The objectives of this research were to determine the net energy (NE) of dry extruded expelled soybean meal (DESBM) using an indirect calorimetry (IC) in growing pigs, to determine the effect of multi-enzyme supplementation on the NE content of DESBM fed to growing pigs and to validate the NE system for feed formulation. In Exp 1, the values obtained with the IC method were consistently greater than those obtained with prediction equations. The discrepancy between the determination technique used was about 1% when diets were formulated with a constant protein content or corn:soybean meal ratio (1.0% and 0.7%, respectively), however, this was 4.1% when diet was formulated with simple substitution technique. Thus the NE value of DESBM was evaluated to be 2,548 kcal/kg DM when diets were formulated on a constant ratio between the other energy yielding components. In Exp 2, addition of enzyme increased the NE value of both the diet and the test ingredient; DESBM. Supplementation with multi-enzyme complex (Superzyme-OM, Canadian Bio-System Inc., Calgary, Canada) at 0.05% and 0.1% of the diet improved NE values of DESBM by 4.9 % and 3.7%, respectively. In Exp 3, the results indicate a better growth performance (ADG and G:F) when diets were formulated on NE basis compared to the DE system of diet formulation. Moreover addition of enzyme improved the performance for the NE system of diet formulation

Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Steven S. Dritz / A total of 8 experiments and a meta-analysis were performed with the overarching goal to improve amino acid and energy utilization in swine diets. The first experiment used a total of 255 nursery pigs to evaluate the optimum dietary standardized ileal digestible (SID) tryptophan to lysine (Trp:Lys) ratio. Four experiments also were conducted using 6,668 finishing pigs to determine the effects of SID Trp:Lys ratio in diets containing dried distillers grains with solubles (DDGS) on growth performance and carcass characteristics. A subsequent experiment evaluated the interaction between Trp and large neutral amino acids (Trp:LNAA) on growth performance of early and late-finishing pigs. Lastly, data from 41 trials and 2 validation trials were used to develop a regression equations to predict ADG or gain to feed (G:F) as influenced by BW and net energy (NE) content in growing-finishing pigs. In Exp. 1, the growth performance and economics indicated the optimum SID Trp concentration for 6-to 10-kg nursery pigs at 20.3% of Lys. In Exp. 2, 3, and 4, there were no differences in growth performance due to SID Trp:Lys ratio; however, increasing the SID Trp:Lys ratio suggested an opportunity to improve carcass yield and lean in pigs fed high levels of DDGS. Experiment 5 indicated an optimum SID Trp:Lys ratio of 20% for 71- to 127-kg pigs fed high level of DDGS. In Exp. 6, growth performance was unaffected by dietary treatment suggesting that 16.5% SID Trp:Lys was adequate to prevent a negative impact on growth when SID Trp:LNAA was as low as 3.0% in finishing period. Overall, the experiments suggested a higher optimum SID Trp:Lys ratio than is currently standard practice. The regression analysis from the meta-analysis showed that increasing dietary NE improved ADG and G:F. However, the magnitude of improvement will be minimized if the SID Lys concentration is limiting. The validation experiments indicated that the prediction equations provided a good estimation of growth rate and feed efficiency of growing-finishing pigs fed different levels of dietary NE except for pigs fed the diet with DDGS. These predictions of growth performance can then be used to model economic value of different dietary energy strategies.

To support further technology development and to promote the growth of a renewable biofuels industry that will satisfy the stated expectations of anticipated energy needs, it is essential that energy production systems provide a net energy gain over the course of their lifetime. As a means to provide accurate analysis to the value of alternative energy systems this paper provides a mechanism to evaluate energy systems in terms of energy generation ratios that is in terms of existing analysis techniques utilized in existing energy generation areas, such as the oil industry. This paper also proposes techniques that help perform this net energy analysis in terms of the specific economy considering the infrastructure investment.

