Submitted in fulfilment of the requirements of the egree of Master of Technology: Chemical Engineering, Durban University of Technology, 2011. / The South African electroplating industry generates large volumes of hazardous waste water that has to be treated prior to disposal. The main source of this waste water has been the rinse system. Conventional end-ofpipe waste water treatment technologies do not meet municipality standards. The use of technologies such as membranes, reverse osmosis and ion exchange are impractical, mainly due to their cost and technical requirements. This study identified source point reduction technologies, close circuiting of the electroplating process, specific to the rinse system as a key development. Specifically the application of a low flow counter current rinse system for the recovery of the rinse water in the plating bath was selected. However, the recovery of the rinse tank water was impeded by the low rates of evaporation from the plating bath, which was especially prevalent in the low temperature operating plating baths. This master’s study proposes the use of an induced draft evaporative cooling tower for facilitation of evaporation in the plating bath. For total recovery of the rinse tank water, the rate of evaporation from the plating bath has to be equivalent to the rinse tanks make up water requirements. A closed circuit plating system mathematical model was developed for the determination of the mass evaporated from the plating bath and the cooling tower for a specified time and the equilibrium temperature of the plating bath and the cooling tower. The key criteria in the development of the closed circuit plating system model was the requirement of minimum solution specific data as this information is not readily available. The closed circuit plating system model was categorised into the unsteady state and steady state temperature regions and was developed for the condition of water evaporation only. The closed circuit plating system model was programmed into Matlab and verified. The key factors affecting the performance of the closed circuit plating system were identified as the plating solution composition and operational temperature, ambient air temperature, air flow rate and cooling tower iv packing surface area. Each of these factors was individually and simultaneously varied to determine their sensitivity on the rate of water evaporation and the equilibrium temperature of the plating bath and cooling tower. The results indicated that the upper limit plating solution operational temperature, high air flow rates, low ambient air temperature and large packing surface area provided the greatest water evaporation rates and the largest temperature drop across the height of the cooling tower in the unsteady state temperature region. The final equilibrium temperature of the plating bath and the cooling tower is dependent on the ambient air temperature. The only exception is that at low ambient air temperatures the rate of water evaporation from the steady state temperature region is lower than that at higher ambient air temperatures. Thus the model will enable the electroplater to identify the optimum operating conditions for close circuiting of the electroplating process. It is recommended that the model be validated against practical data either by the construction of a laboratory scale induced draft evaporative cooling tower or by the application of the induced draft evaporative cooling tower in an electroplating facility.

Submitted in fulfillment of requirements of the degree of Master in Health Sciences: Dental Technology, Durban University of Technology, Durban, South Africa, 2016. / Pumice is used in the polishing of dental appliances to remove surface irregularities. It is usually used in a slurry form that is pumice powder mixed with water. In Nigeria, the increased cost of pumice as a result of its limited supply into the country has encouraged dental technicians to re-use pumice slurry for longer periods than advocated when polishing acrylic dentures, whether new or old dentures which have been worn in the mouth. Consequently, this is likely to increase cross-infection of communicable diseases in the dental technology laboratory. Although materials such as white sand, black sand and porcelnite can be used, literature documents that these materials are less effective in the polishing of acrylic dentures (Areeg 2011). The focus of this study was to use eggshells, a natural waste product, to develop and test the quality of an alternative material to reduce the surface roughness