Odour Production, Evaluation and Control

Posted in: Environment by admin on January 1, 2002 | No Comments

An extensive literature review has been conducted to collect and analyze information on technologies and practices in odour measurement and mitigation. The review and analysis are focused on the following nine areas: (1) odour measurement and odour evaluation technologies; (2) odour production and odour release quantification; (3) feed additives and dietary manipulation for odour reduction; (4) manure additives; (5) in-barn manure handling systems; (6) manure storage design and management; (7) biofiltration; (8) dust control; and (9) emerging technologies for odour measurement and control. The suitabilities of odour management technologies to Manitoba are evaluated in terms of cost and climatic conditions. Over 168 odour compounds have been identified in livestock odours. These individual odour compounds may be measured with analytical instrument such as GC or GC/MS, but there is no established correlation between the individual odour compounds and the human perception of odour. The most reliable way of measuring odour is using the human olfactory sense (nose). Dynamic-dilution olfactometers with trained human assessors are considered to be the industry standard for measuring odour concentration. However, there are considerable inconsistencies in the design and operation of olfactometers. A national standard should be developed, or existing standards, such as the European Union Standard, should be adopted, to provide guidelines for conducting olfactometry measurements of livestock odours. The human sniffing technique shows the potential of evaluating odour directly in the field. This technology is relatively inexpensive and may be adopted by various levels of regulatory agencies for evaluating odour complaints. Research on the quantification of odour emissions from swine operations has been mainly focused on production buildings, with limited information available on manure storage, land application and mortality disposal. Odour emission rates vary widely among different facilities and within the same types of facilities. Reported odour emission rates range from 0.1 to 62 OU/s per m2 of floor area for various swine production facilities. Limited data have shown that emission rates from earthen manure storage (EMS) are mostly below 10 OU/s per m2 of manure surface area. An EMS normally exposes a much larger surface area than other storage types, and is therefore commonly associated with more odour complaints. Odour emission from land application could be minimized by proper injection. Adoption of manure injection by producers has appeared to shift odour complaints from land application to animal production facilities and manure storage units. Field measurements should be conducted to collect odour emission data from earthen manure storage under Manitoba climate conditions. Scientific methods should also be developed to assess the downwind impact of odour sources from swine operations and to establish setback requirements for Manitoba conditions. Dietary manipulations have been shown to potentially reduce odour generation in swine operations. Although much of research to date has been done elsewhere, primarily in the Netherlands and the Midwestern region of the US, the results of the majority of the research can be translated to the Canadian situation either directly or with further refinement. However, differences in primary cereal crops used in feed and the associated differences in chemical composition warrant further research in Manitoba. Many chemical and biological products are being marketed as manure additive for odour control. Research reported in the literature is mostly focused on the evaluation of manure additives, with little on the mechanism of action or the development of products. Researchers have reported conflicting results on the effectiveness of using manure additives. This is partially due to the lack of universally accepted protocols for evaluating manure additives. Although some existing manure additive products have been shown to be effective in odour reduction under laboratory conditions, they may not perform well in actual production facilities. Many other factors, such as the building, ventilation, manure handling, feeding, and the overall management practice, may conceal the effect of manure additives in actual production facilities. The in-barn manure handling system plays an important role in odour management. An effective manure handling system should promote quick separation of manure from animals to minimize odour generation. Properly designed slatted floor systems provide an effective way of separating manure from animals with minimum efforts. If manure is stored under the floors in the barn, well-designed ventilation systems are necessary to provide under-floor pit ventilation for minimizing odour problems. Solid manure systems usually result in less odour emission, but are more expensive and difficult to operate. Research should be conducted to evaluate solid manure handling systems for Manitoba conditions, in terms of their effectiveness in odour reduction, economic feasibility, and agronomic impacts of using solid manure as fertilizer. Open-top manure storages such as earthen manure storage (EMS) are a main source of odour from swine operations. Covering the manure storage is an effective way of minimizing odour emission. Biocovers, such as straw, provide a cost-effective and farmer-friendly solution to odour problems associated with EMS, however they have not been adopted on a widespread basis by the swine industry. The straw cover is easy to apply, but will sink over time, and thus reapplication is required. Additional agitation and straw chopping are required for pump-out if straw covers are used. Straw covers also increase the volume of manure that must be transported. Synthetic plastic covers that provide complete year-round odour control in a cost-effective manner are commercially available. Research is needed to quantify the odour reduction by using various covers under Manitoba conditions. Treating manure before or during storage may reduce odour emission from manure storage. Some technologies that have been studied are solid-liquid separation, anaerobic digestion, and composting (for solid manure). Most odorous compounds are contained in small manure particles. Therefore, removal of fine particles is necessary for effective odour reduction when using solid-liquid separation. Anaerobic digestion is performed in closed digesters and it reduces odour emission by converting odorous intermediate products of anaerobic decomposition into odourless end products of carbon dioxide and methane. Mesophilic and thermophilic anaerobic digestion seem hard to be accepted in Manitoba because of associated high heating cost during long and cold winter. Anaerobic digestion at lower temperatures of psychrotrophic or psychrophilic range holds some potential for Manitoba conditions. Biofiltration is a potential technology for reducing odours from livestock facilities. Open-bed biofilters are the most common style for treating exhaust air from livestock facilities. The open-bed filters usually use compost and wood chips as filter medium and odour removal efficiencies of between 75% and 90% may be achieved. Biofilters associated with livestock operations generally do not need supplementary heat; the heat from the exhaust air and exothermic microbial activity in the filter bed is usually sufficient to keep the filter bed in the right temperature range even under Manitoba climate conditions. Despite the success of open-bed biofilters, there is a need to continue research efforts to improve both the economics and aesthetics of biofiltration systems for livestock operations. Dust may act as an important odour carrier. Odour compounds attached to small dust particles stays in the air longer, thus having a greater downwind impact. Furthermore, many of the respirable dust particles are odorous because of their fecal origin. Spraying oil or oil-water mixture inside the building seems to be effective in reducing dust and odour emissions. Other options, such as mechanical and electrical dust remov
al, are expensive. One of the greatest obstacles to the advancement of odour management is the difficulty of measuring odour itself. Olfactometers are only capable of measuring the odour concentration. The electronic nose (e-nose) technology has the potential of measuring both quality and quantity of odour. Research is needed to correlate human perceptions of odours to e-nose measurements and to develop portable e-noses for field measurements of odour.

