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.
Relationship between trace elements status in mane hair and atrial fibrillation in horse. To investigate the relationships between trace elements concentrations in hair and atrial fibrillation (AF) in horses, concentrations of nineteen trace elements were detected in hair using the particle induced X-ray emission (PIXE) method. The horses were assigned to either control (n=22, no abnormalities) or AF groups (n=5) based on electrocardiograph findings. The mean concentrations of Ca and Zn in the hair of the AF group were significantly higher than those in the control group. The Zn/Cu ratio of the hair in the AF group (29.8 +/- 5.5) was significantly higher than that in the control gr...
Serum concentrations of calcium, phosphorus, magnesium and calciotropic hormones in donkeys. To provide reference values for serum biochemical variables that are used for evaluation of mineral metabolism in donkeys and compare values with those in horses. Methods: 18 donkeys and 18 horses. Methods: Total calcium (tCa), total magnesium (tMg), and inorganic phosphorus (P) concentrations were measured in serum samples via spectrophotometry. Ionized calcium (iCa) and magnesium (iMg) concentrations were quantified with selective electrodes. By use of a micropartition system, tCa and tMg were fractionated to separate protein-bound (pCa, pMg) and ultrafiltrable fractions. Complexed calcium (...
Calcium-ions are involved in erythrocyte invasion by equine Babesia parasites. Ethylene glycol bis (beta-aminoethylether)-N,N,N,N-tetraacetic acid (EGTA) is a chelating agent capable of binding to positively-charged metal ions, including a calcium-ion (Ca2+). Here, we demonstrated the inhibitory effect of the chemical on the in vitro asexual growth of the equine protozoan parasites, Babesia caballi and Babesia equi. The growth of both B. caballi and B. equi was significantly inhibited in the presence of EGTA (IC50=1.27 and 2.25 mM, respectively). Under microscopical observation, increased percentages of extracellular merozoites in the total parasites were detected in bot...
Cholesterol-to-phospholipid ratio in whole sperm and seminal plasma from fertile stallions and stallions with unexplained subfertility. Semen samples were collected from six fertile stallions and seven stallions with unexplained infertility. Percentages of motile sperm (77.5 +/- 11.3 versus 67.5 +/- 12.2, P = 0.2), and progressively motile sperm (70.8 +/- 13.6 versus 60.7 +/- 14.0, P = 0.2) were similar between fertile and subfertile stallions, respectively. Morphologic characteristics in ejaculates of control and affected stallions (% normal: 60.2 +/- 18.2 versus 52.9 +/- 11.3, P = 0.4; % abnormal heads 7.3 +/- 4.8 versus 12.1 +/- 5.0, P = 0.11; and % abnormal acrosomes 1.6 +/- 2.1 versus 3.0 +/- 3.4, P = 0.4) did not differ....
Fractionation of calcium and magnesium in equine serum. To establish reference values for protein-bound, ionized, and weak-acid complexed fractions of calcium and magnesium in equine serum and determine stability of ionized calcium (iCa) and ionized magnesium (iMg) in serum samples kept under various storage conditions. Methods: 28 clinically normal horses. Methods: Total calcium (tCa) and magnesium (tMg) in equine serum were fractionated by use of a micropartition system that allows separation of protein-bound calcium (pCa) and magnesium (pMg) and ultrafiltrable calcium (microCa) and magnesium (microMg) fractions. Serum concentrations of iCa and i...
Use of plasma ionized calcium levels and Ca2+ substitution response patterns as prognostic parameters for ileus and survival in colic horses. Hypocalcaemia is a common finding in horses with enterocolitis and severe gastrointestinal disorders. The aims of this study were to investigate in colic horses 1)the parameters related to hypocalcaemia, 2)the influence of hypocalcaemia on outcome and 3)the possible beneficial effect of Ca2+ substitution. Methods: Randomized controlled trial. Methods: Intensive care unit. Methods: One hundred forty-four horses that were admitted with an acute abdomen during a 1.5 year period were enrolled and daily evaluated for clinical criteria and whole blood ionized Ca2+ levels. Colic horses with hypocalca...
An unusual case of generalized soft-tissue mineralization in a suckling foal. An atypical case of severe soft-tissue mineralization in a 3-week-old foal from a herd of Andalusian horses is described. The herd clinical history and the laboratory findings were compatible with a diagnosis of secondary hyperparathyroidism due to a mineral imbalance in the diet (low calcium and high phosphorus intake). Mares showed a marked increase in serum parathyroid hormone (PTH) approximately 10 times normal levels. Serum PTH was marginally elevated in foals. Clinical signs (unthriftiness, painful joints, lameness in one or more limbs, and stiff gait) were more pronounced in foals than ...
