Dry Matter Grain Research Articles

A Semi-Empirical Model of Winter Wheat Grain Protein Content

Winter wheat grain protein content (GPC) is an important criterion for assessing grain quality. A timely and simple GPC model is urgently required for GPC prediction ahead of maturity. The GPC model included regressional models of dry matter and N accumulation and translocation for anthesis and post-anthesis stages, and incorporated both soil nitrogen (N) supply and meterological factors based on historical as well as current season data, final GPC were calculated as the ratio of N accumulation to dry matter in grain at maturity. This study conducted six field experiments during the 2003–2006 and 2008–2011 growing seasons to establish and validate the model. A three-way factorial arrangement of N fertilization, sowing date, and cultivar was conducted using a split-plot design. Critical growth parameters were determined by field measurements, and historical seasonal meteorological data covering the growing period were collected.

The Effect of Polyethylene Film and Polypropylene Non-Woven Fabric Cover on Cobs Parameters and Nutritional Value of Two Sweet Maize (Zea mays L. var. saccharata Bailey) Hybrids

In 2012–2014, at the Research and Didactic Station of the Department of Horticulture at Wroclaw University of Environmental and Life Sciences (51°19′06″ N, 17°03′49″ E), field studies were conducted to evaluate the responses of two sweet maize hybrids to sowing dates (early and optimum) and five methods of maize plant coverings—polyethylene film: perforated (PE), red (PER), green (PEG), polypropylene non-woven fabric (PP), and control (C), with non-irrigation systems. Total yield and morphological characteristics of cobs were compared. In 2012 soluble sugars and carotenoids content were measured. The use of maize cover at the beginning of growth (PE and PER) significantly influenced the number of rows, while PE and PEG increased the number of grains per cob. Covering maize sown at a later date, with polyethylene film and non-woven fabric, ensured better production effects than using such covers after earlier sowing. Signet F1 hybrid was charact0erized by significantly higher sugar content and Rustler F1 by higher lutein and zeaxanthin levels. The application of the optimum sowing date resulted in a significantly higher yield of cobs, by 11.3%, than after early sowing. The yield increase as a result of the applied covers was higher after sowing at a later date. The content of dry matter in grains was positively correlated with the content of sucrose, glucose, and fructose. The change in carotenoids content also depended on the accumulation of dry matter in the kernels. The study confirmed the correlation of sweet maize accumulated growing degree days (AGDD), and revealed dependence of grain quality on dry matter content in the grain.

Correlation and path analysis of interaction between green pea yield and its components with crop management

Determinations of interaction between yield its components and foliar mixed application of Lactofol® with insecticides and herbicides. The path-coefficient analysis is very important statistical technique that can be used to quantify the interrelationship of different yield components. It was applied to study the interaction of applied agronomic activities on productivity of mid-early Bulgarian garden peas Pisum sativum cv. Promethei seeking to minimize pesticide use and to maintain sustainable quality and quantity of yield, and to prevent underground water pollution caused by using Dual 930EK/930g/l-s (metachloras) minimized herbicide doses from vegetative herbicide Basagran-200g/l (Bentazon) and Fusillade-200g/l (Fluasifop-P-Butil). Data was collected from long years trials on plants treated with different combinations of foliar suspension fertilizer Lactofol® with insecticides and herbicides. Results showed that grain yield (0.997), dry matter of the grain (0.996), Chlorophyll "a" (0.993), Zn (0.992), N (0.991), grain/whole pod ratio (0.984), total nitrogen (0.982), K (0.975), weight of 50 grains (0.973) fresh weight of 50 beans (0.962), fertile pollen (0.961), plant density/ m2 (0,873), the length of beans (0.871), sterile pollen (0.837) had positive impact on yield. Dry matter, grain yield, dry matter of grains, chla, N, weight of 50 pods, fertile pollen, and plant density/ m2 showed positive direct and indirect effects on yield. Other factors such as sugars (0.797), chlorophyll “b” (0.739), and starch (0.620) had an indirect effect on total yield. Grain yield should be given prior attention in field pea improvement programmers due to its major influence on yield. This research gave valuable information about which steps of agro techniques needs more attention to enhance best quality and quantity of sustainable yield.