The effects of certain antibiotics on biogas production in the anaerobic digestion of pig waste slurry

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On-Farm Monitoring of Soil Nitrate-Nitrogen in Irrigated Cornfields in the Ebro Valley (Northeast Spain)

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Airborne Dust, Endotoxin and DNA Downwind from Swine Barns: An Update

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There is reason to believe that endotoxins and microbial DNA are present in dust exhausted from swine barns. Endotoxins are a pulmonary irritant. When inhaled, endotoxins can cause cough, phlegm, wheezing, fever and in sever cases lead to chronic airway inflammation. To determine the impact of barn aerosols, endotoxin and DNA concentrations must be tested. This study attempted to quantify the amount of airborne endotoxin and DNA downwind from a swine facility. As was hypothesized, results proved that endotoxin and DNA concentrations were high close to the fan outlets, lower concentrations 100m downwind, and no different then the air upwind from the barn.
Total dust and endotoxin concentrations declined significantly at a distance from the barn. It was also found that there was no significant difference between the dust and endotoxin concentrations 600m downwind compared to 2400m upwind of the swine barns. Location did not have a significant effect on DNA concentrations.
It appears that swine facilities have a modest environmental impact downwind from the barns, which may be managed with such controls as landscaping.

Feeding Growing and Finishing Pigs to Maximize Net Income

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Feed accounts for 40 to 60% of total cost of production and is therefore important when attaining lowest possible cost. The goal is the best possible carcass in the shortest amount of time. Using a feed budget helps to estimate the quantity of each diet that will be fed to a pig. It helps prevent overfeeding a high quality diet and therefore decreases the cost per pig sold. The last 2 phases of the feeding program must be carefully formulated to avoid additional costs. Excessive energy, phosphorus, and lysine should be avoided. Sow productivity, cheaper grains, cheaper processing costs, and increasing feed intake by a lower number during the entire grow/finish period can affect feed cost. Individual farms can have different targets that could include economic targets or increasing productivity. Caution should be taken to not focus on productivity so much that expenses are increased rather than revenue. Feed intake is the driving force of growth and should therefore be maximized. If feed intake is compromised, the barn temperature should be checked that it isn’t too high, especially in summer. Genetics plays a role in feed intake because different genotypes will have different levels of feed intake. Extras that can be done/checked are: bigger pigs entering grow/finish, correct floor space allowance, adequate feeder and water access, reduce the amount of pig mixing, health status, proper diet composition (balanced amino acids, adequate energy, etc.), anti-nutritional factors (any natural feed part that has a negative influence), and keeping feeders full. There is research going on that is investigating the theory that increased energy in feed will improve feed efficiency but not growth rate. Any change in dietary composition should be followed by closely monitoring the effects. Production problems can be very much influenced by past stages of production (e.g. – a finisher problem could very well be a result of an error or mismanagement of those pigs in the nursery or even farrowing). Nursery barn feeders should have a 40% covered bottom to maximize intake and minimize feed wastage. Ergot can safely be fed to nursery pigs up to a level of 0.1%.

The effects of fear of humans and pre-slaughter handling on the meat quality of pigs

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Effect of transport time on welfare and meat quality in pigs.

