scholarly journals A computational framework for a nutrient flow representation of energy utilization by growing monogastric animals

2001 ◽  
Vol 86 (6) ◽  
pp. 661-674 ◽  
Author(s):  
Stephen Birkett ◽  
Kees de Lange
Keyword(s):  
Nutrient Intake ◽  
Process Model ◽  
Nutrient Utilization ◽  
Energy Utilization ◽  
Metabolic Effects ◽  
Energetic Efficiency ◽  
Net Energy ◽  
Biological Processes ◽  
Computational Framework ◽  
Body Protein

A computational framework to represent nutrient utilization for body protein and lipid accretion by growing monogastric animals is presented. Nutrient and metabolite flows, and the biochemical and biological processes which transform these, are explicitly represented. A minimal set of calibration parameters is determined to provide five degrees of freedom in the adjustment of the marginal input–output response of this nutritional process model for a particular (monogastric) animal species. These parameters reflect the energy requirements to support the main biological processes: nutrient intake, faecal and urinary excretion, and production in terms of protein and lipid accretion. Complete computational details are developed and presented for these five nutritional processes, as well as a representation of the main biochemical transformations in the metabolic processing of nutrient intake. Absolute model response is determined as the residual nutrient requirements for basal processes. This model can be used to improve the accuracy of predicting the energetic efficiency of utilizing nutrient intake, as this is affected by independent diet and metabolic effects. Model outputs may be used to generate mechanistically predicted values for the net energy of a diet at particular defined metabolic states.

scholarly journals Calibration of a nutrient flow model of energy utilization by growing pigs

2001 ◽  
Vol 86 (6) ◽  
pp. 675-689 ◽  
Author(s):  
Stephen Birkett ◽  
Kees de Lange
Keyword(s):  
Process Model ◽  
Calibration Procedure ◽  
Growing Pigs ◽  
Energy Utilization ◽  
Metabolic Effects ◽  
Energetic Efficiency ◽  
Body Protein ◽  
Energy Flows ◽  
Model Response ◽  
Maintenance Requirements

A computational framework to represent energy utilization for body protein and lipid accretion by growing pigs is presented. Nutrient and metabolite flows, and the biochemical and biological processes which transform these, are explicitly represented in this nutritional process model. A calibration procedure to adjust the marginal input–output response is described, and applied, using reported experimental results, to determine a complete set of parameters for representing energy utilization by growing pigs. A reasonable value for minimum basal energy requirements is also determined. Although model inputs and outputs need not at any time be converted to equivalent energy flows, to facilitate comparison of model response with that of conventional energy-based models, a simple means to estimate energy flows from model-predicted nutrient flows is described. The well-known hierarchy of marginal (biological) energetic efficiencies with which pigs use different classes of nutrients is predicted by the model, based only on simple biological and biochemical principles. The significance of independent diet and metabolic effects on both energetic efficiency and maintenance requirements is examined using model predictions from simulated experiments.

ENERGY UTILIZATION BY THE LACOMBE AND YORKSHIRE BREEDS OF PIG

1971 ◽  
Vol 51 (3) ◽  
pp. 761-770 ◽  
Author(s):  
V. D. SHARMA ◽  
L. G. YOUNG ◽  
G. C. SMITH
Keyword(s):  
Metabolizable Energy ◽  
Energy Utilization ◽  
Energy Requirements ◽  
Coefficient Of Determination ◽  
Energetic Efficiency ◽  
Net Energy ◽  
Reference Base ◽  
Diet Formulation ◽  
Yorkshire Pigs ◽  
Energy Equilibrium

A comparative slaughter trial involving 32 weanling pigs was conducted to estimate the energy requirements for maintenance and production and to compare the energetic efficiency of Lacombe and Yorkshire pigs. The coefficients of digestible energy (DE), metabolizable energy (ME), and ME/DE ratio were similar for the two breeds. The fasting heat production and energy requirements for maintenance of energy equilibrium for the Yorkshire pigs were significantly higher (P < 0.01) than for the Lacombe pigs. Differences in the efficiency of utilization of ME for the function of maintenance and for production were not significant. Estimates of net energy for maintenance and net energy for gain of the corn-soybean meal diet are presented. The study suggests that these net energy values, like the DE and ME values, may be used for diet formulation without need for correction for breed. The use of the exponent 0.56 rather than 0.75 as the reference base of metabolic body size led to increased precision, as indicated by higher estimates of the coefficient of determination.

scholarly journals Fiftieth Anniversary of the California Net Energy System Symposium: What are the energy coefficients for cows?1