of heat-cured acrylic resins. A quantitative research paradigm and an experimental research strategy were adopted. The research design included two phases. In phase one of this study, different characterisation techniques such as Brunnae-Emmer Teller (BET); Fourier Transform Infrared Spectroscopy (FTIR); X-ray Diffraction (XRD); Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscope (SEM); Transmission Electron Microscopy (TEM); Laser Scattering Particle Size Distribution Analyser (PSA); Thermo-Gravimetric Analysis (TGA); and Induction-Coupling-Optical Emission Spectroscopy (ICP-OES) were used to assess the suitability of the new abrasive material (NAM). In addition, the level of microbial contamination of the NAM was assessed in line with the specified microbial limits for cosmetic products. In contrast, phase two investigated the product-based quality of the NAM as an abrasive material for removable dental appliances. There were two sample groups, that is, the NAM (test group) and Pumice (control), and each sample group had 50 PMMA acrylic specimens. The surface roughness (Ra) was measured using a Talysurf profilometer. An Independent Tukey test was used to analyse the Ra values (p=0.05). A Scanning Electron Microscope (SEM) and Optical Microscope (OEM) were further used to support the results of the profilometer in terms of the quality of surface finish and polish. Validity of the study was achieved following the ISO 20795-1 (2013) methods of preparation and fabrication of the acrylic specimens. The reliability was determined via reproducibility and repeatability of tests. The BET analysis showed that the NAM is predominantly a mesoporous powder. The FTIR and XRD analyses confirmed that the NAM is pure calcite with unique water absorbing characteristics, and is free of bacteria. The EDX and ICP-OES analyses revealed calcium, oxygen and carbon as the major elemental composition of the NAM. The SEM and TEM images revealed irregular shaped particles in the NAM. The PSA analysis of the particle distribution showed the NAM to be superfine (50nm to 0.3µm) and medium (44µm powder), respectively. The TGA analysis revealed a high-grade carbonate product in the NAM (>66.0 mass% of calcium carbonates). In addition, and in terms of in the qualities of the NAM in reducing the surface roughness of PMMA resins, the test group and the control group produced Ra values that were significant different (p<0.0001). The SEM and OEM analyses further confirmed the differences in the surfaces between the polished sample groups at different magnifications. Overall, the control showed the highest mean average (0.1056±0.03688µm), whereas the test group had the lowest Ra values (0.0476±0.01379). The lowest Ra values measured with the test group indicated that the NAM improves the surface smoothness of PMMA acrylic specimens. Notably, this study conclusively showed that the NAM effectively reduces the surface roughness to below the threshold limit value of 0.2µm. Significantly, and in associating the Ra values to the threshold limit value of 0.2µm, the NAM produced better results than pumice. Hence the use of the NAM as a polishing material for acrylic dentures is highly recommended. Finally and in line the NAM being a suitable alternative to pumice as it effectively reduces the surface roughness of PMMA specimens, future investigation into the use of eggshell nanoparticles to develop dental prophylaxes will be encouraged. / M

Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The aim of this study was to determine whether a lamb finishing ration that is balanced for essential amino acids (EAA), at a specific level of non-structural carbohydrates (NSC) would yield better feedlot performance when compared to a standard commercial finishing ration. Metionine (Met) and Lysine (Lys) were identified as the first limiting amino acids for growing lambs. These two amino acids, as well as Threonine (Thr), Arginine (Arg), Leucine (Leu), Isoleucine (Ile) and Phenylalanine (Phe) were included in an optimized protein (OP) feedlot ration at optimal levels. This ration was formulated to contain 157 g/kg crude protein (CP) and 477 g/kg NSC, with Met, Lys, Arg and Thr at 2.48, 7.45, 8.51 and 8.12 g/kg on dry matter (DM) basis respectively. The second treatment, FIN, was a standard commercial lamb finishing feed without optimized amino acids and contained similar total protein and NSC to OP of 152 g/kg CP and 468 g/kg NSC but with Met, Lys, Arg and Thr at 2.08, 5.49, 7.47 and 4.80 g/kg on DM basis respectively. A third treatment, a low protein (LP) diet served