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Context. Improved knowledge of the quality of the diet ingested by grazing cattle requires measurement of the diets selected, including in native pasture rangeland. Aims. The goal of the present study was to develop empirical equations to predict the intake, digestibility and protein concentration of the diet selected from faecal crude protein concentration of cattle grazing heterogeneous native grasslands through seasonal cycles in the Pampa biome of southern South America. Methods. In Experiment 1, cattle held in metabolism pens were fed native pasture at 15 and 22.5 g DM/kg bodyweight, or ad libitum. In Experiment 2, cattle also housed in metabolism pens were offered mixtures of the native pasture and Italian ryegrass at a proportion of 0.33 and 0.66 of the mixture, or pure ryegrass. Organic-matter intake (OMI), faecal crude protein excretion (fCP), faecal crude protein concentration (fCPc), OM digestibility (OMD) and diet crude protein concentration (dCPc) were measured in Experiments 1 and 2 and relationships were developed between the diet attributes and faecal crude protein (CP). In the Experiment 3, steers grazed native grasslands (NatG), or native grasslands overseeded with Italian ryegrass (NatG + RyeG). Intake and digestibility equations generated in Experiments 1 and 2 were then evaluated in Experiment 3 to estimate diet attributes from faecal protein measures. Key results. Three non-linear models (exponential, hyperbolic and mixed, i.e. exponential + hyperbolic) were examined to evaluate the OMD. The mixed model had the highest R2 value (0.74) and the lowest relative prediction error. OMI and dCPc were both linearly related to fCP. The OMD, OMI and dCPc equations were able to detect differences among diets in Experiment 3. Conclusions. It was verified that the faecal CP can be used to estimate key nutritional characteristics in cattle grazing heterogeneous grasslands in the Pampa biome in South America. Implications. Relationships between faecal CP and key diet attributes can be used to support further research and models for nutritional assessment of the diet and productivity of grazing cattle in the rangeland system examined. [ABSTRACT FROM AUTHOR]

Lemongrass essential oil (LEO) has been evaluated as a silage additive to improve silage fermentation and reduce fermentative losses. The present study aimed to evaluate the effects of increasing levels of LEO on whole-plant sorghum silage (WPSS) fermentation profile, fermentation losses, chemical composition, dry matter (DM) and neutral detergent fibre (NDF) in vitro degradation and aerobic stability. Five cultivars and fifty experimental silos were used to evaluate the following LEO levels: 0, 1, 2, 3 and 4 ml kg−1 DM of WPSS. The material was compacted (650 kg m−2) and the silos were sealed, weighed and stored at room temperature for 167 days. The addition of LEO linearly decreased butyric acid content and the ratio between lactic and acetic acids. Intermediate levels of LEO increased NH3-N and reduced lactic and acetic acids content. LEO linearly decreased silage gas losses. However, LEO did not affect total silage losses and DM recovery. Intermediate levels of LEO addition decreased organic matter and crude protein in the WPSS. The addition of LEO did not affect other chemical composition parameters, DM and NDF in vitro degradation, and pH and temperature of the silage after aerobic exposure. Thus, LEO supply in WPSS reduces gas losses, butyric acid concentration, and the ratio between lactic and acetic acids. However, LEO does not improve the chemical composition, in vitro degradation, and aerobic stability of WPSS. [ABSTRACT FROM AUTHOR]

Lolium multiflorum, one of the most important temperate forage grasses in the world, is used in integrated crop-livestock systems and as a cover crop. However, it is also one of the main weeds in winter crops. The continuous use of glyphosate to manage this species has led to the selection of resistant biotypes (LOLMU-R), making it important to prevent the dispersal of these seeds. This study aimed to assess the recovery and germination of LOLMU-R that have passed through the digestive system of cattle. The experiments were carried out in metabolism cages, using a completely randomized design with six replications. The animals were given 12 112 seeds each, which were recovered from their faeces over a period of 6 days. Germination of the recovered seeds was assessed in a germination chamber and compared against a control (no animal passage). After germination, a glyphosate dose-response curve was constructed. The results obtained showed a total recovery of 1109 seeds (9.1%), with maximum recovery 2 days after ingestion, decreasing to almost zero on day 6. Germination declined linearly as a function of recovery time; however, 4 days after ingestion, germination potential was 18%. The dose-response curve proved the resistance of the recovered seeds. Cattle is a dispersal agent for LOLMU-R seeds, with animals requiring 7 days of quarantine before moving from one infested area to another. [ABSTRACT FROM AUTHOR]

