Total Ca Content Research Articles

Mineral Composition Evaluation in Energy Drinks Using ICP OES and Chemometric Tools.

This study reports the simultaneous determination of the total concentrations of Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, and Zn in17 samples of commercial energy drinks through inductively coupled plasma optical emission spectrometry and multivariate methods, such as Pearson correlation and principal component analysis (PCA), in order to conduct a more thorough evaluation of the original data. The samples studied were stored in two types of containers (polyethylene terephthalate bottles and aluminum cans) and purchased in the city of Belém (State of Pará, Brazil). The results showed high Na content in energy drinks, followed by K, Ca, and Mg. The accuracy of the optimized method was evaluated with the certified reference materials to assess trace elements in water (NIST 1643e); the resultant recoveries varied from 83 to 105%. Energy drinks stored in cans presented higher levels of aluminum and magnesium, while those bottled in polyethylene terephthalate bottles had a higher K content. There were significant differences between the observed Na concentrations and the values dictated on the drink package. Furthermore, PCA explained 70.38% of the total variance, allowing for an evaluation of the degree of similarity between the energy drinks studied and showing that the main contributions to the formation of groups are related to Fe, Na, Mg, and Zn contents. These results will be used to better understand the distribution of inorganic elements contained in energy drinks.

The Chemistry of Sub-Alpine Streams in Mined Regions of the North Cascades Range

One hundred and fifty years of mineral extraction throughout the mountainous Ruby Creek watershed, Washington has left a legacy of historical hard rock mines and placer claims and their wastes. We conducted a watershed-scale chemical analysis of these gold-bearing tributaries, accounting for seasonal variability in streamflow, to identify spatial and temporal changes in stream chemistry and attribute them to natural processes or mining activities. We used hierarchical cluster analysis (HCA) to group chemically similar water samples based on concentrations of 23 metals, pH, and conductivity and compared the chemistry of HCA-generated clusters of water samples using pairwise comparisons to find chemical patterns. Total concentrations of As, Ba, Ca, Mg, Na, Sb, and Se, dissolved concentrations of Fe, and conductivity increased as streamflow progressed from snowmelt-influenced to baseflow. High total concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, V, and Zn during spring snowmelt and after rains were attributable to acid mine drainage at historical hard rock mines and prospect sites. Smaller-scale placer mining, by way of suction dredging and motorized gold panning, was associated with high concentrations of Al, Ba, Cd, Co, Fe, Mg, Mn, Mo, and Zn downstream. Stream biota may be adversely affected by exposure to Pb, which exceeded USEPA’s Aquatic Life Criteria, and exposure to particulate metals suspended in the water column.

Calcium dynamics of reproductive apple buds during the dormant season in the Western Cape, South Africa

Calcium (Ca) deficiency in apples results in unwanted physical disorders in mature fruit that reduce fruit value. Ca deficiency associated with bitter pit is already prevalent early in the season, as it is initiated a few weeks after full bloom. Information regarding Ca concentration in reproductive buds or bud tissues is lacking, thus we investigated the Ca concentration in reproductive buds of the bitter pit susceptible ‘Braeburn’ and non-susceptible ‘Cripps Pink’ apple cultivars during the dormant season. Wavelength-dispersive x-ray spectroscopy (WD SEM) was used to quantify total Ca concentration of parenchyma and vascular tissues, from June to September, for two seasons (2012 and 2014). Results showed a changing trend in Ca concentration from June to September for total Ca concentration and between cultivars. Total Ca concentration was the highest in ‘Cripps Pink’ during the whole period and related to the non-susceptibly to Ca related disorders. Ca concentration in ‘Cripps Pink’ declined towards September in contrast with the increasing trend of ‘Braeburn’. This may indicate that the total Ca concentration of the buds, and not the change of Ca concentration in buds during winter, is associated with a higher Ca status of fruit on non-susceptible cultivars. The actual Ca concentration of ‘Cripps Pink’ at the end of August was still higher than that of ‘Braeburn’. Results may be explained partly by the time of primary xylem formation in the bud, which happens earlier in ‘Cripps Pink’, as well as the associated increase in Ca translocation, indicating the role of generic differences between cultivars, contributing towards final changes in the inherent Ca concentration at the beginning of the dormant season.