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The purpose of this study was to determine the effects of transport duration on some welfare and meat quality parameters. One hundred and forty four pigs were used. Half of the animals were subjected to 15 min and the others to 3 h transport time. Blood from all animals was analyzed in order to detect stress-susceptible pigs and assess pre-slaughter stress. Meat quality parameters, such as pH, water holding capacity, grade, were measured or assessed. It was concluded that under normal Spanish commercial conditions, pigs subjected to short transport showed a more intense stress response and poor meat quality than pigs subjected moderately long transport when they were immediately slaughtered on arrival at the slaughterhouse. Transport of 3 h might have allowed the animals to adapt to transport conditions and then could act as a resting period like a lairage time. The effect of transport time on welfare and meat quality parameters was more important than genotype and sex. Nevertheless, from the point of view of blood enzyme activities, genetically stress susceptible females transported for 3 h were more sensitive to muscles damage.

Maternal presence limits the effects of early bottle feeding and petting on lambs' socialization to the stockperson

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Herbivores that are raised by their mother tend to be more fearful of humans than those that are reared artificially. In previous studies, the effect of the human behaviour has been confounded by the rearing and maternal environment. This experiment examined the socialization of the lamb to the stockperson when the lambs were petted and bottle fed by humans, early in life, in the presence or absence of the dam. From one day of age until seven weeks of age (weaning), the lambs were either reared individually in the presence of the dam and their twin was behind a grid (M0) or only in the presence of their twin behind the grid (M1). The dams were removed at weaning. Half of the M0 and M1 lambs received human contact until 6 days of age (H1), while the other lambs were not handled by humans and had no visual contact with humans during feeding and other husbandry duties (H0). The lamb’s response to the stockperson was measured during the initial period of human contact, while in the rearing pen (at 4 and 9 weeks of age) and in a test pen at 5 and 10 weeks of age. As well, the lamb’s response to a novel object was tested at 3 and 8 weeks of age and their preference for a stockperson or familiar conspecific was assessed at 6 and 11 weeks of age. Regardless of whether the dam was present, during periods of human contact the lamb remained in contact with the stockperson. Regardless of age, lambs that received human contact during rearing approached the stockperson more quickly and spent more time interacting with the stockperson, than those lambs that did not have human contact during rearing. More specifically, lambs reared with the dam and that received human contact approached the stockperson more readily than other lambs, even when they had to choose between the stockperson and a familiar conspecific. The lambs reared with the dam were more willing to approach the novel object at three weeks of age, than those reared away from the dam, but this difference was not evident after weaning. Thus, the results illustrated that the maternal environment affects the lambs’ ability to socialize with humans. The desire of lambs to remain close to the dam during rearing likely affects the development of other relationships made at an early age. However, the results bring to question how the contact and separation of the lamb from the ewe at an early age affects the lambs’ ability to socialize with humans, and how this improves their reaction to the stockperson.

Saving Money by Maximizing Energy Use Efficiency in Swine Production

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With the rising price of gas, there is energy saving techniques that can be used to reduce the cost of production. Proper management includes monitoring, setting, and maintenance of equipment to minimize the energy bill. An example of this is running fans too fast in winter, which will increase heating. Benchmarking will allow a farm to monitor energy use on a comparative basis. Creep heating can be made more efficient by using high radiant output/lower wattage heat lamps, diode dimmer switches to meet growing piglet needs, and hot water floor heating or electric heat pads to replace heat lamps. Hot water heating improves air quality and is the most efficient source. Radiant tube heating heats objects in the room rather than the air. Forced air systems heat the air itself, and must be re-circulated to disperse this heat. Gas-fired forced air systems consume oxygen and give off carbon dioxide, carbon monoxide, and water vapour. The new standards for lighting are T-8 fluorescent tubes with electronic ballast. These are 4 times more efficient than conventional incandescent lamps. Ventilation fans must be properly sized to meet production requirements. A properly designed system will optimize cubic foot/meter output and reduce capital costs. A heat exchanger can be used to recover heat from exhaust air.

Effects of density and perch availability on the immune status of broilers.

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Commercial broiler hens were raised from hatch to 42 days of age with 10, 15 and 20 birds per m2 in pens with or without the availability of horizontal perches to examine the effects of the housing on the immune status of the birds. The immune parameters assessed were lymphoid organ weights, antibody response to SRBC in the last 10 days of growth, heterophil:lymphocyte ratios at 32 and 42 days of age, and lymphocyte blastogenesis of peripheral blood lymphocytes collected at 32 and 42 days of age. As bird density increased, bursa weight and bursa/body weight ratios decreased. The bursa weights and bursa/body weight index were also significantly decreased by the addition of perches to the environment. No other significant effects were observed for the flock performance, morphometric data, or immunological tests between treatments. Conclusions stated that, under the conditions of the study, which tried to simulate commercial conditions, the bursal weight was the best indicator of stress related to housing density. Stress appeared to increase with the addition of perches because the birds used the perches infrequently. Therefore, there may have been a further reduction in the availability of floor space to the birds with the addition of perches.