specific electrode for samples obtained from 39 healthy horses. Mean (+/- SD) serum ionized calcium concentration was 6.6 +/- 0.3 mg/dl (1.6 +/- 0.1 mmol/L) and the mean serum ionized calcium percentage was 58.2 +/- 3.4%. Serum ionized calcium percentage was not significantly correlated with serum pH. Plasma ionized calcium percentage was weakly correlated with plasma pH (r = -0.480; P less than or equal to 0.05). Ionized calcium concentrat...
In vitro fertilization of horse follicular oocytes matured in vitro. In vitro fertilizing ability of stallion spermatozoa was assessed using horse follicular oocytes matured in vitro. After collection, stallion spermatozoa were either: 1) washed and incubated in TALP medium with 3 mg/ml bovine serum albumin (BSA) and 10 micrograms/ml heparin for 4h, 2) washed and incubated in TALP with 3 mg/ml BSA for 3 h and cultured for a further 1 h with 1 mM caffeine and 5 mM dbcAMP, 3) washed and incubated in TALP medium with 3 mg/ml BSA at pH 7.9-8.2 for 2-4 h, or 4) diluted and incubated in TALP medium with 10 mg/ml BSA and 7.14 microM calcium ionophore A 23187 for 5-10 ...
Clinical nutrition of adult horses. Horses suffering from trauma, sepsis, and severe burns need 12% to 16% of protein (dry matter basis) in their diet. Since reduced appetite may be a problem, relatively energy dense (greater than 2 Mcal DE/kg) feeds should be offered. In hepatic failure, maintenance protein requirements (8% on a dry matter basis for adult horses) should be met with feeds that are high in short branched-chain amino acids and arginine but low in aromatic amino acids and tryptophan (for example, milo, corn, soybean, or linseed meal) in addition to grass hay. Vitamins A, C, and E should also be supplemented. In cas...
Effect of show jumping on heart rate, blood lactate and other plasma biochemical values. This study investigated some physiological responses to exercise performed by a horse during show jumping. The effects of jumping on heart rate (HR), blood lactate (LA) and some other blood values were studied in nine normal horses participating at the Belgian Junior Championship. Venous blood was sampled before and immediately after the show jumping and was analysed for packed cell volume, LA, blood glucose (GLU), total plasma protein, bicarbonate, sodium, potassium (K+), chloride, calcium and activities of plasma lactate dehydrogenase, creatine phosphokinase (CK) aspartate amino transferase ...
Some factors influencing plasma AST/CK activities in thoroughbred racehorses. Sixty-six Thoroughbred horses in training (2 or 3 years of age) were studied during one flat racing season, to investigate the relationship between age, sex, time of year, dietary electrolyte imbalances and plasma aspartate aminotransferase/creatine kinase (AST/CK) activities. Management and training variations were minimised. Between February to October, monthly 24 h post exercise samples were collected and analysed for AST and CK activities. Sex and/or age were shown to have a significant effect on the occurrence of high CK (> 100 iu/litre) and AST (> 300 iu/litre) activities. Fillies ...
Potential of alfalfa as a source of calcium for calcium deficient horses. The potential of short-cutting cycle, high temperature-dried alfalfa as a source of calcium for horses was determined by means of a 4 x 4 Latin square digestibility trial using four thoroughbred horses (mean liveweight 531 kg). The four dietary treatments were timothy hay alone, 33 per cent alfalfa and 67 per cent timothy hay, 67 per cent alfalfa and 33 per cent timothy hay, and alfalfa alone. Significantly more calcium and magnesium were absorbed from the alfalfa than from the hay. Phosphorus absorption appeared to be unaffected by treatment. Alfalfa calcium was more available than timothy ha...
Relationship between plasmatic concentrations of K, Na and Ca, and ECG from foals during postnatal phase. The correlations between different electrocardiographic variables and plasma concentrations of K, Na and Ca ions were studied in foals of 1 to 14 days of age. The results obtained are only significant in neonate individuals of 1 day of age. Whilst the PQ segment and R wave duration showed a positive linear correlation (p less than or equal to 0.05) with plasma concentrations of Na and Ca ions respectively, the amplitude of the T wave showed a negative linear correlation (p less than or equal to 0.05) with the K ion. Moreover, the variability in duration of the QT and ST intervals can be explai...