Invasion of Rosa rugosa induced changes in soil nutrients and microbial communities of coastal sand dunes

The aim of this study was to investigate the influence of R. rugosa invasion on soil physicochemical and microbial properties of coastal sand dunes. The study was performed at 25 paired invaded-native plots along the Hel Peninsula at the coast of the Baltic Sea. A number of soil physicochemical and microbial parameters were measured, namely organic matter layer thickness, pH, electrical conductivity, organic C, total Ca, N, Na, P, N-NH4, N-NO3 and P-PO4 concentrations, phospholipid and neutral fatty acid (PLFA, NLFA) markers of total microbial, bacterial, fungal biomass and microbial community structure, as well as arbuscular mycorrhizal fungi (AMF) spore and species numbers, and the degree of AMF root colonization. Since potential alterations in soil parameters induced by R. rugosa may be related to large amounts of secondary metabolites provided to the soil with litter or root exudates, total phenolic concentration in senescing tissues of R. rugosa and native species was compared. Rosa rugosa invasion was associated with increased organic C, total N and P-PO4 concentrations in mineral soil relative to native vegetation. Organic matter layer under R. rugosa was thicker, had higher pH and Ca concentration. Rosa rugosa invasion was associated with reduced total microbial, bacterial and G+ bacterial biomass and increased AMF biomass markers (16:1ω5 NLFA and 16:1ω5 NLFA/PLFA), and changes in microbial community structure in mineral soil. The reduction in total and bacterial biomass under R. rugosa might have been related to the production of secondary metabolites as total phenolic concentration was approx. 5 times higher in senescing tissues of R. rugosa than in native vegetation. The observed increase in element concentrations and alterations in microbial community structure suggest that invasion of R. rugosa may threaten nutrient-poor habitats of coastal dunes. Changes in the soil environment may hinder restoration of these valuable habitats after invader removal.

Lowering dietary cation-anion difference increases sow blood and milk calcium concentrations.

A study was conducted to evaluate the effects of feeding an acidogenic diet with a low dietary cation-anion difference (DCAD) on acid-base balance, blood, milk, and urine Ca concentrations of sows during lactation. A total of 30 multiparous sows (parity: 4.5 ± 2.9, Smithfield Premium Genetic, Rose Hill, NC) were allotted to 1 of 2 dietary treatments: CON (control diets were corn-soybean meal based with a calculated DCAD of 170 and 226 mEq/kg during late gestation and lactation, respectively) or ACI (acidogenic diets had a DCAD 100 mEq/kg lower than the control diets). The lower DCAD was achieved by the addition of an acidogenic mineral. The DCAD was calculated as mEq (Na + K - Cl)/kg diet. Sows had a daily access to 2-kg feed from day 94 of gestation to parturition and ad libitum access to feed during lactation. Blood and urine pH and Ca, serum macrominerals, serum biochemistry, Ca-regulating hormones, and milk composition were measured. Sows in ACI had a lower (P < 0.05) blood pH than sows in CON at day 1 of lactation. Sows in ACI had a lower (P < 0.05) urine pH at day 108 of gestation, days 1, 9, and 18 of lactation compared with sows in CON. Sows in ACI had greater (P < 0.05) concentrations of serum total Ca at days 1 and 18 of lactation than sows in CON. There was a greater (P < 0.05) concentration of colostrum Ca in ACI than in CON. There was no difference in urine Ca concentration between treatments during lactation. Concentrations of parathyroid hormone and 1,25-dihydroxycholecalciferol were not different between treatments at either day 1 or 18 of lactation. Sows in ACI tended to have a smaller (P = 0.086) concentration of total alkaline phosphatase in serum at day 18 of lactation compared with sows in CON. At day 1 of lactation, the concentration of serum Cl in ACI was greater (P < 0.05) than that in CON. Feed intake, BW loss, and litter performance were not different between treatments. Collectively, feeding an acidogenic diet with a low DCAD to sows can induce a mild metabolic acidosis at farrowing, reduce the urine pH consistently, and increase serum total Ca and colostrum Ca concentrations during lactation but without altering the parathyroid hormone and 1,25-dihydroxycholecalciferol levels during lactation.