Selection of bean lineages regarding the use and response to phosphorus available in nutrient solution

The objectives of this work were to evaluate the genetic variability of bean lineages in relation to phosphorus accumulation in plant tissues and yield, in addition to identifying efficient bean lineages in the use of phosphorus and responsive to the application of phosphorus in the crop environment. Work was carried out at Plant Science Department of the Federal University of Santa Maria. Concentrations of phosphorus in the nutrient solution between 1.33 and 1.84 mmol L-1 provide higher dry mass of pods, grains, number of grains and grain yield for the cultivars Pérola and IPR88 Uirapurú in the growing seasons autumn-winter and spring-summer. Concentrations between 1.37 and 1.96 mmol L-1 have the highest values of phosphorus in plant tissues, grain yield and phytic acid. Characteristics dry matter of leaves, stem and pods in pod filling, dry matter of grains on maturation, number of grains, number of pods and phosphorus concentration in plant tissues at the pod filling stage are promising because it allows for indirect selection. The nutritional value of leaves in young plants, for phosphorus, equivalent to that of grains. There is genetic variability among the bean lineages studied, for the production of dry mass, yield and accumulation of phosphorus in the tissues. Lineage L 2527 showed to be efficient and responsive to the use of phosphorus for the shoot of the plant. Lineage L 2225 showed to be efficient in the use of phosphorus in shoot, grains and grain production, besides maintaining this characteristic in the two growing seasons.

STUDY OF PHYSIOLOGICAL PROCESSES IN CORN GRAIN DURING STORAGE UNDER HERMETIC CONDITIONS

In recent decades, in addition to the traditional grain storage in dry conditions, the technology of grain storage without access of air - in hermetic conditions has gained a widespread in polymeric grain bags (silobags). The aim of the research was to study the regularities of the physiological processes of respiration in maize grain when stored in hermetic conditions, which would determine the terms of safe storage of different humidity grain in polymeric grain bags and reduce the costs of its processing and storage. The object of research is the technology and processes of freshly harvested corn grainstorage. As the main subject of the study, a dent-type hybrid of corn DKS 3705 was used, which, according to its botanical and agronomic properties, was better for use on food and non-food needs and for export. On the basis of the conducted researches it was established that with an increase in initial moisture of grain from 14% to21% and subsequent storage in hermetic conditions at constant temperatures the natural losses of dry matter of grain increase in comparison with losses of dry matter of grain with standardhumidity (14%), in particular, at a temperature of 18 ºС by 112%, at a temperature of 11 ºС by 296% and at a temperature of 4 ºС by 123%. Thus, it is shown that the decrease of the temperature regimes of grain storage of maize with different initial humidity under hermetic conditions contributes to the reduction of the intensity of thenatural physiological processes in it and, consequently, the natural losses of its dry matter. It has been established that during storage of corn grain for three months and reduction of temperature storage conditions from 18 ºС to 11 ºС in samples of grain with an initial humidity of 14% decrease: the absorption rate of oxygen by 34%, carbondioxide emissions, loss of dry matter and the production of thermal energy by 66%. For a grain with an initial humidity of 21%, the reduction in intensity under the same conditions is: for absorption of oxygen 22%, the production of carbon dioxide 28%, losses of dry matter 37% and the production of thermal energy 23%. Reducing the storage temperatures of corn from 11 ° C to 4 ° C in samples of grain with an initial humidity of 14% reduces the intensity: absorption of oxygen by 79%, carbon dioxide generation by 60%, dry matter loss by 60%, and the generation ofthermal energy by 60%. For grain with an initial moisture content of 21% under the same conditions, the intensity decreases: oxygen absorption by 28%, carbon dioxide generation by 77%, dry matter loss by 77%, and heat generation by 77%. Established regularities of the physiological processes in corn grain with different initial humidity when stored in hermetic conditions at different temperatures, it is possible to predict the characteristics of gas exchange processes in the grain mass, natural losses of dry matter and the generation of heat during storage of grain.