The aim of this thesis is to take a broad conceptual overview of the global energy system and investigate what the aims of sustainability might entail for such a system. The work presented uses a biophysical economic approach in that the dynamics of the global economy are investigated using the tool box of the physical sciences, including the laws of thermodynamics and the methods of energy analysis. Modern society currently uses approximately 500 exajoules (EJ = 10^18 J) of total primary energy supply (TPES) each year. This energy consumption has been increasing at roughly 2% per year for the past two hundred years. TPES is currently dominated by three non-renewable energy sources: coal, oil and gas which, together with energy from nuclear fission of uranium, make up around 85% of the energy market. Consumption of finite resources at a continuously growing rate is not sustainable in the long-term. A trend in policy direction is to seek a transition to renewable sources of energy. This thesis seeks to explore two questions: are the technical potentials of renewable energy sources enough to supply the current and/or projected demand for energy and what would be the effect on the physical resource economy of a transition to an energy supply system run entirely on renewable energy sources? The Global Energy Model using a Biophysical Approach (GEMBA) methodology developed here is compared and contrasted with other approaches that are used to study the global energy-economy system, including the standard neoclassical economic approach used in such models as MESSAGE and MARKAL. A number of meta-analyses have been conducted in support of the GEMBA model. These include: meta-analysis of historic energy production from all energy sources; meta-analysis of global energy resources for all energy sources; meta-analysis of energy-return-on-investment (EROI) for all energy sources. The GEMBA methodology uses a systems dynamic modelling approach utilising stocks and flows, feedback loops and time delays to capture the behaviour of the global energy-economy system. The system is decomposed into elements with simple behaviour that is known through energy analysis. The interaction of these elements is captured mathematically and run numerically via the systems dynamics software package, VenSim. Calibration of the model has been achieved using historic energy production data from 1800 to 2005. The core of the GEMBA methodology constitutes the description of a dynamic EROI function over the whole production cycle of an energy resource from initial development, through maturation to decline in production, in the case of non-renewable resources, or to the technical potential in the case of renewable resources. Using the GEMBA methodology, the global energy-economy system is identified as a self-regulating system. The self-regulating behaviour acts to constrain the amount of total primary energy supply that the system can produce under a renewable-only regime. A number of analyses are conducted to test the sensitivity of the system to such changes as: an increase of the technical potential of renewable resources; technological breakthroughs which would significantly increase the EROI of renewable resources; a decrease in the capital intensity of renewable resources and; an increase in the energy intensity of the economy, A statistical analysis reflecting the wide range of values of both the estimates of EROI and technical potentials of renewable energy sources has also been undertaken using a Monte Carlo approach. The results from the modelling suggest that not all levels of energy demand projected by the WEA can be supplied by an energy system running solely on renewable energy. The Monte Carlo analyses suggest that reduction in total energy yield over current (2010) levels might occur with a 20-30% possibility. The middle and high growth scenarios from the WEA are greater than 95% of all scenarios modelled, hence seem unlikely to be sustained by an energy system running solely on renewable energy. This finding has implications for the future direction of both engineering and technology research as well as for energy policy. These implications are discussed.

In the last couple of decades, there has been an increased awareness of the effects that electricity generation has on the environment through the emission of greenhouse gases and the depletion of natural resources. This realisation, coupled with an increased drive towards ensuring the sustainability of the energy supply system, has lead many, including the United Kingdom government to investigate the options for moving away from traditional fossil fuel-burning generation methods towards “lowcarbon” generators, such as renewables and nuclear power. Specifically, wind power, the more mature systems (with the exception of hydro power) of the available renewable energy supply, and nuclear power, a technology seen as producing large amounts of electricity with very few associated greenhouse emissions, have been promoted but also pitted against each other by analysts and policy makers. This work aims to provide a balanced analysis of wind power and nuclear power with respect to their effects on the natural environment. As such, modeling has been undertaken of a Generation III+ nuclear reactor, an onshore wind farm located in southern Scotland and an offshore wind farm near the Thames estuary while environmental indicators have been created to permit the comparative assessment of these three electricity generation technologies, in a U.K. context. These indicators thus facilitate an assessment of the energy requirements, the associated greenhouse gas emissions, the natural resource requirements, as well as the displaced carbon dioxide emissions from operation of each power plant. A parametric analysis has also been conducted to show the range of likely variations in each indicator’s values. The results of this research show that all three technologies demonstrate similar performance with respect to their energetic and environmental impacts. More specifically, the wind farms demonstrate better energy gain ratios than the nuclear power plant when they are credited for not depleting non-renewable fuel sources. The wind farms also are shown to pay back their energy investments faster than the nuclear power plant. On the other hand, the nuclear power plant is found to produce slightly lower greenhouse gas emissions than either onshore or offshore wind farms. With respect to the assessment of natural resource depletion, it is estimated that both wind farms need more land per unit of electricity produced than the nuclear power plant, but all three power plants permanently sequester similar amounts of water. The wind farms and the nuclear power plant are found to have similar performance with respect to their material requirements, while the calculation of the avoided emissions factors for all technologies are of similar orders of magnitude. All results are shown to be highly sensitive to the assumptions made about the prospective lifecycles, and as such caution should be exercised when drawing conclusions about any comparative advantages. Nethertheless both technologies are clearly shown to have lower environmental impacts than traditional electricity generation technologies.

