993 resultados para Dry matter accumulation rate


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The aim of this study was to investigate the effect of a soy diet on the excretion of Brachyspira hyodysenteriae in five farms with subclinically infected pigs. The effects on general health, faecal consistency and dry matter were analysed. In total, 200 pigs of different ages (group 1 <100 days of age (n=120) and group 2 ≥100 days (n=80)) were randomly assigned to the control (C) and the treatment (T) groups. Group C received the farm's standard diet. In group T half of the daily feed ration was replaced by pure soy on two consecutive days. Faecal scores were used to determine faecal consistency and a microwave method to assess faecal dry matter content (FDMC). In age group 1, soy feeding resulted in a statistically significant decrease of the FDMC of 2.5 per cent compared with group C and in age group 2 in a significant increase of 2.2 per cent compared with group C at day 2. Overall seven (T: 5, C: 2) out of 597 faecal samples tested positive for B hyodysenteriae by PCR. In conclusion, a high soy diet applied over two days influenced the faecal consistency and the FDMC in growers, finishers and sows under field conditions. Further investigations with more sensitive diagnostic methods are needed to prove a potential influence of a high soy diet on the detection rate of B hyodysenteriae in subclinically infected herds.

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Low concentrations of organic carbon in slowly accumulating sediments from Sites 597, 600, and 601 reflect a history of low marine productivity in the subtropical South Pacific since late Oligocene times. The distributions of n-alkanes, n-alkanoic acids, and n-alkanols provide evidence of the microbial alteration of sediment organic matter. Landderived hydrocarbons, possibly from eolian transport, dominate n-alkane distributions in these samples.

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A diverse range of concentrate allocation strategies are adopted on dairy farms. The objectives of this study were to examine the effects on cow performance [dry matter (DM) intake (DMI), milk yield and composition, body tissue changes, and fertility] of adopting 2 contrasting concentrate allocation strategies over the first 140 d of lactation. Seventy-seven Holstein-Friesian dairy cows were allocated to 1 of 2 concentrate allocation strategies at calving, namely group or individual cow. Cows on the group strategy were offered a mixed ration comprising grass silage and concentrates in a 50:50 ratio on a DM basis. Cows on the individual cow strategy were offered a basal mixed ration comprising grass silage and concentrates (the latter included in the mix to achieve a mean intake of 6 kg/cow per day), which was formulated to meet the cow’s energy requirements for maintenance plus 24 kg of milk/cow per day. Additional concentrates were offered via an out-of-parlor feeding system, with the amount offered adjusted weekly based on each individual cow’s milk yield during the previous week. In addition, all cows received a small quantity of straw in the mixed ration part of the diet (approximately 0.3 kg/cow per day), plus 0.5 kg of concentrate twice daily in the milking parlor. Mean concentrate intakes over the study period were similar with each of the 2 allocation strategies (11.5 and 11.7 kg of DM/cow per day for group and individual cow, respectively), although the pattern of intake with each treatment differed over time. Concentrate allocation strategy had no effect on either milk yield (39.3 and 38.0 kg/d for group and individual cow, respectively), milk composition, or milk constituent yield. The milk yield response curves with each treatment were largely aligned with the concentrate DMI curves. Cows on the individual cow treatment had a greater range of concentrate DMI and milk yields than those on the group treatment. With the exception of a tendency for cows on the individual cow treatment to lose more body weight to nadir than cows on the group treatment, concentrate allocation strategy had little effect on either body weight or body condition score over the experimental period. Cows on the individual cow treatment had a higher pregnancy rate to first and second service and tended to have a higher 100-d in calf rate than cows on the group treatment. This study demonstrates that concentrate allocation strategy had little effect on overall production performance.