Fate of phosphorus in soil during a long‐term fertilization experiment in Finland

AbstractAccumulation and depletion of soil phosphorus (P) was studied in a long‐term (37 y) field experiment in Southern Finland. The loam soil had a high pH (7.5–7.7) due to an earlier liming. Spring barley, spring wheat, oat, and ryegrass, grown in rotation, were annually fertilized with 0, 32, or 67 kg P ha−1 y−1 (P0, P1, and P2K) and sufficient N. The average dry matter grain yield 2,600 kg ha−1 of the P0 plots increased by about 500 kg ha−1 at P1 treatment and another 600 kg ha−1 by P2K. Soil samples were collected in 1978 (beginning), 1995, 2005, and 2015. According to the Chang and Jackson sequential extraction, the P2K and P1 treatments increased the inorganic soil P by 732 and 32 kg P ha −1 in 37 years, respectively, while the P0 plots were depleted by –459 kg P ha −1. The P2K treatment increased all four P fractions, extracted with NH4Cl (easily soluble), NH4F (Al‐P), NaOH (Fe‐P), and H2SO4 (Ca‐P). Continuous depletion (P0) decreased the NH4Cl‐P and NH4F‐P pools, NaOH‐P and H2SO4‐P pools remaining stable. None of the P pools changed significantly at P1. The remarkable gap between the measured change and the balance for the P2K and P1 treatments cannot be explained solely by lateral soil movement, meaning that a significant proportion of the applied P was lost either in surface runoff or transported below the investigated depth of 40 cm. Despite large P applications, the degree of P saturation reached only 20% in the P2K topsoil, assuming a 50% reactivity of Fe and Al oxides. As derived from sorption isotherms, a high EPC0 (i.e., equilibrium P concentration at zero net P sorption or desorption) of 1.30 mg L−1 had been built up in the P2K treatment, while in the P1 treatment EPC0 (0.33 mg L−1) had remained unchanged and P depletion (P0) had caused a decrease to 0.12 mg L−1. These results demonstrate that P sorption and desorption properties respond strongly to both P fertilization and null fertilization treatments and that in a long‐term field experiment only a low proportion of the residual fertilizer P can be recovered from soil.

Effects of long term tillage practices on photosynthetic characteristics and grain yield of wheat

A field experiment was conducted to study the effects of long-term tillage practices on photosynthetic characteristics of flag leaf, dry matter accumulation and its allocation, and grain yield, with a wheat cultivar, Jimai 22, in both 2013-2014 and 2014-2015 growing seasons. Four tillage practices, namely rotary tillage (R), plowing (P), strip rotary tillage and subsoiling at an interval of 2 years (SRS), and rotary tillage and subsoiling at an interval of 2 years (RS), were conducted in field for 9 years since 2007. The results showed that the net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (gs) of flag leaves under SRS treatment were significantly higher than those of other treatments from 21 to 35 days after anthesis. The SRS treatment had higher average photosynthetically active radiation (PAR) capture ratio than RS and P treatments, while the lowest values were found under R treatment during grain-filling stage. Compared with the other treatments, the plants of SRS treatment had the highest accumulation of dry matter at maturity, the highest allocation of dry matter in grains, and the highest contribution ratio of dry matter from vegetative organs to grains after anthesis. The grain yield and water use efficiency of SRS treatment were significantly higher than those of the other treatments, and the water consumption amount of SRS treatment was significantly higher than that of both R and P treatments, with no significant difference from the RS treatment. Under the current experimental condition, it was suggested that SRS would be the most effective tillage practice to increase both grain yield and water use efficiency for winter wheat production.

