Suchergebnisse

Beneficial effects of silicon (Si) in the plants growth under conditions of drought stress have been associated with to uptake and accumulation ability of element by different species. However, the effects of Si on soybean under water stress are still incipient and inconclusive. This study investigated the effect of Si application as a way to confer greater soybean tolerance to drought stress. The experiment was carried out in 20-L pots under greenhouse conditions. Treatments were arranged in a randomized block design in a 2 × 4 factorial: two water regimes (no stress or water stress) and four Si rates (0, 50, 100 and 200 mg kg–1). Soybean plants were grown until beginning flowering (R1) growth stage with soil moisture content near at the field capacity, and then it started the differentiation of treatments under drought by the suspension of water supply. Changes in relative water content (RWC) in leaf, electrolyte leakage from cells, peroxidase activity, plant nutrition and growth were measured after 7 days of drought stress and 3 days recovery. The RWC in soybean leaves decreased with Si rates in the soil. Silicon supply in soil with average content of this element, reduced dry matter production of soybean under well-irrigated conditions and caused no effect on dry matter under drought stress. The nitrogen uptake by soybean plants is reduced with the Si application under drought stress. The results indicated that the Si application stimulated the defense mechanisms of soybean plants, but was not sufficient to mitigate the negative effects of drought stress on the RWC and dry matter production.

The aim of this study was to characterize the dehydration curve and, gas exchange of bermudagrass (Cynodon dactylon L.) as well as the nutritional value of hay under different conditions of storage. The dehydration curve was evaluated at 7 time point (0, 13, 18, 22, 37, 42, and 44 hours after cutting) until baling, using five replicates. The time 0 (zero) corresponded to the time before cutting, performed at 19:00 hours. The design was completely randomized with measures repeated over time. Gas exchanges was evaluated 0, 14, and 18 hours after cutting, using 10 replicates. The nutritional value of cowpea hay was evaluated in two open and closed environments (SO and CS), three storage times (30, 60, and 90 days), and five replications. Dehydration of hay was carried out for 44 hours, rapid rates of dehydration was observed in the leaves. Gas exchange was more intense before cutting and up to 14 hours after cutting. Crude protein (CP) content was higher at the time of cutting and decrease after storage. The in vitro dry matter digestibility (IVDMD) and neutral detergent fiber (NDF) content showed no variation between the sampling time and storage systems evaluated. Bermuda grass hay presents rapid dehydration and undergoes changes in the bromatological composition with storage time. Internal temperature of the hay bale did not exceed the ambient temperature.

Understanding the influence of row spacing and plant density on grain yield and yield components of crambe is critical in order to obtain higher grain yields. Therefore, the objective of this study was to evaluate the effects of row spacing and plant density on grain yield and its components in crambe in two distinct regions of Brazil (Marechal Candido Rondon-PR, MCR-PR, and Botucatu-SP, BTU-SP). Narrow and wide row spacing (0.20 and 0.40 m) combined with four plant densities (15, 25, 35, and 45 plants m-1) were evaluated in a randomized block layout with four replications in a 2 × 4 factorial design. The experiment at BTU-SP was run under rainfed conditions with supplementary irrigation, whereas the experiment at MCR-PR was run under rainfed conditions without supplementary irrigation. Both experiments were run in soils classified as Oxisols. There was no interaction between row spacing and plant density. Highest grain yield with supplementary irrigation was observed at 0.20 m row spacing. Without irrigation, row spacing did not affect grain yield owing to the plasticity of crop. The highest grain yield was observed with approximately 30 plants m-1 at both experimental locations. A strong negative correlation was observed between final plant population and number of grains per plant. There was high plant mortality, particularly at high plant densities cultivated under irrigation. Higher mortality occurred because of high intraspecific competition and a larger disease incidence due to the higher humidity in the irrigated experiment. A mechanism of self-adjustment by plant density was observed in crambe, with its intensity dependent on plant density and environmental conditions, such as water and nutrient availability and light incidence.