Determination of some enzymes and macro- and microelements in stallion seminal plasma and their correlations to semen quality. Seminal plasma is very important for sperm metabolism as well as sperm function and survival and transport in the female genital tract. Analysis of enzyme activities and concentrations of elements can estimate integrity and function of sperm cell membranes. In man much data are available about biochemical analyses of seminal plasma. However, not many studies have been conducted in horses yet. We collected ejaculates from 72 stallions, measured the volume, obtained seminal plasma by centrifugation and examined spermatozoa with light microscopy for motility, concentration, for dead sperm and mor...
Effects of induction of capacitative calcium entry on equine laminar microvessels. To determine the effects of induction of capacitative Ca2+ entry on tone in equine laminar arteries and veins. Methods: Laminar arteries and veins from 6 adult mixed-breed horses. Methods: Arteries and veins were isolated and mounted on small vessel myographs for the measurement of isometric tension. Capacitative Ca2+ entry was induced by incubating the vessels with the specific Ca2+-ATPase inhibitor thapsigargin (100nM) in a Ca2+-free physiologic salt solution. Capacitative Ca2+ entry-associated contractile responses were determined by the subsequent addition of 2mM Ca2+ to the solution bathi...
Correlation between 25 element contents in mane hair in riding horses and atrioventricular block. The influence of atrioventricular block (AV-block) on the trace elemental status in a horse hair was studied. The particle-induced X-ray emission (PIXE) method has provided a reliable, rapid, easy, and relatively inexpensive diagnostic method. Twenty-five elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, S, Se, Si, Sr, Ti, Y, and Zn) in mane hair and serum were measured by the PIXE method. A horse hair with first- and second-degree AV-block contained significantly greater amounts of Br, Ca, Sr, and Zn than those of horses without electrocardiographic abnormalities...
Effect of repeated oral administration of hypertonic electrolyte solution on equine gastric mucosa. Electrolyte supplementation is common in horses during endurance competitions, but the effect on the gastric mucosa is unknown. Objective: Repeated oral administration of hypertonic electrolyte solution is associated with exacerbation of gastric ulcers in mature horses. Methods: The study design was a randomised, blinded, crossover trial. Fourteen horses were divided randomly into equal groups and administered either 60 ml water (placebo) or 56.7 g commercial electrolyte supplement mixed with 60 ml water by dose syringe orally once an hour for 8 h. The minimum concentration of individual const...
Twenty-eight element concentrations in mane hair samples of adult riding horses determined by particle-induced X-ray emission. The concentrations of 28 elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, S, Se, Si, Sr, Ti, V, Y, and Zn) were measured in mane hair by the particle-induced X-ray emission method. Except for Br, Cl, K, S, and P, the trace element concentrations in mane hair of horses are similar to literature values for human hair. The values obtained are not dependent on the horse's age, breed, and sex and could be used as reference values in the assessment of diseases and nutritional status in equines.
Association of pneumonia in foals caused by Rhodococcus equi with farm soil geochemistry. To quantify and compare geochemical factors in surface soils from horse-breeding farms with horses with pneumonia caused by Rhodococcus equi (affected farms) and horse-breeding farms with no history of pneumonia caused by R equi (unaffected farms). Methods: Soil from 24 R equi-affected farms and 21 unaffected farms. Methods: Equine veterinary practitioners throughout Texas submitted surface soil samples from areas most frequented by foals, on R equi-affected and unaffected horse-breeding farms in their practice. Soil samples were assayed for the following factors: pH, salinity, nitrate, phosph...
Clinical biochemistry of pregnant and nursing mares. Pregnancy and lactation result in increased metabolic demands. Although homeostatic mechanisms function to keep substances in blood at relatively constant levels, some changes in the concentrations of routine clinical chemistry analytes are likely to occur. Objective: The purpose of this study was to determine what physiological changes occur in serum clinical biochemistry analytes in pregnant and nursing mares, and to determine whether the changes were substantial enough to warrant separate reference intervals for pregnant or lactating horses. Methods: Forty-two Quarter Horse, Thoroughbred, S...