This study was undertaken to compare the effects of changing energy intake, either by restricting feed intake or by altering dietary energy concentration, on the growth performance of pigs. The relative abilities of the DE, ME and NE systems to predict pig growth performance were also evaluated. A total of 72 barrows, having initial body-weights of 30 ± 2 kg, were randomly assigned to one of nine dietary treatments. These treatments were organized in a 3 x 3 factorial arrangement consisting of three dietary energy concentrations (2.18, 2.29 and 2.40 Mcal NE/kg) and three levels of feed allowance (80, 90 and 100% of ad libitum). Actual feed allowances of 79, 91 and 100% of ad libitum were achieved. No interactive effects of feeding level and dietary energy concentration were observed (P > 0.10). Increases in feed allowance from 79 to 91 to 100% of ad libitum resulted in increases in daily intakes of feed (P < 0.0001) and energy (P < 0.0001). Improvements in the rate (P < 0.0001) and efficiency (P < 0.0001) of body-weight gain were also noted. Additionally, feeding level affected the amount of energy available for body-weight gain on a daily (P < 0.0001) but not on a total (P > 0.10) basis. The efficiency with which dietary energy was used for weight gain was unaffected by feeding level (P > 0.10). Increases in dietary energy concentration were accompanied by decreases in daily feed intakes (P = 0.0016); however, dietary energy concentration did not affect daily energy intakes (P > 0.10). Neither average daily gains nor feed conversion efficiencies were affected by changes in dietary energy concentration (P > 0.10). Additionally, there were no differences among energy concentration treatments in terms of the amount of dietary energy available for body-weight gain (P > 0.10) or the efficiency with which it was used (P > 0.10). No differences were observed between the DE, ME and NE systems in terms of their abilities to predict the growth performance of pigs. The present study demonstrates that the energy intake of pigs can be effectively manipulated via adjustments in feeding level and that changes in dietary energy density, over the range studied here, are unable to affect changes in energy intake. This finding indicates that extreme caution should be used when extrapolating data obtained from studies in which feed allowance was manipulated to scenarios (e.g. commercial practice) in which energy density is to be altered, and vice versa.

Stated simply, this thesis focuses on the relationship between energy and the economy. Using the foundation of King 2010, this analysis expands the scholarship from a U.S. focus to perform Energy Intensity Ratio analysis on forty-four countries for the time period 1978-2010. There are four fuels examined: coal, natural gas, crude oil and electricity. Using both the price and expenditures based Energy Intensity Ratio methods, outputs for each fuel in any applicable sector was determined. In addition, this work compiles an estimate of the total energy expenditures for the majority of the world. By examining the overall expenditures of gross domestic product spent on energy, the data showed two points in time where energy appears to become a constraint on growth. Though this thesis does not answer the question directly as to whether an increase in energy expenditures “causes” an increase in economic growth, or whether an increase in economic growth “causes” an increase in energy expenditures, the research shows that vi there may be a “threshold” effect whereby as energy expenditures become a greater share of output, the ability of economic growth to take place is affected. / text