A field study of post-exercise values of blood biochemical constituents in jumping horses: relationship with score, individual and event. The variability of the post-exercise values (PEV) of blood lactate and of some other blood constituents were studied in 8 healthy and fit jumpers through 5 national competitions of equal difficulty. The effects of factors such as the individual, performance and competition on these PEV were analysed. Venous blood was sampled immediately after the 5 show-jumping contests and was analysed for packed cell volume (PCV), blood lactate, blood glucose (GLU), total plasma protein (TPP), bicarbonate (HCO3-), sodium (Na+), potassium (K+), chloride (Cl-), calcium (Ca2+), serum activities of lactate dehyd...
Calcium-ionophore-induced formation of platelet-activating factor and leukotrienes by horse eosinophils: a comparative study. Horse eosinophils preincubated with 3H-labelled acetate and stimulated with the Ca2+ ionophores ionomycin or A23187 form a radioactive compound, which we have shown to be 1-O-alkyl-2-[3H]acetyl-sn-glycero-3-phosphocholine (platelet-activating factor). We could detect no 1-O-acyl-2-[3H]acetyl-glycero-3-phosphocholine in the radioactive fraction. The formation of platelet-activating factor was strongly correlated to the generation of leukotriene C4, the main arachidonate metabolite in horse eosinophils, suggesting that platelet-activating factor and leukotriene C4 have a common precursor pool (1...
[The content of Hb and the hematocrit value in blood and the total proteins, urea, glucose, free fatty acids, Na, K, Ca, Mg, Pa, Fe, Fe-binding capacity, Cu and Zn in the blood plasma of Warmblood horses during feeding with oat-hay or barley-hay rations over a period of 9 months]. 4 horses (Group A) received an oat-hay ration, through 9 months running, while 3 horses (Group B) were fed a barley-hay ration over the same period of time. Blood samples were collected and examined in 4-week intervals. All values considered, no differences were found to exist between the 2 groups with regard to Hb and haematocrit in blood as well as to protein, glucose, sodium, potassium, magnesium, iron fixation capacity, copper, and zinc in blood plasma. The urea level in plasma of Group A was higher than that in Group B, values being 5.76 +/- 0.64 mmol/l and 5.14 +/- 0.72 mmol/l. The same ...
Effect of calcium-channel blockers and salbutamol on the isolated mare uterus–interaction with the calcium agonist Bay K 8644. The effects of nifedipine, verapamil and diltiazem were investigated in the isolated mare uterus in comparison with salbutamol. All the calcium-channel blockers and salbutamol inhibited the spontaneous, KC1- and electrically induced contractions; nifedipine and salbutamol were the most potent compounds. The calcium agonist Bay K 8644 (10(-8)-10(-6) mol/l) competitively antagonized the inhibitory effect of nifedipine (pA2 value = 8.54 +/- 0.06), whereas it was only slightly or totally ineffective against verapamil, diltiazem and salbutamol. These results indicate that calcium-channel blockers a...
Antagonism in isolated equine digital vessels of contraction induced by epinephrine in the presence of hydrocortisone and an aqueous extract of black walnut (Juglans nigra). Prazosin, isoxsuprine, and nifedipine were screened for ability to reverse contraction of isolated equine digital vascular strips produced by epinephrine (Epi) in the presence of hydrocortisone (Hc) and an aqueous extract of black walnut (Juglans nigra) (BW). Two arteries and two veins from each of three horses for each drug (n = 9) were maintained in isolated tissue baths in Krebs' bicarbonate buffer with 95% oxygen at 37 degrees C. Six-point Epi concentration-response (C-R) curves were obtained for each vessel in the presence of Hc, BW, and the appropriate vehicle. This was repeated for each...
Altered sarcoplasmic reticulum function after high-intensity exercise. This study examined the effects of acute high-intensity exercise on the rate and capacity of Ca2+ uptake and Ca2+-stimulated adenosinetriphosphatase (ATPase) activity of the sarcoplasmic reticulum and the reversibility of these effects. Thoroughbred horses were run at maximal O2 uptake on a high-speed treadmill until fatigued. Muscle temperatures and biopsy samples were collected at rest, immediately after exercise, and 30 and 60 min after exercise. Blood samples were collected at rest and 5 min after exercise. Muscle and blood (lactate concentration) were three- and fivefold greater than pre-...
Comparison of the binding of Ca2+ and Mn2+ to bovine alpha-lactalbumin and equine lysozyme. The enthalpy change of the binding of Ca2+ and Mn2+ to equine lysozyme was measured at 25 degrees C and pH 7.5 by batch microcalorimetry: delta H degrees Ca2+ = -76 +/- 5 kJ mol-1, delta H degrees Mn2+ = -21 +/- 10 kJ mol-1. Binding constants, log KCa2+ = 6.5 +/- 0.2 and log KMn2+ = 4.1 +/- 0.5, were calculated from the calorimetric data. Therefore, delta S degrees Ca2+ = -131 +/- 20 JK-1 mol-1 and delta S degrees Mn2+ = 8 +/- 44 JK-1 mol-1. Removal of Ca2+ induces small but significant changes in the circular dichroism spectrum, indicating the existence of a partially unfolded apo-conformatio...