Concretionary horizons, unusual pedogenetic processes and features of sulfate affected soils from Antarctica

Although acid sulfate soils have been previously reported in Maritime Antarctica, no detailed study about the nature of the sulfide oxidation process and its effect on pedogenesis has been carried out to this day. The present study evaluate the soil genesis from Barton Peninsula along two toposequences developed under sulfides influence, emphasizing active chemical processes in a typical periglacial environment of Maritime Antarctica, and the unusual formation of petroplintite. Seven pedons were selected, described, sampled and classified according to the U.S. Soil Taxonomy and the IUSS Working Group WRB. Soil morphological, physical, chemical, microchemical and mineralogical properties were analyzed. The geochemical composition (total contents of Al, Ca, Co, Cu, Fe, K, Mg, Na, Ni, S, Si, Ti, Th, V and Zn) was determined with X-ray Fluorescence Spectrophotometer. Unlike previous studies that considered chemical weathering as insignificant in Barton Peninsula, this study demonstrates that some areas have active and pronounced chemical weathering processes (sulfurization and phosphatization), which cannot be underestimated. These chemical processes, together or individually, promote strong soil acidification, release exchangeable bases and accelerate mineralogical changes. Precipitation of secondary crystalline iron oxides, plinthization and petroplintite formation occur in these soils, resulting in unusual pedogenic features, unknown to occur in Antarctica to this day. Further studies on Antarctic soils with petroplinthic horizons, with or without ornithogenesis, deserve attention regarding micromorphological attributes and clarification about these new, unusual pedological processes in periglacial environments and their possible use as indicators of environmental change.

Effect of photoperiod on growth performance and quality characteristics of tibia and femur in layer ducks during the pullet phase

This study aimed to evaluate the effect of photoperiod on growth performance and bone development in layer ducks during the pullet phase. A total of 480 11-wk-old Jinding layer ducks were randomly divided into 5 groups, receiving 6L (light): 18D (dark), 8L: 16D, 10L: 14D, 12L: 12D, 14L: 10D, respectively. Each group had 6 replicates of 16 birds each. The feeding trial lasted 80 d until 150 d of age. The results showed that 8L: 16D increased body weight (BW) and average daily gain (ADG; P < 0.05) compared with 6L:18D, whereas average daily feed intake, feed conversion ratio, and mortality rate had no difference among all treatments (P > 0.05). The midpoint perimeter (tibia and femur) and work to fracture (Wu; tibia) increased quadratically (P < 0.05), in response to photoperiod increment. Compared with 6L:18D, 8L:16D had higher tibia midpoint perimeter, ultimate load (Fu), and cortical cross-sectional area (P < 0.05), accompanied with higher content of total Ca, distal bone mineral content (BMC), and cortical volumetric BMC (vBMC; P < 0.05). A linear increase was observed in trabecular volumetric bone mineral density (vBMD) and vBMC (tibia and femur), elastic energy (femur), work to fracture Wu and young modulus of elasticity E (tibia) in response to photoperiod increase (P < 0.05), and treatment with 14L:10D had higher ultimate load Fu and total Ca of tibia (P < 0.05). Besides, estradiol and testosterone levels (serum), estrogen receptor gene mRNA expression (bone tissue), alkaline phosphatase and tartrate-resistant acid phosphatase activities, transforming growth factor-β, osteocalcin and tumor necrosis factor-α contents increased in ≥12 h photoperiods (P < 0.05). In summary, appropriate photoperiod increased BW, ADG, cortical bone generation, and bone mineralization, whereas only medullary bone formation increased with photoperiods. These results suggest that 8L:16D could be an adequate photoperiod for layer ducks' growth and bone development during the pullet phase.