2019 ◽  
Vol 3 (3) ◽  
pp. 969-975 ◽  
Author(s):  
Harvey C Freetly
Keyword(s):  
Energy Metabolism ◽  
Energy Use ◽  
Current Model ◽  
Energy System ◽  
Energy Utilization ◽  
Energetic Efficiency ◽  
Production Cycle ◽  
Net Energy ◽  
Support Functions ◽  
Animal Metabolism

Abstract The same model structure used to describe energy metabolism in the growing animal is often used to model energy metabolism in the cow. Energy requirements of the cow are modeled as the summation of energy required for maintenance and recovered energy, where recovered energy is the summation of energy for the conceptus, milk, and tissue energy. Energetic requirements of the cow fluctuate throughout the production cycle depending on whether they are pregnant, lactating, or both. The current model requires energy cost to be associated with either net energy of maintenance or the partial efficiencies of conceptus growth, milk production, and tissue energy change. Mathematically, they are not independent. Incorrectly estimating one will result in an erroneous estimate in the other. Most of the current models in production agriculture allocate energy use into maintenance, and synthesis of tissues making it difficult to assign energy utilization by tissues that provide support functions to pregnancy, lactation, and weight fluctuation. The consequence is the assignment of partial efficiencies that reflect whole animal efficiencies rather than tissue efficiencies. Historically, these models have been predictive of energy metabolism, but caution should be used when inferring the energetic efficiency at the tissue level. Alternative modeling approaches more thoroughly describe tissue energy metabolism and have been used to estimate whole animal metabolism. These models resolve the problems associated with developing coefficients that lack biological meaning but are more complex. There is a critical need for independent data sets to test new components of the model for cows.

scholarly journals Diet complexity and l-threonine supplementation: effects on nutrient digestibility, nitrogen and energy balance, and body composition in nursery pigs

2020 ◽  
Vol 98 (5) ◽  
Author(s):  
Bonjin Koo ◽  
Jinyoung Lee ◽  
Charles Martin Nyachoti
Keyword(s):  
Body Composition ◽  
Dairy Product ◽  
Nutrient Utilization ◽  
Nutrient Digestibility ◽  
Energy Output ◽  
Net Energy ◽  
Adaptation Period ◽  
Plasma Urea ◽  
Body Protein ◽  
Nursery Pigs

Abstract This study was conducted to investigate the effects of dietary complexity and l-Thr supplementation on energy and nutrient utilization in nursery pigs. Thirty-two nursery pigs (7.23 ± 0.48 kg) were randomly assigned to a 2 × 2 factorial treatment arrangement based on diet complexity (complex vs. simple) with different levels of l-Thr supplementation. The complex diet contained animal protein sources (e.g., fish meal and plasma) and a dairy product (e.g., dried whey) to mimic a conventional nursery diet. The simple diet was formulated with corn, wheat, and soybean meal. Both diets were supplemented with l-Thr to contain either 100% or 115% (SUP Thr) of the estimated standardized ileal digestible Thr requirement for 9 kg body weight pigs (NRC, 2012). The pigs were individually housed in metabolism crates and fed an experimental diet ad libitum for a 7-d adaptation period and 5 d of total but separate urine and fecal collection. On day 14, all pigs were euthanized to determine body composition. The diet complexity, l-Thr supplementation, and their interactions were considered main effects. Pigs fed the complex diet tended to exhibit greater (P &lt; 0.10) apparent total tract digestibility (ATTD) of ash and urinary energy output than those fed the simple diet. The complex diet had greater (P &lt; 0.05) digestible energy and net energy contents than the simple diet. Furthermore, the complex diet-fed pigs had lower (P &lt; 0.05) plasma urea nitrogen concentration on day 14 than simple diet-fed pigs. The SUP Thr decreased (P &lt; 0.05) ATTD of acid detergent fiber but trended (P &lt; 0.10) toward a decrease in urinary nitrogen (N) output and an increase in N retention and body N mass. In conclusion, the simple diet for nursery pigs had lower digestible and net energy contents than a complex diet. The SUP Thr can improve N utilization and body protein deposition, irrespective of diet complexity.

scholarly journals Limitations of conventional models and a conceptual framework for a nutrient flow representation of energy utilization by animals

2001 ◽  
Vol 86 (6) ◽  
pp. 647-659 ◽  
Author(s):  
Stephen Birkett ◽  
Kees de Lange
Keyword(s):  
Conceptual Framework ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Experimental Methodology ◽  
Energetic Efficiency ◽  
Net Energy ◽  
Analytical Methodology ◽  
Statistical Issues ◽  
Conventional Models ◽  
Animal Effects