Digestible energy intake, dry matter digestibility and mineral status of grazing New Zealand Thoroughbred yearlings. To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and to determine the effect of Ca, P, Cu, Zn, and Se supplementation on growth rate and degree of physeal swelling in Thoroughbred yearlings grazed on pasture. Methods: Fourteen yearling horses were randomly allocated to 1 of 2 groups and rotationally grazed on a ryegrass/white clover pasture for 7 months. One group was supplemented daily with a mineral mix. Liveweight changes were recorded at fortnightly intervals and pasture mineral composition determined at monthly interva...
Digestible energy intake, dry matter digestibility and effect of increased calcium intake on bone parameters of grazing Thoroughbred weanlings in New Zealand. To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and the effects of increased calcium (Ca) intakes on apparent mineral absorption and bone characteristics in grazing weanling Thoroughbreds. Methods: DM intake (DMI) and DEI were determined in 16 weanling Thoroughbreds grazing pasture from their daily faecal DM output, measured over 8 days, divided by the DM indigestible fraction (1-digestible DM) determined in a 6-day digestibility trial. The DM, gross energy content, crude protein, soluble carbohydrate, acid detergent fibre...
Prediction of foaling using mammary secretion constituents. To test published models for predicting time of foaling using data derived from prepartum mammary secretions and to develop a new model based on concentrations of mammary secretion constituents that accurately predicts time of foaling in Thoroughbred mares. Methods: Concentrations of sodium, potassium, calcium, citrate and lactose were measured in prepartum mammary secretions of 20 Thoroughbred mares in the 2 weeks before expected date of foaling. Models to predict time of foaling were fitted to data based on absolute concentration, change in concentration, and percentage change in concentrati...
Investigation and management of a cluster of cases of equine retained fetal membranes in Highland ponies. Four at-risk Highland ponies on the same premises all retained their fetal membranes in the same breeding season. The ponies were treated with a combination of oxytocin, infusion and distension of the allantochorionic sac with fluid, gentle traction in one case, and supportive therapy. The possible causes of the condition were investigated with clinicopathological tests and analyses of the herbage for its species composition and fungal contamination. No obvious possible causative abnormalities were identified apart from a low total serum calcium level in one case. No fescue grass was found and...
Study of cartilage and bone layers of the bearing surface of the equine metacarpophalangeal joint relative to different timescales of maturation. A detailed and comprehensive insight into the normal maturation process of the different tissues that make up functional units of the locomotor system such as joints is necessary to understand the influence of early training on musculoskeletal tissues. Objective: To study simultaneously the maturation process in the entire composite structure that makes up the bearing surface of a joint (cartilage, subchondral and trabecular bone) in terms of biochemical changes in the tissues of juvenile horses at 2 differently loaded sites of the metacarpophalangeal joint, compared to a group of mature horse...
Effects of draught load exercise and training on calcium homeostasis in horses. This study was conducted to investigate the effects of draught load exercise on calcium (Ca) homeostasis in young horses. Five 2-year-old untrained Standardbred horses were studied in a 4-month training programme. All exercise workouts were performed on a treadmill at a 6% incline and with a constant draught load of 40 kg (0.44 kN). The training programme started with a standardized exercise test (SET 1; six incremental steps of 5 min duration each, first step 1.38 m/s, stepwise increase by 0.56 m/s). A training programme was then initiated which consisted of low-speed exercise sessions (LSE; ...
Influence of the coat color on the trace elemental status measured by particle-induced X-ray emission in horse hair. The influence of hair color on the trace elemental status in horse's hair has been studied. A current analytical technique such as particle-induced X-ray emission (PIXE) used in this study has provided reliable, rapid, easy, and relatively inexpensive diagnostic methods. Twenty-eight elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, S, Se, Si, Sr, Ti, V, Y, and Zn) in mane hair were detected by the PIXE method. The gray hair contains significantly greater amounts of Cu, Ti, and Zn, and lower amounts of Br, Ca, Se, and Sr than those in other colored horse h...
The influence of calcium intake on phosphorus digestibility in mature ponies. Literature data show conflicting results on the effect of feeding high calcium (Ca) levels on phosphorus (P) digestibility in ponies. None of the studies reported involved a dose response as to the effect of Ca intake on apparent P digestibility while keeping P intake constant. Thus, the influence of high dietary Ca level on apparent P digestibility was studied in balance trials by feeding six mature ponies three different Ca levels against a constant P intake. The ponies received 148, 316 and 535 mg Ca/kg BW/day with the low, intermediate and high Ca diet. Phosphorus intake was approximately ...