Kinetics and Products of Air Plasma Induced Oxidation in Water of Imidacloprid and Thiamethoxam Treated Individually and in Mixture

Imidacloprid (I) and thiamethoxam (T) are widely used neonicotinoid insecticides with high persistence in the environment and thus included in the watch list of substances for European Union-wide monitoring reported in the Decision 2015/495/EU. In this work aqueous solutions of I, T and I + T were subjected to advanced oxidation by air plasma produced by negative DC corona discharges above the liquid surface. The oxidative degradation of each pollutant was investigated by monitoring the rate and the products of its decay when treated alone and in the presence of variable amounts of the other compound. The results show that both I and T are readily degraded and that mineralization can be achieved in this process, as proven by the measurement of the residual organic carbon and by the quantitative conversion of chlorine and sulfur into inorganic chloride and sulfate, respectively. The major organic intermediates formed during the complex stepwise oxidation of I and T were identified and monitored by HPLC–MS/MS analysis. The results of kinetic studies show that both for I and T the reaction rate depends inversely on the insecticide initial concentration, that I and T have similar reactivities and that they do not interfere reciprocally in any specific way when treated in mixture at a total concentration of ca 1 × 10−4 M. Based on literature data and on previous results with the same reactor, it is reasonable to propose that the oxidation of I and T is initiated by the reaction with OH radicals.

Elemental chemical composition of products derived from kefir fermented milk

Kefir grains have been applied for milk fermentation, obtaining products derived from kefir fermented milk (kefir, Greek yogurt and whey). During fermentation, proteins become easily digestible and lactose is hydrolyzed, becoming a good option for lactose-intolerant individuals. However, fermentation process can change the essential elements distribution in kefir milk products. Therefore, the aims of the study were to evaluate the total concentration of Ca, Cu, Fe, K, Mg, Mn, Na, P, S and Zn in kefir, whey and Greek yogurt produced with kefir grains inoculated into cow’s milk. Phosphorous was the highest concentration in kefir milk fermented products ranging from 1220 ± 88 μg mL−1 (whey) to 2090 ± 27 μg g−1 (Greek yogurt), whereas Fe was the lowest concentration ranging from 6.7 ± 0.2 μg g−1 (kefir) to 8.9 ± 0.2 μg g−1 (Greek yogurt). Considering the dietary reference intake values, mainly Greek yogurt has proved to be a good source of Ca (21.2%), P (59.7%), and Fe (22.3%).

Determination of total concentration and bioaccessible fraction of metals in infant cereals by MIP OES

The present study provides information about the total concentration and bioaccessible fraction of metals Al, Ba, Bi, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Pb, Ti and Zn in nine different infant cereal samples. An in vitro digestion method was employed to evaluate the bioaccessibility. The determinations were performed by microwave induced plasma optical emission spectrometry (MIP OES). The bioaccessibility varied according to the type of infant cereal sample. The values of bioaccessible fraction (minimum and maximum) for Cu, Fe, Mn, Pb and Zn were 24–68, 1–10, 7–58, 24–100 and 1–7% of the total concentration, respectively. Al and Ti presented bioaccessibility in only two samples: 6% in the multicereal A and 14% in the rice and oat cereal B, respectively. The concentration of Ba, Bi, Cd, and Cr was below the limit of detection for the bioaccessibility method. The obtained concentrations were lower than the daily recommended intake for essential and toxic elements, with exception of Pb in the rice and oat A sample.

Meta-analysis of the effects of prepartum dietary cation-anion difference on performance and health of dairy cows