Responses of plasma glucose and nonesterified fatty acids to intravenous insulin tolerance tests in dairy cows during a 670-day lactation

The metabolic response of dairy cows undergoing an extended lactation to an insulin tolerance test (ITT) was investigated. Twelve multiparous Holstein-Friesian cows that calved in late winter in a pasture-based system were managed for a 670-d lactation by delaying rebreeding. Four 5-wk experimental periods commenced at approximately 73, 217, 422, and 520 d in milk (DIM). Cows were offered a diet of perennial ryegrass (73 and 422 DIM) or pasture hay and silage (217 and 520 DIM) supplemented with 1 kg dry matter (DM) of grain (control; CON) or 6 kg DM of grain (GRN). Daily energy intake was approximately 160 and 215 MJ of metabolizable energy/cow for CON and GRN, respectively. At all other times, cows were managed as a single herd and grazed pasture supplemented with grain to an estimated daily intake of 180 MJ of metabolizable energy/cow. Cows were fitted with a jugular catheter during the final week of each experimental period. An ITT using 0.12 IU of insulin/kg of body weight (BW) was conducted on each cow at approximately 100, 250, 460, and 560 DIM. Cows in the GRN treatment had greater milk yield, milk solids yield, and BW than cows in the CON treatment. Within treatment, individual cow responses to the ITT were highly variable. Plasma glucose and nonesterified fatty acid (NEFA) concentrations declined at all stages of lactation. The clearance rate of plasma glucose was slower before 300 DIM than after 300 DIM, which indicates greater inhibition of hepatic glucose synthesis and uptake of glucose by insulin-dependent tissues later in the lactation. The clearance rate, area under the curve, and recovery of plasma NEFA were greatest at 100 DIM, indicating greater responsiveness to the antilipolytic effect of insulin in early lactation, but also greater lipolytic responsiveness. The variation in response to the ITT was mostly a result of DIM rather than diet. However, the plasma NEFA response showed interactions between diet and DIM, indicating that energy intake may affect tissue responses to insulin. The responsiveness of peripheral tissues to insulin, primarily adipose tissue, changed throughout a 670-d lactation and contributed to a greater proportion of nutrients being partitioned to body reserves at the expense of milk yield as lactation progressed. Both stage of lactation and dietary intake have a role in the determination of whole-body and peripheral tissue responses to insulin; however, the exact mechanisms in control of this are unclear.

Volume, water content, epidermal cell area, and XTH5 expression in growing grains of wheat across ploidy levels

The cellular expansion of maternal tissues has been suggested as strongly associated to grain volume determination in wheat and is therefore a key process to understand potential grain weight determination. The dynamics of grain growth in seed size-contrasting diploid, tetraploid and hexaploid genotypes of wheat were evaluated to explore the relationships between the final grain weight and: a) grain volume, b) water content, c) epidermal pericarp cell size and d) the rate of cell area (area per cell) increase. The assessment of cell expansion was reinforced by the study of the expression of the XTH5 gene in pericarp tissues, as this gene codifies a cell wall-remodeling agent. Differences in grain weight across ploidies and experiments (greenhouse and field evaluations) were attributable to the grain-filling rate (ANOVA p<0.05; R2=0.91 and R2=0.98, respectively), with no significant effect of grain filling duration. Strong correlations were found between final dry matter of grain and both volume (R2=0.98; p<0.01) and stabilized water content (R2=0.99; p<0.01) of grains across genotypes. The epidermal cell area was positively correlated with the final grain volume (R2=0.71; p<0.05) and with the grain-stabilized water content (R2= 0.72; p<0.05). The increases in grain volume and grain elongation were accompanied by epidermal cell enlargement during grain growth across the genotypes. Also, at each ploidy, the rate of cell area increase was greater in the heavier grain genotype, which showed faster dry matter accumulation (p<0.05). The XTH5 gene was expressed during the high-rate water accumulation phase with a significant decrease (p<0.05) at 320 - 350°Cd after anthesis, shortly before the grain water content leveled off. This work provides new evidence for the relevance of pericarp cell size in the regulation of grain volume and the potential grain weight of wheat.

