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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Essays on Modeling the Economic Impacts of a Foreign Animal Disease on the United States Agricultural Sector

Hagerman, Amy Deann 2009 December 1900 (has links)
Foreign animal disease can cause serious damage to the United States (US) agricultural sector and foot-and-mouth disease (FMD), in particular, poses a serious threat. FMD causes death and reduced fecundity in infected animals, as well as significant economic consequences. FMD damages can likely be reduced through implementing pre-planned response strategies. Empirical studies have evaluated the economic consequences of alternative strategies, but typically employ simplified models. This dissertation seeks to improve US preparedness for avoiding and/or responding to an animal disease outbreak by addressing three issues related to strategy assessment in the context of FMD: integrated multi region economic and epidemic evaluation, inclusion of risk, and information uncertainty. An integrated economic/epidemic evaluation is done to examine the impact of various control strategies. This is done by combining a stochastic, spatial FMD simulation model with a national level, regionally disaggregated agricultural sector mathematical programming economic model. In the analysis, strategies are examined in the context of California's dairy industry. Alternative vaccination, disease detection and movement restriction strategies are considered as are trade restrictions. The results reported include epidemic impacts, national economic impacts, prices, regional producer impacts, and disease control costs under the alternative strategies. Results suggest that, including trade restrictions, the median national loss from the disease outbreak is as much as $17 billion when feed can enter the movement restriction zone. Early detection reduces the median loss and the standard deviation of losses. Vaccination does not reduce the median disease loss, but does have a smaller standard deviation of loss which would indicate it is a risk reducing strategy. Risk in foreign animal disease outbreaks is present from several sources; however, studies comparing alternative control strategies assume risk neutrality. In reality, there will be a desire to minimize the national loss as well as minimize the chance of an extreme outcome from the disease (i.e. risk aversion). We perform analysis on FMD control strategies using breakeven risk aversion coefficients in the context of an outbreak in the Texas High Plains. Results suggest that vaccination while not reducing average losses is a risk reducing strategy. Another issue related to risk and uncertainty is the response of consumers and domestic markets to the presence of FMD. Using a highly publicized possible FMD outbreak in Kansas that did not turn out to be true, we examine the role of information uncertainty in futures market response. Results suggest that livestock futures markets respond to adverse information even when that information is untrue. Furthermore, the existence of herding behavior and potential for momentum trading exaggerate the impact of information uncertainty related to animal disease.
2