The objectives were to use meta-analytic methods to determine the effects of changes in dietary cation-anion difference (DCAD) prepartum on productive performance and health of dairy cows. The literature was systematically reviewed, searching randomized experiments with transition cows that manipulated the prepartum DCAD or experiments with acidogenic diets in which dietary Ca, P, or Mg was manipulated. Forty-two experiments, including 134 treatment means and 1,803 cows, were included in the meta-analysis. Of those, 5 experiments with 15 treatment means reported responses for 151 nulliparous cows. Data collected included the mineral composition of prepartum diets, parity group prepartum, breed, days on treatment, and means and respective measure of variance for urine pH, dry matter intake (DMI), body weight, body condition, productive performance, concentrations of minerals and metabolites in blood, and incidence of diseases. Mixed effects meta-analyses were conducted weighting by the inverse of standard error of the means squared to account for the precision of each experiment. Models include the effects of DCAD, parity group prepartum, interaction between DCAD and parity group, and other covariates that showed significance in univariable analysis. Final models were selected based on parsimony and model fit. Reducing the prepartum DCAD reduced intake prepartum but improved intake postpartum in both parity groups. Interactions between DCAD and parity group occurred for yields of milk, fat-corrected milk (FCM), fat, and protein because reducing the DCAD improved those responses in parous cows; however, reducing the DCAD either had no effect on yields of milk and protein or reduced the yield of FCM and fat in nulliparous cows. The resulting equations from the statistical models predicted that reducing the DCAD from +200 to -100 mEq/kg would increase blood total Ca on the day of calving from 1.86 to 2.04 ± 0.05 mM, DMI postpartum 1.0 kg/d, and milk yield 1.7 kg/d in parous cows. The increased concentrations of blood total Ca at calving and postpartum explained the marked reduction in risk of milk fever in parous cows with a reduction in DCAD. As the DCAD decreased, the risk of retained placenta and metritis also decreased, resulting in fewer disease events per cow in both nulliparous and parous cows. Dietary concentrations of Ca, P, or Mg prepartum had no effect on DMI or yields of milk and FCM; however, increasing dietary Ca within the study range of 0.16 to 1.98% of dry matter tended to increase the risk of milk fever in parous cows regardless of DCAD fed. Collectively, results support the recommendation of prepartum acidogenic diets to result in a negative DCAD to parous cows with improvements in lactation performance and reduced risk of diseases; however, the range of DCAD fed did not allow for detection of an optimum value for postpartum performance. On the other hand, despite improvements in blood concentrations of Ca and reduction in uterine diseases with a reduction in DCAD fed to nulliparous cows, productive performance was either depressed or unaffected and the limited number of experiments did not provide sufficient evidence for a recommended DCAD for this group of cows.

Numerical simulation of modification of non-metallic inclusions by calcium treatment in the argon-stirred ladle

Nowadays, depending on the steel grade, Ca treatment with the aim of modifying the morphology and melting temperature of non-metallic inclusions is performed in the secondary steelmaking process. The addition of calcium to steel melts rises a technological challenge because at steelmaking temperatures Ca has the tendency to vaporize from the ladle. Efforts are actively pursued in developing solutions that increase Ca yield and improve repeatability of results from treatment to treatment. This work presents a two-phase Euler-Euler flow model of a steel ladle with gas stirring through bottom porous plugs. The model considers that before gas exits through the ladle top, some Ca is transferred from the gas to the liquid steel. The yield is thus defined as the ratio between the Ca transferred to the steel and the total calcium injected into the ladle. The fluid-dynamic calculations are coupled with ArcelorMittal thermodynamic software CEQCSI to get the evolution of the local concentration of dissolved species and non-metallic inclusions assuming local thermodynamic equilibrium. Industrial trials have been performed at one of ArcelorMittal’s facilities with the aim of obtaining data to validate the model. Samples of steel were taken before, during, and after the Ca injection treatment. The total Ca content and the inclusion populations in the steel samples can be compared against the results given by the model, as well as the measured and calculated Ca yield.

Dietary calcium supplementation affects nutrient digestibility and antler-production performance during the antler-velvet growth period of male sika deer

Effects of calcium (Ca) supplementation on nutrient digestibility, physiochemical characteristics and antler growth in farmed male sika deer were investigated. Eighteen sika deer (6 years old, 105.50 ± 5.05 kg) were assigned into the following three treatments where they had ad libitum access to water for 90 days: (1) control (C), basal diet containing 0.5% Ca; (2) Ca1.10, basal diet supplemented with 0.6% Ca; and (3) Ca1.70, basal diet supplemented with 1.2% Ca. The basal diet contained 0.50% Ca and 0.34% phosphorus (P). Each group consisted of the same ratio of Ca to P (provided as CaCO3 and CaHPO4). The results showed that the digestibility of dry matter (DM) and crude protein in the Ca1.70 group was lower than in the other two groups. The digestibilities of Ca, P and neutral detergent fibre in the Ca1.10 group were higher than those in the C group and Ca1.70 group (P &amp;lt; 0.05). Concentrations of Ca and P in faeces increased with an increasing supplementation level of Ca and the highest concentrations were observed in the Ca1.70 group (P &amp;lt; 0.05). There were no differences in the concentrations of parathyroid hormone, alkaline phosphatase and osteocalcin among the treatments. Testosterone and oestradiol concentrations of the Ca1.7 group were higher than those of the C and Ca1.10 groups (P &amp;lt; 0.05). Average daily gains of fresh antler weight and dry antler weight of the groups Ca1.10 and Ca1.70 were greater than those of the C (P &amp;lt; 0.05). Fresh and dry antler yields of the Ca1.10 group were higher than those of the other groups (P &amp;lt; 0.05). In conclusion, optimal level of Ca supplement was found to be total Ca concentration of 1.10–1.70%, on the basis of DM, which significantly increased feed digestibility and antler daily gain for the 6-year-old sika deer.