YIELDS AND QUALITY OF PHASEOLUS BEAN CULTIVARS UNDER FARMERS’ CONDITIONS IN EASTERN AND SOUTHERN AFRICA

SUMMARYCommon bean (Phaseolus vulgaris L.) is a dominant grain legume in eastern and southern Africa, where it constitutes a major source of protein and microminerals in peoples’ diet. The current studies aimed at determining how initially promising genotypes of bean responded in terms of yield and grain element composition under farmers’ cropping conditions. It was found that variations between genotypes in the proportions of elements in the grain dry matter across a wide range of conditions could be linear with an additional 20% iron (Fe) or zinc (Zn) for some genotypes. However, this linearity was only identifiable under relatively favourable conditions. Further, a favourable season could enhance the proportion of Fe in the grains of the same genotypes by up to 20%, whereas Zn did not respond. Fe and Zn correlated only to some degree with P (r2 &gt; 0.35). It is concluded that the supply of elements in the diet may best be secured by selecting for high-yielding cultivars as the amounts of phosphorus (P), Fe and Zn in the grains correlated strongly (r2 &gt; 0.93) to the dry matter grain yield.

Potential Nitrogen Source from Field Bean for Rainfed Mediterranean Cropping Systems

Field bean (Vicia faba L. var. minor Beck) is cultivated in the Mediterranean basin in rotation with winter cereals for dry grain production for animal feed, green forage, hay, silage, or green manure. This study aimed to (i) quantify the field bean fixed N during 2 yr at two Italian locations under rainfed conditions, (ii) quantify the proportion of N and fixed N allocated by field bean to grain, straw, and recoverable roots, and (iii) estimate the potential contribution of field bean to the cropping system N balance. The mean N percentage derived from N2 fixation of field bean grain and straw was 76%, corresponding to 114 kg ha–1 of fixed N in the aboveground biomass. On average, field bean fixed 42, 12, and 9 kg N Mg–1 dry matter in grains, straw, and roots, respectively. Recoverable roots contributed &lt;5% of the total plant fixed N, but estimates did not take into account rhizodeposition and fine root turnover. The net N balance was positive for green manure (117 kg N ha–1) and grain field bean without straw removal (31 kg N ha–1) but negative (–31 kg N ha–1) when straw was removed. The N gain vs. a non‐fixing species was 79, 62, and 117 kg ha–1 yr–1 for field bean used as grain without straw removal, grain with straw removal, and green manure, respectively. Our study indicated that field bean can play a significant role as a N source in rainfed cereal‐based cropping systems.

Assessing Light Competition for Cereal Production in Temperate Agroforestry Systems using Experimentation and Crop Modelling

AbstractIn every agroforestry system, the tree canopy reduces the incident radiation for the crop. However, cereal varieties were selected, and most crop growth models were designed for unshaded conditions, so both may be unsuited to agroforestry conditions and performance. In southern France, durum wheat productivity was monitored over 2 years in an agroforestry system including walnut trees and under artificial shade conditions. Yield components were measured in both full and reduced light conditions. The cereal yield was always decreased by shade; by almost 50% for the heaviest shade conditions (31% of light reduction). The main effect of the shade was the reduction in the number of grains per spike (35% at the most) and in the weight of grains (16% at the most). The mean grain weight was moderately affected, while the protein content was increased in shaded conditions (by up to 38% for artificial shade). Consequently, the protein yield per hectare was less reduced by the shade than the dry matter grain yield. A crop model (STICS) was also used to simulate the crop productivity in full light and shaded conditions, but the crop LAI and the yield components were not correctly simulated in the shade. The simulations emphasized the sensitivity of the wheat grain filling to shade during the critical period, 30 days before flowering, for yield elaboration. Further experimental and modelling studies should take into account the heterogeneity of shade intensity due to the shape of the tree crown, the width of the crop alley and the orientation of the tree rows and the modification of carbon allocation inside the plant.

