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Jan Kleissl - One of the best experts on this subject based on the ideXlab platform.
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inversion reduction method for real and complex distribution Feeder models
Power and Energy Society General Meeting, 2019Co-Authors: Zachary K Pecenak, Matthew J Reno, Vahid R Disfani, Jan KleisslAbstract:The proliferation of distributed generation on distribution Feeders triggers a large number of integration and planning studies. Further, the complexity of distribution Feeder models, short simulation timesteps, and long simulation horizons rapidly render studies computational burdensome. To mend this issue, we propose a methodology for reducing the number of nodes, loads, generators, line, and transformers of p-phase distribution Feeders with unbalanced loads and generation, non-symmetric wire impedance, mutual coupling, shunt capacitance, and changes in voltage and phase. The methodology is derived on a constant power load assumption and employs a Gaussian elimination inversion technique to design the reduced Feeder. Compared to previous work by the authors, the inversion reduction takes half the time and voltage errors after reduction are reduced by an order of magnitude. the reduction is tested on six additional publicly available Feeders with maximum voltage error 0.0075 p.u. regardless of Feeder size or complexity, and typical errors on the order of 1×10−4 p.u. For a day long QSTS simulation on the UCSD A Feeder, errors are shown to increase with changes in loading when a large number of buses removed, but shows less variation for less than 85% of buses removed.
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inversion reduction method for real and complex distribution Feeder models
IEEE Transactions on Power Systems, 2019Co-Authors: Zachary K Pecenak, Matthew J Reno, Vahid R Disfani, Jan KleisslAbstract:The proliferation of distributed generation on distribution Feeders triggers a large number of integration and planning studies. Further, the complexity of distribution Feeder models, short simulation time steps, and long simulation horizons rapidly render studies computational burdensome. To mend this issue, we propose a methodology for reducing the number of nodes, loads, generators, line, and transformers of p -phase distribution Feeders with unbalanced loads and generation, non-symmetric wire impedance, mutual coupling, shunt capacitance, and changes in voltage and phase. The methodology is derived on a constant power load assumption and employs a Gaussian elimination inversion technique to design the reduced Feeder. Compared to previous work by the authors, the inversion reduction takes half the time and voltage errors after reduction are reduced by an order of magnitude. Using a snapshot simulation the reduction is tested on six additional publicly available Feeders with a maximum voltage error 0.0075 p.u. regardless of Feeder size or complexity, and typical errors on the order of $1\times 10^{-4}$ p.u. For a day long quasi-static time series simulation on the UCSD A Feeder, errors are shown to increase with changes in loading when a large number of buses removed, but shows less variation for less than 85% of buses removed.
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multiphase distribution Feeder reduction
IEEE Transactions on Power Systems, 2018Co-Authors: Zachary K Pecenak, Matthew J Reno, Vahid R Disfani, Jan KleisslAbstract:Quasi-static time-series simulations (QSTS) of distribution Feeders are a critical element of distributed solar PV integration studies. QSTS are typically carried out through computer simulation tools, such as OpenDSS. Since a typical Feeder contains thousands of buses, for long investigation periods or at fine time scales such simulations are computationally costly. Simulation times are reduced in this paper through a reduction of the number of buses in the model. The Feeder reduction algorithm considers p -phase distribution Feeders with unbalanced loads and generation, unbalanced wire impedance, and mutual coupling, while preserving the spatial variation of load and generation. An extensive Monte Carlo sensitivity analysis was performed on a real Feeder from a California utility. All bus voltage differences are found to be less than 1.13% with a root mean square error of 0.21%. Simulation time savings were up to 96% when only one bus is selected to remain in the model. Example applications of the proposed algorithm are interconnection studies of utility-scale photovoltaic system to the distribution grid, siting analyses of other distributed energy resources and dynamic behavior of devices in large systems, such as smart inverters on distribution grids.
Zachary K Pecenak - One of the best experts on this subject based on the ideXlab platform.