Spatial and temporal changes of P and Ca distribution and fractionation in soil and sediment in a karst farmland-wetland system

Phosphorus (P) is a critical element affecting eutrophication in aquatic ecosystems. Its availability is closely related to calcium (Ca) in calcareous soils and sediments, but their relations are unclear. In this study, the spatial and temporal changes in P and Ca fractionation and distribution in a karst farmland-wetland ecosystem were investigated. The results showed that total P concentrations were 1.25–3.19 g kg−1, with higher concentrations in paddy soil than in sediment. Total Ca concentrations were 3.93–10.2 g kg−1, with higher Ca being accumulated in sediments than in soils. The P fractionations varied seasonally, with Ca-bound P being dominant. The moderately-stable Fe/Al-bound P showed temporal variation, while Ca was dominant in acid-soluble fraction, both probably playing an important role in controlling P availability. Correlation analysis showed seasonal relation between Ca and P distribution in soil/sediment. This study suggests that P migration from farmland to wetland may be a major source for P accumulation in sediments in a karst farmland-wetland system.

Preliminary results on the feasibility of producing selenium-enriched pink (Pleurotus djamor) and white (Pleurotus ostreatus) oyster mushrooms: Bioaccumulation, bioaccessibility, and Se-proteins distribution

The consumption of white (Pleurotus ostreatus) and pink (Pleurotus djamor) oyster mushrooms has been highlighting due to nutritional value and ability to accumulate essential elements, such as selenium (Se). Therefore, the aims of the present study were to evaluate the Se-enriched mushrooms production and enrichment effects on the bioaccessibility of Ca, Cu, Fe, K, Mg, Mn, P, S, Se, and Zn, and proteins and Se-proteins distribution. The Se enrichment of edible mushrooms (white and pink) with different Se(IV) concentrations did not alter the moisture (77 to 89%) and biological efficiency (21 to 27%). The Se total concentration increased significantly in mushrooms cultivated in enriched medium, ranging from 19 ± 1 μg g−1 (white) to 76 ± 2 μg g−1 (pink). It was verified that Se enrichment did not significantly change the total concentration of Ca, Cu, Fe, K, Mg, Mn, S, and Zn of both mushroom species. However, the Se enrichment promoted an increase in the bioaccessible percentage of Fe (7 to 11%), Mg (12 to 13%), P (4 to 6%), S (7 to 12%), and Zn (10 to 14%) for pink oyster mushroom and a decreased in Fe (18 to 28%) and P (7 to 13%) of the white oyster mushroom. In the distribution of proteins, it was verified that the enrichment changed the solubility and distribution of proteins in white oyster (prolamins and glutelins) and pink oyster mushrooms (globulins). Lastly, Se is mainly associated to albumins (white oyster: 4.5 ± 0.4 μg g−1, pink oyster: 9.5 ± 0.7 μg g−1) and glutelins (white oyster: 4.2 ± 0.6 μg g−1, pink oyster: 11.1 ± 0.4 μg g−1). These results demonstrate the ability of these fungi to absorb and bioaccumulate Se, favoring the formation of Se-proteins that are more bioaccessible species.