as a positive control and was formulated on lower specifications (139 g/kg CP, 455 g/kg NSC) and was also not optimized for amino acids. This treatment contained Met, Lys, Arg and Thr at 1.93, 4.99, 6.66 and 4.73 g/kg on DM basis respectively. Lambs grazing kikuyu pasture served as the negative control (CON) group. These lambs also received additional supplementary feed at 500 g/day as a production lick to be comparable to a scenario where lambs are finished on grazing. Forty cross-bred Merino x Döhne-Merino lambs with an average weaning weight of 24.35 ± 0.648 kg were finished in a feedlot for 57 days where after they were slaughtered at an average weight of 41.41 ± 1.259 kg. During the feedlot trial lamb performance was measured by monitoring daily growth rates and feed intake. Also, an in vivo digestibility study was carried out on the OP and FIN lambs. During the slaughter process the rumen was removed which was done to collect a sample of the rumen wall from next to the rumino-reticular fold. These rumen samples were mounted onto slides so that the development of the rumen could be examined. The M. longissimus dorsi from both sides of the carcass between the 2nd and 3rd last thoracic vertebra and the 4th and 5th lumbar vertebra were removed. There was no significant difference (P > 0.05) between any of the concentrate feed treatments with regards to the average daily gain (ADG), feed conversion ratio (FCR) or dressing percentage (DP). The CON lambs, as expected, had lower growth rates (P < 0.05) than the concentrate fed lamb and thus showed significant differences (P < 0.05) in terms of ADG. The DP of 45.96 % ± 0.711 for the CON lambs differed significantly (P < 0.05) from the OP (51.44 % ± 0.358), FIN (52.72 % ± 0.653) and LP (51.74 % ± 0.611) treatments. As expected the concentrate feeds were much more effective in maintaining higher growth rates when compared to the CON lambs while the optimizing of EAA in the OP diet did not lead to improved feedlot performance as the FIN and LP treatments were able to achieve similar (P > 0.05) growth rates. Within the feedlot treatments there was no significant difference (P > 0.05) with regard to the papillae length and rumen wall thickness. There was however a numerical increase in the papillae length as the NSC levels in the feed increased. The CON lambs differed from the OP lambs (P < 0.05) in terms of papillae length. This illustrated the importance of having increased levels of NSC in a feedlot diet as it is this fraction that is responsible for the initialisation and maintenance of rumen morphological development. The in vivo digestibility study therefore confirmed that the commercial finishing feed was just as effective as the optimized feed in terms of nitrogen retention as well as in maintaining suitable energy balance. Although the in vivo digestibility for Met and Lys in the OP feed was higher (P < 0.05) than the FIN feed, this did not lead to improved feedlot performance of the OP lambs. The increased digestibility of these amino acids is due to the fact that the OP diet was higher in levels of bypass amino acids than the FIN feed. The in vitro true digestibility (IVTD) of the OP feed was higher (P < 0.05) than that of the FIN feed. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om te bepaal of ‘n lamafrond rantsoen wat gebalanseerd is vir beperkende essiensiële aminosure (EAA) teen ‘n spesifieke vlak van nie-strukturele koolhidrate (NSK) beter voerkraal prestasie teweeg sou bring wanneer gemeet word teen ‘n standaard kommersiële afrond rantsoen. Metionien (Met) en Lisien (Lis) is geïdentifiseer as die eerste beperkende aminosure vir groeiende lammers. Hierdie twee aminosure, asook Treonien (Tre), Leusien (Leu), Isoleusien (Ile) en Fenielalanien (Fen) is teen optimale vlakke ingesluit in ‘n geoptimeerde voerkraal rantsoen, OP. Hierdie rantsoen is geformuleer om 157 g/kg RP en 477 g/kg NSK te bevat asook Met, Lis, Arg en Tre teen 2.48, 7.45, 8.51 en 8.12 g/kg onderskeidelik. Die tweede behandeling, FIN, was ‘n kommersiële lamafrond voer waarin die aminosure nie geoptimeer is nie en het soortgelyke vlakke van proteïene en NSK bevat teen 152 g/kg RP en 468 g/kg NSK met Met, Lis, Arg en Tre teen 2.08, 5.49, 7.47, 4.80 g/kg onderskeidelik. ‘n Derde voer, LP, het gedien as ‘n positiewe kontrole en was ‘n lae proteïen voer met laer spesifikasies (139 g/kg RP, 455 g/kg NSK) waarin die aminosure ook nie geoptimeer is nie. Die LP voer het Met, Lis, Arg en Tre bevat teen 1.93, 4.99, 6.66 en 4.73 g/kg onderskeidelik. Die negatiewe kontrole behandeling, CON, is verteenwoordig