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inversion reduction method for real and complex distribution Feeder models
Power and Energy Society General Meeting, 2019Co-Authors: Zachary K Pecenak, Matthew J Reno, Vahid R Disfani, Jan KleisslAbstract:The proliferation of distributed generation on distribution Feeders triggers a large number of integration and planning studies. Further, the complexity of distribution Feeder models, short simulation timesteps, and long simulation horizons rapidly render studies computational burdensome. To mend this issue, we propose a methodology for reducing the number of nodes, loads, generators, line, and transformers of p-phase distribution Feeders with unbalanced loads and generation, non-symmetric wire impedance, mutual coupling, shunt capacitance, and changes in voltage and phase. The methodology is derived on a constant power load assumption and employs a Gaussian elimination inversion technique to design the reduced Feeder. Compared to previous work by the authors, the inversion reduction takes half the time and voltage errors after reduction are reduced by an order of magnitude. the reduction is tested on six additional publicly available Feeders with maximum voltage error 0.0075 p.u. regardless of Feeder size or complexity, and typical errors on the order of 1×10−4 p.u. For a day long QSTS simulation on the UCSD A Feeder, errors are shown to increase with changes in loading when a large number of buses removed, but shows less variation for less than 85% of buses removed.
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inversion reduction method for real and complex distribution Feeder models
IEEE Transactions on Power Systems, 2019Co-Authors: Zachary K Pecenak, Matthew J Reno, Vahid R Disfani, Jan KleisslAbstract:The proliferation of distributed generation on distribution Feeders triggers a large number of integration and planning studies. Further, the complexity of distribution Feeder models, short simulation time steps, and long simulation horizons rapidly render studies computational burdensome. To mend this issue, we propose a methodology for reducing the number of nodes, loads, generators, line, and transformers of p -phase distribution Feeders with unbalanced loads and generation, non-symmetric wire impedance, mutual coupling, shunt capacitance, and changes in voltage and phase. The methodology is derived on a constant power load assumption and employs a Gaussian elimination inversion technique to design the reduced Feeder. Compared to previous work by the authors, the inversion reduction takes half the time and voltage errors after reduction are reduced by an order of magnitude. Using a snapshot simulation the reduction is tested on six additional publicly available Feeders with a maximum voltage error 0.0075 p.u. regardless of Feeder size or complexity, and typical errors on the order of $1\times 10^{-4}$ p.u. For a day long quasi-static time series simulation on the UCSD A Feeder, errors are shown to increase with changes in loading when a large number of buses removed, but shows less variation for less than 85% of buses removed.
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multiphase distribution Feeder reduction
IEEE Transactions on Power Systems, 2018Co-Authors: Zachary K Pecenak, Matthew J Reno, Vahid R Disfani, Jan KleisslAbstract:Quasi-static time-series simulations (QSTS) of distribution Feeders are a critical element of distributed solar PV integration studies. QSTS are typically carried out through computer simulation tools, such as OpenDSS. Since a typical Feeder contains thousands of buses, for long investigation periods or at fine time scales such simulations are computationally costly. Simulation times are reduced in this paper through a reduction of the number of buses in the model. The Feeder reduction algorithm considers p -phase distribution Feeders with unbalanced loads and generation, unbalanced wire impedance, and mutual coupling, while preserving the spatial variation of load and generation. An extensive Monte Carlo sensitivity analysis was performed on a real Feeder from a California utility. All bus voltage differences are found to be less than 1.13% with a root mean square error of 0.21%. Simulation time savings were up to 96% when only one bus is selected to remain in the model. Example applications of the proposed algorithm are interconnection studies of utility-scale photovoltaic system to the distribution grid, siting analyses of other distributed energy resources and dynamic behavior of devices in large systems, such as smart inverters on distribution grids.
Jim L. Nelssen - One of the best experts on this subject based on the ideXlab platform.