Effect of diets containing sulfate or chloride-based anionic salts, fed to grazing prepartum dairy cows, on concentrations of Ca in plasma, disease incidence and milk yield

AIMS: To compare the effect of two partial mixed ration diets containing either sulfate or chloride-based anionic salts, fed to grazing prepartum dairy cows, on concentrations of Ca, Mg, P and beta-hydroxybutyrate (BHB) in plasma, disease incidence and milk yield during the early postpartum period.METHODS: The study was conducted on a seasonal-calving grazing dairy farm located in Benton (MO, USA). In August 2016, two groups of 200 cows were randomly assigned at 30 days before expected parturition to receive either a sulfate or chloride-based anionic diet, to achieve a dietary cation–anion difference (DCAD) of −25 mEq/kg DM. Cows were fed partial mixed rations to provide 50% of their DM intake, with 50% provided by grazing fescue pasture. Urine samples were collected from 20 cows from each group once a week for 5 weeks until calving for pH assessment. At parturition, 42 cows per group were selected at random and blood samples collected on Days 1, 2, 3 and 7 postpartum. The study continued until 100 cows per group calved. Health events and cumulative milk yield until 30 days postpartum were recorded. Concentrations of Ca, P, and Mg in plasma at Days 1, 2, 3, and 7, and BHB in plasma at Day 7 postpartum were assessed.RESULTS: Mean urine pH was lower in cows in the chloride than sulfate group (p≤0.06) on four of five sampling occasions. Mean concentrations of Ca in plasma on Day 1 were 2.00 (95% CI=1.94–2.05) and 1.91 (95% CI=1.88–1.97) mmol/L for the chloride and sulfate groups, respectively (p=0.15), and on Day 3 were 2.03 (95% CI=1.97–2.08) and 1.90 (95% CI=1.84–1.96) mmol/L, respectively (p=0.038). Concentrations of Mg, P and BHB in plasma and incidence of diseases postpartum were similar in both groups (p>0.05). There were no cases of clinical hypocalcaemia in either group.CONCLUSIONS AND CLINICAL RELEVANCE: Prepartum cows fed a partial mixed ration with a negative DCAD containing chloride-based anionic salts and free access to a fescue pasture had lower prepartum urine pH, and higher concentrations of total Ca in plasma during the first week postpartum, than cows receiving a partial mixed ration containing sulfate-based anionic salts.

Risk factors for subclinical hypocalcaemia, and associations between subclinical hypocalcaemia and reproductive performance, in pasture-based dairy herds in New Zealand

AIMSTo estimate the herd-level prevalence of subclinical hypocalcaemia within 3 days of calving, to determine cow and herd-level risk factors for this condition, and associations with reproductive performance, in pasture-based cows in New Zealand.METHODSBetween 10 and 15 clinically healthy cows ≥3-years-old (n=1,051) were enrolled from 76 spring-calving dairy herds. Blood samples were collected from all cows on 1 or 2 days within 3 days of calving, and assayed for total concentrations of Ca in serum. Subclinical hypocalcaemia was defined as concentrations of Ca in serum ≤2.14 mmol/L, and herd-level prevalence was the percentage of sampled cows with subclinical hypocalcaemia. Breeding and pregnancy diagnosis data were obtained for each cow to calculate reproductive outcomes. Herd-level data about management practices were collected from farmers at enrolment. Associations between cow-level variables, and reproductive outcomes, and subclinical hypocalcaemia were examined using multivariable logistic regression mixed models. Associations between herd-level variables and prevalence of subclinical hypocalcaemia were examined using a multivariable linear regression model.RESULTSMean herd-level prevalence of subclinical hypocalcaemia was 52 (95% CI=49–55)%. Risk of subclinical hypocalcaemia at the cow-level was associated with an interaction between age of cow and interval from calving to sampling (p=0.03). Increasing age of cow was associated with increased risk of subclinical hypocalcaemia, and cows sampled on the day of calving had an increased risk compared with cows sampled 1 or 2 days after calving. Increased herd-level prevalence of subclinical hypocalcaemia was associated with feeding grass silage (p=0.06) or maize silage (p=0.004), and feeding increasing amounts of elemental Mg in the form of magnesium oxide (p=0.02). The mean farmer-reported herd-level prevalence of clinical hypocalcaemia was 2.9 (95% CI=2.1–3.8)%. Subclinical hypocalcaemia was not associated with any of the reproductive outcomes measured.CONCLUSIONS AND CLINICAL RELEVANCEThere was a high prevalence of subclinical hypocalcaemia in the pasture-fed, spring-calving dairy herds sampled and a large between-herd variation in prevalence. Subclinical hypocalcaemia increased with increasing age, and declined with time postpartum. Herd-level prevalence was associated with feeding grass silage and maize silage to pre-calving cows and with increasing amounts of supplemented magnesium oxide. Subclinical hypocalcaemia was not associated with reproductive outcomes.