An integral biochemical analysis of the main constituents of articular cartilage, subchondral and trabecular bone. In articular joints, the forces generated by locomotion are absorbed by the whole of cartilage, subchondral bone and underlying trabecular bone. The objective of this study is to test the hypothesis that regional differences in joint loading are related to clear and interrelated differences in the composition of the extracellular matrix (ECM) of all three weight-bearing constituents. Methods: Cartilage, subchondral- and trabecular bone samples from two differently loaded sites (site 1, dorsal joint margin; site 2, central area) of the proximal articular surface of 30 macroscopically normal equ...
Effects of pharmacological doses of Vitamin D3 on mineral balance and profiles of plasma Vitamin D3 metabolites in horses. Metabolism and functions of Vitamin D in horses differ from those in humans, pigs and rats. In horses, calcidiol and calcitriol concentrations in blood plasma are remarkably low (<10 nmol L(-1); 20-40 pmol L(-1), respectively). When a toxic amount of Vitamin D(3) is administered, the responsiveness of calcium and calcitriol concentrations in blood plasma is much reduced compared to the other domestic animal species but inorganic phosphate (Pi) response is much more marked, leading to an increase of the Ca x Pi product. Also, soft tissue calcifications have been observed to develop in horses...
The apparent digestibility of phytate phosphorus and the influence of supplemental phytase in horses. Availability of phytate-bound P as influenced by supplemental phytase was studied in eight horses consuming four diets in a 4 x 4 Latin square design experiment. The treatments were a control (containing a low P level, 18.4 g/d) and three high-P diets. These diets contained P as monocalcium phosphate (MCP; 43.7 g/d), myoinositol hexakisphosphate in the form of wheat and rice bran (MIHP; 41.8 g/d), or MIHP with microbial phytase (MIHPP; 42.5 g/d). The proportions of phytate-bound P were 3, 1, 55, and 56% for the control, MCP, MIHP, and MIHPP, respectively. The MIHPP diet was supplemented with 3...
Dietary risk factors and colonic pH and mineral concentrations in horses with enterolithiasis. A prospective, unmatched case control study was performed to identify dietary and environmental risk factors for enterolithiasis in horses in California and to determine whether colonic ingesta analyses differed between horses with and without enteroliths. Forty-three horses with enterolithiasis were compared with 19 horses with surgical colic attributable to nonstrangulating obstruction of the colon without enteroliths. Colonic ingesta samples were collected at surgery from horses with enteroliths and control horses. Colonic pH and colonic concentrations of magnesium, phosphorus, sulfur, sodi...
Comparison of Ca2+ release and uptake characteristics of the sarcoplasmic reticulum in isolated horse and rabbit cardiomyocytes. Both the cardiac action potential duration (APD) (0.6-1 s) and resting heart rate (30-40 beats/min) in the horse are significantly different from humans and smaller mammals, including the rabbit. This would be anticipated to have consequences for excitation-contraction (EC) coupling and require adaptation of the individual processes involved. The sarcoplasmic reticulum (SR) is one of the main components involved in EC coupling. This study examines and compares the activity of this organelle in the horse with that of the rabbit. In particular, the study focuses on SR Ca2+ release via the Ca2+ r...
Therapeutic clenbuterol treatment does not alter Ca2+ sensitivity of permeabilized fast muscle fibres from exercise trained or untrained horses. Clenbuterol is a beta2-adrenoceptor agonist primarily used for treating bronchospasm and alleviating the symptoms of chronic obstructive pulmonary disease (COPD) in the horse. In other species (rats, mice, sheep, and cattle), chronic high doses of clenbuterol (typically in the milligram per kilogram body weight range) has been shown to cause a muscle directed protein anabolic response. Clenbuterol can also modify muscle fibre composition and therefore potentially affect muscle function. This has implications for the performance of exercising horses being treated with therapeutic doses of clenb...
Parathyroid hormone (PTH) secretion, PTH mRNA and calcium-sensing receptor mRNA expression in equine parathyroid cells, and effects of interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha on equine parathyroid cell function. Parathyroid hormone (PTH) is secreted by the chief cells of the parathyroid gland in response to changes in ionized calcium (Ca(2+)) concentrations. In this study, we measured PTH secretion, and PTH mRNA and calcium-sensing receptor (CaR) mRNA expression by equine parathyroid chief cells in vitro. We also evaluated the effects of interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha on PTH secretion, and PTH and CaR mRNA expression. The relationship between PTH and Ca(2+) was inversely related. PTH secretion decreased from 100% (day 0) to 13% (day 30). PTH mRNA expression decline...