Characterisation and modeling of cattle movements in Cameroon

Motta, Paolo Roberto January 2017 (has links)
Introduction In sub-Saharan Africa, rapid urbanisation and per capita consumption of animal source foods are expected to accelerate in the short-medium term and to increase the movements of live animals and animal products in the region. In Cameroon, where the livelihood of most of the rural population depends on the agricultural and livestock sector, a wide range of endemic transboundary infectious diseases (TADs) affect livestock production and trade, and have direct detrimental effects on animal, human and environmental health. Livestock mobility represents a central economic activity in the livestock value chain of the country as well as a central strategy of seasonal adaptation to the ecosystem. Livestock movements, however, are also a central driver of infectious diseases dynamics and contacts between livestock populations are major risk factors for disease introduction and circulation. In countries where financial and technical resources are constrained, such as Cameroon, strategic interventions aiming at the surveillance and control of multiple infectious diseases simultaneously are essential for optimising their cost-effectiveness. The overall aim of this study was to apply a methodological framework to contribute to the understanding of cattle movements in Cameroon and of their implications for disease circulation. Methods This project used a variety of epidemiological and statistical methods to characterise cattle movements in the country across different scales. The collection of primary data and information targeted both the formal cattle trade system, across the country, and the informal seasonal transhumance, across the main livestock production areas. Between September 2014 and May 2015 diverse strategies were applied for collecting empirical data and various data sources from multiple Regions of the country were combined. Cattle trade in Cameroon mainly occurs via multiple trading points owned and managed either by the veterinary authorities or the municipalities. A total of 62 livestock markets, and the relevant offices of the Ministry of Livestock, Fisheries and Animal Products (MINEPIA), were targeted for collecting official data on cattle trade referring to a 12-month period ranging between September 2013 and August 2014. Additionally, a questionnaire-based survey with the various livestock markets stakeholders (herders, traders, butchers and veterinary officials) was carried out to collect a variety of information on the cattle market system. During this 9-month period of field work, data on cattle seasonal transhumance were simultaneously collected using a combination of GPS-tracking technology and questionnaire-based survey. Results Volumes of cattle trade, the type of traded animals and their commercial values varied over the year and across the Regions of the country included in this study. Nevertheless, the market supply of live cattle showed similar temporal trends over the year and across the Regions. Although for almost the entire study area the peak of traded animals in the market system was in December 2013, the trade volume was consistently higher during the rainy season (May to September). On the contrary, the reduction in the trade volume during the dry season was accompanied by an opposite trend in the cattle price, with their commercial value being higher during the dry season. Furthermore, a cattle price differential was highlighted between production Regions and high consumption Regions of the country. The highest volume of cattle trade was recorded in the Adamawa Region, which was the main source of cattle for the country while also receiving animals from neighbouring countries, such as Chad and Central African Republic. In contrast, major urban markets in the Littoral and Central Regions were the main receivers of cattle originating from almost all the other areas of the country. Interestingly, the North-West Region appeared to be more independent and isolated within the cattle trade network of Cameroon, particularly receiving few animals from other Regions. Importantly, there was little variation in the structural characteristics of the cattle trade network as well as in its properties across seasons, showing that, despite the seasonality in traded numbers, the network of cattle moving between markets in Cameroon is very stable. This consistent structure of the network over the year increases the robustness of strategic targeted interventions. We found that targeting the top 20% of the most connected markets would significantly reduce the network cohesiveness providing opportunities for strategic disease surveillance, communication and risk mitigation interventions. The centrality of the market within the trading network was also found to be positively associated with the price of live cattle, which tended to be heavily affected by phenotypic characteristics of the traded cattle. The seasonal cattle transhumance has been found as a common and widespread practice for herders attending the market system across whole the study area, highlighting the close relation between formal trading movements and informal pastoral movements across the country. Transhumant herds were observed to undertake migrations across multiple Regions for period exceeding 6 months and showing the potential for multiple types of interactions with domestic and wild animals. Discussion Multiple livestock infectious diseases were identified as being related to the cattle trade system. As neighbouring and non-neighbouring countries were found to be epidemiologically connected it is clear that national strategies for surveillance and control are likely to have limited effectiveness. Regional coordination for designing and implementing prevention and mitigation strategies against infectious diseases is essential to improve animal health also at national level. This study highlights the opportunity for strategic surveillance, control and communication interventions targeting key livestock markets and Regions of Cameroon. Live cattle price and centrality of markets, represented by their connectedness within the trading network, highlights the need to further investigate the links between economic factors and drivers of disease dynamics, such as livestock movements. The complexity of cattle movements in this context was further evidenced by the seasonal transhumance representing an established common mechanism for managing livestock, and closely interacting with the formal trading system as well as with other domestic and wild animal populations. Better data collection and analysis of livestock movements is required for improving the effectiveness of surveillance and control of infectious diseases. Although animal identification and registration systems would represent an ideal step for increasing traceability of cattle movements, enhancing animal health management and the overall competitiveness of the livestock industry, in the short-term a cost-effective intervention should aim at further developing the current data recording and management systems. Pastoralism, for long seen as an economic and environmental activity with little future, also needs to be acknowledged as a key component of the livestock production system in the country and to be considered accordingly in the management of infectious diseases.
3

Surveillance for Multi-Drug Resistant <i>Salmonella</i> <i>enterica</i> Serovar Heidelberg in Livestock Markets

Reese, Daysia Marie January 2020 (has links)
No description available.

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