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The current research was carried out to evaluate the use of crude protein and fibre components in faeces for estimating intake and digestibility in sheep fed with pearl millet (Pennisetum americanum (L.) Leeke). The equations were developed from four trials in metabolism cages with 16 sheep in each trial. Each animal received a different quantity of millet leaves in the diet: 0·015, 0·020 and 0·025 dry matter (DM) as a proportion of live weight (LW) and ad libitum with at least 0·2 of daily feed refusals. Organic matter intake (OMI, g/day) was measured, through the difference between offer and refusals; total faeces were collected for 5 days, which was used to determine faecal crude protein (CPf, g/day and g/kg of organic matter (OM)), faecal neutral detergent fibre (NDFf, g/day and g/kg OM), faecal acid detergent fibre (ADFf, g/day and g/kg OM) and OM digestibility (OMD). Linear regression equations were calculated to determine the relationship between OMI and CPf (P<0·001, R2=0·90, relative prediction error (RPE=14·02%). A multiple linear equation was generated for OMI including CPf and NDFf (P<0·001, R2=0·94; RPE=9·25%). Hyperbolic (single and multiple) and exponential models were tested to estimate OMD, where the hyperbolic multiple model including CPf and NDFf showed lower RPE (3·90%). These equations for estimating OMI and OMD were evaluated on sheep grazing P. americanum fertilized with increasing levels of nitrogen (N) (50, 100, 200 and 400 kg N/ha), comparing measured and estimated OMI. The intake estimated by multiple regression (CP and NDFf) showed a higher R2 (0·98) and lower RPE (5·25%) than the simple (CPf only) linear equation (R2=0·94; RPE=20·45%). The results demonstrated the feasibility of using the faecal index generated in metabolism cages for estimating intake and digestibility in sheep grazing P. americanum. [ABSTRACT FROM PUBLISHER]

Management actions are essential for mitigating the potentially harmful changes in biodiversity, ecosystem function and crop/forest productivity caused by invasive species. Species distribution models, if reliable, could be used to design effective management strategies. Although several modelling methods well suited for studying invasive species have been developed for presence-only data, often the size of available data sets for modelling is small and results are not validated with test samples. Moreover, the impact of such methods in practical applications has been overlooked. Here, we evaluated the reliability of the modelling approach based on ecological-niche factor analysis ( ENFA) implemented in Biomapper software when applied to environmental weed data in the Azores. Presence-only data sets of two top invasive woody species ( Pittosporum undulatum and Acacia melanoxylon) were used. The continuous Boyce curve was used for validation, calculated either in Biomapper (cross-validation) or based on test samples. The species' most habitable areas that should be regarded as management targets were thus estimated from modelling and validation. By imposing size restrictions on the presence-only data sets used in modelling and validation, other habitable areas were defined and compared. The ENFA proved to be a suitable method for modelling environmental weed distributions, regardless of the presence-only dataset size. Moreover, the cross-validation of Biomapper was reliable, although its results should be interpreted with caution as they could potentially lead to statistically different management target areas. [ABSTRACT FROM AUTHOR]