The genetics of environmental variation of dry matter grain yield in maize

Dry matter grain yield per plot from three genetically homogeneous single-cross maize hybrids were analysed to investigate whether environmental variance depends on genotype. Three genotypes were tested at 20 locations in 3 years. The data were analysed using a non-parametric approach and fully parametric Bayesian models. Both analyses reveal effects of genotype on environmental variation. The Bayesian analyses indicate that genotype by location-year interactions are the most important effects acting at the level of the mean. The best-fitting Bayesian model is one postulating genotype by location-year interactions acting on the mean and main effects of genotype and of location-year on the variance. Despite the detection of genotypic effects acting on the variance, location-year effects constitute the biggest relative source of variance heterogeneity.

Application of DSSAT models for an agronomic adaptation strategy under climate change in Southern of Italy: optimum sowing and transplanting time for winter durum wheat and tomato

Many climate change studies have been carried out in different parts of the world to assess climate change vulnerability and adaptation capacity of agricultural crops for determined environments characterized from climatic, pedological and agronomical point of view. The objective of this study was to analyse the productive response of winter durum wheat and tomato to climate change and sowing/transplanting time in one of most productive areas of Italy (i.e. Capitanata, Puglia), using CERES-Wheat and CROPGRO cropping system models. Three climatic datasets were used: i) a single dataset (50 km x 50 km) provided by the JRC European centre for the period 1975-2005; two datasets from HadCM3 for the IPCC A2 GHG scenario for time slices with +2°C (centred over 2030-2060) and +5°C (centred over 2070-2099), respectively. All three datasets were used to generate synthetic climate series using a weather simulator (model LARS-WG). No negative yield effects of climate change were observed for winter durum wheat with delayed sowing (from 330 to 345 DOY) increasing the average dry matter grain yield under forecasted scenarios. Instead, the warmer temperatures were primarily shown to accelerate the phenology, resulting in decreased yield for tomato under the + 5°C future climate scenario. In general, under global temperature increase by 5°C, early transplanting times could minimize the negative impact of climate change on crop productivity but the intensity of this effect was not sufficient to restore the current production levels of tomato cultivated in southern Italy.

Effect of climate on the in vitro first-order ruminal disappearance kinetics of dry matter in grain of semi-arid native barley cultivars

An experiment was conducted to determine the in vitro first-order disappearance kinetics of dry matter in grain of six semi-arid native barley cultivars (Hordeum vulgare) adapted to grow at different climates known as cold (Bahman, Makoeei), moderate (Reyhan 03, Kavir) and hot (Dasht and Sahra). Samples (n=10) were assessed for bulk density (BD) and chemical composition. In addition, in vitro first-order kinetics of dry matter disappearance, medium pH and NH3-N concentration were determined using fermentation culture. Data were fitted to an exponential equation model: D(t) = D(i).exp (-k. time) + I; where D(t) was potentially a digestible residues at time t, D(i) was a potentially digestible fraction, k is a fractional rate constant of digestion (h -1 ) and I was an indigestible fraction. Results showed there was significant effect of adaption of varieties to climate on bulk density and crude protein, ash, NDF (neutral detergent fiber), ADF (acid detergent fiber), soluble sugars and starch concentrations in grain of the barley cultivars evaluated (P < 0.01). Barley grain cultivars from cold climate had the highest concentration of NDF and starch, whilst hot climate cultivars showed the highest amount of BD and CP (crude fiber). The amount of ash, ADF and soluble sugar in moderate climate barley grain cultivars was higher than those of the other climates. In vitro first order disappearance of dry matter was significantly (P < 0.01) influenced by the climate. Digestible fraction, fractional rate constant of digestion and indigestible fraction of grain from cold (0.78, 0.15, 0.146), moderate (0.77, 0.16, 0.157) and hot (0.75, 0.19, 0.206) were not similar in pattern. Dasht and Bahman grains had the highest and the lowest fractional rate constant (0.23 and 0.12 h -1 , respectively). Barley grain cultivars from cold and hot climates had the largest digestible fraction and fractional rate constant of digestion, respectively. The relationship between NDF content (g/kg DM) and fractional rate constant of digestion (X) was negative: NDF = 520.9X + 334.2, R 2 = 0.723. It was concluded that ruminal dry matter disappearance kinetic differences