Conventional models of energy utilization by animals, based on partitioning metabolizable energy (ME) intake or net energy (NE), are reviewed. The limitations of these methods are discussed, including various experimental, analytical and conceptual problems. Variation in the marginal efficiency of utilizing energy can be attributed to various factors: diet nutrient composition; animal effects on diet ME content; diet and animal effects on ME for maintenance (MEm); experimental methodology; and important statistical issues. ME partitioning can account for some of the variation due to animal factors, but not that related to nutrient source. In addition to many of the problems associated with ME, problems with NE pertain to: estimation of NE for maintenance (NEm); experimental and analytical methodology; and an inability to reflect variation in the metabolic use of NE. A conceptual framework is described for a new model of energy utilization by animals, based on representing explicit flows of the main nutrients and the important biochemical and biological transformations associated with their utilization. Differences in energetic efficiency from either dietary or animal factors can be predicted with this model.

scholarly journals 224 A method for estimating the target for protein energy retention in sheep

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 143-143
Author(s):  
Holland C Dougherty ◽  
Hutton Oddy ◽  
Mark Evered ◽  
James W Oltjen
Keyword(s):  
Body Composition ◽  
Protein Content ◽  
Heat Production ◽  
Crude Protein ◽  
Muscle Protein ◽  
Energy Utilization ◽  
Body Protein ◽  
Protein Mass ◽  
Reference Weight ◽  
Animal Growth

Abstract Target protein mass at maturity is a common “attractor” used in animal models to derive components of animal growth. This target muscle protein at maturity, M*, is used as a driver of a model of animal growth and body composition with pools representing muscle and visceral protein; where viscera is heart, lungs, liver, kidneys, reticulorumen and gastrointestinal tract; and muscle is non-visceral protein. This M* term then drives changes in protein mass and heat production, based on literature data stating that heat production scales linearly with protein mass but not liveweight. This led us to adopt a modelling approach where energy utilization is directly related to protein content of the animal, and energy not lost as heat or deposited as protein is fat. To maintain continuity with existing feeding systems we estimate M* from Standard Reference Weight (SRW) as follows: M* (kJ) = SRW * SHRINK * (1-FMAT) * (MUSC) * (CPM)* 23800. Where SRW is standard reference weight (kg), SHRINK is the ratio of empty body to live weight (0.86), FMAT is proportion of fat in the empty body at maturity (0.30), MUSC is the proportion of empty body protein that is in muscle (0.85), CPM is the crude protein content of fat-free muscle at maturity (0.21), and 23800 is the energetic content (kJ) of a kilogram of crude protein. Values for SHRINK, FMAT, MUSC and CPM were derived from a synthesis of our own experimental data and the literature. For sheep, these values show M* to be: M* (kJ) = SRW * 0.86* (1-0.3) * 0.85 * 0.21 *23800 = SRW * 2557. This method allows for use of existing knowledge regarding standard reference weight and other parameters in estimating target muscle mass at maturity, as part of a model of body composition and performance in ruminants.

159 Evaluation of Bacillus Subtilis PB6 Probiotic (CLOSTAT® 500) on Feedlot Phase Growth Performance, Efficiency of Dietary Net Energy Utilization, and Fecal and Subiliac Lymph Node Salmonella Prevalence

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 119-120
Author(s):  
Zachary K Smith ◽  
Paul Rand R Broadway ◽  
Keith Underwood ◽  
Warren C Rusche ◽  
Julie Walker ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Lymph Node ◽  
Lymph Nodes ◽  
Growth Performance ◽  
Block Design ◽  
Average Daily Gain ◽  
Energy Utilization ◽  
Experimental Unit ◽  
Net Energy ◽  
Fecal Samples

Abstract Yearling beef steers (n = 238; initial BW=402 ± 31.2 kg) were used to evaluate a Bacillus subtilis probiotic on growth performance, dietary net energy (NE) utilization, carcass characteristics, and fecal and subiliac lymph node Salmonella prevalence during a 140-d finishing period. Steers were allotted to 24 pens (n = 9 to 10 steers/pen) and assigned to one of two treatments (12 pens/treatment): no probiotic (CON) or 0.50 g·steer-1·d-1 of a Bacillus subtilis PB6 probiotic (CLOSTAT® 500, Kemin Industries, Des Moines, IA; CLO). Steers were transitioned to a 90% concentrate diet (DM basis) over 14-d. Steers were fed once daily at 0700 h; bunks were managed according to a slick bunk management. Fecal samples were collected on d 1, 28, 56, 112, and 140 from each pen (n = 5 steers/pen) via rectal palpation and composited by pen for determination of Salmonella prevalence. Upon harvest, subiliac lymph nodes were obtained from 60 steers in CON and 57 steers in CLO. Data were analyzed as a randomized complete block design; pen was the experimental unit; α of 0.05 determined significance. No differences were detected (P ≥ 0.25) between treatments for live or carcass-adjusted average daily gain, dry matter intake, gain efficiency, dietary NE utilization, nor calculated dietary NE content based upon performance. No differences were detected between treatments for any carcass traits (P ≥ 0.15). Salmonella was not recovered in any fecal samples except on d 112, where steers from CLO had a numerically lower (P = 0.17; 8.3 vs. 25.0%) incidence of fecal Salmonella compared to CON and on d 140 fecal, where Salmonella incidence did not differ (P = 0.34; 0.0 vs. 8.3%) for CON and CLO, respectively. Salmonella was not recovered in any subiliac lymph nodes. These data indicate that CLO did not influence growth performance or Salmonella prevalence.

