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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

Comparison of Neospora seroprevalence in Virginia dairy herds with high and low abortion rates

Murphy, Julia M. 28 July 1998 (has links)
Neospora has become a commonly recognized infectious cause of abortion in dairy cattle. The organism is associated with mid to late term abortion outbreaks with rates exceeding 30% in some herds. Cows infected with this organism exhibit no other clinical signs. While this disease has been reported in other parts of the country, no assessment of Neospora seroprevalence has been undertaken in the Southeast. This study sampled commercial dairy herds to assess Neospora seroprevalence in dairy cows and investigate its significance as an abortifacient agent in Virginia. Twenty four herds participated in the study. Twelve herds had DHIA reported annual abortion rates of 6% or greater (high abortion rate herds) and twelve herds had abortion rates of 2% or less (low abortion rate herds). High abortion rate herds were each paired to a low abortion rate herd (control) herd within the same county. A single blood sample was collected from all cows confirmed to be 90 to 240 days pregnant, with a maximum of thirty samples per herd. A random sample of cows was selected in herds with more than 30 pregnant cows between 90 and 240 days gestation. Neospora antibody titers were determined using a serum ELISA test at the California Veterinary Diagnostic Laboratory. Both mean and median seroprevalence of high and low abortion rate herds were compared using the Mann-Whitney Rank Sum test and the Median test, respectively. No significant difference was found in either case (p=0.56, p=0.41). These findings suggest that Neospora does not contribute significantly to the average abortion rate in Virginia's dairy cattle. / Master of Science
2

Validation of participatory appraisal for use in animal health information systems in Africa

Catley, Andrew Paul January 2004 (has links)
Participatory appraisal (PA) is a methodology for problem description and analysis that has been widely used in less developed countries (LDCs) since the 1980s. The use of PA by veterinarians in LDCs has been restricted to mainly small-scale community-based animal health projects. Adoption of PA by veterinarians, particularly those working for government, was limited because of concerns about the reliability and validity of the methods. Three studies were conducted with pastoralist and agropastoralist communities in East Africa to vaiidate PA, by comparison of data derived from PA with conventional veterinary investigation and epidemiological information. In southern Sudan, research was conducted on a chronic wasting syndrome in adult cattle in Dinka and Nuer communities; in Kenya, research was conducted on bovine trypanosomiasis in Orma communities; and in Tanzania research was conducted on possible association between a chronic heat intolerance syndrome (HI) and foot and mouth disease (FMD). Participatory appraisal methods, called matrix scoring, seasonal calendars and proportional piling, were standardised and repeated to generate quantitative data. The level of agreement between informant groups was assessed using the Kendal coefficient of concordance (Jf). Matrix scoring was adapted for use by veterinarians to enable comparison of veterinarian's perceptions of disease signs and causes, with those of pastoralist informants. The data were compared using direct visual assessment, hierarchical cluster analysis and multidimensional scaling. Matrix scoring, seasonal calendars and proportional piling were judged to have good validity and reliability. In Tanzania, adaptation of proportional piling enabled calculation of the relative risk of HI cases being observed in cattle herds with previous history of FMD, and demonstrated significant association between HI and FMD. This finding was confirmed by detection of antibody to non-structural proteins to FMP in herds with and without HI. It was concluded that PA methods were reliable and valid methods for veterinary epidemiology when used by trained PA practitioners in agropastoral and pastoral settings. The methods were valuable for data collection and analysis, and for enabling greater involvement of livestock keepers in veterinary service development and research. Participatory appraisal could be further adapted to improve the design of primary veterinary services and disease surveillance systems. In veterinary research, PA was considered to be particularly useful during the exploratory phase of research and for generating research hypotheses. It was also concluded that institutional changes were required for the widespread adoption of PA by veterinarians in Africa.
3

Epidemiology and prophylaxis of diseases and mortality in housed dairy calves

Watt, Bruce Richard January 2011 (has links)
Photocopy of typescript. / Digitized by Kansas Correctional Industries
4

Epidemiology of black rhinoceroses (Diceros bicornis) in captivity in the United States

Dennis, Patricia Marie. January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2004. / Document formatted into pages; contains xiii, 126 p. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2007 Sept. 21.
5

Using pre-diagnostic data fom veterinary laboratories to detect disease outbreaks in companion animals

Shaffer, Loren Eldon, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 122-137).
6

The development of a syndromic surveillance system for the extensive beef cattle producing regions of Australia

