Hazards in confinement housing–gases and dusts in confined animal houses for swine, poultry, horses and humans

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A review of methods for estimating the role of dust deposition in removal of dust from livestock building airspaces.

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Four practical methods of estimating the rate of dust removal by deposition onto surfaces were examined. The most promising for use in occupied livestock buildings involves the measurement of steady-state dust levels under conditions of known rates of dust removal by ventilation or filtration. Practical experience and literature data on dust sedimentation rates suggest that dust deposition in pig buildings could be equivalent to at least spring/autumn ventilation rates, in terms of the rate at which dust is removed from the airspace.

Enironmental Considerations in Land Application of Animal Manure – Air Pollution

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Association of environmental air contaminants with disease and productivity in swine.

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A cross-sectional epidemiological study associating air quality with swine health was conducted on 28 pig farms in southern Sweden. Correlation of housing air environment to swine diseases and productivity (data collected over the preceding 12 months) were investigated. The most prevalent swine health problems detected at slaughter were pneumonia and pleuritis. During farrowing and in the postnatal period the most prevalent problem was neonatal pig mortality. Several air contaminants (dust, ammonia, carbon dioxide, and microbes) were correlated with these swine health problems. Maximum safe concentrations of air contaminants were estimated on the basis of dose-response correlation to swine health or human health problems. Recommended maximum concentrations of contaminants were: dust, 2.4 mg/m3, ammonia, 7 ppm; endotoxin, 0.08 mg/m3; total microbes, 105 colony-forming units/m3; and carbon dioxide, 1540 ppm. The overall quality of the ventilation system was correlated with lower concentration of ammonia, carbon dioxide, microorganisms, and endotoxin, but not with dust concentrations. High animal density was related to high ammonia and air microbe concentrations. Animal density measured as kilograms of swine per cubic meter (compared with kilograms of pig weight or swine per square meter) had the highest correlation to animal health and air contaminants.

A Full-scale Sequencing Batch Reactor Treatment of Dilute Swine Wastewater.

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The hydraulic retention time in the reactor was calculated to be 22,9 hours and the sludge was removed from the digestors every 14 days. The reactor was monitored regularly over a period of 25 weeks from March through August with ambient temperatures ranging from 12 to 38 C. This technology is promissing however more research has to be done to verify the behavior of the reactor during winter conditions. Verifications have also to be made for very cold temperature that can be observed in many areas in Canada.

Dust in hog growing facilities: a research update.

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Treatment of Liquid Swine Manure in the Sequencing Batch unde Aerobic and Anoxic Conditions

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The treatment as been done using a sequence of aeration and non-aeration periods. Test were done to verify the effect of the aeration – non-aeration period to find the optimal combination as limiting aeration result in a reduction in the energy consumption. Based on the result the anoxic (without aeration) period should not exceed 8 hours between fill and react sequences as the sludge settling process deteriorate and odour emissions can be a problem. This study showed that the air supply could be reduced by 42% without affecting the performances. No statistical analysis of the results is presented so it is difficult to evaluate if the difference between the tests done are significant.

Spatial variability of airborne and settled dust in a piggery.

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An experiment was conducted to assess the spatial variability of dust within the airspace of an occupied piggery. Measurements of airborne and settled dust were made for 16 d at 16 locations within a 180 place, partially slatted-floor, grower-finisher piggery. Eight locations were in a vertical cross-section covering half the width of the building. Two of these locations were used in conjunction with 8 further locations over the remaining pen barriers to establish a horizontal sampling plane. Aerial dust samples were collected every 24 h and settled dust samples every 4 days. Particle size analysis was carried out on all of the settled dust and half of the aerial dust samples. Measurements were made of airspace temp. and air velocity at each sampling location, and of pen cleanliness throughout the building. Results are discussed.

Phosphorus Availability and Requirements in Pigs

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As the phosphorus (P) available or digestible for the pig in feed originating from plants additional P from inorganic sources is to be added to the diet. In order to lower P excretion, the pigs requirements have to be well known and the digestibility of P well assessed in the feedstuffs from plants, animal or feed phosphate. The results of digestibility tests made on many feedstuffs are presented. And the apparent digestibility varies from 10 to 50% for plant origin feedstuffs and from 65 to 90% for feedstuff of animal origin and feed phosphates. The factors affecting the P digestibility are the origin of feedstuff, the concentration of phytate and of the total P and the presence of phytase. Plant phytase and also microbial phytase enhance the digestibility of P. Using 1000 units of microbial in the pigs’ feed will enhance the P digestibility by 20%. The requirements for P for the pig have also to be well determined and can vary according to the physiological stages, to environment, genotype (very lean pigs will have slightly higher requirements of 5 to 6%), feeding level and major ingredients used (wide variation can be observed between countries). Recommendations on P requirements should be made considering the digestibility of P and not the total P available.

Phosphorus requirements and absorption by pigs is well presented. The approach using the P digestibility of feedstuffs to meet the pig’s requirements is an efficient one toward excessive and unnecessary P excretion.

Assessment of dustfall collectors used in livestock buildings.

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The relative collection efficiency of several different types of dustfall collector was assessed over different collection intervals in a piggery. Flat plate collectors and collectors with sidewalls 10 and 50 mm high were placed on a slow-speed turntable to minimize positional effects. For each sampler type, collection intervals of 1, 3, 6 and 12 wk were used. The collection medium was generally a 47 mm glass fibre filter located on a 75 mm diam. aluminium disc. Cellulose nitrate membrane filters were used for one treatment. The dust sedimentation rate determined from the weekly samples varied from 80 to 200 mg m-2h-1 over the 12 wk period. Dust deposits on the filters varied linearly with time from 2.3 mg/cm2 of collector surface for the 1-wk interval to 27.9 mg/cm2 over 12 wk. The measured dust sedimentation rate was about 3.0% less on the membrane filters than on the glass fibre filters and also for those collectors with the 50 mm high sidewall when compared with the flat plate collectors. The length of sample collection interval did not significantly affect the measured dust sedimentation rate. It is suggested that handling errors and edge effects may affect accuracy when deposits are greater than about 7 mg/cm2 of collector surface.