This paper presents a degradation study of the pesticide atrazine using photo-assisted electrochemical methods at a dimensionally stable anode (DSAw) of nominal composition Ti/Ru0.3Ti0.7O2 in a prototype reactor. The effects of current density, electrolyte flow-rate, as well as the use of different atrazine concentrations are reported. The results indicate that the energy consumption is substantially reduced for the combined photochemical and electrochemical processes when compared to the isolated systems. It is observed that complete atrazine removal is achieved at low current densities when using the combined method, thus reducing the energy required to operate the electrochemical system. The results also include the investigation of the phytotoxicity of the treated solutions. [ABSTRACT FROM AUTHOR]

In the present study, photo-assisted electrochemical degradation of real textile wastewater was performed. Degradation assays were performed at constant current (40mAcm-2) in a combined electro/photochemical flow-cell using a Ti/Ru0.3Ti0.7O2 DSAw type electrode. The results show that the method is capable of removing color and chemical oxygen demand (COD) from the effluent. Additionally, the effect of initial pH and type of supporting electrolyte (Na2SO4 or NaCl) was investigated. The principal figures of merit used in this study were COD removal and color removal (605 nm). The results show that up to 72% color and up to 59% COD removal in 120 min is possible under the operating conditions employed. Studies of the phytotoxicity of the wastewater before and after the photo-assisted degradation assays are also presented and the results demonstrate that the toxicity of the effluent is dependent on the length of electrolysis time and the treatment procedure employed. [ABSTRACT FROM AUTHOR]

This work assesses the efficiency of polyacrylamides for natural organic matter (NOM) removal from Paraíba do Sul River (Brazil) raw water for drinking purposes. Jar tests were performed following an experimental design protocol. Three kinds of polyacrylamides (anionic, cationic, and non-ionic) at 0.2mgL-1 were tested. After coagulation, turbidity, DOC, UVA254 and SCAN (UV-absorbing material) were determined. Color and pH were also measured. It was found that polyacrylamides did not reduce the amounts of alum and lime needed in the process and that the amount of alum alone for removing UV-absorbing organic matter is significantly higher. Efficiency of the coagulation process decreased as follows: non-ionic → cationic → anionic → no polyacrylamide. Removal efficiencies for the best case were: 100%, 90%, 83%, and 68% for turbidity, DOC, UVA254, and SCAN, respectively. [ABSTRACT FROM AUTHOR]

Butadiene is marketed containing p-tertbutylcatechol (p-TBC), a polymerization inhibitor that should be removed before butadiene utilization in synthetic rubber production. p-TBC can be removed from butadiene by washing with sodium hydroxide (NaOH) solution, producing a wastewater with pH 14, which contains high amounts of p-TBC, a toxic chemical compound, The aim of this work was to develop a treatment process that could reduce the content of p-TBC from the wastewater. Since p-TBC is very soluble in basic, but not in neutral and acid solutions, acidification tests were performed with phosphoric acid (H3PO4) to precipitate p-TBC. Reaction between NaOH and H3PO4 can result in crystallization of large amounts of salt without p-TBC precipitation. Under selected acidifyfng conditions p-TBC precipitates and the wastewater COD is highly reduced (> 90%). Chromatographic determinations showed that the precipitated p-TBC could be recovered with 99% purity. [ABSTRACT FROM AUTHOR]

The objective of was to determine the influence of grazing methods with a relatively low or high herbage allowance in the first 84 gestation days on ewes/lambs daily weight gain (DWG) and area production. The study was conducted at an 8.4 ha natural grassland in South Brazil. During the winter, early pregnancy ewes were submitted to two grazing methods (continuous (CS) and rotative (RS) stoking) and two herbage allowances (HA; 12 and 18% live weight)), resulting in four treatments: CS18, CS12, RS18 and RS12. It was measured the DWG and body condition score (BCS) from ewes and from ewes and lambs after born, as well lambs area production. During the winter only the HA change the DWG from the ewes. During the spring differences were found only in the lambs DWG from grazing method, been higher in CS. A grazing method × HA interaction indicate that the higher lambs area production was achieved in the CS12 treatment. The results indicate that the grazing methods and HA had a little influence in the animal performance over winter and the herbage could be better used in this period. [ABSTRACT FROM AUTHOR]