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the effects of Feeder design and dietary dried distillers grains with solubles on the performance and carcass characteristics of finishing pigs
Journal of Animal Science, 2014Co-Authors: J R Bergstrom, Jim L. Nelssen, Michael D Tokach, Robert D Goodband, Steven S Dritz, Joel M DeroucheyAbstract:: Three experiments were conducted to compare the effects of a conventional dry (five 30.5-cm spaces 152.4 cm wide; Staco Inc., Schaefferstown, PA) vs. a wet-dry (double sided; each side = 38.1-cm space; Crystal Spring; GroMaster Inc., Omaha, NE) finishing Feeder (Exp. 1 and 2) and to evaluate the effects of Feeder design and dietary level of dried distillers' grains with solubles (DDGS; >10% oil; Exp. 3) on performance and carcass characteristics of finishing pigs. In Exp. 1, 1,186 pigs (32.1 kg BW) were used in a 69-d experiment. There were 26 to 28 pigs per pen and 22 pens per Feeder design, and all pigs received the same diets in 4 phases. In Exp. 2, 1,236 pigs (28.7 kg BW) were used in a 104-d experiment, with 25 to 28 pigs per pen and 23 pens per Feeder design, and all pigs received the same diets in 5 phases. Carcass measurements were obtained from 11 pens of each Feeder design after harvest. In Exp. 3, 1,080 pigs (35.1 kg BW) were used in a 99-d 2 × 2 factorial with main effects of Feeder design (dry vs. wet-dry Feeders) and DDGS (20 vs. 60%) with 10 pens of 27 pigs per treatment and all diets fed in 4 phases. Jowl fat samples were collected from 2 pigs per pen for fatty acid analysis and iodine value (IV) determination. In all experiments, pigs fed with the wet-dry Feeder had greater (P < 0.05) ADG, ADFI, and final BW. In Exp. 2 and 3, HCW and backfat depth were increased (P < 0.05) for pigs fed with a wet-dry Feeder, but G:F and fat-free lean index (FFLI) were reduced. Jowl IV was also reduced (P < 0.05) with a wet-dry Feeder in Exp. 3. Pigs fed 60% DDGS in Exp. 3 had decreased (P < 0.05) ADG, G:F, final BW, HCW, and backfat but increased jowl IV and a tendency (P < 0.07) toward greater FFLI regardless of Feeder type. In conclusion, pigs fed with this specific type of wet-dry Feeder had improved ADG and ADFI, poorer G:F, and increased backfat depth compared to pigs fed with a conventional dry Feeder. The poorer growth performance and increased jowl IV of pigs fed diets with 60% DDGS was similarly exhibited for pigs fed on both Feeders.
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the effects of diet form and Feeder design on the growth performance of finishing pigs
Journal of Animal Science, 2013Co-Authors: A J Myers, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Jim L. NelssenAbstract:: Two studies were conducted to determine the effects of diet form (meal vs. pellet) and Feeder design (conventional dry vs. wet/dry) on finisher pig performance. Experiments were arranged as 2 × 2 factorials with 11 replications per treatment and 26 to 29 pigs per pen. In Exp. 1, pigs (n = 1,290; initial BW 46.8 kg) were used in a 91-d study. Pelleted diets averaged approximately 35% fines throughout the study. Overall, pigs fed pelleted diets or via wet/dry Feeders had greater (P < 0.07 and 0.001, respectively) ADG than pigs fed meal diets or fed with a dry Feeder. Diet form × Feeder interactions (P < 0.02) were observed for G:F. Pigs fed either meal or pelleted diets via a wet/dry Feeder had similar G:F, but pigs fed pelleted diets in dry Feeders had poorer G:F than pigs with meal diets in dry Feeders. In Exp. 2, pigs (n = 1,146; initial BW 38.2 kg) were used in a 104-d study. From d 0 to 28, a diet form × Feeder design interaction (P < 0.01) was observed for ADG, which was due to decreased ADG in pigs fed pelleted diets from a conventional dry Feeder compared with pigs fed meal diets from the same Feeder type whereas there was no difference in wet/dry Feeders based on diet form. Pigs fed pelleted diets had poorer (P < 0.01) G:F than pigs fed meal diets. This result appeared to be due to poor pellet quality (39.6% fines). From d 42 to 86, pellet quality improved (4.4% fines) and a diet form × Feeder interaction was observed for ADG in which pigs fed meal diets in a dry Feeder had decreased (P < 0.05) ADG than pigs fed pelleted diets in dry Feeders or pigs presented either diet in wet/dry Feeders. Pigs fed pelleted diets had improved (P < 0.001) G:F. Pigs fed via wet/dry Feeders had increased (P < 0.03) ADFI and G:F compared with pigs fed via dry Feeders. Overall, pigs fed with wet/dry Feeders had increased (P < 0.02) ADG and ADFI and poorer G:F than pigs with dry Feeders whereas pigs given pelleted diets had improved (P = 0.05) G:F compared with pigs presented meal diets. These studies found that pigs fed from wet/dry Feeders had increased ADG and ADFI compared with pigs fed via dry Feeders regardless of diet form. Additionally, pellet quality appeared to influence responses because pigs fed high-quality pellets via dry Feeders had better growth performance than pigs fed meal diets. Conversely, if pellet quality was poor, the feed efficiency benefits associated with pelleting were lost.