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Reconstructing the long-term evolution of organic sedimentation in the eastern Equatorial Atlantic (ODP Leg 159) provides information about the history of the climate/ocean system, sediment accumulation, and deposition of hydrocarbon-prone rocks. The recovery of a continuous, 1200 m long sequence at ODP Site 959 covering sediments from Albian (?) to the present day (about 120 Ma) makes this position a key location to study these aspects in a tropical oceanic setting. New high resolution carbon and pyrolysis records identify three main periods of enhanced organic carbon accumulation in the eastern tropical Atlantic, i.e. the late Cretaceous, the Eocene-Oligocene, and the Pliocene-Pleistocene. Formation of Upper Cretaceous black shales off West Africa was closely related to the tectonosedimentary evolution of the semi-isolated Deep Ivorian Basin north of the Côte d'Ivoire-Ghana Transform Margin. Their deposition was confined to certain intervals of the last two Cretaceous anoxic events, the early Turonian OAE2 and the Coniacian-Santonian OAE3. Organic geochemical characteristics of laminated Coniacian-Santonian shales reveal peak organic carbon concentrations of up to 17% and kerogen type I/II organic matter, which qualify them as excellent hydrocarbon source rocks, similar to those reported from other marginal and deep sea basins. A middle to late Eocene high productivity period occurred off equatorial West Africa. Porcellanites deposited during that interval show enhanced total organic carbon (TOC) accumulation and a good hydrocarbon potential associated with oil-prone kerogen. Deposition of these TOC-rich beds was likely related to a reversal in the deep-water circulation in the adjacent Sierra Leone Basin. Accordingly, outflow of old deep waters of Southern Ocean origin from the Sierra Leone Basin into the northern Gulf of Guinea favored upwelling of nutrient-enriched waters and simultaneously enhanced the preservation potential of sedimentary organic matter along the West African continental margin. A pronounced cyclicity in the carbon record of Oligocene-lower Miocene diatomite-chalk interbeds indicates orbital forcing of paleoceanographic conditions in the eastern Equatorial Atlantic since the Oligocene-Miocene transition. A similar control may date back to the early Oligocene but has to be confirmed by further studies. Latest Miocene-early Pliocene organic carbon deposition was closely linked to the evolution of the African trade winds, continental upwelling in the eastern Equatorial Atlantic, ocean chemistry and eustatic sea level fluctuations. Reduction in carbonate carbon preservation associated with enhanced carbon dissolution is recorded in the uppermost Miocene (5.82-5.2 Ma) section and suggests that the latest Miocene carbon record of Site 959 documents the influence of corrosive deep waters which formed in response to the Messinian Salinity Crisis. Furthermore, sea level-related displacement of higher productive areas towards the West African shelf edge is indicated at 5.65, 5.6, 5.55, 5.2, 4.8 Ma. In view of humid conditions in tropical Africa and a strong West African monsoonal system around the Miocene-Pliocene transition, the onset of pronounced TOC cycles at about 5.6 Ma marks the first establishment of upwelling cycles in the northern Gulf of Guinea. An amplification in organic carbon deposition at 3.3 Ma and 2.45 Ma links organic sedimentation in the tropical eastern Equatorial Atlantic to the main steps of northern hemisphere glaciation and testifies to the late Pliocene transition from humid to arid conditions in central and western African climate. Aridification of central Africa around 2.8 Ma is not clearly recorded at Site 959. However, decreased and highly fluctuating carbonate carbon concentrations are observed from 2.85 Ma on that may relate to enhanced terrigenous (eolian) dilution from Africa.

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Due to the lack of information about the effects of soybean fertilization anticipation and the use of Eleusine coracana (L.) Gaerm. (ANSB Pe-de-galinha 5352) as cover culture, and the need for new techniques for the management of the agro-ecosystem in a more conservationist, sustainable and functional manner the goal of this research was to study the effects of anticipated fertilization on the production of dry matter in E. coracana. The experiments were carried out in an Oxisol, during the growing seasons of 200112002, 200212003 and 200312004, in Piracicaba, SP Brazil (22`50`25""S and 48`01`65""W). The experimental design was of totally randomized blocks and twelve treatments (lev- els of anticipated fertilization) were used with three repetitions. The base fertilization of soybean culture was partially anticipated, in the sowing for the finger-millet crop. Approximately 70 days after sowing, samples of the finger millet plants were collected in order to evaluate the dry matter production and to desiccate them thereafter It is concluded that the anticipation of phosphorus and potassium fertilization of soybean increases the dry matter production of E. coracana; in addition, E. coracana holds a great potential for the production of plant residues and it can be used in culture rotation or in no-tillage production systems.