The lipoxygenase pathway and chemiluminescence in horse eosinophilic leukocytes. It was shown in several cell types that the dual lipoxygenase and cyclooxygenase inhibitor eicosatetraynoic acid but not the cyclooxygenase inhibitor acetylsalicylic acid suppressed luminol-dependent chemiluminescence. Since lipoxygenase is known to generate chemiluminescence in vitro, these observations were interpreted as evidence for a direct contribution of the lipoxygenase pathway to light emission in intact cells. We have investigated a possible contribution of the lipoxygenase to the chemiluminescence of horse eosinophils by directly comparing the formation of the byproduct chemilumines...
(+)-[3H]-PN 200-110 binding to cell membranes and intact strips of portal vein smooth muscle: characterization and modulation by membrane potential and divalent cations. 1. Specific binding of the calcium-antagonist dihydropyridine derivative, (+)-[3H]-PN 200-110 (isradipine), to cell membranes of equine portal vein smooth muscle was compared with binding to intact strips isolated from rat portal veins. 2. Specific binding to vascular smooth muscle membranes was of high affinity, saturable and reversible. The dissociation constant obtained from association and dissociation kinetics of (+)-[3H]-PN 200-110 was similar to that obtained from equilibrium binding and competition experiments. 3. Specific binding of (+)-[3H]-PN 200-110 was completely displaced by unla...
Evaluation of three strip tests for measuring electrolytes in mares’ pre-partum mammary secretions and for predicting parturition. Three strip test kits which measure calcium and/or magnesium in mares' mammary secretions were compared and assessed for their accuracy in:- 1) measuring these electrolytes compared to standard laboratory measurements, and 2) predicting the time of parturition. Daily samples of mammary secretions were obtained pre-partum from 35 Thoroughbred mares and allocated a score. Measurement of mammary secretion calcium and/or magnesium by the strip tests and laboratory methods correlated significantly (P less than 0.001). The results obtained for prediction of parturition were analysed by two methods. ...
Effects of dietary energy and phosphorus content on blood chemistry and development of growing horses. Growth and clinical biochemistry were examined over 30 wk in 42 light horse weanlings fed high-forage diets (73 to 77% alfalfa) or high-concentrate diets (63 to 65% grain and grain by-products) that were either low (.24 to .35%), normal (.68%) or high (.95 to 1.06%) in P. Body weights and blood samples were taken every 2 wk. Forage and concentrate diets contained 2.65 and 3.09 Mcal digestible energy/kg DM, respectively. Calcium and P digestibilities were highest (P less than .01) in those horses fed the low P diets, but only horses fed forage-low P diets may have absorbed insufficient P. Serum...
Induction of equine postanesthetic myositis after halothane-induced hypotension. Wick catheters were used to measure intracompartmental pressures of the extensor carpi radialis muscles and long heads of the triceps brachii muscles of 7 horses maintained under halothane anesthesia during controlled ventilation. Horses were positioned in left lateral recumbency on a water bed for 4 hours. Using a crossover design, 6 of the 7 horses were subjected to normotensive and hypotensive anesthesia on separate occasions. Hypotension was achieved by increasing the inspired halothane concentration. Hematologic and biochemical measurements were determined at designated intervals before, ...
Digestion, fecal, and blood variables associated with extensive large colon resection in the horse. Nutritional alterations were evaluated in 9 horses before surgery and 3 weeks, 3 months, and 6 months (4 total trials) after sham operation (group 1; n = 3) or extensive large colon resection (group 2; n = 6). Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, crude protein, calcium, phosphorus, magnesium, potassium, manganese, zinc, copper, and iron, and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables included the percentage of f...
Nutrient utilization by limit- and ad libitum-fed growing horses. Eighteen Quarter Horse and Paint weanling colts were assigned to two treatments, either limit or ad libitum feeding. Nutrient digestibilities of diets were evaluated between 6 and 12 mo, 12 and 18 mo and 18 and 24 mo of age. From 6 to 12 mo, energy digestibility (64 to 68%) was unaffected by feed intake level. Ad libitum-fed horses had energy digestibilities 9 to 10% greater (P less than .05) than limit-fed horses between 12 and 24 mo of age, but adjustment for DM intake removed these differences. Limit-fed, mature ponies used dietary energy similarly to growing horses from 6 to 18 mo of age, ...