ABSTRACT Two experiments were conducted to determine the net energy (NE) of wheat-corn distillers dried grains with solubles (wcDDGS) using the comparative slaughter (CS), the indirect calorimetry (IC) and the chemical composition (CH) methods. Based on the CS method, NE values of 2,407, and 2,424 kcal/kg DM were obtained for wcDDGS included at 15% and 30%, respectively. For the IC method, the NE values of 2,407, and 2,403 kcal/kg DM were obtained for wcDDGS included at 15% and 30%, respectively; corresponding values for the CH method were 2,536 and 2,197 kcal/kg DM, respectively. It is concluded that NE value of wcDDGS ranges from 2,367 kcal/kg DM to 2,416 kcal/kg DM depending on the method used. As the values obtained from the various methods were not different, the average NE value for the wcDDGS evaluated was 2,396 ± 25.71 kcal/kg DM.

ABSTRACT Two experiments were conducted to determine the net energy (NE) of wheat-corn distillers dried grains with solubles (wcDDGS) using the comparative slaughter (CS), the indirect calorimetry (IC) and the chemical composition (CH) methods. Based on the CS method, NE values of 2,407, and 2,424 kcal/kg DM were obtained for wcDDGS included at 15% and 30%, respectively. For the IC method, the NE values of 2,407, and 2,403 kcal/kg DM were obtained for wcDDGS included at 15% and 30%, respectively; corresponding values for the CH method were 2,536 and 2,197 kcal/kg DM, respectively. It is concluded that NE value of wcDDGS ranges from 2,367 kcal/kg DM to 2,416 kcal/kg DM depending on the method used. As the values obtained from the various methods were not different, the average NE value for the wcDDGS evaluated was 2,396 ± 25.71 kcal/kg DM.

Marketplace volatility in the pork industry demands that producers re-evaluate production practices in order to remain profitable. Stocking density and dietary energy concentration independently affect performance and economic returns of growing finishing pigs. However, there is limited information on whether the interaction between these two factors is important for optimizing productivity and maximizing economic returns. The objective of this study was to determine if the dietary energy concentration that maximizes performance and economic returns varies with stocking density. Treatments were arranged as a 2 × 3 × 3 factorial included; sex (barrows and gilts), dietary energy (2.15, 2.30 and 2.45 Mcal NE/kg) and stocking density (14, 17 or 20 pigs per pen providing 0.92, 0.76 and 0.65 m2 per pig, respectively). A total of 932 pigs were used with three replications of 18 treatments. Pigs were randomly assigned to pens within sex to achieve an average initial BW of 75 kg. Wheat and barley based diets were formulated to meet or exceed the pigs’ nutrient requirements (National Research Council, 2012) and were fed in three phases within sex at each energy concentration. Overall (75 to 118 kg BW), as dietary energy increased from 2.15 to 2.45 Mcal NE/kg, ADG increased from 1.17 to 1.23 kg/d, ADFI decreased from 4.09 to 3.77 kg/d, G:F improved from 0.29 to 0.33 and caloric intake increased from 8.81 to 9.29 Mcal NE/d (P < 0.05). When stocking density was increased from 14 to 20 pigs per pen, ADG (1.21 to 1.17 kg/d), ADFI (4.00 to 3.82 kg/d) and caloric intake (9.19 to 8.12 Mcal NE/d) decreased (P < 0.05). Neither dietary energy concentration nor stocking density had a significant effect on the utilization of calories for growth (Gain:Mcal). Feeder visits per pig and time at the feeder per pig were decreased when stocking density increased from 14 to 20 pigs per pen (P < 0.01). Total time at the feeder and time at the feeder per pig were increased when dietary energy decreased from 2.45 to 2.15 Mcal of NE/kg. Per pen, aggressive incidents at the feeder increased (P < 0.05) and there was a tendency for increased aggressive incidents per pig (P = 0.09) when stocking density was increased. There was a linear increase (P < 0.01) in income over feed cost (IOFC) with increased stocking density, and there was a tendency (P = 0.08) for a linear increase in IOFC when dietary energy was increased. The dietary energy which maximized the IOFC did not vary with stocking density. Dietary energy and stocking density independently affect pig performance, behavior, and economic returns and the optimal dietary energy does not depend on stocking density (dietary energy by stocking density interaction).