<p>The objective of this study was to evaluate the growth performance of two crossbreed genetic groups, ½ Nelore ½ Angus and ¼ Nelore ¼ Angus ½ Guzera, which originate from the rotational crosses of Nellore cows with Angus bulls and ½ Nellore ½ Angus cows with Guzera bulls, respectively. The growth performance was evaluated at the end of the yearling and feedlot stages, and carcass characteristics were evaluated after the slaughter. A completely randomized trial design was used, with 12 cows in each group. The yearling stage lasted 270 days, and the cattle were fed with pasture of <em>Brachiaria brizantha </em>'Marandu' with 2.0 UA ha-1 and a forage allowance of 2.5 kg of dry matter (DM) per 100 kg of live weight (LW), during this stage the animals, with an average age of 365 ± 10 days, received protein and energy supplementation <em>ad libitum</em>. After the yearling stage, the cows were confined until they reached the age of 22–24 months and received 6.0 kg DM of sugar cane + urea and 4.0 kg DM of concentrate, with 150 g kg-1 of crude protein (CP), daily during 90 days. The daily average weight gain (DAWG) during the yearling stage was higher for the ½ Nelore ½ Angus group. The ¼ Nelore ¼ Angus ½ Guzera group reached higher slaughter weight because they had higher DAWG during the feedlot stage (1.022 vs. 728 g dia-1). No significant difference (P &gt; 0.05) was found between the groups when the hot carcass weights were compared. The ½ Nelore ½ Angus group reached a higher carcass weight percentage (53 vs. 50 %) and subcutaneous fat thickness (4.3 vs. 4.0 mm).</p>

The objective of this study was to evaluate the influence of five levels of N and two regrowth intervals on the structural, productive, and nutritional characteristics of Tifton 85 grass (Cynodon spp). The experiment was conducted in a hay production field at the State University of West Paraná, planted in 2004 with Cynodon spp. cv. Tifton 85. The experiment was established in a randomized block design with factorial treatments of five N fertilization amounts (0, 25, 50, 75 and 100 kg ha-1 cut-1) applied as urea after each cut, and two regrowth intervals (28 and 35 d), with four replicates. N application promoted changes in plant structure, such as increased canopy height, stem length, leaf elongation rate, and dry mass (DM) production. The greatest N use efficiency, considering the four harvests, occurred in the plot with 25 kg N ha-1 cut-1 at the 35-d interval, with a production of 13.79 kg DM kg-1 of N applied. A nutritional analysis indicated that 100 kg ha-1 of N cut-1 promoted higher crude protein (CP) at 28 d, with the highest concentration observed in the fourth cut (208.2 g kg-1 DM) and the lowest in the second cut (140.12 g kg-1 DM). The content average in the four cuts for CP and LIG at 28 days of regrowth was 175.85 and 104.33 kg-1 g MS and at 35 days of regrowth interval was of 164.45 and 118.65 g kg-1 DM, respectively. No differences were found between regrowth intervals in the contents of mineral matter and acid detergent fiber (ADF). Environmental factors including the wide variation in precipitation (greater than 200 mm between the peak in December 2010 and the lowest in March 2011) greatly influenced Tifton 85 grass production, affecting DM and the nutritional value of the forage in each cut.

This study aimed to evaluate the digestive power of waste of cassava starch extraction dried (WCSEd) and corn, in addition to determining the appropriate level of WCSEd to replace corn in the diet of cattle. Studies to evaluate the in vitro digestibility and in situ degradability were performed. The study used four cattle with rumen cannula, individually fed with diets containing increasing levels (0, 33, 66 and 100%) of WCSEd to replace corn, to evaluate the dry matter and nutrient intake and digestibility, pH and ammonia concentration of rumen fluid. The WCSEd showed differences in the in vitro digestibility of DM, OM and NDF (P &lt; 0.05) compared to corn, but did not change the NDT and in situ degradability. As for in vivo reviews, the DM and nutrient intake was influenced by treatments in decreasing order, resulting in changes in the digestibility of DM, OM and NDT of diet, and a decreased concentration of N-NH3, but the pH was not affected. The residue from the extraction of cassava starch showed lower in vitro digestibility; however, ruminal degradability did not differ from corn. Their use in ruminant feed reduces the intake and degradation of feed, but improves the use of N-NH3 in the rumen.

