Medical doctors from regional health authorities in some agricultural regions have been raising concerns about odor and human health. They suggest that odor and dust from confined feeding operations (CFO) are responsible for increases in respiratory disease, including asthma and allergies, in communities that reside near these feeding operations.
In fact, some local doctors have even gone so far as to tell their patients, especially young children, not to go outside on certain days. A review of the scientific literature shows that there are few documented studies evaluating CFO air emissions and community health. Thus, the question remains unanswered. Do emissions from CFOs reduce air quality that results in health problems? As agriculture producers, we want to know this as well, since these gases and dust may impact our families, workers, and livestock. We all know that odors, particularly strong odors from manure, are not pleasant. Nor are high levels of dust, either generated from gravel roads, harvesting or cattle mingling in feedlots at sunset.
Each province sets air quality guidelines for various gases and particulate matter and their environmental departments measure them. Some of these guidelines are based on odor perception, while others are based on an eight-hour occupational exposure limit. As can be expected, when we spread manure, and empty or agitate liquid manure holding tanks, we generate odor. Different people have different sensitivities to odor and the nose is the best measure of odor. Odor is made up of a complex mixture of gases and molecules; therefore, it is difficult to measure objectively and consistently. If the intensity or duration of odor remains high for a time, it can cause some people to get irritated, both mentally and physically. High odor levels can cause runny eyes and noses and other health effects.
Science, at this time, has limited information on the effects of odor on health. However, we all know that odor can create conflict with neighbors; thus, it is best to use management practices that reduce odor. As well, dust generated by gravel roads during silaging or combining or from cattle movement in the feedlot can generate a haze and that is not pleasant for workers, animals, or neighbors. In limited studies in the U.S. dust was associated with increases in respiratory disease in cattle. Thus, as producers, we must use practices that reduce dust.
What can we do to reduce odors? If animals are housed indoors, then ventilation within the barn can be managed to protect workers and animals from health problems. We know that poor ventilation, high odor levels and dust may contribute to pneumonia in animals and reduce performance. As well, some workers may develop respiratory symptoms and will not want to work within that kind of environment. Therefore, if you find the air within your barns is high in odor or dust, contact a local agricultural engineer for some help on seeing what changes, sometimes really simple ones, can be made to your ventilation systems to improve air quality.
Proper manure management, whether on solid or slatted floors is important. Manure should be removed regularly and not be allowed to build up. If manure pits are under the barn, the frequency and type of clean-out can impact odor generation. Therefore, attention should be paid to these practices.
How we store manure is important, whether liquid or solid manure. Fresh manure and manure that is moved will generate odors. Various covers, such as straw and plastic, and manure treatments are available to reduce odor in liquid manure storage tanks and pits. Composted manure has very little odor; however, odors are released during composting. For solid manure in feedlots, it is important to design pens properly for adequate drainage so that wet spots within pens and alleyways are not a problem, because they generate odor. When spreading manure, either solid or liquid, incorporate the manure as quickly as possible. For liquid manure, direct injection will reduce odors. Spread manure early in the morning, not on evenings or weekends or holidays when neighbors are home and will be bothered by the odors.
There are various methods to reduce dust. In feedlots, this may include a combination of watering down driveways, local roads during silaging, and using irrigation sprinklers in pens. Planting trees around the feedlot will also help collect dust and control odors. Therefore, if there are neighbors downwind of the feedlot, plant trees around the feedlot to help catch the air that might travel downwind and bother the neighbors. As well, if they can’t see the feedlot, sometimes they can’t smell it!
For more detailed information on methods to control odor and dust, contact your industry association or local agriculture department. There are numerous beneficial practices available that are simple and not costly to apply which can improve air quality for your family, workers, animals, and local community. Improving air quality will reduce conflicts with neighbors and local municipalities. Currently, odor issues are one of the main reasons that livestock expansions and new developments are so difficult to get, therefore they shouldn’t be taken lightly.
In Alberta, additional information on odor and dust reduction practices is available through in Environmental Beneficial Management Practice manuals, which are available from Alberta Pork (780-474-8288) and Alberta Cattle Feeders’ Association (403-250-2509).