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effects of Feeder design conventional dry vs wet dry on growth performance of 45 to 246 lb pigs
Kansas Agricultural Experiment Station Research Reports, 2012Co-Authors: S Nitikanchana, Jim L. Nelssen, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Steven S DritzAbstract:A total of 1,253 pigs (PIC 1050 × 337; initially 45 lb) were used in a 104-d study to evaluate the effects of using a wet-dry (WD) or conventional dry (CD) Feeder on growth performance of growing-finishing pigs. At the start of the trial, pens of pigs were weighed and randomly allotted to 1 of the 2 Feeder types. The CD Feeder was a singlesided, 56-in.-wide, stainless steel Feeder (Thorp Equipment, Inc., Thorp, WI) with 4 14-in. feeding spaces and a 4.25-in.-deep trough. A cup waterer in pens using CD Feeders ensured ad libitum access to water as well as feed. The WD Feeder was double-sided (15-in.-wide Feeder opening on each side) with a single nipple waterer (Crystal Springs, GroMaster, Inc., Omaha, NE), and the Feeder was the only source of water. All pigs were fed the same corn-soybean meal diets containing 30% bakery by-product and 10 to 45% dried distillers grains with solubles (DDGS) during 5 dietary phases. For the overall period, pigs fed with the WD Feeder had greater ADG (P < 0.01) and ADFI (P = 0.01) with no differences in F/G (P = 0.50) compared with pigs fed using the CD Feeder. This study confirms previous results where pigs fed using a WD Feeder have greater ADG and ADFI than those fed with a CD Feeder.
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the effects of Feeder design conventional dry vs wet dry in the nursery and in the finisher on growth performance of finishing pigs
Kansas Agricultural Experiment Station Research Reports, 2011Co-Authors: S Nitikanchana, Jim L. Nelssen, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Steven S DritzAbstract:A total of 1,296 pigs (PIC 1050 × 337; initially 36 lb) were used in a 102-d study to determine the effects of Feeder type (conventional dry vs. wet-dry) on nursery and finishing pig growth performance for pigs reared under commercial conditions. In the nursery, pigs were housed in rooms with either conventional dry or wet-dry Feeders. At movement to the finisher, 312 barrows and 336 gilts from a room with conventional dry Feeders and an equal number of pigs from a room with wet-dry Feeders were randomly selected and distributed to have a similar number of barrows and gilts in each finisher pen. At the start of the trial, pens of pigs were weighed and randomly allotted to the 2 Feeder types in finishing barn to arrange the treatments as a 2 × 2 factorial with main effects of Feeder type in nursery and Feeder type in finisher.