deur lammers wat op kikuyu gewei het terwyl addisionele supplementêre voeding teen 500g/lam/dag voorsien is. Hierdie supplementêre voeding het gedien as ‘n produksie lek om sodoende vergelykbaar te wees met scenario waar lammers op weiding afgerond word. Veertig kruisgeteelde Merino x Döhne-Merino lammers met ‘n gemiddelde gewig van 24.35 ± 0.648 kg is vir 57 dae in ‘n voerkraal afgerond waarna hulle, teen ‘n gemiddelde gewig van 41.41 ± 1.259 kg, geslag is. Tydens die voerkraal proef is prestasie gemonitor deur die meet van daaglikse groei en voerinname. Hiertydens is daar ook ‘n in vivo verteringsproef op die OP en FIN lammers gedoen. Tydens die slagproses is die rumen verwyder waarna ‘n monster van die rumenwand langs die rumino retikulêre vou geneem is. Hierdie rumenmonsters is op skyfies geplaas sodat die ontwikkeling van die rumen ondersoek kan word. Die M. longissimus dorsi was aan beide kante van die karkas tussen die 2de en 3de laaste torakale werwels en die 4de en 5de lumbale werwels verwyder. Daar was geen betekenisvolle verskille (P > 0.05) tussen enige van die konsentraat behandelings ten opsigte van gemiddelde daaglikse toename (GDT), voeromset verhouding (VOV) of uitslag persentasie nie. Die CON lammers het egter, soos verwag, beduidend (P < 0.05) stadiger gegroei en het dus verskille getoon ten opsigte van GDT. Die uitslag persentasie van 45.96 % ± 0.711 vir die CON lammers het ook betekenisvol verskil (P < 0.05) van die OP (51.44 % ± 0.358), FIN (52.72 % ± 0.653) en LP (51.74 % ± 0.611) behandelings. Binne die voerkraal behandelings was daar geen betekenisvolle verskille (P > 0.05) ten opsigte van die papillae lengte en rumenwand dikte nie, alhoewel daar ‘n numeriese toename in papillae lengte was soos die NSK vlakke in die voer gestyg het. Die CON lammers het wel van die OP lammers verskil (P < 0.05) ten opsigte van papillae lengte. Hierdie bevinding het bevestig hoe belangrik NSK is in die inisiasie en instandhouding van die morfologiese ontwikkeling van die rumen. Die in vivo verterings studie het daarop gedui dat die kommersiële afrond voer net so effektief soos die geoptimeerde voer was in terme van stikstof retensie asook die handhawing van ‘n geskikte energie balans. Alhoewel die in vivo verteerbaarheid van Met en Lis in die OP hoër was (P < 0.05) as in die FIN voer, het hierdie verskille nie gelei tot beter groei in die OP lammers nie. Hierdie verskil in verteerbaarheid is toegeskryf aan die feit dat die aminosure in die OP voer meer rumen-beskermd was as dié in die FIN voer. Die in vitro verteringstudie het daarop gedui dat die OP voer beduidend beter (P < 0.05) verteer is as die FIN voer.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

A local company instituted a new chemical procedure in their spray phosphating system used in the pretreatment of large components for industrial racking systems. An inorganic conversion coating is deposited on the workpiece surface during phosphating and this prepares the surface to receive an organic top-coat. The organic coating is applied to the workpiece surface in the form of a powder and cured to form a continuous film about 80 u.m thick. The solution chemistry of the phosphating system was monitored by sampling and chemical analysis and taking direct reading instrumental measurements on the process and rinse solutions. The process was also evaluated using the results of a waste minimisation audit. This involved gathering data on composition, flow rates and costs of inputs and outputs of the process. Two types of information were collected and used during the audit, namely chemical monitoring (concentration levels of Na, Fe, Zn, Mo, Mn and Cr and measurements of conductivity, TDS, SS and pH) and water usage data on the Phosphating Line and existing data (raw materials, workpieces and utility inputs as well as domestic waste, factory waste and scrap metal outputs). The data were analysed using four established waste minimisation techniques. The Scoping Audit and the Water Economy Assessment results were determined using empirically derived models. The Mass Balance and the True Cost of Waste findings were obtained through more detailed calculations using the results of the chemical analysis. The results of the audit showed that the most important area for waste minimsation in the Phosphating Line was the (dragged-out phosphating chemicals present in) wastewater stream. According to the scoping audit, water usage had the third highest waste minimisation potential behind powder and steel consumption for the entire powder coating process. While the scoping