Tipburn Severity and Calcium Distribution in Lisianthus (Eustoma Grandiflorum (Raf.) Shinn.) Cultivars under Different Relative Air Humidity Conditions

Tipburn is a major problem for the production of lisianthus (Eustoma grandiflorum (Raf.) Shinn.) cultivars. Relative air humidity is regarded as a key environmental factor affecting tipburn severity in commercial crops. However, there are limited studies comparing the occurrence of tipburn and calcium (Ca) distribution in lisianthus cultivars under different relative air humidity conditions. Accordingly, we investigated the effect of relative air humidity on tipburn severity, transpiration rate, and Ca content in seven lisianthus cultivars. Under a high humidity treatment (70%), only two cultivars (“Voyage pink” (VP) and “Azuma-no-kaori” (AK)) showed significantly higher tipburn severity than those under a low humidity treatment (50%), which suggests that high humidity conditions do not always increase tipburn severity in lisianthus. Transpiration rates of all cultivars, except for AK, were either significantly lower under the high humidity treatment than under the low humidity treatment, or did not vary significantly between the treatments. In contrast, total Ca concentrations in all cultivars, except for “Piccolosa snow” (PS), were significantly higher under the high humidity treatment than under the low humidity treatment. These results suggest that Ca acquisition and distribution in lisianthus cultivars are strongly influenced by Ca uptake from root pressure.

Peach rootstock tolerance to excess zinc in sandy acidic soil

In some areas dedicated to the cultivation of peach plants, soils are characterized by high levels of zinc (Zn) as a consequence of successive applications of Zn-containing fungicides and/or use of animal manure as fertilizer. In these cases, choosing an appropriate Zn-tolerant rootstock is essential to optimize orchard production. The current study evaluated the behavior of three peach rootstocks grown in a soil containing variable levels of Zn availability. Samples of a Typic Hapludalf soil were collected from a natural grassland in southern Brazil. The soil was dried and sieved. Subsamples of the soil were amended with increasing rates of Zn added as ZnSO4, incubated for 60 days, transferred to rhizoboxes, and planted with three types of peach rootstocks (Tsukuba-1, Rigitano and Flordaguard). The treatments were arranged in a completely randomized experimental design with three replications per rootstock X Zn dosage treatment. The rootstocks were grown for 65 days, at which time dry matter production of leaves, shoots and stem, as well as increase in height and stem diameter at ground level, were measured. Total concentrations of Zn, Fe, N, P, Ca and Mg were analyzed in each organ. The photosynthetic pigments and catalase (CAT) activity were analyzed in the leaves. Concentrations of Zn increased linearly in all the organs of all the rootstocks; however, the Tsukuba-1 rootstock presented greater sensitivity to high levels of Zn availability in soil, with a reduction in leaf dry matter production, chlorophyll a and carotenoid concentrations, and CAT activity. The Flordaguard rootstock showed an increase in height with increasing Zn concentration applied to the soil. Development of the Rigitano rootstock plants was unaffected by Zn amendment.

EXOGENOUS APPLIED PUTRESCINE ELEVATE DROUGHT TOLERANCE OF SUNFLOWER PLANTS BY MODIFYING OF SOME PHYSIO-BIOCHEMICAL PARAMETERS

Field Experiments were conducted at the Experimental Farm, Faculty of Agriculture, Ain Shams University, Shoubra El-Kheima, Egypt during 2014 and 2015 seasons to evaluate the effect of foliar spray of putrescine (Put) at 0.1 and 0.2 mM on growth and some physio-biochemical compounds of drought stressed sunflower. Putrescine application could be mitigate the negative effect of drought by increasing leaf relative water content (LRWC), proline, total soluble sugars, K and Ca concentrations of sunflower leaves. Correlation coefficient revealed that LRWC was inversely proportional to proline concentration on the one hand and directly proportional to K+ and Ca++ concentrations on the other hand. The modification of physio-biochemical parameters by Put treatments led to increase plant growth and seed-oil yield of sunflower under drought stress.