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the effects of diet form and Feeder design on the growth performance and carcass characteristics of growing finishing pigs
Kansas Agricultural Experiment Station Research Reports, 2010Co-Authors: A J Myers, J R Bergstrom, Jim L. Nelssen, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Steven S DritzAbstract:A total of 1,290 growing pigs (PIC 1050 × 337, initially 103.1 lb) were used in a 91-d study to evaluate the effects of diet form (meal vs. pellet) and Feeder design (conventional dry vs wet-dry) on finisher pig performance. The treatments were arranged in a 2 × 2 factorial with 11 replications per treatment and 25 to 27 pigs per pen. Half of the pens were equipped with a 5-hole conventional dry Feeder while the other half had a double-sided wet-dry Feeder. All pigs were fed a corn-soybean meal-based diet containing 45 to 65% by-products in 4 phases. The only difference among treatments was diet form (meal vs. pellet). Pen weights and feed disappearance were measured on d 0, 16, 21, 43, 57, 71, and 91. Pictures of Feeder pans were taken during Phase 4 and then evaluated by a panel of 4 for percentage of pan coverage. From d 0 to 91, no diet form × Feeder design interactions were observed for ADG. Pigs fed pelleted diets had a tendency for improved (P < 0.07) ADG compared to those given meal diets. In addition, pigs fed with wet-dry Feeders had improved (P < 0.01) ADG compared to those with conventional dry Feeders. A diet form × Feeder design interaction was observed (P < 0.04) for ADFI. When using a wet-dry Feeder, pigs given meal diets had similar ADFI as those fed pelleted diets. However, when using dry Feeders, pigs given pelleted diets had a much greater ADFI than pigs fed meal diets. In addition, a diet form × Feeder design interaction was observed for F/G. Pigs fed both meal and pelleted diets via wet-dry Feeders had similar F/G, but pigs fed pelleted diets in a conventional dry Feeder had poorer F/G compared to pigs given meal diets in a conventional dry Feeder. The pellets used during this experiment had average percentage fines of 35.1 ± 19% and an average pellet durability index (PDI) of 75.8 ± 8.4. We attribute the interactions to the poor pellet quality, leading to more feed wastage from the dry Feeders. These results suggest that pellet quality is important to decrease feed wastage and sorting by the pigs and to optimize growth performance.
Steven S Dritz - One of the best experts on this subject based on the ideXlab platform.
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the effects of Feeder design and dietary dried distillers grains with solubles on the performance and carcass characteristics of finishing pigs
Journal of Animal Science, 2014Co-Authors: J R Bergstrom, Jim L. Nelssen, Michael D Tokach, Robert D Goodband, Steven S Dritz, Joel M DeroucheyAbstract:: Three experiments were conducted to compare the effects of a conventional dry (five 30.5-cm spaces 152.4 cm wide; Staco Inc., Schaefferstown, PA) vs. a wet-dry (double sided; each side = 38.1-cm space; Crystal Spring; GroMaster Inc., Omaha, NE) finishing Feeder (Exp. 1 and 2) and to evaluate the effects of Feeder design and dietary level of dried distillers' grains with solubles (DDGS; >10% oil; Exp. 3) on performance and carcass characteristics of finishing pigs. In Exp. 1, 1,186 pigs (32.1 kg BW) were used in a 69-d experiment. There were 26 to 28 pigs per pen and 22 pens per Feeder design, and all pigs received the same diets in 4 phases. In Exp. 2, 1,236 pigs (28.7 kg BW) were used in a 104-d experiment, with 25 to 28 pigs per pen and 23 pens per Feeder design, and all pigs received the same diets in 5 phases. Carcass measurements were obtained from 11 pens of each Feeder design after harvest. In Exp. 3, 1,080 pigs (35.1 kg BW) were used in a 99-d 2 × 2 factorial with main effects of Feeder design (dry vs. wet-dry Feeders) and DDGS (20 vs. 60%) with 10 pens of 27 pigs per treatment and all diets fed in 4 phases. Jowl fat samples were collected from 2 pigs per pen for fatty acid analysis and iodine value (IV) determination. In all experiments, pigs fed with the wet-dry Feeder had greater (P < 0.05) ADG, ADFI, and final BW. In Exp. 2 and 3, HCW and backfat depth were increased (P < 0.05) for pigs fed with a wet-dry Feeder, but G:F and fat-free lean index (FFLI) were reduced. Jowl IV was also reduced (P < 0.05) with a wet-dry Feeder in Exp. 3. Pigs fed 60% DDGS in Exp. 3 had decreased (P < 0.05) ADG, G:F, final BW, HCW, and backfat but increased jowl IV and a tendency (P < 0.07) toward greater FFLI regardless of Feeder type. In conclusion, pigs fed with this specific type of wet-dry Feeder had improved ADG and ADFI, poorer G:F, and increased backfat depth compared to pigs fed with a conventional dry Feeder. The poorer growth performance and increased jowl IV of pigs fed diets with 60% DDGS was similarly exhibited for pigs fed on both Feeders.