audit and the specific water intake value showed that water consumption for the process was not excessive, it did not indicate that the pollution level in the rinse waters was high. Further, drag-out calculations showed that drag-out volumes were typical of those found in the metal finishing industry. However the presence of high levels of metal species in the rinse waters was highlighted through the chemical monitoring of the Phosphating Line. The True Cost of Waste Analysis estimated potential financial savings for the effluent stream at about R8000 for a period of 105 days. However this does not take into consideration the cost of the liability associated with this stream when exceeding effluent discharge limits (given in the Trade Effluent Bylaws) or of the chemical treatment necessary to render this stream suitable for discharge to sewer. Intervention using only "low-cost-no-cost" waste minimisation measures was recommended as a first step before contemplating further areas for technical or economic feasibility studies. However, a further study involving monitoring the sludge was recommended in order to establish the potential financial savings offered by this waste stream. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

This study involved an assessment of the Pietermaritzburg Waste Minimisation Club (PWMC) during 2001, and a waste minimisation audit conducted at two coil coating lines. Waste minimisation is the reduction or elimination of waste at source4 • It is often achieved through waste minimisation clubs which comprise a small number of companies, generally in the same geographicaI area, that are interested in reducing waste 1"711 . The success of the PMWC was evaluated in terms of the degree to which members implemented waste minimisation principles. Two questionnaires were used to assess the success of the club. These indicated that although the training material gave the members a good understanding of the basic principles of waste minimisation, the material has not given the members enough practical information to implement a waste minimisation programme in their companies. The main barriers to waste minimisation identified include production pressure, operational constraints, lack of human resources and a lack of management time. The drivers for waste minimisation were financial savings, improved plant utilisation and improved environmental performance. Coil coating is a continuous process where a coiled sheet of aluminium is cleaned, pretreated and coated with paint. The flow rates, compositions and costs of all input and output streams to the cleaning and pretreatment sections were gathered from operators or measured. The data were collected over a three-month period to obtain a representative sample, and then analysed to determine waste minimisation opportunities using mass balances, monitoring and targeting, a scoping audit and a true cost of waste assessment. The scoping audit was found to be the most useful technique because it accurately prioritised the waste minimisation opportunities but required a relatively small amount of data for its application. However, the scoping audit underestimated the savings that could be achieved at the coil coating department and therefore the 'scope to save' percentages, which were developed for United Kingdom industries, need modification to better reflect South African industry. Opportunities for waste minimisation on Coil Coating Line 1 (CCL1) included reducing the water consumption, reducing the acid and chromium raw materials consumption, and finding a cheaper energy source for heating the process and rinse tanks. Potential fmancial savings of R116 000 and environmental savings of 18 200 kL of water or effluent per year were calculated for CCL1. The chromium and acid effluent treatment and solid waste disposal are the main areas for waste minimisation on Coil Coating Line 2 (CCL2). Savings could be achieved in these areas by using roller application ofthe chromium pretreatment rather than spray application, and by preventing a leak of chromium pretreatment into the acid process and rinse tanks. Other savings can also be achieved by operating the chromium process tank as a fed-batch process, and operating the alkali and acid process tanks as continuous processes at the specified chemical concentrations and with recycle of the rinse water (dragout). The total financial savings that can be achieved on CCL2 are R5.3 million, and potential environmental savings are 31 600 kL ofeffluent per year. / Thesis (M.Sc.)- University of Natal, Pietermaritzburg, 2002.

