This study was carried out to evaluate the effectiveness of a commercially-available program, the Good Neighbor System (GNS), at reducing gaseous emissions from swine facilities. In addition, the impact of the GNS on manure composition and animal performance was also evaluated. The Good Neighbor System is a fully-automated, three-part process that consists of the following: 1. Treatment of the stored manure with a neutralizing agent to increase the pH of the slurry to reduce the release of hydrogen sulfide and volatile fatty acids (major components of “swine” odor) from the manure. 2. Covering the surface of the manure in the pit with a liquid oil “lid” to reduce gaseous emissions. 3. Spraying the building air space with an atomized oil-based liquid acidifier to reduce ammonia and dust levels within the building. The study was carried out in four identical commercial wean-to-finish barns as a completely andomized design with two treatments: 1. Good Neighbor System (barns treated with the full system) 2. Control treatment (barns left untreated). There were two replicates (barns) per treatment with the four barns being randomly allotted to either the GNS or the control treatments. The barns had totally-slatted floors with deep pits and were tunnel ventilated with curtain sides. Five room-exhaust fans were located at one end of the buildings and there were four pit fans, two on each side of the buildings. The study was carried out over a 12-month period that involved two complete cycles of pigs (from filling of the barn with newly-weaned piglets to emptying of the barn and shipping of the pigs for harvest). The manure pits were not emptied during the study period. Gas levels (ammonia, hydrogen sulfide, and carbon dioxide) were automatically measured at the air inlet into the barn, and at two of the room-exhaust fans and one of the pit fans. The time of operation and the speed of all of the fans were continuously measured to calculate ventilation rates. Calculation of emission rates was based on the difference in concentration of the gases between the air inlet and the exhaust fans and the ventilation rate. Samples of exhaust air were taken periodically during the study from one of the room-exhaust fans and one of the pit fans and odor levels were measured using olfactometry. The pH of the manure was measured every two weeks during the study and a sample of manure was taken at the end of the study to measure nutrient composition. A subsample of 10% of the pigs (104 pigs from each barn in each cycle) was weighed at entry into the barn at weaning and at 10 and 20 weeks postweaning to measure growth rates, and the number of treatments that were given to the animals for health problems and all deaths were recorded for the first cycle of the barn only.
Total emission rates for ammonia, averaged across the 12-month period of the study were not different (P = 0.34) between barns treated with the GNS and untreated control barns (440 and 520 g/day, for the GNS and control respectively; SEM = 33.7). Total emission rates for hydrogen sulfide were higher (P = 0.03) for the GNS compared to the control (81.8 and 63.2 g/day, respectively; SEM = 0.54). There was no effect of barn treatment on total emission rates for carbon dioxide. Average odor concentrations measured at one of the room-exhaust and one of the pit-exhaust fans were lower (P = 0.07) for the GNS than the control (1463 and 2198 threshold units, respectively; SEM = 331.1). There was no effect of the GNS on either total bacterial counts in the barn exhaust air or on manure pH. The concentrations of sulfur and copper were lower (P < 0.05) in the manure from the GNS than the control, however, treatment differences were small. Also, the growth rate of the pigs from weaning to
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week 20 postweaning, the number of treatments administered to the animals for health problems, and mortality levels were similar (P > 0.05) for the GNS and control treatments. Overall, results of this study suggest that the Good Neighbor System was effective in reducing odor concentrations at the room-exhaust and pit-exhaust fans. However, the system was not effective at reducing ammonia and hydrogen sulfide emissions and had no effect on any other parameter measured, including manure composition and animal performance.