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effects of Feeder design conventional dry vs wet dry on growth performance of 45 to 246 lb pigs
Kansas Agricultural Experiment Station Research Reports, 2012Co-Authors: S Nitikanchana, Jim L. Nelssen, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Steven S DritzAbstract:A total of 1,253 pigs (PIC 1050 × 337; initially 45 lb) were used in a 104-d study to evaluate the effects of using a wet-dry (WD) or conventional dry (CD) Feeder on growth performance of growing-finishing pigs. At the start of the trial, pens of pigs were weighed and randomly allotted to 1 of the 2 Feeder types. The CD Feeder was a singlesided, 56-in.-wide, stainless steel Feeder (Thorp Equipment, Inc., Thorp, WI) with 4 14-in. feeding spaces and a 4.25-in.-deep trough. A cup waterer in pens using CD Feeders ensured ad libitum access to water as well as feed. The WD Feeder was double-sided (15-in.-wide Feeder opening on each side) with a single nipple waterer (Crystal Springs, GroMaster, Inc., Omaha, NE), and the Feeder was the only source of water. All pigs were fed the same corn-soybean meal diets containing 30% bakery by-product and 10 to 45% dried distillers grains with solubles (DDGS) during 5 dietary phases. For the overall period, pigs fed with the WD Feeder had greater ADG (P < 0.01) and ADFI (P = 0.01) with no differences in F/G (P = 0.50) compared with pigs fed using the CD Feeder. This study confirms previous results where pigs fed using a WD Feeder have greater ADG and ADFI than those fed with a CD Feeder.
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the effects of Feeder design conventional dry vs wet dry in the nursery and in the finisher on growth performance of finishing pigs
Kansas Agricultural Experiment Station Research Reports, 2011Co-Authors: S Nitikanchana, Jim L. Nelssen, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Steven S DritzAbstract:A total of 1,296 pigs (PIC 1050 × 337; initially 36 lb) were used in a 102-d study to determine the effects of Feeder type (conventional dry vs. wet-dry) on nursery and finishing pig growth performance for pigs reared under commercial conditions. In the nursery, pigs were housed in rooms with either conventional dry or wet-dry Feeders. At movement to the finisher, 312 barrows and 336 gilts from a room with conventional dry Feeders and an equal number of pigs from a room with wet-dry Feeders were randomly selected and distributed to have a similar number of barrows and gilts in each finisher pen. At the start of the trial, pens of pigs were weighed and randomly allotted to the 2 Feeder types in finishing barn to arrange the treatments as a 2 × 2 factorial with main effects of Feeder type in nursery and Feeder type in finisher.
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the effects of diet form and Feeder design on the growth performance and carcass characteristics of growing finishing pigs
Kansas Agricultural Experiment Station Research Reports, 2010Co-Authors: A J Myers, J R Bergstrom, Jim L. Nelssen, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Steven S DritzAbstract:A total of 1,290 growing pigs (PIC 1050 × 337, initially 103.1 lb) were used in a 91-d study to evaluate the effects of diet form (meal vs. pellet) and Feeder design (conventional dry vs wet-dry) on finisher pig performance. The treatments were arranged in a 2 × 2 factorial with 11 replications per treatment and 25 to 27 pigs per pen. Half of the pens were equipped with a 5-hole conventional dry Feeder while the other half had a double-sided wet-dry Feeder. All pigs were fed a corn-soybean meal-based diet containing 45 to 65% by-products in 4 phases. The only difference among treatments was diet form (meal vs. pellet). Pen weights and feed disappearance were measured on d 0, 16, 21, 43, 57, 71, and 91. Pictures of Feeder pans were taken during Phase 4 and then evaluated by a panel of 4 for percentage of pan coverage. From d 0 to 91, no diet form × Feeder design interactions were observed for ADG. Pigs fed pelleted diets had a tendency for improved (P < 0.07) ADG compared to those given meal diets. In addition, pigs fed with wet-dry Feeders had improved (P < 0.01) ADG compared to those with conventional dry Feeders. A diet form × Feeder design interaction was observed (P < 0.04) for ADFI. When using a wet-dry Feeder, pigs given meal diets had similar ADFI as those fed pelleted diets. However, when using dry Feeders, pigs given pelleted diets had a much greater ADFI than pigs fed meal diets. In addition, a diet form × Feeder design interaction was observed for F/G. Pigs fed both meal and pelleted diets via wet-dry Feeders had similar F/G, but pigs fed pelleted diets in a conventional dry Feeder had poorer F/G compared to pigs given meal diets in a conventional dry Feeder. The pellets used during this experiment had average percentage fines of 35.1 ± 19% and an average pellet durability index (PDI) of 75.8 ± 8.4. We attribute the interactions to the poor pellet quality, leading to more feed wastage from the dry Feeders. These results suggest that pellet quality is important to decrease feed wastage and sorting by the pigs and to optimize growth performance.