Master of Science / Department of Animal Sciences and Industry / Joel DeRouchey / Thirteen experiments using a total of 7,589 nursery and finishing pigs were conducted to evaluate the effects of deoxynivalenol (DON), feed additives and processing conditions on nursery pig growth performance. In addition, feed withdrawal and diet blending were evaluated in finishing pigs. Experiment 1 tested 3 feed additives in DON-contaminated diets with only Defusion Plus improving performance. Experiment 2 evaluated Biofix in both low- and high-DON diets and showed no effects on growth. Experiments 3 and 4 further evaluated levels of Defusion and the effects of pelleting and supplemental nutrients in DON-contaminated diets. Defusion improved growth in low-DON diets, but had variable effects in high DON diets. Pelleting DON-contaminated diets resulted in comparable growth to pigs fed positive control diets in meal form. In Exp. 5 and 6, pilot studies evaluated DON-detoxification using sodium metabisulfite (SMB) with hydrothermal treatment in both an autoclave and a pellet mill. These conditions reduced analyzed DON by as much as 89 and 75% for the autoclave and pellet mill, respectively. In Exp. 7 and 8, pelleting DON-contaminated diets with SMB improved growth. Experiments 9 and 10 evaluated feed-withdrawal time on carcass composition and economic returns. These experiments showed that pre-slaughter fasting for up to 36 h prior can be used to avoid weight discounts in heavyweight pigs without negatively impacting carcass composition and maintaining overall revenue. However, these advantages come with a potential reduction in carcass weight and increased incidence of leaking ingesta, which can result in condemned heads. Experiments 11, 12, and 13 compared phase-feeding to blending diets using an automated feed delivery system. These studies showed that corn-supplement blending is not economical and feeding diets blended to a Lys curve results in lower feed costs compared to phase-feeding, but due to reductions in growth and carcass weight, these savings do not translate into higher income over feed cost. Finally, Exp. 13 showed that over- and under-budgeting situations do not significantly influence overall returns, but pigs fed under-budgeted diets performed more closely to those fed correctly estimated feed budgets.

Master of Science / Department of Animal Science and Industry / Jim L. Nelssen / Three experiments used 777 pigs to study the effects of fiber source; wheat middlings (midds), dried distillers grains with solubles (DDGS), and choice white grease (CWG), and reduction strategies for growing and finishing pigs. Also a fourth study utilizing 1,360 pigs was conducted to determine the effect of immunocastration (IC) and DDGS withdrawal on growth performance, carcass characteristics, fatty acid analysis, and iodine value (IV) of pork fat depots in growing and finishing pigs. Experiment 1 determined that the ingredient source of fiber (wheat middlings or DDGS) was more important than NDF level alone, for characterization of growth, carcass, and yield responses. Experiment 2 showed that a short (23 d) fiber reduction strategy was successful at fully recovering yield loss; however, a longer reduction (47 d) was necessary for further improvements in carcass fat quality (IV). Experiment 3 further proved that yield loss can be recovered with a short fiber reduction strategy (19 d), and that adding energy from CWG during the fiber reduction period can improve feed efficiency, but was unsuccessful at further improving carcass yield or carcass fat quality. Experiment 4 showed that carcass yield was lower for IC pigs than barrows regardless of dietary DDGS or withdrawal strategy. Also pigs fed 30% DDGS throughout had decreased carcass yield; however, withdrawing DDGS from the diet on d 74 was effective at recovering the yield loss. While DDGS withdrawal strategy was successful at lowering IV, but was unsuccessful at fully lowering IV to values of pigs fed the control diet throughout. Iodine values were somewhat variable within fat depot, showing the jowl and clear plate fat were less accurate in showing changes from the diet, most likely due to the fact they are deposited earlier and are slower to turnover. Iodine value tended to be greater for IC pigs than barrows on d 107, but by d 125 there were no differences in IV between IC and barrows. This dramatic improvement from d 107 to 125 could be caused by the dilution of unsaturated fatty acids, specifically C18:2 and C18:3, due to the rapid deposition of fat in IC pigs.