Grain Nitrogen Concentration in Wheat Grown under Intensive Organic Manure Application on Andosols in Central Japan

Grain nitrogen concentration (N%) is a major determinant of grain quality in winter wheat. The objective of this study was to compare the responses of wheat grain N% to organic manure with those to inorganic fertilizer in long-term experiments. We analyzed the grain N accumulation using soft wheat (Kinunonami) and hard wheat (Yumeshihou) cultivars grown with a high rate of organic manure application (OM; 80 t ha-1 yr-1 for >10 years and 30 t ha-1 yr-1 during the three years of the present study) and with standard (SF; 204–252 kg N ha-1 yr-1) or low (LF; 102–126 kg N ha-1 yr-1) rates of inorganic fertilizer for three years in Japan. The results agreed with previous research on the underlying mechanisms for grain N% under conventional fertilizer management: both sink and source regulation affected N accumulation in grains, and the accumulation of N in grains and of dry matter in grains are independent. Grain N% was significantly higher in the OM treatment than in the SF and LF treatments as a result of lower dry matter accumulation in the grains. High straw N% led to higher N accumulation in grains in the OM treatment during the late grain-filling period in Yumeshihou. Our results suggest that too much organic manure was applied, i.e., more than was required to optimize grain N%, when manure application was designed to produce a grain yield equivalent to that in conventional fertilizer management. We discuss ways to stabilize grain N% under intensive organic manure application.

The effect of leaf area reduction on corn plants during the reproduction phase

Reduction in leaf area in corn plants during reproduction changes physiological metabolism and consequently the accumulation of dry matter in grains. The aim of this work was to study changes in agronomic characteristics caused by defoliation in corn during the reproduction phase. The experiment was carried out in Uberlândia, Minas Gerais state, in the agricultural year 2007/2008. The experiment was arranged in a randomized block design, consisting of seven treatments: control without defoliation, removal of two apical leaves, removal of four apical leaves, removal of all leaves above spike, removal of four intermediate leaves, removal of all leaves below spike, and removal of all plant leaves, with five repetitions. The genotype used for the evaluations was hybrid NB 7376. Defoliation was carried out when plants were at the growth stage R2. The variables assessed were: yield, density of spikes and corncobs, root resistance and stem integrity. When all leaves above the spike were removed, grain yield was reduced by 20%. Corncob density, stem integrity and root resistance to uprooting were also affected. Spike density was only affected when all plant leaves were removed. The leaf area remaining physiologically active above the spike was found to be most efficient in terms of grain yield.

METABOLISMO DE CARBOIDRATOS NÃO-ESTRUTURAIS EM RUMINANTES

Os carboidratos constituem de 50 a 80% da matéria seca dos volumosos e grãos epodem ser divididos em estruturais (celulose, hemicelulose) e não-estruturais (amido,pectina e açúcares). Os carboidratos não-estruturais são digeridos principalmente norúmen e seu processo é uma seqüência dinâmica para o fornecimento de nutrientes aointestino. A qualidade e a quantidade de produtos resultantes da fermentação ruminal sãodependentes do tipo e atividade dos microrganismos do rúmen influenciado pelo tipo dealimentação e processamento em que são submetidos os grãos de cereais que compõe adieta. Os CNE escapam da fermentação ruminal para serem digeridos em glicose nointestino delgado pelas enzimas de origem pancreáticas (α-amilase) e mucosa intestinal(maltase e isomaltase). O amido é o maior componente fornecedor de energia dos grãosde cereais, os quais são importantes componentes das dietas utilizadas para asproduções intensivas de leite e carne.

