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Improvements to the efficiency of dietary nitrogen use by lactating dairy cattle can be made by altering the concentration and form of protein in the diet. This study collected urine and feces from dairy cows from selected crude protein (CP) treatments of 2 lactation studies. In the first trial, collections were made from cattle fed a diet with high (19.4%)(More)
A series of experiments was conducted using small wind tunnels to assess the influence of a range of environmental, manure and management variables on ammonia emissions following application of different manure types to grassland and arable land. Wind speed and dry matter content (for cattle slurry in particular) were identified as the parameters with(More)
Federal and state regulations are being promulgated under the Clean Air Act to reduce hazardous air emissions from livestock operations. Although much is known about air emissions from livestock operations in Europe, few data are available on emissions from livestock facilities in the United States and the management practices that may minimize these(More)
Dairy barns are thought to emit large amounts of ammonia, which can have detrimental effects on human health and natural ecosystems. In the U.S., relatively little is known about the processes that affect the rate and magnitude of ammonia emissions from dairy barns. The end of a conventional tie-stall dairy barn was remodeled into four chambers (four(More)
Dairy cattle barns are a major source of NH3 emissions to the atmosphere. Previous studies have shown that the bedding material used in the barn can influence the magnitude of NH3 emissions, but little is known about which bedding characteristics are important in this respect. The aims of this study were to assess, at a laboratory scale, the relative(More)
Federal and state regulations are being promulgated under the Clean Air Act to reduce hazardous air emissions from livestock operations. Few data are available on emissions from livestock facilities in the USA and the management practices that may minimize emissions. The objective of this study was to measure seasonal and bedding impacts on ammonia(More)
A number of techniques have been developed to quantify ammonia (NH(3)) emissions following land application of manure or fertiliser. In this study, coefficients of variation were determined for three commonly used field techniques (mass balance integrated horizontal flux, wind tunnels and the equilibrium concentration technique) for measuring emissions from(More)
The application of untreated or treated animal manure to soils can result in increased N and C gaseous emissions contributing to ecosystem change and global warming. In the present study, dairy cattle slurry (liquid manure) was subjected first to pre-treatment by separation using a screw press to obtain a liquid (LF) and a solid fraction (SF). Then, the(More)
Ammonia emissions (NH3) are characterised by a high spatial variability at a local scale. When modelling the spatial distribution of NH3 emissions, it is important to provide robust emission estimates, since the model output is used to assess potential environmental impacts, e.g. exceedance of critical loads. The aim of this study was to provide a new,(More)