Master of Science / Department of Animal Sciences and Industry / Joel DeRouchey / Seven experiments using a total of 2,997 nursery and finishing pigs were used to determine the effects of: 1) dietary wheat middlings (midds), dried distillers grains with solubles (DDGS), and NE diet formulation on nursery pig growth performance; 2) corn particle size, complete diet grinding, and diet form on finishing pig growth performance, and carcass characteristics, and 3) particle size, complete diet grinding, and diet form on nursery pig growth. Experiments 1-4 evaluated dietary wheat middlings at levels of up to 20% of the diet for 7 to 23 kg pigs. Increasing dietary midds decreased growth performance but mainly when 10% of more was added. Balancing diets containing 10 or 20% midds on a NE basis had no significant effects on performance compared with not adjusting for NE of the diet. In Exp. 5, the effects of decreasing particle size, complete diet grinding, and diet form were evaluated on finishing pig growth performance, and carcass characteristics. Diet form × portion ground interactions existed for ADG, ADFI, and HCW as grinding the complete diet in meal form was detrimental to performance but advantageous to performance when diets were fed in pelleted form. Reducing the particle size of corn improved G:F and caloric efficiencies. Pelleting the diet improved ADG, G:F, caloric efficiencies, HCW, and loin depth. Experiment 6 evaluated varying particle sizes, diet form, and complete diet grinding on nursery pig growth performance. Pigs fed pelleted diets had improved ADG, G:F, and caloric efficiencies. Fine grinding corn or the complete diet with high by-products diet decreased ADG, ADFI, G:F, and final BW. Experiment 7 evaluated varying particle sizes of corn and DDGS, diet form, and complete diet grinding on nursery pig growth performance. Pigs fed finely ground corn had decreased ADFI when the diet was fed in pellet form and more severe reductions in ADFI when diets were fed in meal form resulting in a diet form × corn particle size interaction. Pigs fed pelleted diets had decreased ADG, ADFI, G:F and final BW, but improved caloric efficiencies. Finely grinding corn decreased ADG, and feeding DDGS decreased ADG, ADFI, and NE caloric efficiency.

Master of Science / Department of Animal Sciences and Industry / Robert Goodband / Three experiments used 1,756 pigs to evaluate the effects of corn dried distillers grains with solubles (DDGS) varying in oil content on growth performance, carcass characteristics, and fat quality in growing-finishing pigs. A fourth experiment used 12 pigs and determined the energy concentration and nutrient digestibility of the DDGS sources used in the previous 3 growth studies. Lastly, a fifth experiment used 576 pigs to determine the effects of DDGS and wheat middlings (midds) withdrawal 24 d before harvest in diets without or with ractopamine HCl (RAC) on growth performance, carcass characteristics, fat quality, and organ/intestine weights. Experiment 1 determined that increasing 7.4% oil DDGS decreased (linear, P < 0.02) ADG and G:F. Also, final BW, HCW, and carcass yield decreased (linear, P < 0.03), but jowl iodine value (IV) increased (linear, P < 0.001) as DDGS increased. Experiments 2 and 3 utilized DDGS sources that contained 5.2 vs. 9.3, and 9.2 vs. 11.8% oil, respectively. In brief, results suggested that while ADG was unaffected, feeding DDGS with 5.2% oil reduced G:F. In Exp. 4, stepwise regression was used to develop prediction equations based to determine that a 1% change in oil content of DDGS will change the DE by 71 kcal/kg and NE by 118 kcal/kg. Experiment 5 determined that pigs fed corn-soy (CS) diets throughout the finishing phase had greater (P < 0.03) ADG, G:F, and carcass yield and lower (P < 0.01) IV than those fed high fiber (HF; DDGS and wheat midds) diets throughout, with pigs fed the fiber withdrawal intermediately. Pigs fed RAC had greater (P < 0.01) ADG, G:F, and carcass yield than pigs not fed RAC. Iodine values were lowest (P < 0.01) for pigs fed the CS diets, highest (P < 0.01) for those fed HF diets throughout, and intermediate for pigs fed the withdrawal diet. Withdrawal of the HF diet to a CS diet partially mitigated negative effects on carcass yield and IV, and feeding RAC, regardless of dietary fiber regimen, improved growth performance and carcass yield.