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the effects of Feeder space and adjustment on growth performance of finishing pigs
Kansas Agricultural Experiment Station Research Reports, 2010Co-Authors: A J Myers, J R Bergstrom, Jim L. Nelssen, Joel M Derouchey, Michael D Tokach, Robert D Goodband, Steven S DritzAbstract:A total of 288 pigs (PIC TR4 × 1050, initially 82 lb) were used in a 91-d study to evaluate the effects of Feeder trough space (1.75 vs. 3.5 in/pig) and minimum Feeder-gap opening of 0.5 in. (narrow), vs. 1.0 in. (wide) on finisher pig performance. Our hypothesis was that at minimal Feeder trough space (1.75 in./pig), Feeders should be set at a wide gap opening to avoid limiting feed intake and ADG. The Feeders were adjusted to the minimum gap setting, but the agitation plate could be moved upward to a maximum gap opening of 0.75 in. or 1.25 in., respectively. The treatments were arranged in a 2 × 2 factorial with 6 replications per treatment. All pens had the same Feeder with 2, 14-in.-wide by 4.5-in.-deep Feeder holes. Feeder trough space was adjusted by placing 8 or 16 pigs per pen. Gating was adjusted to give each pig 8 ft2 of floor space. Pigs had ad libitum access to feed and water. All pigs were fed a corn-soybean meal-based diet containing 20% dried distillers grains with solubles (DDGS) in 4 phases. Pen weights and feed disappearance were measured every 2 wk. Narrow-adjusted Feeders averaged approximately 48% coverage, and wide-adjusted Feeders averaged approximately 85% coverage. Overall (d 0 to 91) there were no trough space × Feeder adjustment interactions observed (P > 0.10). However, there was a tendency (P = 0.08) for increased ADG as Feeder trough space increased from 1.75 to 3.5 in./pig. Pigs fed with the wide Feeder-gap setting had increased (P < 0.01) feed disappearance and poorer (P < 0.01) F/G compared to pigs with the narrow Feeder-gap setting. These results suggest that, regardless of Feeder trough space, pigs with the wide Feeder adjustment appeared to waste more feed, as evidenced by the poorer F/G.
Melissa K Carpenter - One of the best experts on this subject based on the ideXlab platform.
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Feeder free growth of undifferentiated human embryonic stem cells
Nature Biotechnology, 2001Co-Authors: Margaret S Inokuma, Jerrod Denham, Kathaleen Golds, Pratima Kundu, Joseph D Gold, Melissa K CarpenterAbstract:Previous studies have shown that maintenance of undifferentiated human embryonic stem (hES) cells requires culture on mouse embryonic fibroblast (MEF) Feeders. Here we demonstrate a successful Feeder-free hES culture system in which undifferentiated cells can be maintained for at least 130 population doublings. In this system, hES cells are cultured on Matrigel or laminin in medium conditioned by MEF. The hES cells maintained on Feeders or off Feeders express integrin alpha6 and beta1, which may form a laminin-specific receptor. The hES cell populations in Feeder-free conditions maintained a normal karyotype, stable proliferation rate, and high telomerase activity. Similar to cells cultured on Feeders, hES cells maintained under Feeder-free conditions expressed OCT-4, hTERT, alkaline phosphatase, and surface markers including SSEA-4, Tra 1-60, and Tra 1-81. In addition, hES cells maintained without direct Feeder contact formed teratomas in SCID/beige mice and differentiated in vitro into cells from all three germ layers. Thus, the cells retain fundamental characteristics of hES cells in this culture system and are suitable for scaleup production.
