Browsing by Subject "Livestock"

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Beurteilung von Geruchsimmissionen aus der Tierhaltung
(2011) Gallmann, Eva; Jungbluth, Thomas
Odours from farm animal production can cause significant problems. It is therefore appropriate to develop suitable procedures for their assessment and limitation in the sense of immission control. The challenge comprises the objectification of the odours, bearing in mind that their effect is very individual, subjective and emotion-based. The resultant work offers a contribution towards the classification and further development of procedures for assessment of odours from farm animal production. The latest knowledge of the various aspects of measurement and evaluation of farm animal production odour immissions will be analysed in detail through ongoing literature assessment and from results of own investigations. The perceived nuisance effect relies on multiple stimulus-based variables associated with context and person. Measuring the associated effect can take place through psychometric surveys. Assessment of a significant nuisance effect within a group is conventionally based on the proportion of subjected persons that can be regarded as tolerable. Odours from farm animal production in particular are considered on the basis of investigations and data concerning odour components and their emission, transmission and immission. The extent of available data including results from own odour emission measurements give a high degree of scatter. This scatter is caused by the multiplicity of influences on emissions and also through the imprecision of measurements based on olfactometry. There are limitations on the extent to which reduction measures can be quantified. Dispersion modelling is an important tool for assessing odour immissions, but is also associated with limitations as shown by validation and sensitivity investigations. Particularly decisive are the appropriate illustration of the transmission and the choice and modification of the model structure and input parameters. The modelling of diffuse and varying sources near the ground surface remains a challenge. The consideration of cold air outflows is essential for immission assessment. The common odour threshold distances from pig and cattle production units determined via odour plume measurements are discussed using numerous trial results as examples. The results of own grid measurements at four locations are detailed, also with regard to the effect of a plausibility control, the variation of the odour hour criterion, and compared with dispersion calculations. Grid measurements help in the differentiated measurement of the immission situation. In the interpretation of absolute values, the imprecision area around the real value must be considered. The effect of immission reduction measures is hardly quantifiable nor able to be generalised. The knowledge is based, above all, on flow simulations and on experience. Main points of influence are the dilution of outflow air, the transmission conditions and the location circumstances. The immission hedonics from farm animal production odours were compared and recorded for own investigations and within the framework of a cooperative project “Odour assessment in agriculture“. The hedonic differences were not, however, nuisance-relevant as shown by evaluation of the exposition effect relationships within the same trial framework. The differences regarding type of farm animal are, however, relevant. The results from various epidemiological studies were thoroughly analysed because these were oriented on the assessment procedure for immissions and their effects. The starting point for assessing odour emissions from farm animal production can differ more through source-oriented distance rules or immission regulations for the limitation of odour hour frequency or odour concentration. Both points provide possibilities for recognition of animal type differences via factor weighting of animal mass, animal numbers or key immission figures. The assessment principle for distance standards that apply to all types of farm animals with factor weighting for source, transmission and immission parameters, or as empirical distance model, are explained and assessed based on examples from Switzerland, Austria and Germany. The methods and the establishment of factors are less well able to be appreciated as the degree of differentiation increases. The determinations within the odour immission guideline are compared with the regulations for odour exposition limits in the Netherlands, and in other countries. The suitability of the assessment bases and procedures for assessment are finally evaluated for assessment in practical conditions and recommendations for further developments suggested.
Livestock asset dynamics among pastoralists in Northern Kenya
(2017) Sousa-Poza, Alfonso; Mburu, Samuel; Kaiser, Micha
Understanding household-level asset dynamics has important implications for designing relevant poverty reduction policies. To advance this understanding, we develop a microeconomic model to analyze the impact of a shock (for example a drought) on the behavioral decisions of pastoralists in Northern Kenya. Using household panel data this study then explores the livestock asset dynamics using both non-parametric and semi-parametric techniques to establish the shape of the asset accumulation path and to determine whether multiple equilibria exist. More specifically, using tropical livestock units as a measure of livestock accumulation over time, we show not only that these assets converge to a single equilibrium but that forage availability and herd diversity play a major role in such livestock accumulation.