Evaluation of Energy Efficiency for a CCHP System With Available Microturbine

2007 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang
Keyword(s):  
Gas Turbine ◽  
Waste Heat ◽  
Energy System ◽  
Primary Energy ◽  
Economic Benefits ◽  
Optimal Operation ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Energetic Efficiency ◽  
Efficiency Evaluation

This paper deals with the problem of energy utilization efficiency evaluation of a microturbine system for Combined Cooling, Heating and Power production (CCHP). The CCHP system integrates power generation, cooling and heating, which is a type of total energy system on the basis of energy cascade utilization principle, and has a large potential of energy saving and economical efficiency. A typical CCHP system has several options to fulfill energy requirements of its application, the electrical energy can be produced by a gas turbine, the heat can be generated by the waste heat of a gas turbine, and the cooling load can be satisfied by an absorption chiller driven by the waste heat of a gas turbine. The energy problem of the CCHP system is so large and complex that the existing engineering cannot provide satisfactory solutions. The decisive values for energetic efficiency evaluation of such systems are the primary energy generation cost. In this paper, in order to reveal internal essence of CCHP, we have analyzed typical CCHP systems and compared them with individual systems. The optimal operation of this system is dependent upon load conditions to be satisfied. The results indicate that CCHP brings 38.7 percent decrease in energy consumption comparing with the individual systems. A CCHP system saves fuel resources and has the assurance of economic benefits. Moreover, two basic CCHP models are presented for determining the optimum energy combination for the CCHP system with 100kW microturbine, and the more practical performances of various units are introduced, then Primary Energy Ratio (PER) and exergy efficiency (α) of various types and sizes systems are analyzed. Through exergy comparison performed for two kinds of CCHP systems, we have identified the essential principle for high performance of the CCHP system, and consequently pointed out the promising features for further development.

PSX-B-5 Effect of replacement of dry-rolled corn with un-processed rye on growth performance, efficiency of dietary net energy utilization, and carcass traits of finishing heifers

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 458-459
Author(s):  
Keith M Buckhaus ◽  
Warren C Rusche ◽  
Zachary K Smith
Keyword(s):  
Body Weight ◽  
Growth Performance ◽  
Block Design ◽  
Average Daily Gain ◽  
Estradiol Benzoate ◽  
Energy Utilization ◽  
Net Energy ◽  
Final Body Weight ◽  
Trenbolone Acetate ◽  
Finishing Diets

Abstract Continental × British beef heifers were used in a randomized complete block design experiment to evaluate the effects of replacing dry-rolled corn with unprocessed rye on growth performance, efficiency of dietary net energy (NE) utilization, and carcass trait responses in finishing heifers. Heifers (n = 56; 433 ± 34.0 kg) were transported 241 km from a regional sale barn to the Ruminant Nutrition Center in Brookings, SD. Heifers were blocked by weight grouping and then allotted to pens (n = 7 heifers/pen and 4 pens/treatment). Treatments included a finishing diet that contained 60% grain (DM basis) as dry-rolled corn (DRC) or unprocessed rye grain (RYE). On d 14, heifers were consuming the final diet and were implanted with 200 mg of trenbolone acetate and 28 mg of estradiol benzoate (Synovex-Plus, Zoetis, Parsippany, NJ). RYE heifers had decreased (P ≤ 0.01) final body weight, average daily gain, and gain efficiency; but tended (P = 0.08) to have a greater dry matter intake compared to DRC. RYE had decreased (P ≤ 0.01) observed dietary NE and decreased (P ≤ 0.01) observed-to-expected dietary NE ratio for maintenance and gain compared to DRC. Dressing percentage, 12th rib fat thickness, ribeye area, and the distribution of USDA yield and quality grades were not altered (P ≥ 0.12) by diet. Hot carcass weight, yield grade, estimated empty body fat (EBF), and body weight at 28% EBF decreased (P ≤ 0.02) and retail yield increased (P= 0.01) in RYE compared to DRC. These data indicate that unprocessed rye is a palatable feed ingredient for inclusion in finishing diets for beef cattle and that rye inclusion only minimally influences carcass quality. The feeding value of unprocessed rye is considerably less (21.4%) than that of dry-rolled corn using current standards and approximately 91% of the NE value of processed rye.

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