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Canola (Brassica napus L.) and sunflower (Helianthus annuus L.), two important oilseed crops, are sensitive to low boron (B) supply. Symptoms of B deficiency are often more severe during the reproductive stage, but it is not known if this is due to a decreased external B supply with time or an increased sensitivity to low B during this stage. Canola and sunflower were grown for 75 days after transplanting (DAT) in two solution culture experiments using Amberlite (IRA-743) B-specific resin to maintain constant B concentration in solution over the range 0.6 - 53 muM. Initially, the vegetative growth of both crops was good in all treatments. With the onset of the reproductive stage, however, severe B deficiency symptoms developed and growth of canola and sunflower was reduced with less than or equal to 0.9 and less than or equal to 0.7 muM B, respectively. At these concentrations, reproductive parts failed to develop. The critical B concentration (i.e. 90% of maximum shoot dry matter yield) in the youngest opened leaf was 18 mg kg(-1) in canola and 25 mg kg(-1) in sunflower at 75 DAT. The results of this study indicate that the reproductive stage of these two oilseed crops is more sensitive than the vegetative stage to low B supply.

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Effects of soil water availability on seedling growth, dry matter production and allocation were determined for Gympie ( humid coastal) and Hungry Hills ( dry inland) provenances of Eucalyptus cloeziana F. Muell. and for E. argophloia Blakely ( dry inland) species. Seven-month-old seedlings were subjected to well-watered (100% field capacity, FC), moderate (70% FC) and severe (50% FC) soil water regimes in a glasshouse environment for 14 wk. There were significant differences in seedling growth, biomass production and allocation patterns between species. E. argophloia produced twice as much biomass at 100% FC, and more than three times as much at 70% and 50% FC than did either E. cloeziana provenance. Although the humid provenance of E. cloeziana had a greater leaf area at 100% FC conditions than did the dry provenance, total biomass production did not differ significantly. Both E. cloeziana provenances were highly sensitive to water deficits. E. argophloia allocated 10% more biomass to roots than did E. cloeziana. Allometric analyses indicated that relative biomass allocation patterns were significantly affected by genotype but not by soil water availability. These results have implications for taxon selection for cultivation in humid and subhumid regions.

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There are few assessments of lifetime dry matter production for tropical trees. However, several studies, have been carried out for palms. This study measures dry matter production for Jessenia bataua,a useful palm common in many areas of the Amazon Valley. Palms In the Ducke Forest Reserve Of INPA were studied. Approximately 34% of total aboveground dry matter production in this palm was, alllocated to reproductive effort, eg., the production of in florescences and fruits. The meaning of this percentage, to discussed, relative to percentages identified in other Neotropical palms.

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A trial was conducted on Latossol Vermelho Escuro Orto (Orthox) at Buri, State of São Paulo, Brazil. The material was collected from 'Ohio Beauty¹ and 'Brasil¹ apples trees grafted on 'Doucin'; the trees were 3-4, 4-5 and 6-7 years old. The authors concluded that at the dormant period differen ces were observed on the dry matter production as well on the nutrients exported by the leaves and branches of the two varieties. Branches exported higher amounts of P, Ca, B, Cu and Zn. Larger quantities of N, P and Mn were exported by the 1 eaves.

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Selostus: Kohotetun lämpötilan ja kohotetun CO2-pitoisuuden vaikutukset peltoon kylvetyn nurminadan kasvuun, satoon ja kuiva-aineen jakautumiseen

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Maize is among the most important crops in the world. This plant species can be colonized by diazotrophic bacteria able to convert atmospheric N into ammonium under natural conditions. This study aimed to investigate the effect of inoculation of the diazotrophic bacterium Herbaspirillum seropedicae (ZAE94) and isolate new strains of plant growth-promoting bacteria in maize grown in Vitória da Conquista, Bahia, Brazil. The study was conducted in a greenhouse at the Experimental Area of the Universidade Estadual do Sudoeste da Bahia. Inoculation was performed with peat substrate, with and without inoculation containing strain ZAE94 of H. seropedicae and four rates of N, in the form of ammonium sulfate (0, 60, 100, and 140 kg ha-1 N). After 45 days, plant height, dry matter accumulation in shoots, percentage of N, and total N (NTotal) were evaluated. The bacteria were isolated from root and shoot fragments of the absolute control; the technique of the most probable number and identification of bacteria were used. The new isolates were physiologically characterized for production of indole acetic acid (IAA) and nitrogenase activity. We obtained 30 isolates from maize plants. Inoculation with strain ZAE94 promoted an increase of 14.3 % in shoot dry mass and of 44.3 % in NTotal when associated with the rate 60 kg ha-1 N. The strains N11 and N13 performed best with regard to IAA production and J06, J08, J10, and N15 stood out in acetylene reduction activity, demonstrating potential for inoculation of maize.