Short communication: Feeding method affects the feeding behavior of growing dairy heifers

There is limited information available on what is the most appropriate feeding method for growing dairy heifers. The objective of this study was to determine the effect of feeding method on the feeding behavior and diet selection of growing dairy heifers. Six prepubescent Holstein heifers (158.2±4.0 d old, weighing 168.2±15.7kg), fed once per day for 1.0kg/d of growth, were subjected to each of 3 treatments in 3 successive 7-d treatment periods using a replicated 3×3 Latin square design. Treatments consisted of feeding 2.02kg/d dry matter of grain concentrate and ad libitum chopped grass hay as: 1) choice (grain concentrate and hay in separate feed bins), 2) top-dressed ration (grain concentrate placed on top of the hay in one feed bin), and 3) total mixed ration (TMR, grain concentrate mixed with hay in one feed bin). Dry matter intake (DMI) and feeding behavior were monitored for 7 d for each animal on each treatment, and feed sorting was monitored for the last 3 d of each treatment period. The provision of grain concentrate and hay in either a choice or top-dressed situation resulted in young dairy heifers rapidly consuming the grain concentrate portion of their ration in very few, large meals before consuming the hay portion of their ration. The provision of the 2 ration ingredients as a TMR increased the distribution of DMI over the day and reduced the amount of sorting (against long forage particles, and for short grain concentrate particles) by heifers. These results suggest that the provision of a TMR to growing dairy heifers, as opposed to feeding concentrate and hay as either a choice or top-dressed, promotes a more balanced intake of nutrients across the day.

The effects of grain treatment, grain feed level and grass silage feed value on the performance of and meat quality from, finishing beef cattle

A completely randomised design study involving 132 continental crossbred beef steers was undertaken to evaluate the effects of method of grain treatment and feed level, and grass silage feed value on animal performance, carcass characteristics and meat quality of beef cattle. Winter wheat was harvested and the grain was stored either ensiled crimped and treated with 4.5 l/t of a proprietary acid-based additive (crimped), ensiled whole and treated with 20 kg feed-grade urea per t (urea) or stored conventionally in an open bin treated with 3 l propionic acid per t. Two grass silages, of contrasting feed value (L and H) were ensiled. For the conventional, crimped and urea treatments, grain dry matter (DM) concentrations were 802, 658 and 640 g/kg, respectively. For the L- and H-feed value silages, DM concentrations were 192 and 240 g/kg and D values were 671 and 730 g/kg DM, respectively. The silages were offered as the sole forage supplemented with either conventional, crimped or urea-treated grain-based concentrate at either 3.5 or 6.0 kg DM per steer per day. The grain supplement consisted of 850 and 150 g/kg DM of grain and citrus pulp, respectively. For the conventional, urea and crimped treatments, DM intakes were 8.85, 9.43 and 9.04 kg/day (standard error (s.e.) = 0.129); estimated carcass gains were 0.60, 0.55 and 0.61 kg/day (s.e. = 0.020), respectively. For the low- and high- feed value grass silages, estimated carcass gains were 0.56 and 0.61 kg/day (s.e. = 0.014), respectively. For the low and high grain feed levels, estimated carcass gains were 0.56 and 0.61 kg/day, respectively. Grain treatment, grain feed level or silage feed value did not alter (P > 0.05) meat quality, lean colour or fat colour. There were significant silage feed value × grain feed level interactions (P < 0.05) for final live weight (LW) and daily live-weight gain (DLWG). Increasing grain feed level increased final LW and DLWG when offered with the low-feed value silage, however, grain feed level had no effect on final LW or DLWG when offered with the high-feed value silage. It is concluded that urea treatment of grain increased silage intake and feed conversion ratio (kg DM intake per kg carcass) and tended to decrease carcass gain. Crimping provides a biologically equally effective method to store grain as conventional methods. Improving grass silage feed value had a greater impact on animal performance than increasing grain feed level by 2.4 kg DM per day.