Survey of current Swiss pig feeding practices and potential for ammonia emission reduction

Controlling potentially harmful and polluting emissions from farms is important in the developed world, where legislation exists in many countries limiting emissions such as ammonia and controlling how manure is disposed of from intensive farming operations. In Switzerland, there are legal agreements concerning controls of ammonia emissions, most especially from farms. Ammonia production from pig farms can be controlled by dietary intervention, such as reducing protein levels, which in turn reduces excretion, mainly via urine. The following paper surveys current practices for nitrogen use on Swiss pig farms, and how feeding strategies may assist in controlling ammonia production from pig production systems. The survey found that 70-75% of all feeds used for pigs of all categories were reduced in protein and nitrogen, with 90% being reduced in protein in high animal density areas. Regression analysis showed that CP levels explained up to 49% of the nitrogen efficiency, suggesting that other factors are important in pollution control. Although piglet diets are more tightly regulated in terms of controlling N input, excessive protein levels in so-called reduced protein diets for finisher pigs and dry sows are common in the market. Hence, there is considerable potential to reduce N-input and ammonia emissions from Swiss pig production, which could be implemented at no or minimal extra cos

Effect of a by-product of solid state fermentation (Synergen™) on broiler performance

The trial was conducted to evaluate the effect of a by-product of solid state fermentation (Synergen™ (SGN), Alltech Inc, Nicholasville KY, USA) on broiler performance and health. One thousand two hundred and eighty male Ross 308 broilers were used in a 42 day pen trial. The trial was designed as a 2×2 factorial, with two diet specifications (standard and reformulated) plus or minus SGN (0 and 200g/t, SGN replaced with commercial enzyme Ronozyme™ at 150g/t) to give four dietary treatments in total in a corn-soy based diet formulated to commercial standards. Birds fed the reduced energy diets had significantly lower cumulative feed intakes at 42 d (P<0.01) compared to those on the full specification standard diet. There were no significant differences in broiler body weight due to treatments at any age. Significant improvements (P<0.05) in FCR, primarily due to SGN inclusion in the feed, were observed for all weekly reported data. There were no significant differences in either mortality or EPEF for any of the treatment diets. The present study indicates that SGN, a by-product of solid state fermentation (SSF) can improve feed conversion of broilers fed a corn-soy die

Effect of 3 dietary phytogenic products on production performance and coccidiosis in challenged broiler chickens

A pen trial using 1,080 male Ross 308 broiler chicks (6 treatments with 6 replicates each) was conducted to examine the effects of 3 dietary phytogenic products on avian coccidiosis. The dietary treatments included (1) a negative control (NC), (2) a positive control (PC) without feed additive, (3) Narasin at 0.7 kg/t (COCC), (4) PHYT1 (oregano) at 2.0 kg/t, (5) PHYT2 (combination of Curcuma, saponins, and inulin) at 1.0 kg/t, and (6) PHYT3 (Quillaja) at 1.0 kg/t. Treatments 2 through 6 were challenged with a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella at d 15 via feed. Standard performance parameters and coccidial lesion scoring (d 22) were conducted. One week after coccidial challenge, chicks BW of the COCC treatment and the NC were higher than all other treatments. Body weights on d 39 were 2.47 (NC), 2.34 (PC), 2.51 (COCC), 2.35 (PHYT1), 2.39 (PHYT2), and 2.41 kg (PHYT3) with an SEM of 0.033. For the entire trial period, Narasin yielded a significantly better FCR in comparison with the PC and PHYT3. Overall mean lesion score was 0.54 (NC), 0.91 (PC), 0.50 (COCC), 0.81 (PHYT 1), 1.02 (PHYT 2), and 1.13 (PHYT 3) with an SEM of 0.122. It was concluded that all 3 phytogenic products were not effective at the used dosage in alleviating the negative effects observed in coccidiosis-challenged bird

Scaling of load in communications networks

We show that the load at each node in a preferential attachment network scales as a power of the degree of the node. For a network whose degree distribution is p(k) ~ k^(-gamma), we show that the load is l(k) ~ k^eta with eta = gamma - 1, implying that the probability distribution for the load is p(l) ~ 1/l^2 independent of gamma. The results are obtained through scaling arguments supported by finite size scaling studies. They contradict earlier claims, but are in agreement with the exact solution for the special case of tree graphs. Results are also presented for real communications networks at the IP layer, using the latest available data. Our analysis of the data shows relatively poor power-law degree distributions as compared to the scaling of the load versus degree. This emphasizes the importance of the load in network analysis.Comment: 4 pages, 5 figure

A natural carbohydrate fraction Actigen™ from Saccharomyces cerevisiae cell wall: effects on goblet cells, gut morphology and performance of broiler chickens