The dairy industry is characterised by a wide diversity of production systems. In this diverse environment, some of the difficulties can be minimised through the grouping of production units through the study of typology. The objective was to characterise the systems of milk production from West Parana State by considering production rates, area, power, facilities, and marketing of milk. To this end, 735 semi-structured interviews with dairy farmers were performed by using a questionnaire for management practices and feed that is used on the farms. To obtain the explanatory variables used for principal component analysis (PCA) and hierarchical cluster analysis (HCA), a homogeneous division of 735 farmers in five groups was used. Ten per cent of producers were randomly selected for the performance of field visits to the properties, where a new questionnaire was applied with specific points regarding feeding management on the property, and feed was collected to determine its composition. The collected data were tabulated and feed was ranked based on the classification proposed by the NRC (2001). Analyses of feed were carried out in the Laboratory of Animal Nutrition of Unioeste. The West Parana State has five groups of dairy production systems. There is great variability in the fresh forages that are used, but maize silage is the main forage utilised for fermented feed, and concentrate supplementation is adopted by more than 60% of farms during both seasons. Changes in the levels of feed components are high among systems.

This research aimed to measure the microbiological, chemical composition profile and fermentative characteristics during storage of fresh olive bagasse, in natura and incorporated with corn, soybean and rice brans, respectively. The experimental design was completely randomized, with the plots constituting the four main treatments (olive bagasse in natura or with added corn, soybean and rice brans, respectively), and the subplots allocated the three sampling times, which corresponded to time zero (at the ensilage moment) and 28 and 56 days of ensilage. The fermentative characteristics (dry matter content [DM], pH and ammoniacal nitrogen [NH3-N], microbiological profile (populations of filamentous fungi, lactic acid bacteria, enterobacteria and Clostridia) and chemical composition profile (mineral matter, organic matter, crude protein [CP], ether extract, neutral detergent fiber, acid detergent fiber, lignin, cellulose and hemicellulose) were determined. The corn grain and rice meal treatments, which demonstrated pH 4.08 and 3.96 at 28 days of fermentation, respectively, provided the best fermentation profile. After storage for 56 days, the samples with added soybean and rice meal reached the highest levels of CP (166.15 and 93.78 g kg-1 DM), respectively. Increasing the storage period reduced the pH of the obtained silages but increased the losses of DM, NH3-N and contributed to the losses of some nutrients. Rice meal and corn grain have been recommended to be used as additives in olive bagasse storage. However, the choice of additives studied is dependent on their commercial availability in each region.

The aim of this study was to evaluate the supply of wet brewers grain silage with and without nutrient additives in ensiling (wheat bran, soybeans hulls and ground corn), and the effect of additives on the intake and digestibility of dry matter and nutrients as well as the efficiency, production and milk composition of Holstein cows. Four multiparous Holstein cows were used, with an average milk production of 25 liters per day. The cows were randomly assigned, via the Latin Square design (4x4), to one of four experimental diets. The experimental period was 21 days. The results obtained in the experiment were evaluated by analysis of variance, Fisher's F test and Tukey's test at 5 % probability. The experimental diets consisted of wet brewers grain silage alone, and this silage with the addition of wheat bran, soybean hulls or ground corn. The diets did not affect the initial body weight of the animals. Diets containing wheat bran and ground corn provided a higher intake of dry matter (21.78 and 21.50 kg day-1) and organic matter (20.42 and 20.22 kg day-1) compared to the wet brewers grain silage alone and the diet containing soybean hulls. The results observed for dry matter (636.96 and 632.96 g kg-1), organic matter (659.16 and 654.35 g kg-1 DM), crude protein (712.84 and 717.79 g kg-1 DM) and neutral detergent fiber (598.99 and 538.90 g kg-1 DM) when cows were fed diets containing soybean hulls and ground corn, respectively, were higher than other diets. The different diets did not change daily milk production, milk production corrected for 3.5 % fat or milk composition. The milk urea nitrogen from cows fed ground corn diets was a lower concentration (17.67 mg dL-1), however, it was still above the suitable range (10 to 14 mg dL-1). Providing wet brewers grain silage with soybeans hulls or ground corn to Holstein cows increased the digestibility of dry matter and nutrients. However, the use of silages with wheat bran, soybean hulls or ground corn did not alter the efficiency, production or milk composition of cows fed with these silages.