Shephard, Richard William. January 2006 (has links)
Thesis (Ph. D.)--University of Sydney, 2008. / Title from title screen (viewed 19 January 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Veterinary Science. Degree awarded 2008; thesis submitted 2006. Includes bibliographical references. Also available in print form.
7

A retrospective analysis of the epidemiology of Rift Valley fever in Namibia

Gadha, Shepherd January 2015 (has links)
Rift Valley fever (RVF) is a peracute or acute disease of domestic ruminants and humans in sub-Saharan Africa, caused by a mosquito-borne virus. It is a high priority pathogen because of its potential to cause severe economic harm to the livestock industry and to cause life threatening haemorrhagic disease in humans. The disease was first recorded in southern Africa when a large epidemic occurred in the South Africa in 1950, and the first recorded outbreak in Namibia was in 1957. Since then, occasional large epidemics have occurred in southern Africa, with long interepidemic periods. The epidemiology of RVF is complex and many questions regarding the movements of the virus and its survival during the interepidemic period remain unanswered. The aim of this study was to compile a comprehensive description of the history of RVF in Namibia and to describe its epidemiological characteristics. This was accomplished using information available in the scientific literature, annual reports, disease reports and reports to the OIE. The geographical location and temporal occurrence of each outbreak was recorded as accurately as allowed by available records. Also recorded were suspected RVF outbreaks, defined as those outbreaks in which samples were not collected for laboratory analysis or RVF was not confirmed on submitted samples but where the clinical picture was suggestive of the disease. Serological surveys done in humans and animals were also included in the study. The collected data were analysed descriptively, by risk mapping and by cluster analysis. The relatively low number of recorded outbreaks and the poor spatial resolution of much of the data prevented more detailed multivariable analysis. Maps were produced to show the districts affected for the outbreaks with no coordinates and the exact location of the outbreaks which had coordinates. This was then followed by a detailed description of each outbreak showing the species affected and the mortalities caused. Risk mapping was done to identify areas of the country which are at high risk of having outbreaks. A quarter degree square grid was used to show the cumulative number of confirmed outbreaks occurring from 1957 to 2011. The accuracy of this was, however, limited due to the poor spatial resolution of data prior to 1986, which recorded only the district(s) affected. The risk map was visually compared with maps of sheep and cattle density and rainfall. A space-time permutation model, using case-only data, was used to detect space-time clusters with high rates, using SaTScan software on all the confirmed outbreaks with GPS coordinates. The objective was to detect areas of significantly high rates of RVF in Namibia, testing whether the outbreaks were randomly distributed over space and time. Space time permutation requires the use of precise geographic coordinates; therefore the only confirmed outbreaks that could be used for this analysis were those occurring during 2010 and the 2011. A total of six years had outbreaks of RVF in Namibia, the major outbreaks occurring in 1957, 1974, 1984, 2010 and 2011. Rift Valley fever was confirmed in the Karas, Hardap, Khomas, Erongo, Otjozondjupa, Omaheke and Oshikoto regions, with suspected outbreaks occurring in the Kavango and Caprivi regions. SaTScan analysis showed that there were two statistically significant outbreak clusters observed, one in the Hardap region in 2010 and the other in the Oshikoto region in 2011. The south-eastern part of the country was shown to be predisposed to RVF outbreaks; this correlated with sheep population density. The southern part of Namibia receives less rainfall and is hotter than the north, with colder winters, factors which may reduce vector and virus survival and therefore limit continuous viral circulation. This likely renders livestock highly susceptible to infection and if there is an introduction of the virus a severe epidemic may occur. In the Northern Communal Areas and adjacent Etosha National Park the positive serological results in humans and wildlife show that there is continuous or intermittent low level circulation of the virus. This could be leading to high levels of herd immunity and hence no confirmed outbreaks recorded in these areas to date. Nevertheless, all suspected cases should be tested for RVF to avoid misdiagnosis and under-reporting of cases. / Mini-dissertation (MSc)--University of Pretoria, 2015. / tm2016 / Veterinary Tropical Diseases / MSc / Unrestricted
8

Some aspects of the epidemiology treatment and control of bovine mastitis

Frost, Alan, 1943- Unknown Date (has links)
No description available.
9

Some aspects of the epidemiology treatment and control of bovine mastitis

Frost, Alan, 1943- Unknown Date (has links)
No description available.
10

Studies of the epizootiology of Rocky Mountain spotted fever in Ohio /

Harlan, Harold Jonathan January 1984 (has links)
No description available.

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