A study was conducted to evaluate a natural carbohydrate fraction Actigen™ (NCF), derived from mannanoligosaccharide, in feed on growth performance, intestinal morphology and goblet cell number and area of male broilers'. Dietary treatments included: 1) control diet (antibiotic and NCF free), 2) NCF at 200g/t, 3) NCF at 400g/t, and 4) NCF 800g/t. Two hundred and forty birds were placed into 12 replicate pens per treatment (5 birds/pen), sixty birds per treatment. Body weight and feed intake were recorded weekly up to day 42. At this time a 2.5cm section of jejunum and duodenum were excised post mortem for morphological analysis. Birds fed 200g/t and 800g/t NCF were significantly (P<0.01) heavier from day 14 onwards than the control birds. Feed intake was significantly higher in birds fed 200g/t NCF compared to those fed the control at 21 and 35 days (P<0.05). Diets containing 200g/t and 800g/t of NCF significantly decreased broiler feed conversion ratio (FCR) compared to the control in the first phase (1-14 days) (P<0.01) and levels of NCF decreased FCR (P<0.05) in the second phase (15-28 days). NCF had no significant effect on villus height, villus width, crypt depth or villus to crypt ratio in either duodenum or jejunum. NCF did not significantly affect goblet cell area or goblet cell number in the duodenum, however, in the jejunum, 800g/t NCF significantly (P<0.05) increased goblet cell area over the control. In conclusion, NCF showed a positive effect on broiler performance in the starter and grower phases, and increased goblet cell area in the jejunum, suggesting higher levels of mucin production. This indicated that the performance benefit of NCF could be age-dependent, with younger birds responding more than the older ones. There were no additional benefits to performance when feeding NCF for a longer period (after 28 d of age), however it is postulated that birds fed NCF would have greater defence to pathogenic challenge through increased storage capacity of muci

The Large Scale Curvature of Networks

Understanding key structural properties of large scale networks are crucial for analyzing and optimizing their performance, and improving their reliability and security. Here we show that these networks possess a previously unnoticed feature, global curvature, which we argue has a major impact on core congestion: the load at the core of a network with N nodes scales as N^2 as compared to N^1.5 for a flat network. We substantiate this claim through analysis of a collection of real data networks across the globe as measured and documented by previous researchers.Comment: 4 pages, 5 figure

Risk assessment of an offshore wind turbine and remaining useful life estimation of the power converter. Improving availability by prioritising failures with higher risk to operation

By 2014, almost 2500 offshore wind turbines were installed in Europe representing 8GW of capacity connected to the grid and, there is a growing market penetration for the next years. Offshore wind farm operators are facing many challenges related to disparate data sources utilisation for O&M logistic optimisation. Therefore, the decision-making process needs to be based on sound analysis of the wind farm information or data available. According to several technical reports operation and maintenance (O&M) cost could reach until 30% of the levelised cost of energy (LCOE). Understanding the reliability of an offshore wind turbine and the resources required to maintain it is crucial to reduce O&M costs and thus, to reduce the levelised cost of energy (LCOE). There is a need to reduce unnecessary tasks, prioritise the most urgent tasks, improve usage of vessels, crew and technicians, reduce the cost of spare parts held and schedule preventative maintenance to minimise downtime and maximise revenue. Currently, risk assessment plays an important role in the operation and maintenance (O&M) strategies of offshore wind farms. A comprehensive failure mode and effect analysis (FMEA) has been carried out to determine critical assemblies of a generic offshore wind turbine with an induction generator, three stages gearbox and monopile foundation. The main objectives of undertaking this comprehensive FMEA was to identify those failures with significant impact on the wind turbine operation and to identify or highlight areas of risk for maintainability and availability. The FMEA is validated with; widely-used data available in the public domain; Lloyd’s Register’s experience of working with wind farm operators and; Lloyd’s Register experience of working on reliability of the mechanical system of different industrial sectors for decades. The FMEA is further augmented and updated by the use of on-going measurements from operating wind farms. Yaw system, pitch system, power converter and gearbox have been identified in the FMEA as the most critical assemblies regarding risk to the turbine operation. Power converter analysis shows high failure rates and a large proportion of undetectable failures, therefore maintenance resources have been spent on fault finding with its corresponding cost. New approaches are necessary to tackle electrical or electronic failures, especially on the power converter. To improve overall reliability, a method to estimate the remaining useful life (RUL) of a fully-rated converter in a variable speed wind turbine is proposed using data commonly available for offshore wind farm operators. Studies show that the economic impact is dominated by failures related to power electronic components such as IGBTs and capacitors due to their higher repair cost. Mathematical models have been developed to correlate turbine operation variables and environmental conditions with failure root causes to define wear and maintenance actions based on the probability of failur

Effect of Pelleting Temperature on the Activity of Different Enzymes

The effects of different pelleting temperatures on the activity of cellulase, bacterial amylase, fungal amylase, and pentosanase were tested. Samples of a commercial barley-wheat-soybean diet containing different enzyme preparations were pelleted at 60, 70, 80, 90, and 100 C (pellet temperature measured at the die outlet) through a die containing holes 2.5 mm in diameter. Enzymatic analyses were conducted on either soluble substrates or by measuring the ability of the tested enzymes to decrease the viscosity of the diet. Measurements made on soluble substrates suggest that cellulase, fungal amylase, and pentosanase maintained activity when being pelleted at temperatures up to 80 C and bacterial amylase maintained activity at temperatures up to 90 C. Pentosanase and amylases showed little or no effect on the viscosity of the diet. Cellulase addition decreased the viscosity at all temperature levels, even after being pelleted at 90 and 100 C (P < 0.05). No cellulolytic activity was detected on the soluble substrate after these pelleting temperatures. Measurements on a soluble substrate might therefore not always reflect the true stability of a preparation because the ability of a carbohydrase to decrease the viscosity of the digesta is important to its effect in the gastrointestinal tract. Measurements on soluble substrates suggest that cellulase, fungal amylase, and pentosanase can be pelleted at temperatures up to at least 80 C and bacterial amylase up to 90 C without a considerable loss in analyzed activit